Journal articles on the topic 'Absolute Navigation'
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Martín Mur, T., J. M. Dow, and C. García Martínez. "Relative and absolute navigation in earth orbit." Advances in Space Research 23, no. 4 (January 1999): 667–72. http://dx.doi.org/10.1016/s0273-1177(99)00141-6.
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Li, Jinshan, Jinkui Chu, Ran Zhang, and Kun Tong. "Brain-Inspired Navigation Model Based on the Distribution of Polarized Sky-Light." Machines 10, no. 11 (November 4, 2022): 1028. http://dx.doi.org/10.3390/machines10111028.
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This paper proposes a brain-inspired navigation model based on absolute heading for the autonomous navigation of unmanned platforms. The proposed model combined the sand ant’s strategy of acquiring absolute heading from the sky environment and the brain-inspired navigation system, which is closer to the navigation mechanism of migratory animals. Firstly, a brain-inspired grid cell network model and an absolute heading-based head-direction cell network model were constructed based on the continuous attractor network (CAN). Then, an absolute heading-based environmental vision template was constructed using the line scan intensity distribution curve, and the path integration error was corrected using the environmental vision template. Finally, a topological cognitive node was constructed according to the grid cell, the head direction cell, the environmental visual template, the absolute heading information, and the position information. Numerous topological nodes formed the absolute heading-based topological map. The model is a topological navigation method not limited to strict geometric space scale, and its position and absolute heading are decoupled. The experimental results showed that the proposed model is superior to the other methods in terms of the accuracy of visual template recognition, as well as the accuracy and topology consistency of the constructed environment topology map.
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Ashkenazi, V., and T. Moore. "The Navigation of Navigation Satellites." Journal of Navigation 39, no. 3 (September 1986): 377–93. http://dx.doi.org/10.1017/s0373463300000850.
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The orbits of navigation satellites have to be determined very precisely. The Transit broadcast (predicted) ephemeris, which is computed by the US Navy Astronautics Group, has an estimated orbital positional accuracy of the order of 25 m in each direction. By contrast, the precise (post-mission) ephemeris, which is determined by the US Defense Mapping Agency, from tracking data collected by the global TRANET network, reaches accuracies of the order of 10 m. These orbital precisions affect the navigation and (static) positioning accuracies which can be achieved by users of the system. The same is true of the GPS system which will become fully operational some time during 1988—89. However, unlike Transit, GPS will allow quasi-instantaneous absolute positioning (i.e. real-time navigation) as well as very high relative positioning accuracies. The latter will be obtained by using special operational and processing techniques (e.g. ‘differential GPS’ and ‘GPS interferometry’).
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Devyatisilny, A. S. "Inertial navigation method based on absolute acceleration measurements." Technical Physics 48, no. 12 (December 2003): 1598–99. http://dx.doi.org/10.1134/1.1634685.
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Ilyas, Muhammad, Kuk Cho, Sangdeok Park, and Seung-Ho Baeg. "Absolute Navigation Information Estimation for Micro Planetary Rovers." International Journal of Advanced Robotic Systems 13, no. 2 (January 2016): 42. http://dx.doi.org/10.5772/62250.
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Van Pham, Bach, Simon Lacroix, and Michel Devy. "Vision-based absolute navigation for descent and landing." Journal of Field Robotics 29, no. 4 (January 12, 2012): 627–47. http://dx.doi.org/10.1002/rob.21406.
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Knuuttila, O., A. Kestilä, and E. Kallio. "Synthetic photometric landmarks used for absolute navigation near an asteroid." Aeronautical Journal 124, no. 1279 (May 13, 2020): 1281–300. http://dx.doi.org/10.1017/aer.2020.41.
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AbstractThe need for autonomous location estimation in the form of optical navigation is an essential requirement for forthcoming deep space missions. While crater-based navigation might work well with larger bodies littered with craters, small sub-kilometer bodies do not necessarily have them. We have developed a new pose estimation method for absolute navigation based on photometric local feature extraction techniques thus making it suitable for missions that cannot rely on craters. The algorithm can be used by a navigation filter in conjunction with relative pose estimation such as visual odometry for additional robustness and accuracy. To estimate the position and orientation of the spacecraft in the asteroid-fixed coordinate frame, it uses navigation camera images in combination with other readily available information, such as orientation relative to the stars and the current time for an initial estimate of the asteroid rotation state. Evaluation of the algorithm when using different feature extractors is performed, on one hand, using Monte Carlo simulations and, on the other hand, using actual images taken by the Rosetta spacecraft orbiting the comet 67P/Churyumov–Gerasimenko. Our analysis, where four different feature extraction methods (AKAZE, ORB, SIFT, SURF) were compared, showed that AKAZE is most promising in terms of stability and accuracy.
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Huang, Lan, Jianmei Song, Chunyan Zhang, and Gaohua Cai. "Observable modes and absolute navigation capability for landmark-based IMU/Vision Navigation System of UAV." Optik 202 (February 2020): 163725. http://dx.doi.org/10.1016/j.ijleo.2019.163725.
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Kuo, C. T., Y. T. Tien, and K. W. Chiang. "VISUAL-BASED INTEGRATED NAVIGATION SYSTEM APPLIED TO A SIMULATION OF LUNAR MODULE LANDING." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B1-2020 (August 6, 2020): 305–13. http://dx.doi.org/10.5194/isprs-archives-xliii-b1-2020-305-2020.
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Abstract. With the development of space technology, more and more lunar researches are performed by different countries. For the lunar landing mission success, the lunar landing module should equip with advanced Positioning and Orientation System (POS) for the navigation requirements. For the pinpoint landing mission formulated by NASA, a good POS with error less than 100 meters is needed in order to make the lunar module land safely at the exact destination on lunar surface. However, the existing technologies for lunar navigation, such as satellite positioning and star tracker, have poor performance for the navigation requirements. The visual-based positioning technology is an alternative way to make sure a lunar landing module reaches the destination. There are two types of visual-based positioning technology, absolute and relative navigation. The relative navigation system can provide the solution at a higher rate, but the error would accumulate over time. On the contrary, the absolute navigation could provide an initial position or updates of position and attitude for relative navigation. Thus, the integrated navigation system from those two methods can take advantage of both stand-alone systems. On the other hand, the Inertial Navigation System (INS) can help it overcome the disadvantage that the images much closer to the lunar surface are not available. This study shows an integrated navigation system that integrates a visual-based navigation system and an INS, which is implemented in a simulated lunar surface.
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Ou, Yangwei, and Hongbo Zhang. "Observability-based Mars Autonomous Navigation Using Formation Flying Spacecraft." Journal of Navigation 71, no. 1 (August 1, 2017): 21–43. http://dx.doi.org/10.1017/s0373463317000510.
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This paper concentrates on designing an autonomous navigation scheme for Mars exploration. In this scheme, formation flying spacecraft are used to realise absolute orbit determination when orbiting around Mars. Inertial Line-Of-Sight (LOS) vectors from “deputy” spacecraft to the “chief” are measured using radio cross-link, optical devices and attitude sensors. Since the system's observability is closely related to the navigation performance, an analytical approach is proposed to optimise the observability. In this method, the gravity gradient tensor difference is chosen as the performance index to optimise two navigation scenarios. When there is one deputy flying around the chief, optimal parameters are obtained by solving the constrained optimisation problem. When a second deputy is added into the formation, the optimal configuration is also obtained. These results reveal that the observability is mainly determined by the magnitude of the in-track and cross-track distances in the configuration. An Extended Kalman Filter (EKF) is used to estimate the position and velocity of the chief. The results of a navigation simulation confirms that adding more deputies can significantly improve the navigational performance.
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Ясюкевич, Юрий, Yury Yasyukevich, Анна Мыльникова, Anna Mylnikova, Всеволод Иванов, and Vsevolod Ivanov. "Estimating the absolute total electron content based on single-frequency satellite radio navigation GPS/GLONASS data." Solar-Terrestrial Physics 3, no. 1 (May 5, 2017): 128–37. http://dx.doi.org/10.12737/article_58f972906c64a5.33470182.
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We present a new technique for estimating the absolute vertical and slant total electron content (TEC). The estimation is based on single-frequency joint phase and pseudorange GPS/GLONASS measurements at single stations. Estimated single-frequency vertical TEC agrees qualitatively and quantitatively with the dual-frequency vertical TEC. For analyzed stations a typical value of the difference between the single-frequency vertical TEC and dual-frequency ones generally does not exceed ~1.5 TECU with RMS up to ~3 TECU.
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Zanetti, Renato, Greg Holt, Robert Gay, Christopher D’Souza, Jastesh Sud, Harvey Mamich, Michael Begley, Ellis King, and Fred D. Clark. "Absolute Navigation Performance of the Orion Exploration Flight Test 1." Journal of Guidance, Control, and Dynamics 40, no. 5 (May 2017): 1106–16. http://dx.doi.org/10.2514/1.g002371.
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Devyatisil'nyi, A. S. "Use of Absolute Acceleration Measurements in Self-Contained Inertial Navigation." Measurement Techniques 47, no. 3 (March 2004): 213–15. http://dx.doi.org/10.1023/b:mete.0000029861.06827.45.
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KAPLAN, GEORGE H. "Angles-Only Navigation: Position and Velocity Solution from Absolute Triangulation." Navigation 58, no. 3 (September 2011): 187–201. http://dx.doi.org/10.1002/j.2161-4296.2011.tb02580.x.
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Kim, Hee-Un, and Tae-Suk Bae. "Deep Learning-Based GNSS Network-Based Real-Time Kinematic Improvement for Autonomous Ground Vehicle Navigation." Journal of Sensors 2019 (March 31, 2019): 1–8. http://dx.doi.org/10.1155/2019/3737265.
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Much navigation over the last several decades has been aided by the global navigation satellite system (GNSS). In addition, with the advent of the multi-GNSS era, more and more satellites are available for navigation purposes. However, the navigation is generally carried out by point positioning based on the pseudoranges. The real-time kinematic (RTK) and the advanced technology, namely, the network RTK (NRTK), were introduced for better positioning and navigation. Further improved navigation was also investigated by combining other sensors such as the inertial measurement unit (IMU). On the other hand, a deep learning technique has been recently evolving in many fields, including automatic navigation of the vehicles. This is because deep learning combines various sensors without complicated analytical modeling of each individual sensor. In this study, we structured the multilayer recurrent neural networks (RNN) to improve the accuracy and the stability of the GNSS absolute solutions for the autonomous vehicle navigation. Specifically, the long short-term memory (LSTM) is an especially useful algorithm for time series data such as navigation with moderate speed of platforms. From an experiment conducted in a testing area, the LSTM algorithm developed the positioning accuracy by about 40% compared to GNSS-only navigation without any external bias information. Once the bias is taken care of, the accuracy will significantly be improved up to 8 times better than the GNSS absolute positioning results. The bias terms of the solution need to be estimated within the model by optimizing the layers as well as the nodes each layer, which should be done in further research.
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Zhang, Shuang. "Mobile robot positioning algorithm based on Kalman filtering method in network environment." MATEC Web of Conferences 327 (2020): 03005. http://dx.doi.org/10.1051/matecconf/202032703005.
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Positioning is the basic link in a multi-mobile robot control system, and is also a problem that must be solved before completing a specified task. The positioning method can be generally divided into relative positioning and absolute positioning. Absolute positioning method refers to that the robot calculates its current position by acquiring the reference information of some known positions in the outside world, calculating the relationship between itself and the reference information. Absolute positioning generally adopts methods based on beacons, environment map matching, and visual positioning. The relative positioning method mainly uses the inertial navigation system INS. The inertial navigation system directly fixes the inertial measurement unit composed of the gyroscope and the accelerometer to the target device, and uses the inertial devices such as the gyroscope and the accelerometer to measure the triaxial angular velocity and The three-axis acceleration information is measured and integrated, and the mobile robot coordinates are updated in real time. Combined with the initial inertial information of the target device, navigation information such as the attitude, speed, and position of the target device is obtained through integral operation [1-2]. The inertial navigation system does not depend on external information when it is working, and is not easily damaged by interference. As an autonomous navigation system, it has the advantages of high data update rate and high short-term positioning accuracy [3]. However, under the long-term operation of inertial navigation, due to the cumulative error of integration, the positioning accuracy is seriously degraded, so it is necessary to seek an external positioning method to correct its position information [4]
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Qian, Chuang, Hongjuan Zhang, Wenzhuo Li, Jian Tang, Hui Liu, and Bijun Li. "Cooperative GNSS-RTK Ambiguity Resolution with GNSS, INS, and LiDAR Data for Connected Vehicles." Remote Sensing 12, no. 6 (March 15, 2020): 949. http://dx.doi.org/10.3390/rs12060949.
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Intelligent vehicles and connected vehicles have garnered more and more attention recently, and both require accurate positions of the vehicles in their operation, which relies on navigation sensors such as Global Navigation Satellite System (GNSS), Inertial Navigation System (INS), Light Detection And Ranging (LiDAR) and so on. GNSS is the key sensor to obtain high accuracy positions in the navigation system, because GNSS Real Time Kinematic (RTK) with correct ambiguity resolution (AR) can provide centimeter-level absolute position. But AR may fail in the urban occlusion environment because of the limited satellite visibility for single vehicles. The navigation data from multiconnected vehicles can improve the satellite geometry significantly, which is able to help improve the AR, especially in occlusion environment. In this work, the GNSS, INS, and LiDAR data from multiconnected vehicles are jointly processed together to improve the GNSS RTK AR, and to obtain high accuracy positioning results, using a scan-to-map matching algorithm based on an occupancy likelihood map (OLM) for the relative position between the connected vehicles, a Damped Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) method with least-squares for a relative AR between the connected vehicles, and a joint RTK algorithm for solving the absolute positioning for the vehicles by involving the relative position and relative ambiguity constraints. The experimental results show that the proposed approach can improve the AR for the connected vehicles with higher ratio values, success rates, and fixed rates, and achieve high-precision cooperative absolute positions compared with traditional GNSS RTK methods, especially in occlusion environments such as below a viaduct.
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Gil, Óscar, Anaís Garrell, and Alberto Sanfeliu. "Social Robot Navigation Tasks: Combining Machine Learning Techniques and Social Force Model." Sensors 21, no. 21 (October 26, 2021): 7087. http://dx.doi.org/10.3390/s21217087.
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Social robot navigation in public spaces, buildings or private houses is a difficult problem that is not well solved due to environmental constraints (buildings, static objects etc.), pedestrians and other mobile vehicles. Moreover, robots have to move in a human-aware manner—that is, robots have to navigate in such a way that people feel safe and comfortable. In this work, we present two navigation tasks, social robot navigation and robot accompaniment, which combine machine learning techniques with the Social Force Model (SFM) allowing human-aware social navigation. The robots in both approaches use data from different sensors to capture the environment knowledge as well as information from pedestrian motion. The two navigation tasks make use of the SFM, which is a general framework in which human motion behaviors can be expressed through a set of functions depending on the pedestrians’ relative and absolute positions and velocities. Additionally, in both social navigation tasks, the robot’s motion behavior is learned using machine learning techniques: in the first case using supervised deep learning techniques and, in the second case, using Reinforcement Learning (RL). The machine learning techniques are combined with the SFM to create navigation models that behave in a social manner when the robot is navigating in an environment with pedestrians or accompanying a person. The validation of the systems was performed with a large set of simulations and real-life experiments with a new humanoid robot denominated IVO and with an aerial robot. The experiments show that the combination of SFM and machine learning can solve human-aware robot navigation in complex dynamic environments.
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Hofer, H., and G. Retscher. "INDOOR SMARTPHONE NAVIGATION USING A COMBINATION OF WI-FI AND INERTIAL NAVIGATION WITH INTELLIGENT CHECKPOINTS." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W4 (September 14, 2017): 327–34. http://dx.doi.org/10.5194/isprs-annals-iv-2-w4-327-2017.
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For Wi-Fi positioning location fingerprinting is one of the most commonly employed localization technique. To achieve an acceptable level of positioning accuracy on the few meter level, i.e., to provide at least room resolution in buildings, such an approach is very labour consuming as it requires a high density of reference points. Thus, the novel approach developed aims at a significant reduction of workload for the training phase. The basic idea is to intelligently choose waypoints along possible users’ trajectories in the indoor environment. These waypoints are termed intelligent checkpoints (iCPs) and serve as reference points for the fingerprinting localization approach. They are selected along the trajectories in such a way that they define a logical sequence with their ascending order. Thereby, the iCPs are located, for instance, at doors at entrances to buildings, rooms, along corridors, etc., or in low density along the trajectory to provide a suitable absolute user localization. Continuous positioning between these iCPs is obtained with the help of the smartphones’ inertial sensors. While walking along a selected trajectory to the destination a dynamic recognition of the iCPs is performed and the drift of the inertial sensors is reduced as the iCP recognition serves as absolute position update. Conducted experiments in a multi-storey office building have shown that positioning accuracy of around 2.0 m are achievable which goes along with a reduction of workload by three quarter using this novel approach. The iCP concept and performance are presented and demonstrated in this paper.
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Paprosky, Wayne, Jeffrey Muir, and Jennifer Sostak. "Imageless Navigation Accurately Measures Component Orientation during Total Hip Arthroplasty: A Comparison with Postoperative Radiographs." Journal of Hip Surgery 03, no. 01 (February 15, 2019): 053–58. http://dx.doi.org/10.1055/s-0039-1678747.
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AbstractAccurate placement of acetabular components during total hip arthroplasty (THA) is paramount in ensuring long-term stability. Current methods for monitoring cup position and leg length intraoperatively are lacking due to susceptibility to inaccuracy or prohibitive cost. The purpose of this study was to evaluate the ability of an imageless surgical navigation tool to accurately measure acetabular cup inclination and leg length differential during THA. The authors retrospectively reviewed the medical records of patients who underwent primary or revision THA (posterolateral approach) at their facility with the assistance of computer-assisted navigation between February 2016 and March 2017. Pre- and postoperative radiographs were analyzed for leg length discrepancies and acetabular cup inclination. Radiographic values were compared with intraoperative values provided by the surgical navigation tool. The mean difference between inclination as measured from radiographs (44.4 ± 5.9 degrees) and navigation (43.0 ± 4.4 degrees) was −1.4 ± 4.6 degrees (mean absolute difference: 3.8 ± 2.8 degrees). Seventy-seven percent (48/62) of navigation measurements were within 5 degrees of radiographs. The mean difference between radiographic (7.39 ± 5.67 mm) and navigation (7.44 ± 4.81 mm) measurements of leg length differential was 0.29 ± 4.20 mm (mean absolute difference: 3.20 ± 2.69 mm). Navigation tool measurements were within 5 mm of radiographic values in 85% (39/46) of cases. At 90 days, idiopathic dislocation requiring revision surgery occurred in one patient (1.2%) with one additional patient (1.2%) requiring revision surgery due to a traumatic injury (fall). Computer-assisted navigation provided accurate intraoperative data regarding inclination and changes in leg length and was associated with a low rate of dislocation and revision surgery at 90-day follow-up.
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Liu, Jiandong, Erhu Wei, Shuanggen Jin, and Jingnan Liu. "Absolute Navigation and Positioning of Mars Rover Using Gravity-Aided Odometry." Journal of Navigation 71, no. 3 (November 23, 2017): 530–46. http://dx.doi.org/10.1017/s0373463317000893.
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Positioning and Navigation (PN) of Martian rovers still faces challenges due to limited observations. In this paper, the PN feasibilities of Mars rovers based on a Gravity-aided Odometry (GO) system are proposed and investigated in terms of numeric simulations and a case study. Statistical features of the Mars gravity field are studied to evaluate the feature diversity of the background map. The Iterative Closest Point (ICP) algorithm is introduced to match gravity measurements with the gravitational map. The trajectories of Mars Exploration Rovers (MER) and Mars Gravity Map 2011 (MGM2011) are used to complete the experiments. Several key factors of GO including odometry errors, measurement uncertainties, and grid resolution of the map are investigated to evaluate their influences on the positioning ability of the system. Simulated experiments indicate that the GO method could provide an alternative positioning solution for Martian surface rovers.
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Yi-ting, Liu, Xu Xiao-su, Liu Xi-xiang, Zhang Tao, Li Yao, Yao Yi-qing, Wu Liang, and Tong Jin-wu. "A Fast Gradual Fault Detection Method for Underwater Integrated Navigation Systems." Journal of Navigation 69, no. 1 (June 24, 2015): 93–112. http://dx.doi.org/10.1017/s0373463315000430.
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Gradual fault detection is always an important issue in integrated navigation systems, and the gradual fault is the most difficult fault to detect. To detect gradual faults in a timely and precise manner in integrated navigation systems, the statistical concepts of the normalised residual mean and the sum of absolute residuals are introduced according to the characteristics of gradual system failure in this paper. The applicability of the improved residual χ2 detection method is discussed. Then, the gradual fault detection program based on the improved residual χ2 detection method is designed with the criterion of normalised residual mean and the sum of absolute residual. The simulation results and vehicle tests show that: 1) The residual of the failed sub-system can be calculated accurately with the improved residual χ2 detection method, which has strong applicability in gradual fault detection; 2) The gradual fault can be detected in a short time by using the normalised residual mean and the sum of absolute residual.
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Jwo, Dah Jing, and Meng Hsien Hsieh. "Mitigation of Multipath Errors Using the Iterative Least Absolute Deviation Approach." Applied Mechanics and Materials 764-765 (May 2015): 555–59. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.555.
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The least squares (LS) approach has been widely used for solving the GPS navigation solution. Despite its many superior properties, however, the LS estimate can be sensitive to outliers and its performance in terms of accuracy and statistical inferences may be compromised when the errors are large and heterogeneous. The GPS signal is strongly affected by the multipath propagation errors. The LS is not able to cope with the above condition to provide a useful and plausible solution. In this paper, an alternative approach based on the least absolute deviation (LAD) criterion for estimating the navigation solution is carried out. The LAD method, which is also known as the L1 method, provides a useful and plausible solution. Unlike the LS method, the LAD method is not as sensitive to the outliers and so as to provide more robust estimates. Simulation results show that the method can effectively mitigate the GPS multipath errors.
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Li, Hui, and Cheng Zhong. "A machine vision based autonomous navigation system for Lunar rover: the model and key technique." Sensor Review 36, no. 4 (September 19, 2016): 377–85. http://dx.doi.org/10.1108/sr-01-2016-0001.
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Purpose This study aims to find a feasible precise navigation model for the planed Lunar rover. Autonomous navigation is one of the most important missions in the Chinese Lunar exploration project. Machine vision is expected to be a promising option for this mission because of the dramatic development of an image processing technique. However, existing attempts are often subject to low accuracy and errors accumulation. Design/methodology/approach In this paper, a novel autonomous navigation model was developed, based on the rigid geometric and photogrammetric theory, including stereo perception, relative positioning and absolute adjustment. The first step was planned to detect accurate three-dimensional (3D) surroundings around the rover by matching stereo-paired images; the second was used to decide the local location and orientation changes of the rover by matching adjacent images; and the third was adopted to find the rover’s location in the whole scene by matching ground image with satellite image. Among them, the SURF algorithm that had been commonly believed as the best algorithm for matching images was adopted to find matched images. Findings Experiments indicated that the accurate 3D scene, relative positioning and absolute adjustment were easily generated and illustrated with the matching results. More importantly, the proposed algorithm is able to match images with great differences in illumination, scale and observation angle. All experiments and findings in this study proved that the proposed method could be an alternative navigation model for the planed Lunar rover. Originality/value With the matching results, an accurate 3D scene, relative positioning and absolute adjustment of rover can be easily generated. The whole test proves that the proposed method could be a feasible navigation model for the planed Lunar rover.
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Napier, M. "Integration of Satellite and Inertial Positioning Systems." Journal of Navigation 43, no. 1 (January 1990): 48–57. http://dx.doi.org/10.1017/s0373463300013813.
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The Global Positioning System (GPS) offers an absolute positioning accuracy of 15 to 100 metres. Inertial navigation complements GPS in that it provides relative positioning and is totally self-contained. These two positioning sensors are ideally suited for system integration for although there is not necessarily an improvement in accuracy, the integration of GPS with inertial navigation systems (INS) does enable an increase in system performance.
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Ye, Lvyang, Yikang Yang, Jiangang Ma, Lingyu Deng, and Hengnian Li. "A Distributed Formation Joint Network Navigation and Positioning Algorithm." Mathematics 10, no. 10 (May 10, 2022): 1627. http://dx.doi.org/10.3390/math10101627.
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In view of the problem that the leader-follower joint navigation scheme relies too much on the absolute navigation and positioning accuracy of the leader node, under the conditions of distributed network-centric warfare (NCW) and to meet the location service accuracy, reliability, and synergy efficiency of the future integrated communication, navigation (ICN), we built a joint navigation and positioning system with low Earth orbit (LEO), airborne data link, and inertial navigation system (INS) as the core; designed a ranging and time-synchronization scheme of the joint navigation and positioning system; and established a joint navigation and positioning method for formation and networking based on mutual ranging and velocity measurement information between aircrafts. Finally, based on the designed LEO constellation, the universality, effectiveness, superiority, and potential superiority of algorithm are verified, respectively. The simulation results show that the scheme can meet the requirements of joint location services in challenging environments, and could be used as a reference scheme for future ICN integration.
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Shen, Chong, Xiaochen Liu, Huiliang Cao, Yuchen Zhou, Jun Liu, Jun Tang, Xiaoting Guo, Haoqian Huang, and Xuemei Chen. "Brain-Like Navigation Scheme based on MEMS-INS and Place Recognition." Applied Sciences 9, no. 8 (April 25, 2019): 1708. http://dx.doi.org/10.3390/app9081708.
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Animals have certain cognitive competence about the environment so they can correct their navigation errors. Inspired by the excellent navigational behavior of animals, this paper proposes a brain-like navigation scheme to improve the accuracy and intelligence of Micro-Electro-Mechanical System based Inertial Navigation Systems (MEMS-INS). The proposed scheme employs vision to acquire external perception information as an absolute reference to correct the position errors of INS, which is established by analyzing the navigation and error correction mechanism of rat brains. In addition, to improve the place matching speed and precision of the system for visual scene recognition, this paper presents a novel place recognition algorithm that combines image scanline intensity (SI) and grid-based motion statistics (GMS) together which is named the SI-GMS algorithm. The proposed SI-GMS algorithm can effectively reduce the influence of uncertain environment factors on the recognition results, such as pedestrians and vehicles. It solves the problem that the matching result will occasionally go wrong when simply using the scanline intensity (SI) algorithm, or the slow matching speed when simply using grid-based motion statistics (GMS) algorithm. Finally, an outdoor Unmanned Aerial Vehicle (UAV) flight test is carried out. Based on the reference information from the high-precision GPS device, the results illustrate the effectiveness of the scheme in error correction of INS and the algorithm in place recognition.
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Renaudin, Valérie, and Pierre-Yves Gilliéron. "Personal Robust Navigation in Challenging Applications." Journal of Navigation 64, no. 2 (March 2, 2011): 235–49. http://dx.doi.org/10.1017/s0373463310000408.
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Personal navigation has grown rapidly with the introduction of ubiquitous computing and the new generation of smart phones. Appropriate localisation is nowadays a central element for many applications and mobile services. However the proper estimation of the user's location remains a challenge. This paper presents an innovative concept for accurate and reliable positioning in challenging applications. It consists of three components: an absolute geographical reference, the hybridisation of complementary technologies and specific motion models. Two different applications illustrate this concept: urban displacement of blind people and guidance of firefighters. The validity of the concept is assessed with indoor experimental results. Finally the conclusion gives a prospective view of robust personal navigation.
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Cross, Michael B., Ran Schwarzkopf, Theodore T. Miller, Eric A. Bogner, Jeffrey M. Muir, and Jonathan M. Vigdorchik. "Improving registration accuracy during total hip arthroplasty: a cadaver study of a new, 3-D mini-optical navigation system." HIP International 28, no. 1 (February 9, 2017): 33–39. http://dx.doi.org/10.5301/hipint.5000533.
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Introduction: Maintaining accuracy of component placement is an important step in ensuring the long-term stability of components during total hip arthroplasty (THA). Computer-assisted navigation has improved accuracy but errors associated with the registration process are known to impact the accuracy of final measurements. The purpose of this cadaver study was to determine the registration error associated with a novel mini-navigation system. Methods: 3 board-certified orthopaedic surgeons performed 4 THA procedures each via the posterolateral approach on 6 cadavers (12 hips) using the mini-navigation tool. Pre- and post-operative radiographs and post-operative computed tomography (CT) images were obtained. Image analysis was performed by 2 radiologists not involved in the surgical procedures. During registration, surgeons aligned the alignment rod with the anterior pelvic plane (APP) to provide a reference plane for comparison with traditional navigation. Cup position from the device was compared with measurements gathered from post-op imaging. Results: The mean difference between CT and device measurements for inclination was -1.7° (standard deviation [SD] 4.9°), while the mean absolute difference was 4.2° (SD 3.2°). The mean difference between anteversion angles calculated from CT scans and from the device was -3.5° (SD 4.5°), with an absolute difference of 4.0° (SD 4.0°). 100% (12/12) of inclination measurements and 92% (11/12) of anteversion measurements fell within both the clinical and statistical limits of agreement when analyzed via the Bland-Altman technique. Conclusions: This study demonstrates that the registration error associated with this new mini-navigation system compares favourably with the known registration error associated with traditional navigation systems.
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Han, Jeong Joon, Sang-Yoon Woo, Won-Jin Yi, and Soon Jung Hwang. "Robot-Assisted Maxillary Positioning in Orthognathic Surgery: A Feasibility and Accuracy Evaluation." Journal of Clinical Medicine 10, no. 12 (June 11, 2021): 2596. http://dx.doi.org/10.3390/jcm10122596.
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Several methods enabling independent repositioning of the maxilla have been introduced to reduce intraoperative errors inherent in the intermediate splint. However, the accuracy is still to be improved and a different approach without time-consuming laboratory process is needed, which can allow perioperative modification of unoptimized maxillary position. The purpose of this study is to assess the feasibility and accuracy of a robot arm combined with intraoperative image-guided navigation in orthognathic surgery. The experiments were performed on 12 full skull phantom models. After Le Fort I osteotomy, the maxillary segment was repositioned to a different target position using a robot arm and image-guided navigation and stabilized. Using the navigation and the postoperative computed tomography (CT) images, the achieved maxillary position was compared with the planned position. Although the maxilla showed mild displacement during the fixation, the mean absolute deviations from the target position were 0.16 mm, 0.18 mm, and 0.20 mm in medio-lateral, antero-posterior, and supero-inferior directions, respectively, in the intraoperative navigation. Compared with the target position using postoperative CT, the achieved maxillary position had a mean absolute deviation of less than 0.5 mm for all dimensions and the mean root mean square deviation was 0.79 mm. The results of this study suggest that the robot arm combined with the intraoperative image-guided navigation may have great potential for surgical plan transfer with the accurate repositioning of the maxilla in the orthognathic surgery.
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Yuan, Yue, Feng Shen, and Dingjie Xu. "Multipath modeling and mitigation by using sparse estimation in global navigation satellite system-challenged urban vehicular environments." International Journal of Advanced Robotic Systems 17, no. 5 (September 1, 2020): 172988142096869. http://dx.doi.org/10.1177/1729881420968696.
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Multipath interference has been one of the most difficult problems when using global navigation satellite system-based vehicular navigation in urban environments. In this article, we develop a multipath mitigation algorithm exploiting the sparse estimation theory that improves the absolute positioning accuracy in urban environments. The navigation observation model is established by considering the multipath bias as additive positioning errors, and the assumption for the proposed method is that global navigation satellite system signals contaminated due to multipath are the minority among the received signals, which makes the unknown bias vector sparse. We investigated an improved elastic net method to estimate the sparse multipath bias vector, and the global navigation satellite system measurements can be corrected by subtracting the estimated multipath error. The positioning performance of the proposed method is verified by analytical and experimental results.
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Xiong, Kai, Peng Zhou, and Chunling Wei. "Autonomous Navigation of Unmanned Aircraft Using Space Target LOS Measurements and QLEKF." Sensors 22, no. 18 (September 15, 2022): 6992. http://dx.doi.org/10.3390/s22186992.
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An autonomous navigation method based on the fusion of INS (inertial navigation system) measurements with the line-of-sight (LOS) observations of space targets is presented for unmanned aircrafts. INS/GNSS (global navigation satellite system) integration is the conventional approach to achieving the long-term and high-precision navigation of unmanned aircrafts. However, the performance of INS/GNSS integrated navigation may be degraded gradually in a GNSS-denied environment. INS/CNS (celestial navigation system) integrated navigation has been developed as a supplement to the GNSS. A limitation of traditional INS/CNS integrated navigation is that the CNS is not efficient in suppressing the position error of the INS. To solve the abovementioned problems, we studied a novel integrated navigation method, where the position, velocity and attitude errors of the INS were corrected using a star camera mounted on the aircraft in order to observe the space targets whose absolute positions were available. Additionally, a QLEKF (Q-learning extended Kalman filter) is designed for the performance enhancement of the integrated navigation system. The effectiveness of the presented autonomous navigation method based on the star camera and the IMU (inertial measurement unit) is demonstrated via CRLB (Cramer–Rao lower bounds) analysis and numerical simulations.
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Liu, Xiaojie, Xiaoting Guo, Donghua Zhao, Chong Shen, Chenguang Wang, Jie Li, Jun Tang, and Jun Liu. "INS/Vision Integrated Navigation System Based on a Navigation Cell Model of the Hippocampus." Applied Sciences 9, no. 2 (January 10, 2019): 234. http://dx.doi.org/10.3390/app9020234.
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Considering the error accumulation problem of a pure inertial navigation system (INS) under the condition of satellite signal outages, this paper proposes a brain-like navigation method based on a navigation cell model of the hippocampus to improve the accuracy and intelligence of the INS. The proposed method employs vision to acquire external perception information as an absolute reference for INS position error correction, which is established by analyzing the navigation mechanism of the rat brain. The prominent advantages of the presented method include: (1) a remarkable effect in reducing the accumulated errors of INS can be obtained; and (2) a hardware implementation procedure of an INS/vision brain-like navigation system on a single-chip microcomputer is designed and established, which makes possible the engineering application of the brain-like navigation system by providing technical detail. Also, an outdoor vehicle test is carried out to verify the superiority of the proposed INS/vision brain-like navigation system in position measurement. Finally, the optimal performance shows the effectiveness of the proposed method in accumulated error correction and accuracy improvement for INS.
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Pecheritsa, D. S., S. Y. Burtsev, and A. A. Frolov. "Method for determining the fractional part of the carrier frequency cycle of the simulator GNSS signals." Izmeritel`naya Tekhnika, no. 11 (2020): 42–48. http://dx.doi.org/10.32446/0368-1025it.2020-11-42-48.
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The article presents the calibration problem of a navigation signals simulator while ensuring the measurements uniformity of coordinate and time measuring instruments. The method of determining the carrier frequency cycle fractional part in the simulator RF circuit output and standart deviation estimate of the pseudorange generation error by the simulator on the carrier phase with using of an oscilloscope is presented. The method essence is to determine the phase difference between two signals: the simulator absolute calibration with a single RF output – the phase difference between the navigation signal generated by the simulator and the reference harmonic signal; the simulator relative calibration with two or more RF outputs – the phase difference between the navigation signals generated by the simulator from different RF outputs. The applying of the simulator absolute calibration by the carrier frequency phase to solve the receiver calibration problem by the carrier frequency phase is shown, which will significantly simplify the implementation of the promising Integer-PPP technology. Presented the use of the simulator relative calibration to determine the accuracy characteristics of angular receiver in its development and testing.
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Luo, Yiran, Li-Ta Hsu, Yang Jiang, Baoyu Liu, Zhetao Zhang, Yan Xiang, and Naser El-Sheimy. "High-Accuracy Absolute-Position-Aided Code Phase Tracking Based on RTK/INS Deep Integration in Challenging Static Scenarios." Remote Sensing 15, no. 4 (February 17, 2023): 1114. http://dx.doi.org/10.3390/rs15041114.
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Many multi-sensor navigation systems urgently demand accurate positioning initialization from global navigation satellite systems (GNSSs) in challenging static scenarios. However, ground blockages against line-of-sight (LOS) signal reception make it difficult for GNSS users. Steering local codes in GNSS basebands is a desirable way to correct instantaneous signal phase misalignment, efficiently gathering useful signal power and increasing positioning accuracy. Inertial navigation systems (INSs) have been used as effective complementary dead reckoning (DR) sensors for GNSS receivers in kinematic scenarios, resisting various forms of interference. However, little work has focused on whether INSs can improve GNSS receivers in static scenarios. Thus, this paper proposes an enhanced navigation system deeply integrated with low-cost INS solutions and GNSS high-accuracy carrier-based positioning. First, an absolute code phase is predicted from base station information and integrated solutions of the INS DR and real-time kinematic (RTK) results through an extended Kalman filter (EKF). Then, a numerically controlled oscillator (NCO) leverages the predicted code phase to improve the alignment between instantaneous local code phases and received ones. The proposed algorithm is realized in a vector-tracking GNSS software-defined radio (SDR). Results of the time-of-arrival (TOA) and positioning based on real-world experiments demonstrated the proposed SDR.
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Laupré, Gabriel, Mehran Khaghani, and Jan Skaloud. "Sensitivity to Time Delays in VDM-Based Navigation." Drones 3, no. 1 (January 14, 2019): 11. http://dx.doi.org/10.3390/drones3010011.
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A recently proposed navigation methodology for aerial platforms based on the vehicle dynamic model (VDM) has shown promising results in terms of navigation autonomy. Its practical realization requires that control inputs are related to the same absolute time frame as inertial measurement unit (IMU) data and all other observations when available (e.g., global navigation satellite system (GNSS) position, barometric altitude, etc.). This study analyzes the (non-) tolerances of possible delays in control-input command with respect to navigation performance on a fixed-wing unmanned aerial vehicle (UAV). Multiple simulations using two emulated trajectories based on real flights reveal the vital importance of correct time-tagging of servo data while that of motor data turned out to be tolerable to a considerably large extent.
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Etienne, A. S., and V. Séguinot. "Navigation by Dead Reckoning and Local Cues." Journal of Navigation 46, no. 3 (September 1993): 364–70. http://dx.doi.org/10.1017/s0373463300011802.
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According to comprehensive theories of navigation, animals navigate by using two complementary strategies: (1) dead reckoning informs the subject in a continuous manner on its actual location with respect to an Earthbound or absolute coordinate system; while (2) long-term associations between particular landmarks and specific locations allow the animal to find its way within a familiar environment. If the subject structures familiar space as a system of interconnected places – the so-called ‘cognitive map’ – it may know through dead reckoning where it is located on its map and relate its route-based expectations to the actually perceived scenario of local cues.
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Guha, Daipayan, Raphael Jakubovic, Shaurya Gupta, Naif M. Alotaibi, David Cadotte, Leodante B. da Costa, Rajeesh George, et al. "Spinal intraoperative three-dimensional navigation: correlation between clinical and absolute engineering accuracy." Spine Journal 17, no. 4 (April 2017): 489–98. http://dx.doi.org/10.1016/j.spinee.2016.10.020.
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Chen, Chengbin, YaoYuan Tian, Liang Lin, SiFan Chen, HanWen Li, YuXin Wang, and KaiXiong Su. "Obtaining World Coordinate Information of UAV in GNSS Denied Environments." Sensors 20, no. 8 (April 15, 2020): 2241. http://dx.doi.org/10.3390/s20082241.
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GNSS information is vulnerable to external interference and causes failure when unmanned aerial vehicles (UAVs) are in a fully autonomous flight in complex environments such as high-rise parks and dense forests. This paper presents a pan-tilt-based visual servoing (PBVS) method for obtaining world coordinate information. The system is equipped with an inertial measurement unit (IMU), an air pressure sensor, a magnetometer, and a pan-tilt-zoom (PTZ) camera. In this paper, we explain the physical model and the application method of the PBVS system, which can be briefly summarized as follows. We track the operation target with a UAV carrying a camera and output the information about the UAV’s position and the angle between the PTZ and the anchor point. In this way, we can obtain the current absolute position information of the UAV with its absolute altitude collected by the height sensing unit and absolute geographic coordinate information and altitude information of the tracked target. We set up an actual UAV experimental environment. To meet the calculation requirements, some sensor data will be sent to the cloud through the network. Through the field tests, it can be concluded that the systematic deviation of the overall solution is less than the error of GNSS sensor equipment, and it can provide navigation coordinate information for the UAV in complex environments. Compared with traditional visual navigation systems, our scheme has the advantage of obtaining absolute, continuous, accurate, and efficient navigation information at a short distance (within 15 m from the target). This system can be used in scenarios that require autonomous cruise, such as self-powered inspections of UAVs, patrols in parks, etc.
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Wang, Mengke, Peidong Yu, and Yunzhi Li. "Performance analysis of GNSS/INS loosely coupled integration systems under GNSS signal blocking environment." E3S Web of Conferences 206 (2020): 02013. http://dx.doi.org/10.1051/e3sconf/202020602013.
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Global Navigation Satellite System (GNSS) and Inertial Navigation System (INS) are the most widely used navigation systems at present. Aiming at the limitations of a single system application, this paper uses kalman filter to fuse the pose information provided by GNSS and INS, respectively. GNSS has the characteristics of being easily affected by the environment but with high absolute positioning accuracy. INS has the characteristics of high sampling frequency and autonomous navigation, but the error accumulates with time. Combining the advantages of the two systems to achieve the purpose of obtaining higher-precision pose information. In addition, aiming at the problem that GNSS/INS integration cannot provide continuous, stable and reliable navigation solutions under the GNSS signal blocking environment, a smoothing post-processing algorithm for GNSS/INS integration is studied. Through experimental verification, this algorithm can effectively improve the pose accuracy under GNSS signal blocking environment.
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Yao, Kai, Qi Dan Zhu, and Bo Zhang. "On In Situ Calibration of SINS and Doppler Dead Reckoning Navigation System." Advanced Materials Research 479-481 (February 2012): 2610–15. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.2610.
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This paper addresses a practical problem arising in the calibration of bottom-lock doppler velocity log for the navigation of surface ships. Firstly, a dead reckoning navigation algorithm and briefly error analyze are proposed. Then, employing ship’s true trajectory and calculated trajectory, the rotational alignment offset between a bottom-lock doppler velocity log and a strapdown inertial navigation system as well as the scale factor error of the doppler velocity log can be experimentally determined using sensors commonly deployed with a vehicle in the field. It requires velocity values from the vehicle's doppler log and strapdown inertial navigation system, and absolute vehicle position fixes from a GPS receiver. Lake experiment results show that the calibration algorithm can calibrate the error parameters effectively, thus the position error decreases significantly after compensating the error parameters.
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Qin, Jifeng, Wang Wang, Wenju Mao, Minxin Yuan, Heng Liu, Zhigang Ren, Shuaiqi Shi, and Fuzeng Yang. "Research on a Map-Based Cooperative Navigation System for Spraying–Dosing Robot Group." Agronomy 12, no. 12 (December 8, 2022): 3114. http://dx.doi.org/10.3390/agronomy12123114.
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To solve the problem encountered when the spraying robot has run out of medicine even though the spraying task on the field is not complete, we developed a spraying–dosing robot group and proposed a collaborative navigation system based on an orchard map. Firstly, we constructed a 3D orchard point cloud map and set up navigation path points on the projected map. Secondly, we developed a master–slave command-based cooperative navigation strategy, where the spraying robot was the master and the dosing robot was the slave. Finally, the spraying robot and the dosing robot completed the cooperative navigation on the constructed map by using the pure pursuit algorithm and D-A control algorithm, respectively. To validate the cooperative navigation system, we conducted field tests on the separate communication and navigation control. The results of communication experiments demonstrated that the packet loss rate was less than 5%, which satisfied communication requirements. The experimental results of the navigation control demonstrated that the maximum value of the absolute lateral error is 24.9 cm for the spraying robot and 29.7 cm for the dosing robot. The collaborative navigation system proposed in this research can meet the automatic navigation requirements of the spraying–dosing robot group for collaborative tasks in traditional orchards.
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Xu, J., W. Veltman, Y. Chai, and W. Walter. "ACCURACY OF ACETABULAR ALIGNMENT USING INERTIAL AND OPTICAL NAVIGATION SYSTEMS DURING HIP ARTHROPLASTY." Orthopaedic Proceedings 105-B, SUPP_2 (February 2023): 105. http://dx.doi.org/10.1302/1358-992x.2023.2.105.
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Navigation in total hip arthroplasty has been shown to improve acetabular positioning and can decrease the incidence of mal-positioned acetabular components. The aim of this study was to assess two surgical guidance systems by comparing intra-operative measurements of acetabular component inclination and anteversion with a post-operative CT scan.We prospectively collected intra-operative navigation data from 102 hips receiving conventional THA or hip resurfacing arthroplasty through either a direct anterior or posterior approach. Two guidance systems were used simultaneously: an inertial navigation system (INS) and optical navigation system (ONS). Acetabular component anteversion and inclination was measured on a post-operative CT.The average age of the patients was 64 years (range: 24-92) and average BMI was 27 kg/m2 (range 19-38). 52% had hip surgery through an anterior approach. 98% of the INS measurements and 88% of the ONS measurements were within 10° of the CT measurements. The mean (and standard deviation) of the absolute difference between the post-operative CT and the intra-operative measurements for inclination and anteversion were 3.0° (2.8) and 4.5° (3.2) respectively for the ONS, along with 2.1° (2.3) and 2.4° (2.1) respectively for the INS. There was significantly lower mean absolute difference to CT for the INS when compared to ONS in both anteversion (p<0.001) and inclination (p=0.02).Both types of navigation produced reliable and reproducible acetabular cup positioning. It is important that patient-specific planning and navigation are used together to ensure that surgeons are targeting the optimal acetabular cup position. This assistance with cup positioning can provide benefits over free-hand techniques, especially in patients with an altered acetabular structure or extensive acetabular bone loss.In conclusion, both ONS and INS allowed for adequate acetabular positioning as measured on postoperative CT, and thus provide reliable intraoperative feedback for optimal acetabular component placement.
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Chen, Shengyang, Weifeng Zhou, An-Shik Yang, Han Chen, Boyang Li, and Chih-Yung Wen. "An End-to-End UAV Simulation Platform for Visual SLAM and Navigation." Aerospace 9, no. 2 (January 19, 2022): 48. http://dx.doi.org/10.3390/aerospace9020048.
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Visual simultaneous localization and mapping (v-SLAM) and navigation of unmanned aerial vehicles (UAVs) are receiving increasing attention in both research and education. However, extensive physical testing can be expensive and time-consuming due to safety precautions, battery constraints, and the complexity of hardware setups. For the efficient development of navigation algorithms and autonomous systems, as well as for education purposes, the ROS-Gazebo-PX4 simulator was customized in-depth, integrated into our previous released research works, and provided as an end-to-end simulation (E2ES) solution for UAV, v-SLAM, and navigation applications. Unlike most other similar works, which can only stimulate certain parts of the navigation algorithms, the E2ES platform simulates all of the localization, mapping, and path-planning kits in one simulator. The navigation stack performs well in the E2ES test bench with the absolute pose errors of 0.3 m (translation) and 0.9 degree (rotation), respectively, for an 83 m length trajectory. Moreover, the E2ES provides an out-of-box, click-and-fly autonomy in UAV navigation. The project source code is opened for the benefit of the research community.
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Chen, Jerry, Hwei Chong, Hee Pang, Darren Tay, Shi-Lu Chia, Ngai Lo, Seng Yeo, and Meng Zhu. "No Difference in Functional Outcomes after Total Knee Arthroplasty with or without Pinless Navigation." Journal of Knee Surgery 31, no. 07 (September 8, 2017): 649–53. http://dx.doi.org/10.1055/s-0037-1606375.
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AbstractThis study aims to investigate the functional outcomes of pinless navigation (BrainLAB VectorVision Knee 2.5 navigation system; Munich, Germany) as an intraoperative alignment guide in total knee arthroplasty (TKA). A prospective, 24-month follow-up study of 100 patients who were scheduled and randomized into two groups, the pinless navigation and conventional surgery, was conducted. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with the 180-degree mechanical axis. The outcomes measured in this study were Oxford Knee Score (OKS), Knee Society Score (KSS), Short Form-36 (SF-36), and range of motion (ROM). At 24-month postoperatively, four and two patients were lost to follow-up from the pinless navigation group and conventional group, respectively. There were no significant differences in absolute scores of the OKS, KSS, and ROM, as well as changes from preoperative baseline, between pinless navigation and conventional groups at both 6 and 24 months postoperatively. Pinless navigation results in comparable functional outcomes as conventional TKA at 6 and 24 months postoperatively.
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Mu, Rongjun, Peng Wu, Yanpeng Deng, and Haofan Song. "Optical Navigation Method and Error Analysis for the Descending Landing Phase in Planetary Exploration." Aerospace 9, no. 9 (September 6, 2022): 496. http://dx.doi.org/10.3390/aerospace9090496.
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To solve the problem of high-precision optical navigation for the descent landing of lunar and planetary probes, an optical navigation method based on the spatial position distribution model is proposed. The method is based on crater detection, and an imaging cosine equivalent mathematical model based on the correspondence of crater objects is constructed. The geometric distribution of the probe spatial position is described to form an Abelian Lie group spatial torus to achieve absolute positioning for parametric optical navigation, Finally, the effect of the measurement error of crater detection on the positioning and attitude of the optical navigation system is discussed, with a fitted ellipse used as a typical analysis object. The effects of different crater distribution configurations and different detection errors on the performance of the proposed optical navigation algorithm are analyzed. The results of Monte Carlo simulation experiments showed that the algorithm proposed in this paper had the advantages of high stability, high accuracy, and good real-time performance, compared with existing methods.
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Clark, Tanner C., and Frank H. Schmidt. "Robot-Assisted Navigation versus Computer-Assisted Navigation in Primary Total Knee Arthroplasty: Efficiency and Accuracy." ISRN Orthopedics 2013 (June 24, 2013): 1–6. http://dx.doi.org/10.1155/2013/794827.
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Background. Since the introduction of robot-assisted navigation in primary total knee arthroplasty (TKA), there has been little research conducted examining the efficiency and accuracy of the system compared to computer-assisted navigation systems. Objective. To compare the efficiency and accuracy of Praxim robot-assisted navigation (RAN) and Stryker computer-assisted navigation (CAN) in primary TKA. Methods. This was a retrospective study consisting of 52 patients who underwent primary TKA utilizing RAN and 29 patients utilizing CAN. The primary outcome measure was navigation time. Secondary outcome measures included intraoperative final mechanical axis alignment, intraoperative robot-assisted bone cut accuracy, tourniquet time, and hospitalization length. Results. RAN navigation times were, on average, 9.0 minutes shorter compared to CAN after adjustment. The average absolute intraoperative malalignment was 0.5° less in the RAN procedures compared to the CAN procedures after adjustment. Patients in the RAN group tended to be discharged 0.6 days earlier compared to patients in the CAN group after adjustment. Conclusions. Among patients undergoing TKA, there was decreased navigation time, decreased final malalignment, and decreased hospitalization length associated with the use of RAN when compared to CAN independent of age, BMI, and pre-replacement alignment.
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Ashkenazi, V. "Coordinate Systems: How to Get Your Position Very Precise and Completely Wrong." Journal of Navigation 39, no. 2 (May 1986): 269–78. http://dx.doi.org/10.1017/s0373463300000126.
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Positioning by navigation satellites is carried out in three-dimensional geocentric cartesian coordinates, X, Y, Z. This applies to both the Transit System, which has now been in operation for over 20 years, and the Global Positioning System which is being tested and is due to become operational in 1988. Traditionally, the cartographer, the seafaring navigator and the geodetic surveyor have always expressed their coordinates in geographical terms, i.e. latitude and longtitude, whereas the land-based civil engineer, surveyor and the foot (or mechanized) soldier preferred theirs in terms of projection grid coordinates, i.e. northings and eastings. Transformations between these various coordinate systems involve not only complex algebraical formulae, but also some very specific numerical parameters, which are appropriate for different countries and continents and which can only be determined empirically. Moreover, the treatment and interpretation of the different systems of coordinates may frequently involve some very basic conceptual misunderstandings. These include confusing astronomical latitudes and longitudes with their geodetic counterparts, treating projection northings and eastings as if they were ordinary plane coordinates and, in the case of positions derived from observations to Transit satellites, applying the wrong set of transformation parameters or using inappropriate geoidal contour maps. These are typical examples of the sort of common misconceptions leading to gross errors and affecting even the most precisely determined absolute positions. Relative positioning, with respect to another point or a framework of points with known coordinates, eliminates some of the worst effects of these systematic sources of error, and is commonly used in geodetic surveying. However, instantaneous navigation (especially by using satellites) is most likely to be based on continuously determined, successive absolute positions and will therefore inevitably be affected by reference system errors. This is particularly important in the case of land navigation where much higher accuracies will be expected. This is a review paper with definitions and descriptions of the various types of coordinate systems and their mutual relationships. Geographical and geodetic coordinates are discussed in section 2, and projection grid coordinates in section 3. This is followed, in section 5, by a description of three-dimensional cartesian coordinates used in conjunction with navigation satellites. A brief discussion on current and proposed navigation satellite systems is given in section 6 and the paper is concluded in section 7.
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Sun, Yuan. "Autonomous Integrity Monitoring for Relative Navigation of Multiple Unmanned Aerial Vehicles." Remote Sensing 13, no. 8 (April 12, 2021): 1483. http://dx.doi.org/10.3390/rs13081483.
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Accurate and reliable relative navigation is the prerequisite to guarantee the effectiveness and safety of various multiple Unmanned Aerial Vehicles (UAVs) cooperation tasks, when absolute position information is unavailable or inaccurate. Among the UAV navigation techniques, Global Navigation Satellite System (GNSS) is widely used due to its worldwide coverage and simplicity in relative navigation. However, the observations of GNSS are vulnerable to different kinds of faults arising from transmission degradation, ionospheric scintillations, multipath, spoofing, and many other factors. In an effort to improve the reliability of multi-UAV relative navigation, an autonomous integrity monitoring method is proposed with a fusion of double differenced GNSS pseudoranges and Ultra Wide Band (UWB) ranging units. Specifically, the proposed method is designed to detect and exclude the fault observations effectively through a consistency check algorithm in the relative positioning system of the UAVs. Additionally, the protection level for multi-UAV relative navigation is estimated to evaluate whether the performance meets the formation flight and collision avoidance requirements. Simulated experiments derived from the real data are designed to verify the effectiveness of the proposed method in autonomous integrity monitoring for multi-UAV relative navigation.
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Yang, Xin Dong, Ai Guo Shi, Zuo Chao Wang, Bao Zhang Yang, and Ben Hui Zhang. "Study on the Extraction Method of Wave Spectrum Based on WaMoSII Wave Measuring Information." Applied Mechanics and Materials 444-445 (October 2013): 1745–50. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1745.
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The wave measuring system can supply massive wave data information, but these data cannot be applied to navigation practice directly. This thesis set WaMoSII(The Wave and Surface Current Monitoring System) as an example , introduced the system and principle of WaMoSII, reprocessed the supplied wave measuring information, and established wave information database based on SQL Server. Through study on the MTF (modulation transfer function), it proved the distribution similarity between practical wave spectrum and the supplied frequency and spectral density information of WaMoSII, then we implemented the function that extracting relative spectrum information then transforming into absolute spectrum information automatically based on MATLAB program, it can provide convenience for wave measuring radar information for navigating application.