Integration of precise point positioning and reduced inertial sensors system

Inertial Sensors ◽

Position Estimation ◽

Dual Frequency ◽

Differential Gps ◽

Static Mode ◽

Land Vehicle ◽

Frequency Code ◽

In Global Positioning System (GPS), Precise Point Positioning (PPP) achieves the highest accuracy in point positioning. It approaches centimetre-level accuracy in static mode and sub-decimetre accuracy in kinematic mode. PPP is an alternative approach to carrier-phase-based Differential GPS (DGPS) and offers advantages over DGPS. PPP uses GPS observations from a single receiver for position estimation, which is simpler than using more than one GPS receiver. However, PPP needs rigorous modelling for all errors and biases, which are otherwise cancelled out or mitigated when using DGPS. PPP’s popularity is on the rise, as it is ideal for land-vehicle positioning and navigation. However, in challenging environments, PPP suffers from a signal loss that prevent continuous navigation or a reduction in the number of visible satellites that causes accuracy degradation. This research integrates PPP with a Reduced Inertial Sensors System (RISS) — a low-cost system that uses data from reduced MEMS-based inertial sensors and vehicle odometry — to provide accurate and inexpensive land-vehicle navigation systems. The system is integrated in a tightly coupled mode through the use of an Extended Kalman Filter (EKF), which employs an improved error model for the RISS data. The system was tested using data from real driving routes with single-frequency code-based PPP/RISS (SF-code-PPP/RISS), dual-frequency code-based PPP (DF-code-PPP/RISS), smoothed dual-frequency code-based PPP (S-DF-code-PPP/RISS), and code- and carrier-phase-based PPP (code-carrier-PPP/RISS). The performance of the developed PPP/RISS was evaluated using position RMS and maximum errors during continuous GPS availability as well as during signal outages. The developed integrated algorithms were assessed using three real road tests that capture different navigational conditions. The results show that when five or more satellites are available, code-carrier-PPP/RISS solution is superior to that of SF- and DF-code-PP/RISS. For latitude, code-carrier-PPP/RISS solution was 47% and 20% more precise than the SF- and DF-code- PP/RISS counterparts, respectively. For longitude, code-carrier-PPP/RISS solution was 65% and 31% more precise than the SF- and DF-Code-PP/RISS counterparts, respectively. Similarly, the altitude solution was improved by 46% and 25%, respectively. During GPS signal outages of 60 seconds, code-carrier-PPP/RISS’s algorithms outperformed that of SF- and DF-code-PPP/RISS by about 35% when the satellite availability level was set to three satellites. For other satellite availability levels, the algorithms performed almost identically.

Integration of precise point positioning and reduced inertial sensors system

10.32920/ryerson.14662584 ◽

2021 ◽

Author(s):

Hassan E. Ibrahim

Keyword(s):

Carrier Phase ◽

Inertial Sensors ◽

Position Estimation ◽

Dual Frequency ◽

Differential Gps ◽

Static Mode ◽

Land Vehicle ◽

Frequency Code ◽

Real-time GNSS precise point positioning for low-cost smart devices

GPS Solutions ◽

10.1007/s10291-021-01106-1 ◽

2021 ◽

Vol 25 (2) ◽

Author(s):

Liang Wang ◽

Zishen Li ◽

Ningbo Wang ◽

Zhiyu Wang

Keyword(s):

Carrier Phase ◽

Measurement Errors ◽

Low Cost ◽

Smart Devices ◽

Dual Frequency ◽

Static Mode ◽

Phase Measurements ◽

Positioning Errors ◽

AbstractGlobal Navigation Satellite System raw measurements from Android smart devices make accurate positioning possible with advanced techniques, e.g., precise point positioning (PPP). To achieve the sub-meter-level positioning accuracy with low-cost smart devices, the PPP algorithm developed for geodetic receivers is adapted and an approach named Smart-PPP is proposed in this contribution. In Smart-PPP, the uncombined PPP model is applied for the unified processing of single- and dual-frequency measurements from tracked satellites. The receiver clock terms are parameterized independently for the code and carrier phase measurements of each tracking signal for handling the inconsistency between the code and carrier phases measured by smart devices. The ionospheric pseudo-observations are adopted to provide absolute constraints on the estimation of slant ionospheric delays and to strengthen the uncombined PPP model. A modified stochastic model is employed to weight code and carrier phase measurements by considering the high correlation between the measurement errors and the signal strengths for smart devices. Additionally, an application software based on the Android platform is developed for realizing Smart-PPP in smart devices. The positioning performance of Smart-PPP is validated in both static and kinematic cases. Results show that the positioning errors of Smart-PPP solutions can converge to below 1.0 m within a few minutes in static mode and the converged solutions can achieve an accuracy of about 0.2 m of root mean square (RMS) both for the east, north and up components. For the kinematic test, the RMS values of Smart-PPP positioning errors are 0.65, 0.54 and 1.09 m in the east, north and up components, respectively. Static and kinematic tests both show that the Smart-PPP solutions outperform the internal results provided by the experimental smart devices.

Precise Point Positioning Using Dual-Frequency GNSS Observations on Smartphone

Sensors ◽

10.3390/s19092189 ◽

2019 ◽

Vol 19 (9) ◽

pp. 2189 ◽

Cited By ~ 27

Author(s):

Qiong Wu ◽

Mengfei Sun ◽

Changjie Zhou ◽

Peng Zhang

Keyword(s):

Frequency Mode ◽

Single Frequency ◽

Dual Frequency ◽

Static Mode ◽

Position Errors ◽

Point Positioning ◽

Similar Accuracy ◽

Positioning Algorithm ◽

Gnss Observations

The update of the Android system and the emergence of the dual-frequency GNSS chips enable smartphones to acquire dual-frequency GNSS observations. In this paper, the GPS L1/L5 and Galileo E1/E5a dual-frequency PPP (precise point positioning) algorithm based on RTKLIB and GAMP was applied to analyze the positioning performance of the Xiaomi Mi 8 dual-frequency smartphone in static and kinematic modes. The results showed that in the static mode, the RMS position errors of the dual-frequency smartphone PPP solutions in the E, N, and U directions were 21.8 cm, 4.1 cm, and 11.0 cm, respectively, after convergence to 1 m within 102 min. The PPP of dual-frequency smartphone showed similar accuracy with geodetic receiver in single-frequency mode, while geodetic receiver in dual-frequency mode has higher accuracy. In the kinematic mode, the positioning track of the smartphone dual-frequency data had severe fluctuations, the positioning tracks derived from the smartphone and the geodetic receiver showed approximately difference of 3–5 m.

Evaluation of precise point positioning algorithm based on original dual-frequency GPS code and carrier-phase observations

2011 International Conference on Electric Information and Control Engineering ◽

10.1109/iceice.2011.5778163 ◽

2011 ◽

Author(s):

Wei Yan ◽

Zishen Li ◽

Dehai Li ◽

Yunbin Yuan

Keyword(s):

Carrier Phase ◽

Dual Frequency ◽

Point Positioning ◽

Positioning Algorithm

Precise Point Positioning for TAI Computation

International Journal of Navigation and Observation ◽

10.1155/2008/562878 ◽

2008 ◽

Vol 2008 ◽

pp. 1-8 ◽

Cited By ~ 39

Author(s):

Gérard Petit ◽

Zhiheng Jiang

Keyword(s):

Time Scale ◽

Carrier Phase ◽

Dual Frequency ◽

Time Transfer ◽

Short Term ◽

Reference Time ◽

Local Clock ◽

Point Positioning ◽

Simple Difference

We discuss the use of some new time transfer techniques for computing TAI time links. Precise point positioning (PPP) uses GPS dual frequency carrier phase and code measurements to compute the link between a local clock and a reference time scale with the precision of the carrier phase and the accuracy of the code. The time link between any two stations can then be computed by a simple difference. We show that this technique is well adapted and has better short-term stability than other techniques used in TAI. We present a method of combining PPP and two-way time transfer that takes advantage of the qualities of each technique, and shows that it would bring significant improvement to TAI links.

PENGGUNAAN KINEMATIK GNSS PRECISE POINT POSITIONING (PPP) PADA SURVEI GAYABERAT AIRBORNE SULAWESI

GEOMATIKA ◽

10.24895/jig.2016.22-2.638 ◽

2016 ◽

Vol 22 (2) ◽

pp. 82

Author(s):

Prayudha Hartanto

Keyword(s):

Base Station ◽

Gravity Survey ◽

Airborne Gravity ◽

Dual Frequency ◽

Differential Gps ◽

Airborne Gravity Survey ◽

Positioning Method ◽

Rms Error ◽

ABSTRAKMetode Precise Point Positioning (PPP) adalah metode penentuan posisi teliti yang hanya menggunakan sebuah receiver GNSS dual frekuensi. Metode ini dapat digunakan untuk menentukan posisi teliti objek-objek yang diam (static) maupun bergerak (kinematic). Pada penelitian ini, akan dipaparkan mengenai penggunaan kinematik PPP dalam penentuan posisi pesawat terbang pada survei gayaberat airborne di Sulawesi tahun 2008. Data yang digunakan adalah jalur terbang pesawat pada day of year (DOY) 291 dan 274. Perangkat lunak yang digunakan adalah Waypoint® Grafnav. Hasil pengolahan menggunakan metode PPP tersebut kemudian dibandingkan dengan hasil pengolahan data Diferensial GPS (DGPS) dengan 1 titik ikat untuk DOY 291 dan 2 titik ikat untuk DOY 274. Hasil perbandingan pada DOY 291 menunjukkan nilai RMS untuk arah timur, utara dan tinggi masing-masing sebesar 0,024 m; 0,020 m dan 0,039 m. Pada DOY 274, RMS yang diperoleh adalah 0,032 m; 0,011 m dan 0,058 m masing-masing untuk arah timur, utara dan tinggi. Hasil-hasil tersebut mengindikasikan bahwa metode PPP dapat digunakan untuk menentukan posisi pesawat terbang dengan fraksi ketelitian sentimeter. Tingkat ketelitian posisi ini sudah memenuhi syarat untuk digunakan pada survei gayaberat airborne.Kata kunci: GNSS, kinematik PPP, gayaberat airborne, DGPS ABSTRACTThe Precise Point Positioning (PPP) is a positioning method which only use a dual frequency GNSS receiver. This method can be used to determine the precise position of either static (static) or moving objects (kinematic). In this paper, we will discuss the application of kinematic PPP for the 2008 Sulawesi airborne gravity survey. By using a commercial GNSS processing software called Waypoint® Grafnav, we determine the PPP solutions for the aircraft trajectory of the day of year (DOY) 291 and 274. Each solution then be compared to the Differential GPS (DGPS) results, which use one base station for DOY 291 and two reference stations for DOY 274. The PPP solution of DOY 291 gives RMS error of 0.024 m eastward, 0.020 m northward, and 0.039 m upward. Moreover, the comparison of DOY 274 gives RMS error of 0.032 m eastward, 0.011 m northward, and 0.058 m upward. These centimeter level RMS errors show that PPP is a compatible positioning method for airborne gravity survey.Keywords: GNSS, kinematic PPP, airborne gravity, DGPS

Triple-Frequency GPS Precise Point Positioning Ambiguity Resolution Using Dual-Frequency Based IGS Precise Clock Products

International Journal of Aerospace Engineering ◽

10.1155/2017/7854323 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11

Author(s):

Fei Liu ◽

Yang Gao

Keyword(s):

Ambiguity Resolution ◽

Carrier Phase ◽

Free Carrier ◽

Convergence Time ◽

Dual Frequency ◽

Phase Measurements ◽

Triple Frequency ◽

Wide Lane ◽

With the availability of the third civil signal in the Global Positioning System, triple-frequency Precise Point Positioning ambiguity resolution methods have drawn increasing attention due to significantly reduced convergence time. However, the corresponding triple-frequency based precise clock products are not widely available and adopted by applications. Currently, most precise products are generated based on ionosphere-free combination of dual-frequency L1/L2 signals, which however are not consistent with the triple-frequency ionosphere-free carrier-phase measurements, resulting in inaccurate positioning and unstable float ambiguities. In this study, a GPS triple-frequency PPP ambiguity resolution method is developed using the widely used dual-frequency based clock products. In this method, the interfrequency clock biases between the triple-frequency and dual-frequency ionosphere-free carrier-phase measurements are first estimated and then applied to triple-frequency ionosphere-free carrier-phase measurements to obtain stable float ambiguities. After this, the wide-lane L2/L5 and wide-lane L1/L2 integer property of ambiguities are recovered by estimating the satellite fractional cycle biases. A test using a sparse network is conducted to verify the effectiveness of the method. The results show that the ambiguity resolution can be achieved in minutes even tens of seconds and the positioning accuracy is in decimeter level.

Usability of the GPS Precise Point Positioning Technique in Marine Applications

Journal of Navigation ◽

10.1017/s0373463313000210 ◽

2013 ◽

Vol 66 (4) ◽

pp. 579-588 ◽

Cited By ~ 18

Author(s):

R.M. Alkan ◽

T. Öcalan

Keyword(s):

Ease Of Use ◽

Reference Station ◽

Single Frequency ◽

Frequency Data ◽

Dual Frequency ◽

Differential Gps ◽

Golden Horn ◽

Point Positioning ◽

Marine Applications

This study investigates the accuracy of an online Precise Point Positioning (PPP) service operated by the Geodetic Survey Division of Natural Resources Canada (NRCan), Canadian Spatial Reference System (CSRS)-PPP, by using single/dual-frequency Global Positioning System (GPS) data collected by dual-frequency geodetic-grade and Original Equipment Manufacturer (OEM) board type single-frequency GPS receivers. In this work, a kinematic test was carried out in Halic Bay (Golden Horn), Istanbul, Turkey, to assess the performance of the PPP method in a dynamic environment. Based on this study, it can be concluded that the coordinates estimated from the online CSRS-PPP service have a potential of about metre-level accuracy by processing single frequency data collected by an OEM receiver and about a decimetre to a few centimetres level accuracy by processing dual frequency data collected by a geodetic-grade receiver. In general, results show that the PPP technique has become a significant alternative to the conventional relative (differential) positioning techniques (i.e., Differential GPS (DGPS), Real-time Kinematic (RTK)). The technique does not suffer from the drawbacks of the DGPS technique and has potential to provide the same position accuracy without the requirement for a reference station. Consequently, it has been concluded that the PPP technique may be effectively used in marine applications due to its ease of use and provision of high accuracy, as well as being able to offer reduced field operational costs.

Functional model modification of precise point positioning considering the time-varying code biases of a receiver

Satellite Navigation ◽

10.1186/s43020-021-00040-4 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Baocheng Zhang ◽

Chuanbao Zhao ◽

Robert Odolinski ◽

Teng Liu

Keyword(s):

Functional Model ◽

Geodetic Network ◽

Temporal Variations ◽

Gps Data ◽

Electron Content ◽

Time Varying ◽

Dual Frequency ◽

Total Electron ◽

AbstractPrecise Point Positioning (PPP), initially developed for the analysis of the Global Positing System (GPS) data from a large geodetic network, gradually becomes an effective tool for positioning, timing, remote sensing of atmospheric water vapor, and monitoring of Earth’s ionospheric Total Electron Content (TEC). The previous studies implicitly assumed that the receiver code biases stay constant over time in formulating the functional model of PPP. In this contribution, it is shown this assumption is not always valid and can lead to the degradation of PPP performance, especially for Slant TEC (STEC) retrieval and timing. For this reason, the PPP functional model is modified by taking into account the time-varying receiver code biases of the two frequencies. It is different from the Modified Carrier-to-Code Leveling (MCCL) method which can only obtain the variations of Receiver Differential Code Biases (RDCBs), i.e., the difference between the two frequencies’ code biases. In the Modified PPP (MPPP) model, the temporal variations of the receiver code biases become estimable and their adverse impacts on PPP parameters, such as ambiguity parameters, receiver clock offsets, and ionospheric delays, are mitigated. This is confirmed by undertaking numerical tests based on the real dual-frequency GPS data from a set of global continuously operating reference stations. The results imply that the variations of receiver code biases exhibit a correlation with the ambient temperature. With the modified functional model, an improvement by 42% to 96% is achieved in the Differences of STEC (DSTEC) compared to the original PPP model with regard to the reference values of those derived from the Geometry-Free (GF) carrier phase observations. The medium and long term (1 × 104 to 1.5 × 104 s) frequency stability of receiver clocks are also significantly improved.

Positioning Evaluation of Single and Dual-Frequency Low-Cost GNSS Receivers Signals Using PPP and Static Relative Methods in Urban Areas

Applied Sciences ◽

10.3390/app112210642 ◽

2021 ◽

Vol 11 (22) ◽

pp. 10642

Author(s):

Rosendo Romero-Andrade ◽

Manuel E. Trejo-Soto ◽

Alejandro Vega-Ayala ◽

Daniel Hernández-Andrade ◽

Jesús R. Vázquez-Ontiveros ◽

...

Keyword(s):

Urban Areas ◽

Low Cost ◽

Observation Data ◽

Dual Frequency ◽

Positional Accuracy ◽

Gnss Receivers ◽

Point Positioning ◽

Error Circle ◽

Vertical Positioning

A positional accuracy obtained by the Precise Point Positioning and static relative methods was compared and analyzed. Test data was collected using low-cost GNSS receivers of single- and dual-frequency in urban areas. The data was analyzed for quality using the TEQC program to determine the degree of affectation of the signal in the urban area. Low-cost GNSS receivers were found to be sensitive to the multipath effect, which impacts positioning. The horizontal and vertical accuracy was evaluated with respect to Mexican regulations for the GNSS establishment criteria. Probable Error Circle (CEP) and Vertical Positioning Accuracy (EPV) were performed on low cost GNSS receiver observation data. The results show that low-cost dual-frequency GNSS receivers can be used in urban areas. The precision was obtained in the order of 0.013 m in the static relative method. The results obtained are comparable to a geodetic receiver in a geodetic baseline of <20 km. The study does not recommend using single and dual frequencies low cost GNSS receivers based on results obtained by the Precise Point Positioning (PPP) method in urban areas. The inclusion of the GGM10 model reduces the vertical precision obtained by using low cost GNSS receivers in both methods, conforming to the regulations only in the horizontal component.