scholarly journals A Smart Realtime Service to Broadcast the Precise Orbits of GPS Satellite and Its Performance on Precise Point Positioning

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3276
Author(s):  
Dehai Li ◽  
Wei Yan ◽  
Jinzhong Mi ◽  
Yamin Dang ◽  
Yunbin Yuan ◽  
...  
Keyword(s):  
Real Time ◽  
Data Stream ◽  
Precise Point Positioning ◽  
Rapid Development ◽  
Relative Distance ◽  
Satellite Orbits ◽  
Gps Navigation ◽  
Point Positioning ◽  
The Difference ◽  
First Time

At present, Global Position System (GPS) navigation ephemeris mainly broadcasts satellite orbits with meter-level precision for standard point positioning and precise relative positioning. With the rapid development of real-time precise point positioning (PPP), the receiver or smartphone has begun to demand more and more convenient, continuous, and reliable access to real-time services of precise orbits. Therefore, this study proposes a solution of utilizing the 18-parameter ephemeris to directly broadcast ultra-rapid precise predicted orbits with centimeter-level precision for real-time PPP. For the first time in GPS, the difference in the PPP results between the precise orbits and the calculated orbits broadcasted from the generated ephemeris parameters is supplied as follows: (1) During the validity period of 2 h, root mean square (RMS) of the relative distance offsets between the results of PPP with the precise orbits and the results of PPP the 18-parameter ephemeris is only 0.0098 m. (2) Within 15 min after the validity period of 2 h, RMS of the relative distance offsets between the results of PPP with the precise orbits and the results of PPP with the predicted orbits by 18-parameter ephemeris is only 0.0057 m. Consequently, the 18-parameter ephemeris is feasible and advisable to broadcast precise predicted orbits for real-time PPP applications. Compared with the classic precise orbits broadcast mode with the orbit corrections defined by the radio technical commission for maritime services standards 10403.2 (RTCM), the mode of broadcasting the precise orbits with the 18-parameter ephemeris achieved the following improvements in convenience, continuity, and reliability: (1) The calculation of satellite position is the same as that of the navigation ephemeris excluding the additional correction operations required to the RTCM; (2) the amount of broadcast parameters was reduced by 20 times; (3) the length of the validity period was expanded 120 times, where the longer valid period helped to overcome the orbit corrections loss caused by RTCM stream failures; and (4) within 15 min after the validity period, the predicted orbits with an accuracy of 2 cm could still be provided by the 18-parameter ephemeris, which can ensure the real-time services of precise orbits in the case of a 15 min communication interruption of the RTCM orbit correction data stream.

scholarly journals Precise Point Positioning Using the Regional BeiDou Navigation Satellite Constellation

2014 ◽  
Vol 67 (3) ◽  
pp. 523-537 ◽  
Author(s):  
Aigong Xu ◽  
Zongqiu Xu ◽  
Xinchao Xu ◽  
Huizhong Zhu ◽  
Xin Sui ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Asia Pacific ◽  
Satellite Orbits ◽  
Navigation Satellite ◽  
Asia Pacific Region ◽  
Point Positioning

On 27 December 2012 it was announced officially that the Chinese Navigation Satellite System BeiDou (BDS) was able to provide operational services over the Asia-Pacific region. The quality of BDS observations was confirmed as comparable with those of GPS, and relative positioning in static and kinematic modes were also demonstrated to be very promising. As Precise Point Positioning (PPP) technology is widely recognized as a method of precise positioning service, especially in real-time, in this contribution we concentrate on the PPP performance using BDS data only. BDS PPP in static, kinematic and simulated real-time kinematic mode is carried out for a regional network with six stations equipped with GPS- and BDS-capable receivers, using precise satellite orbits and clocks estimated from a global BDS tracking network. To validate the derived positions and trajectories, they are compared to the daily PPP solution using GPS data. The assessment confirms that the performance of BDS PPP is very comparable with GPS in terms of both convergence time and accuracy.

scholarly journals Performance of Absolute Real-Time Multi-GNSS Kinematic Positioning

2018 ◽  
Vol 53 (2) ◽  
pp. 75-88 ◽  
Author(s):  
Kamil Kazmierski
Keyword(s):  
Real Time ◽  
Rapid Development ◽  
Vertical Component ◽  
Solution Quality ◽  
Vertical Coordinate ◽  
Satellite Systems ◽  
High Tension ◽  
Point Positioning ◽  
Time Standard ◽  
First Time

Abstract Recently, we observe the rapid development of the Global Navigational Satellite Systems (GNSS), including autonomous positioning techniques, such as Precise Point Positioning (PPP). The GNSS have different conceptions, different spacecraft and use different types of orbits which is why the quality of real-time orbit and clock products is inconsistent, thus, the appropriate approach of the multi-GNSS observation processing is needed to optimize the solution quality. In this paper, the kinematic field experiment is conducted in order to examine multi-GNSS real-time Standard Point Positioning (SPP) and PPP performance. The test was performed on the 26 km-long car route through villages, forests, the city of Wrocław, crossing under viaducts and a high tension line. For the first time, the solution is based on GPS + GLONASS + Galileo + BeiDou observations using streamed corrections for orbits and clocks with two different weighting scenarios. Thanks to the usage of the multi-GNSS constellation the number of positioning epochs possible to determine increases by 10%. The results show also that the appropriate weighting approach can improve the root mean square error in the SPP solution by about 13% and 42% for the horizontal and vertical coordinate components, respectively. In the case of PPP, the maximum quality improvement equals 70% for the horizontal component and the results for the vertical component are comparable with those obtained for the GPS-only solution.

scholarly journals Performance Evaluation of Real-Time Precise Point Positioning with Both BDS-3 and BDS-2 Observations

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6027
Author(s):  
Lin Pan ◽  
Xuanping Li ◽  
Wenkun Yu ◽  
Wujiao Dai ◽  
Cuilin Kuang ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Rapid Development ◽  
Satellite System ◽  
Convergence Time ◽  
Static Mode ◽  
The Real ◽  
Point Positioning ◽  
Time Critical

For time-critical precise applications, one popular technology is the real-time precise point positioning (PPP). In recent years, there has been a rapid development in the BeiDou Navigation Satellite System (BDS), and the constellation of global BDS (BDS-3) has been fully deployed. In addition to the regional BDS (BDS-2) constellation, the real-time stream CLK93 has started to support the BDS-3 constellation, indicating that the real-time PPP processing involving BDS-3 observations is feasible. In this study, the global positioning performance of real-time PPP with BDS-3/BDS-2 observations is initially evaluated using the datasets from 147 stations. In the east, north and upward directions, positioning accuracy of 1.8, 1.2 and 2.5 cm in the static mode, and of 6.7, 5.1 and 10.4 cm in the kinematic mode can be achieved for the BDS-3/BDS-2 real-time PPP, respectively, while the corresponding convergence time with a threshold of 10 cm is 32.9, 23.7 and 32.8 min, and 66.9, 42.9 and 69.1 min in the two modes in the three directions, respectively. To complete this, the availability of BDS-3/BDS-2 constellations, the quality of BDS-3/BDS-2 real-time precise satellite products, and the BDS-3/BDS-2 post-processed PPP solutions are also analyzed. For comparison, the results for the GPS are also presented.

scholarly journals An Investigation of Precise Orbit and Clock Products for BDS-3 from Different Analysis Centers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1596
Author(s):  
Pengli Shen ◽  
Fang Cheng ◽  
Xiaochun Lu ◽  
Xia Xiao ◽  
Yulong Ge
Keyword(s):  
Standard Deviation ◽  
Real Time ◽  
Quality Evaluation ◽  
Precise Point Positioning ◽  
Tropospheric Delay ◽  
Precise Orbit ◽  
Point Positioning ◽  
Kinematic Ppp ◽  
First Time

A quality evaluation of precise products for BDS-3 constellations is presented for the first time in this contribution. Then, the tropospheric delay retrieval and positioning performance of BDS-3 precise point positioning (PPP) solutions using the precise products (gbm, wum, iac, sha, cnt) with observations from 24 stations from DOY 280 to 317 in 2020 was comprehensively investigated. The orbit comparisons present consistencies of 0.09–0.22 m for the C19–C37 satellites and of 0.5–1.2 m for the C38–C46 satellites among the final products. The standard deviation (STD) values of the clock differences of iac showed the best agreement with those of gbm, followed by wum, sha. The clock differences performance of cnt was the worst. For BDS-3 PPP solutions with five Analysis centers (ACs) products, the median convergence times of static PPP mode incorporating the gbm, wum, iac, sha, and cnt products were 31.0, 33.5, 34.5, 37.8, and 72.0 min, respectively; the median convergence times of kinematic PPP model incorporating the same products were 40.5, 41.0, 50.5, 55.0, and 94.0 min, respectively. The positioning accuracies in the static and kinematic modes were approximately 1–4 cm, 2–6 cm in the horizontal and vertical components, respectively. With the final products in kinematic mode, the performance of PPP with real-time products (cnt) is poorer than all PPP with final products. The median of ZTD accuracies of the five products gbm, wum, iac, sha, and cnt were 7.84, 7.58, 7.04, 7.19, and 10.1 mm, respectively, and the accuracy differences were very small among five AC products (gbm, wum, iac, sha).

scholarly journals Exploring Signals on L5/E5a/B2a for Dual-Frequency GNSS Precise Point Positioning

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2046
Author(s):  
Nacer Naciri ◽  
André Hauschild ◽  
Sunil Bisnath
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Positive Impact ◽  
Rapid Evolution ◽  
Global Navigation Satellite Systems ◽  
Satellite Orbits ◽  
Dual Frequency ◽  
Point Positioning ◽  
Block Iif ◽  
Gps Block Iif

Due to its nature, Precise Point Positioning (PPP) depends on the GNSS measurements and quality of satellite correction products used to relatively quickly provide precise and accurate positions. With the rapid evolution of Global Navigation Satellite Systems (GNSSs), new frequencies and signals are being broadcast, which have a positive impact on PPP performance. This paper presents, for the first time, a comprehensive analysis of PPP performance from these new GPS, Galileo and BeiDou-2/3 signals, which are not yet commonly used for PPP, with correct mitigation of errors such as the estimation of GPS Block-IIF L5 variations. Satellite orbits and clocks, as well as GPS Block-IIF L5 corrections, are estimated in real-time using DLR’s RETICLE engine, while the user processing is performed with York University’s PPP engine. First, as a reference, PPP performance is assessed on widely used signals: GPS L1/L2, Galileo E1/E5a, and BeiDou-2/3 B1-2/B3. Horizontal and vertical rms of 2.3 and 2.6 cm, respectively, are achieved in static processing and 5.4 and 7.5 cm in kinematic processing after 1 h of processing using real-time satellite correction products. The compatibility of BeiDou-2 and BeiDou-3 on the shared B1-2/B3 frequencies is analyzed and discrepancies in the receiver clock are found. Next, since all three constellations share two common frequencies, the paper focuses on analyzing PPP performance of GPS, Galileo and BeiDou-3 on [L1, E1, B1] at 1575.42 MHz and [L5, E5a, B2a] at 1176.45 MHz. Horizontal and vertical rms of 6.9 and 7.1 cm are achieved in kinematic processing. The effect of the known GPS Block-IIF L5 biases is studied as well, as it is shown to affect the receiver position and clock, as well as the ionospheric estimates and ambiguities. Average improvements of 15% and 20% in the horizontal and vertical rms, respectively, are observed when these biases are mitigated.

scholarly journals Simulation case study of deformations and landslides using real-time GNSS precise point positioning technique

2016 ◽  
Vol 7 (6) ◽  
pp. 1856-1873 ◽  
Author(s):  
Raquel M. Capilla ◽  
José Luis Berné ◽  
Angel Martín ◽  
Raul Rodrigo
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Positioning Technique ◽  
Point Positioning

scholarly journals Examining the Accuracy of Network RTK and Long Base RTK Methods with Repetitive Measurements

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tamer Baybura ◽  
İbrahim Tiryakioğlu ◽  
Mehmet Ali Uğur ◽  
Halil İbrahim Solak ◽  
Şeyma Şafak
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
High Accuracy ◽  
Base Station ◽  
Network Rtk ◽  
Real Time Kinematic ◽  
Study Results ◽  
Point Positioning

Real-time kinematic (RTK) technique is important for mapping applications requiring short measure time, the distance between rover and base station, and high accuracy. There are several RTK methods used today such as the traditional RTK, long base RTK (LBRTK), network RTK (NRTK), and precise point positioning RTK (PPP-RTK). NRTK and LBRTK are popular with the advantage of the distance, the time, and accuracy. In the present study, the NRTK and LBRTK measurements were compared in terms of accuracy and distance in a test network with 6 sites that was established between 5 and 60 km. Repetitive NRTK and LBRTK measurements were performed on 6 different days in 2015-2017-2018 and additionally 4 campaigns of repetitive static measurements were carried out in this test network. The results of NRTK and LBRTK methods were examined and compared with all relevant aspects by considering the results of the static measurements as real coordinates. The study results showed that the LBRTK and NRTK methods yielded similar results at base lengths up to 40 km with the differences less than 3 cm horizontally and 4 cm vertically.

Enhancing real-time precise point positioning time and frequency transfer with receiver clock modeling

GPS Solutions ◽  
2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Yulong Ge ◽  
Feng Zhou ◽  
Tianjun Liu ◽  
WeiJin Qin ◽  
Shengli Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Receiver Clock ◽  
Frequency Transfer ◽  
Point Positioning ◽  
Positioning Time

scholarly journals GPS AND GLONASS COMBINED STATIC PRECISE POINT POSITIONING (PPP)

2016 ◽  
Vol XLI-B1 ◽  
pp. 483-488 ◽  
Author(s):  
D. Pandey ◽  
R. Dwivedi ◽  
O. Dikshit ◽  
A. K. Singh
Keyword(s):  
Precise Point Positioning ◽  
Rapid Development ◽  
Three Dimensional ◽  
Global Navigation Satellite Systems ◽  
Open Pit ◽  
Positioning Accuracy ◽  
Dilution Of Precision ◽  
Satellite Visibility ◽  
Point Positioning ◽  
Gps Observations

With the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs), satellite navigation is undergoing drastic changes. Presently, more than 70 satellites are already available and nearly 120 more satellites will be available in the coming years after the achievement of complete constellation for all four systems- GPS, GLONASS, Galileo and BeiDou. The significant improvement in terms of satellite visibility, spatial geometry, dilution of precision and accuracy demands the utilization of combining multi-GNSS for Precise Point Positioning (PPP), especially in constrained environments. Currently, PPP is performed based on the processing of only GPS observations. Static and kinematic PPP solutions based on the processing of only GPS observations is limited by the satellite visibility, which is often insufficient for the mountainous and open pit mines areas. One of the easiest options available to enhance the positioning reliability is to integrate GPS and GLONASS observations. This research investigates the efficacy of combining GPS and GLONASS observations for achieving static PPP solution and its sensitivity to different processing methodology. Two static PPP solutions, namely standalone GPS and combined GPS-GLONASS solutions are compared. The datasets are processed using the open source GNSS processing environment <i>gLAB</i> 2.2.7 as well as <i>magicGNSS</i> software package. The results reveal that the addition of GLONASS observations improves the static positioning accuracy in comparison with the standalone GPS point positioning. Further, results show that there is an improvement in the three dimensional positioning accuracy. It is also shown that the addition of GLONASS constellation improves the total number of visible satellites by more than 60% which leads to the improvement of satellite geometry represented by Position Dilution of Precision (PDOP) by more than 30%.

Performance of Real-Time Precise Point Positioning

2013 ◽  
Vol 36 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Junping Chen ◽  
Haojun Li ◽  
Bin Wu ◽  
Yize Zhang ◽  
Jiexian Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Point Positioning
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