Auswahl der wissenschaftlichen Literatur zum Thema „Single station-RTK“

Nowadays the RTK (Real Time Kinematic) method for positioning is used in daily life by different consumers for many purposes. Several different RTK correction techniques are used, starting from single site to network approaches. The GNSS market is filled with receivers from different manufacturers and different capabilities. In this paper we assess the stability of the reference station network transmitted RTK correction. Two different surveying class GNSS receivers in combination with four varied RTK correction techniques under diverse observation conditions are analyzed. This study has been conducted in Latvia, where state wide permanent GNSS reference station network has been maintained since year 2005.

Over the past decade, network RTK technology has become popular as an efficient method of precise, real-time positioning. Its relatively low-cost and single receiver ease-of-use has allowed it to mostly replace static relative GPS and single baseline RTK in urban areas where such networks are economically viable (e.g., cadastral and construction survey). The Ministry of Transportation of Ontario (MTO) and York University have investigated the performance of commercial network RTK services in Southern Ontario, where performance is defined by a set of developed metrics. It was found that the user horizontal solution had an overall precision of ∼2.5 cm (95%), though there were cases of solution biases, drifts and gaps. A follow-up study is developing criteria and pathways for the certification of such commercial network RTK services, focusing on: reference station integration, reference station maintenance, and user solution monitoring. A set of recommendations for network certification is in preparation.

<p>After the late 1990s, GNSS/GPS network RTK technology has become the preferred technique in the world, today widely used in various applications such as monitoring, early warning systems, and mapping and engineering applications. By the end of 2008, the CORS-TR network was being used for engineering applications to determine 3D positions across the whole of Turkey. On the other hand, single base RTK stations are being operated in Turkey. The YLDZ is one of these types of stations. It was established at the Yıldız Technical University by the Department of Geomatic Engineering in 2012. In this paper, the performance of the YLDZ station is examined by use of measurements in 5 Istanbul GPS Triangulation Network (IGNA) benchmark points, with five repeatability measurements up to 50 km from the station. The CORS-TR network RTK solution is used at the same points, and the results are compared. The measured coordinates produced by the two RTK solutions are compared with the IGNA point coordinates. Satellite geometry, initialisation time and the standard deviation of repeatability are also determined. The differences between measured and known coordinates are calculated as 1-2 cm horizontally and close to 3 cm vertically using the YLDZ single base RTK method.</p><p> </p><p><strong>Desempeño de un Método de Navegación Cinética Satelital en Tiempo Real (RTK) de una Sola Base en Comparación de un Sistema RTK</strong></p><p> </p><p><strong>Resumen</strong></p><p>Después de la década de los 90, el Sistema Global de Navegación por satélite/Sistema de Posicionamiento Global (GNSS/GPS, en inglés), basado en tecnología de Navegación Cinética Satelital en Tiempo Real (RTK, del inglés Real Time Kinematic) se convirtió en la técnica preferida en el mundo y que todavía se utiliza en varias aplicaciones como el monitoreo, sistemas de alerta temprana y mapeo e ingeniería de aplicativos. Para finales de 2008, los aplicativos de ingeniería utilizan la red de Estaciones de Referencia de Funcionamiento Continuo (CORS-TR, un proyecto establecido en Turquía) para determinar posiciones en tres dimensiones a lo largo del territorio turco. Por otro lado, las estaciones RTK de una sola base han funcionado en Turquía. La YLDZ es una estación de este tipo que fue establecida en la Universidad Técnica de Yildiz por el departamento de Ingeniería Geomática en 2012. En este trabajo se examina el desempeño dela estación YLDZ a través de la medición de cinco puntos de referencia del Sistema de Triangulación GPS de Estambul (IGNA, en inglés) con cinco mediciones repetitivas a más de 50 km de la estación. Similares medidas RTK se hicieron con la red CORS-TR y se compararon los resultados. Las dos mediciones producidas por las soluciones RTK se compararon con los puntos de coordenadas IGNA. También se determinó la geometría satelital, el tiempo de inicialización y la desviación estándar de la repetibilidad. Las diferencias entre las coordenadas medidas y las coordenadas conocidas se calcularon en un rango de 1-2 centímetros horizontalmente y cerca de 3 centímetros verticalmente para la estación YLDZ con el método RTK.</p>

Ketersediaan layanan dan cakupan Continuously Operating Reference Station (CORS) sangat penting untuk kegiatan yang membutuhkan ketelitian level sentimeter atau lebih baik. Penelitian ini menganalisis ketersediaan layanan CORS Indonesia berdasar data web scraping server InaCORS pada Desember 2018. Cakupan CORS diestimasi dengan asumsi performansi Real Time Kinematic (RTK) single base hingga radius 30 kilometer dan untuk RTK network base hingga 50 kilometer dari masing-masing stasiun yang kemudian dipadukan dengan data cakupan jaringan komunikasi selular Telkomsel, Indosat dan 3 dari opensignal.com. Hasil web scraping menunjukkan terdapat 51 stasiun CORS dengan ketersediaan layanan di atas 80%, empat dengan ketersediaan layanan di bawah 80%, dua dengan ketersediaan layanan di bawah 50%, dan 14 yang tidak memiliki ketersediaan layanan. Cakupan CORS untuk metode RTK single base dan network base masing-masing adalah 72,942% dan 98,299%. Luas cakupan CORS terbesar diperoleh provider Telkomsel baik untuk metode RTK single base maupun network base yaitu masing-masing sebesar 34,622% dan 45,180%. Cakupan riil dari estimasi tersebut mungkin lebih besar karena hasil uji lapangan membuktikan bahwa tingkat ketepatan data dari OpenSignal hanya sebesar 69,444% dan masih banyak area tanpa data sinyal. Hasil analisis tingkat duplikasi cakupan CORS menunjukkan bahwa luas duplikasi cakupan CORS untuk metode RTK single base dan network base masing-masing sebesar 37,076% dan 82,382% dari luas total cakupan CORS. Hasil dari penelitian juga menunjukkan setidaknya ada 20 stasiun CORS yang perlu ditingkatkan ketersediaan datanya.

Around the single station CORS system, a series of relevant experiments were conducted, the measurement was analyzed. Through base station as the center, different distances of single base station GPS-RTK measurement were carried on , the radius of actual operation and its changing law with the base station distance were obtained concluded , the measurement precision was Obtained by measuring static GPS control points,; the measurement actual coverage area positioning accuracy was confirmed, Internal, extern al accord accuracy was calculated and analyzed., the system actual service radius and The extent of different range accuracy was obtained . the results show that the single base station system is more suitable for the development of small and medium-sized cities, its actual operating radius is 28km, it can completely satisfy the city one or two traverse survey in 18 km.

In this contribution, a novel un-differenced (UD) (PPP-RTK) concept, i.e. a synthesis of Precise Point Positioning and Network-based Real-Time Kinematic concept, is introduced. In the first step of our PPP-RTK approach, the UD GNSS observations from a regional reference network are processed based upon re-parameterised observation equations, corrections for satellite clocks, phase biases and (interpolated) atmospheric delays are calculated and provided to users. In the second step, these network-based corrections are used at the user site to restore the integer nature of his UD phase ambiguities, which makes rapid and high accuracy user positioning possible. The proposed PPP-RTK approach was tested using two GPS CORS networks with inter-station distances ranging from 60 to 100 km. The first test network is the northern China CORS network and the second is the Australian Perth CORS network. In the test of the first network, a dual-frequency PPP-RTK user receiver was used, while in the test of the second network, a low-cost, single-frequency PPP-RTK user receiver was used. The performance of fast ambiguity resolution and the high accuracy positioning of the PPP-RTK results are demonstrated.

Correct resolution of ambiguities for GNSS reference network is prerequisite for generation of corrections for network RTK. Due to the presence of atmospheric delay in the double-differenced observations, the convergence time of ambiguity is about a dozen minutes and even dozens of minutes for medium and long baselines. And in the case of loss-of-lock or new rising satellites, the integer ambiguities have to be redetermined over and over again. But for the application of GNSS network RTK, the resolution of ambiguity needs to be determined real time as possible. Atmospheric delays of previous epochs are used to predict atmospheric delays of following epochs, and then wide and narrow lane combination of carrier-phase observations as well as ionosphere-free combination is used to resolve ambiguities with single epoch. Our test results show that the precision of predicted double-differenced tropospheric and ionospheric delays is about 2-3 cm using temporal-and spatial-correlation exponent model, and the success rates of L1 ambiguities resolution with single epoch reach above 90% for medium and long distance GNSS reference station network.

The Global Navigation Satellite Systems (GNSS) becomes the primary choice for device localization in outdoor situations. At the same time, many applications do not require precise absolute Earth coordinates, but instead, inferring the geometric configuration information of the constituent nodes in the system by relative positioning. The Real-Time Kinematic (RTK) technique shows its efficiency and accuracy in calculating the relative position. However, when the cycle slips occur, the RTK method may take a long time to obtain a fixed ambiguity value, and the positioning result will be a “float” solution with a low meter accuracy. The novel method presented in this paper is based on the Relative GNSS Tracking Algorithm (Regtrack). It calculates the changes in the relative baseline between two receivers without an ambiguity estimation. The dead reckoning method is used to give out the relative baseline solution while a parallel running Extended Kalman Filter (EKF) method reinitiates the relative baseline when too many validation failures happen. We conducted both static and kinematic tests to assess the performance of the new methodology. The experimental results show that the proposed strategy can give accurate millimeter-scale solutions of relative motion vectors in adjacent two epochs. The relative baseline solution can be sub-decimeter level with or without the base station is holding static. In the meantime, when the initial tracking point and base station coordinates are precisely obtained, the tracking result error can be only 40 cm away from the ground truth after a 25 min drive test in an urban environment. The efficiency test shows that the proposed method can be a real-time method, the time that calculates one epoch of measurement data is no more than 80 ms and is less than 10 ms for best results. The novel method can be used as a more robust and accurate ambiguity free tracking approach for outdoor applications.

Global Navigation Satellite System (GNSS) positioning is currently a common practice thanks to the development of mobile devices such as smartphones and tablets. The possibility to obtain raw GNSS measurements, such as pseudoranges and carrier-phase, from these instruments has opened new windows towards precise positioning using smart devices. This work aims to demonstrate the positioning performances in the case of a typical single-base Real-Time Kinematic (RTK) positioning while considering two different kinds of multi-frequency and multi-constellation master stations: a typical geodetic receiver and a smartphone device. The results have shown impressive performances in terms of precision in both cases: with a geodetic receiver as the master station, the reachable precisions are several mm for all 3D components while if a smartphone is used as the master station, the best results can be obtained considering the GPS+Galileo constellations, with a precision of about 2 cm both for 2D and Up components in the case of L1+L5 frequencies, or 3 cm for 2D components and 2 cm for the Up, in the case of an L1 frequency. Moreover, it has been demonstrated that it is not feasible to reach the phase ambiguities fixing: despite this, the precisions are still good and also the obtained 3D accuracies of positioning solutions are less than 1 m. So, it is possible to affirm that these results are very promising in the direction of cooperative positioning using smartphone devices.

Precise real-time kinematic (RTK) Global Navigation Satellite System (GNSS) positioning requires fixing integer ambiguities after a short initialization time. Originally, it was assumed that it was only possible at a relatively short distance from a reference station (<10 km), because otherwise the atmospheric effects prevent effective ambiguity fixing. Nowadays, through the use of VRS, MAC, or FKP corrections, the distances to the closest reference station have been increased to around 35 km. However, the baselines resolved in real time are not as far as in the case of static positioning. Further extension of the baseline requires the use of an ionosphere-weighted model with ionospheric delay corrections available in real time. This solution is now possible thanks to the Radio Technical Commission for Maritime (RTCM) stream of SSR corrections from, for example, Centre National d’Études Spatiales (CNES), the first analysis center to provide it in the context of the International GNSS Service. Then, ionospheric delays are treated as pseudo-observations that have a priori values from the CLK RTCM stream. Additionally, satellite orbit and clock errors are properly considered using space-state representation (SSR) real-time radial, along-track, and cross-track corrections. The following paper presents the initial results of such RTK positioning. Measurements were performed in various field conditions reflecting realistic scenarios that could have been experienced by actual RTK users. We have shown that the assumed methodology was suitable for single-epoch RTK positioning with up to 82 km baseline in solar minimum (30 March 2019) mid and high latitude (Olsztyn, Poland) conditions. We also confirmed that it is possible to obtain a rover position at the level of a few centimeters of precision. Finally, the possibility of using other newer experimental IGS RT Global Ionospheric Maps (GIMs), from Chinese Academy of Sciences (CAS) and Universitat Politècnica de Catalunya (UPC) among CNES, is discussed in terms of their recent performance in the ionospheric delay domain.

Sammanfattning   Förutsättning   I examensarbetet har det ingått ett verkligt ärende som handläggs av mig som MBK-ingenjör inom Lantmäteriet. Det är ett naturvårdsuppdrag från Länsstyrelsen och innefattar bl a inmätning och utstakning av gräns på ett blivande naturreservat.   Naturvårdsuppdraget Huskeberget ligger ca 5 km norr om Södra Finnskoga och sydväst om Höljes i norra Värmland. Omkrets 2,38 km. Områdets höjd är ca 550 m över havet och ligger på sydöstra sluttningen av Huskeberget.   Fix   Lantmäteriet använder idag Leica Viva CS15/GS15 mätutrustning vid inmätning av brytpunkter och gränser. I detta fall det blivande naturreservatet. Under vissa omständigheter kan det ta tid att få fix-lösning eller helt utebli. Dessa omständigheter kan bero på ett flertal faktorer bl a kraftiga jonosfärsstörningar och/eller GPRS-nätets täckningsområde för mottagning av SWEPOS nätverks-RTK tjänst.   Inriktning   Fokus har lagts på att utvärdera ett alternativ till nätverks-RTK, en sk enkelstations-RTK med uppkoppling till en tillfällig referensstation.   Närmare undersökning har gjorts på tiden för initialisering vid varje enskild inmätning som sedan jämförts i de två mätmetoderna. Tiden för själva arbetet sätts sedan i relation till resultatet från undersökningen för att ge en helhetsbild av tidsåtgång i arbetet med vardera mätmetoden.   Resultat   Efter alla brytpunkter mätts in visade det sig att i just det här området inte fanns några anmärkningsvärda problem att få fix-lösning med någon av de valda mätmetoderna. Resultatet visar därmed små skillnader i tidsjämförelser.   En oplanerad testmätning med nätverks-RTK gjordes i tät skog alldeles intill en inmätt brytpunkt utan framgång att få fix-lösning. Detta för att belysa problematiken med att få fix-lösning vid mätning i tät skog.   Rapporten innehåller en kortfattad beskrivning av delar av arbetet i Lantmäteriets handläggning av naturvårdsuppdrag.

GNSS-teknik ersätter i allt högre grad terrester mätteknik, dels på grund av sin enkelhet och dels på grund av att den är mindre kostsam än traditionella metoder. En vanlig förekommande GNSS-teknik är RTK (Real Time Kinematic) som är en teknik som beräknar en position i realtid genom bärvågsmätning. Inom RTK-mätning finns det olika tekniker att utöva; enkelstations-RTK (ERTK) och nätverks-RTK (NRTK). I studien undersöktes kvaliteten och lägesosäkerhet på höjdbestämningsdata erhållen från dessa metoder. En envägs variansanalys (ANOVA) användes för att undersöka om det fanns en signifikant skillnad mellan de genomsnittliga avvikelser som erhölls från mätmetoderna. Mätmetoderna utfördes över två punkter med känd höjd som fastställdes tidigare med ett dubbelavvägningståg. ERTK och NRTK varvades med en observationstid på 20 minuter med positioneringsintervall på 3 sekunder. Tidseparationen mellan mätningarna varade i 30 minuter och sammanlagt utfördes 5 mätserier med 400 observationer i varje serie. Grova fel eliminerades genom att kassera värden som föll utanför 3σ-gränsen. Resultaten från ERTK-mätningarna visade att punkten kunde höjdbestämmas med en lägesosäkerhet på 22 mm och en mätosäkerhet på 32 mm (2σ) för samtliga mätserier tillsammans. Internt varierade lägesosäkerheten 13–28 mm mellan serierna. NRTK mätningarna erhöll en total lägesosäkerhet på 14 mm och en mätosäkerhet på 24 mm (2σ). Från enskilda mätserier erhöll serie 3 den lägsta lägesosäkerheten på 9 mm, och serie 4 den högsta med 18 mm. Generellt visade NRTK-metoden lägre och jämnare avvikelser från referensdata än ERTK, resultatet kan dock ha blivit påverkat av basens läge i relation till ett närliggande träd. ANOVA-testet visade att det fanns en signifikant skillnad mellan mätserierna (p =0,00) per enskild metod, men skillnaden av medelavvikelserna mellan dessa metoder var inte signifikanta (p =0,115). Resultatet från denna studie är viktig med avseende på kvalitetsutvärdering av olika GNSS-metoder och kan användas som underlag för beslut om tillämpad metod för andra mätuppdrag.
A quality survey was performed on the position accuracy of two GNSS-methods (single station-RTK and network-RTK) for height determination, and a one-way analysis of variance (ANOVA) was used for statistical investigation of differences in the spread of height deviations. The GNSS-methods were applied on a reference point, which was determined prior with leveling, and measured with 20 minutes observation time and 30 minutes time separation, resulting in 5 series containing 400 observations each from respective method. The ANOVA test was performed by grouping the height deviations with respect to the measurement series, as well as the mean deviations with respect to the methods. Height determination with the ERTK method showed a total positional uncertainty of 22 mm (13-28 mm between the series) and a measurement uncertainty of 32 mm (2σ). Results obtained with NRTK showed a total positional uncertainty of 14 mm (9-14 between the series) and a total measurement uncertainty of 24 mm (2σ). The statistical tests showed that the differences between the measurement series for individual methods were significant (p = 0,000) but that the mean deviations between the methods were not (p = 0,115). NRTK obtained a lower positional uncertainty than ERTK measurements in this study, and the ANOVA test showed that there was no significant difference in the distribution of the mean deviations between the measurement methods. This study is important with regard to quality evaluation of different GNSS-methods and can be used as a basis for deciding on the applied measurement method.

RTK (Real Time Kinematic) method for positioning is used in daily life by different consumers for many purposes. When there are so many measurements, it is essential to know where RTK measurements are concentrated and which stations are obligatory for LitPOS performance. In this paper, using RTK software generated reports and SQL database records, we introduced the geographic information systems show to graphically LitPOS users activity and density of measurements. Using this data we analyze how LitPOS users are divided among Lithuanian municipalities, how much users are working each month and how this affects LitPOS performance. This study is performed in Lithuania, where state wide permanent GNSS reference station network has been maintained since year 2007.