PRELIMINARY ANALYSES OF BEIDOU SIGNAL-IN-SPACE ANOMALY SINCE 2013

As BeiDou navigation system has been operational since December 2012. There is an increasing desire to use multiple constellation to improve positioning performance. The signal-in-space (SIS) anomaly caused by the ground control and the space vehicle is one of the major threats to affect the integrity. For a young Global Navigation Satellite System, knowledge about SIS anomalies in history is very important for not only assessing the SIS integrity performance of a constellation but also providing the assumption for ARAIM (Advanced Receiver Autonomous Integrity Monitoring). <br><br> In this paper, the broadcast ephemerides and the precise ones are pre-processed for avoiding the false anomaly identification. The SIS errors over the period of Mar. 2013-Feb. 2016 are computed by comparing the broadcast ephemerides with the precise ones. The time offsets between GPST (GPS time) and BDT (BeiDou time) are estimated and removed by an improved estimation algorithm. SIS worst-UREs are computed and a RMS criteria are investigated to identify the SIS anomalies. The results show that the probability of BeiDou SIS anomalies is in 10-3 level in last three years. Even though BeiDou SIS integrity performance currently cannot match the GPS integrity performances, the result indicates that BeiDou has a tendency to improve its integrity performance.

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PRELIMINARY ANALYSES OF BEIDOU SIGNAL-IN-SPACE ANOMALY SINCE 2013

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b1-517-2016 ◽

2016 ◽

Vol XLI-B1 ◽

pp. 517-523 ◽

Cited By ~ 3

Author(s):

Y. Wu ◽

J. Ren ◽

W. Liu

Keyword(s):

Global Navigation Satellite System ◽

Space Vehicle ◽

Estimation Algorithm ◽

Satellite System ◽

Ground Control ◽

Navigation Satellite ◽

Receiver Autonomous Integrity Monitoring ◽

Global Navigation Satellite ◽

System Knowledge ◽

Advanced Receiver

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A Subset-Reduced Method for FDE ARAIM of Tightly-Coupled GNSS/INS

Sensors ◽

10.3390/s19224847 ◽

2019 ◽

Vol 19 (22) ◽

pp. 4847

Author(s):

Weichuan Pan ◽

Xingqun Zhan ◽

Xin Zhang ◽

Shizhuang Wang

Keyword(s):

Global Navigation Satellite System ◽

Inertial Navigation System ◽

Satellite System ◽

Civil Aviation ◽

Navigation Satellite ◽

Tightly Coupled ◽

Simulation Results ◽

Receiver Autonomous Integrity Monitoring ◽

Global Navigation Satellite ◽

Advanced Receiver

The advanced receiver autonomous integrity monitoring (advanced RAIM, ARAIM) is the next generation of RAIM which is widely used in civil aviation. However, the current ARAIM needs to evaluate hundreds of subsets, which results in huge computational loads. In this paper, a method using the subset excluding entire constellation to evaluate the single satellite fault subsets and the simultaneous multiple satellites fault subsets is presented. The proposed ARAIM algorithm is based on the tight integration of the global navigation satellite system (GNSS) and inertial navigation system (INS). The number of subsets that the proposed GNSS/INS ARAIM needs to consider is about 2% of that of the current ARAIM, which reduces the computational load dramatically. The detailed fault detection (FD) process and fault exclusion (FE) process of the proposed GNSS/INS ARAIM are provided. Meanwhile, the method to obtain the FD-only integrity bound and the after-exclusion integrity bound is also presented in this paper. The simulation results show that the proposed GNSS/INS ARAIM is able to find the failing satellite accurately and its integrity performance is able to meet the integrity requirements of CAT-I precision approach.

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Optimal Fault Detection and Exclusion Applied in GNSS Positioning

Journal of Navigation ◽

10.1017/s0373463313000155 ◽

2013 ◽

Vol 66 (5) ◽

pp. 683-700 ◽

Cited By ~ 9

Author(s):

Ling Yang ◽

Nathan L. Knight ◽

Yong Li ◽

Chris Rizos

Keyword(s):

Fault Detection ◽

Global Navigation Satellite System ◽

Single Point ◽

Satellite System ◽

Navigation Satellite ◽

Gnss Positioning ◽

Practical Strategy ◽

Receiver Autonomous Integrity Monitoring ◽

Global Navigation Satellite ◽

Made In

In Global Navigation Satellite System (GNSS) positioning, it is standard practice to apply the Fault Detection and Exclusion (FDE) procedure iteratively, in order to exclude all faulty measurements and then ensure reliable positioning results. Since it is often only necessary to consider a single fault in a Receiver Autonomous Integrity Monitoring (RAIM) procedure, it would be ideal if a fault could be correctly identified. Thus, fault detection does not need to be applied in an iterative sense. One way of evaluating whether fault detection needs to be reapplied is to determine the probability of a wrong exclusion. To date, however, limited progress has been made in evaluating such probabilities. In this paper the relationships between different parameters are analysed in terms of the probability of correct and incorrect identification. Using this knowledge, a practical strategy for incorporating the probability of a wrong exclusion into the FDE procedure is developed. The theoretical findings are then demonstrated using a GPS single point positioning example.

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Precise Point Positioning Algorithm for Pseudolite Combined with GNSS in a Constrained Observation Environment

Sensors ◽

10.3390/s20041120 ◽

2020 ◽

Vol 20 (4) ◽

pp. 1120 ◽

Cited By ~ 1

Author(s):

Chuanzhen Sheng ◽

Xingli Gan ◽

Baoguo Yu ◽

Jingkui Zhang

Keyword(s):

High Precision ◽

Global Navigation Satellite System ◽

Low Cost ◽

Estimation Algorithm ◽

Satellite System ◽

Navigation Satellite ◽

Global Navigation ◽

Point Positioning ◽

Global Navigation Satellite ◽

Better Than

In urban canyon environments, Global Navigation Satellite System (GNSS) satellites are heavily obstructed with frequent rise and fall and severe multi-path errors induced by signal reflection, making it difficult to acquire precise, continuous, and reliable positioning information. To meet imperative demands for high-precision positioning of public users in complex environments, like urban canyons, and to solve the problems for GNSS/pseudolite positioning under these circumstances, the Global Navigation Satellite System (GNSS) Precision Point Positioning (PPP) algorithm combined with a pseudolite (PLS) was introduced. The former problems with the pseudolite PPP technique with distributed pseudo-satellites, which relies heavily on known points for initiation and prerequisite for previous high-precision time synchronization, were solved by means of a real-time equivalent clock error estimation algorithm, ambiguity fixing, and validation method. Experiments based on a low-cost receiver were performed, and the results show that in a weak obstructed environment with low-density building where the number of GNSS satellites was greater than seven, the accuracy of pseudolite/GNSS PPP with fixed ambiguity was better than 0.15 m; when there were less than four GNSS satellites in severely obstructed circumstances, it was impossible to obtain position by GNSS alone, but with the support of a pseudolite, the accuracy of PPP was able to be better than 0.3 m. Even without GNSS, the accuracy of PPP could be better than 0.5 m with only four pseudolites. The pseudolite/GNSS PPP algorithm presented in this paper can effectively improve availability with less GNSS or even without GNSS in constrained environments, like urban canyons in cities.

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The Effect of Terrain Mask on RAIM Availability

Journal of Navigation ◽

10.1017/s0373463309990294 ◽

2009 ◽

Vol 63 (1) ◽

pp. 105-117 ◽

Cited By ~ 3

Author(s):

Tomislav Radišić ◽

Doris Novak ◽

Tino Bucak

Keyword(s):

Global Navigation Satellite System ◽

Satellite System ◽

Navigation Satellite ◽

Integrity Monitoring ◽

Specific Location ◽

Gps Satellites ◽

Satellite Geometry ◽

Minimum Number ◽

Receiver Autonomous Integrity Monitoring ◽

Global Navigation Satellite

Receiver Autonomous Integrity Monitoring (RAIM) is a method, used by an aircraft's receiver, for detecting and isolating faulty satellites of the Global Navigation Satellite System (GNSS). In order for a receiver to be able to detect and isolate a faulty satellite using a RAIM algorithm, a couple of conditions must be met: a minimum number of satellites, and an adequate satellite geometry. Due to the highly predictable orbits of the GPS satellites, a RAIM availability prediction can be done easily. A number of RAIM methods exist; however, none of them takes into account the precise terrain masking of the satellites for the specific location. They consider a uniform fixed mask angle over the whole horizon. This paper will introduce the variable mask RAIM algorithm in order to show to what extent the terrain can affect the RAIM availability and how much it differs from the conventional algorithms.

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Multi-Layer Defences for Robust GNSS Timing Retrieval

Sensors ◽

10.3390/s21237787 ◽

2021 ◽

Vol 21 (23) ◽

pp. 7787

Author(s):

Ciro Gioia ◽

Daniele Borio

Keyword(s):

Global Navigation Satellite System ◽

Interference Mitigation ◽

Satellite System ◽

Navigation Satellite ◽

Integrity Monitoring ◽

Gnss Receivers ◽

Mitigation Techniques ◽

Receiver Autonomous Integrity Monitoring ◽

Global Navigation Satellite

A multi-layered interference mitigation approach can significantly improve the performance of Global Navigation Satellite System (GNSS) receivers in the presence of jamming. In this work, three levels of defence are considered including: pre-correlation interference mitigation techniques, post-correlation measurement screening and FDE at the Position, Velocity, and Time (PVT) level. The performance and interaction of these receiver defences are analysed with specific focus on Robust Interference Mitigation (RIM), measurement screening through Lock Indicator (LIs) and Receiver Autonomous Integrity Monitoring (RAIM). The case of timing receivers with a known user position and using Galileo signals from different frequencies has been studied with Time-Receiver Autonomous Integrity Monitoring (T-RAIM) based on the Backward-Forward method. From the experimental analysis it emerges that RIM improves the quality of the measurements reducing the number of exclusions performed by T-RAIM. Effective measurements screening is also fundamental to obtain unbiased timing solutions: in this respect T-RAIM can provide the required level of reliability.

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Performance evaluation of multi-GNSSs navigation in super synchronous transfer orbit and geostationary earth orbit

Satellite Navigation ◽

10.1186/s43020-021-00036-0 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Tao Shi ◽

Xuebin Zhuang ◽

Liwei Xie

Keyword(s):

Global Navigation Satellite System ◽

Autonomous Navigation ◽

Satellite System ◽

Earth Orbit ◽

Navigation Satellite ◽

Geostationary Earth Orbit ◽

Beidou Navigation Satellite System ◽

Transfer Orbit ◽

High Orbit ◽

Global Navigation Satellite

AbstractThe autonomous navigation of the spacecrafts in High Elliptic Orbit (HEO), Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO) based on Global Navigation Satellite System (GNSS) are considered feasible in many studies. With the completion of BeiDou Navigation Satellite System with Global Coverage (BDS-3) in 2020, there are at least 130 satellites providing Position, Navigation, and Timing (PNT) services. In this paper, considering the latest CZ-5(Y3) launch scenario of Shijian-20 GEO spacecraft via Super-Synchronous Transfer Orbit (SSTO) in December 2019, the navigation performance based on the latest BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), Galileo Navigation Satellite System (Galileo) and GLObal NAvigation Satellite System (GLONASS) satellites in 2020 is evaluated, including the number of visible satellites, carrier to noise ratio, Doppler, and Position Dilution of Precision (PDOP). The simulation results show that the GEO/Inclined Geo-Synchronous Orbit (IGSO) navigation satellites of BDS-3 can effectively increase the number of visible satellites and improve the PDOP in the whole launch process of a typical GEO spacecraft, including SSTO and GEO, especially for the GEO spacecraft on the opposite side of Asia-Pacific region. The navigation performance of high orbit spacecrafts based on multi-GNSSs can be significantly improved by the employment of BDS-3. This provides a feasible solution for autonomous navigation of various high orbit spacecrafts, such as SSTO, MEO, GEO, and even Lunar Transfer Orbit (LTO) for the lunar exploration mission.

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OutFin, a multi-device and multi-modal dataset for outdoor localization based on the fingerprinting approach

Scientific Data ◽

10.1038/s41597-021-00832-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Fahad Alhomayani ◽

Mohammad H. Mahoor

Keyword(s):

Global Navigation Satellite System ◽

Urban Areas ◽

Satellite System ◽

Reference Points ◽

Navigation Satellite ◽

Data Types ◽

Entry Barrier ◽

Promising Alternative ◽

Global Navigation ◽

Global Navigation Satellite

AbstractIn recent years, fingerprint-based positioning has gained researchers’ attention since it is a promising alternative to the Global Navigation Satellite System and cellular network-based localization in urban areas. Despite this, the lack of publicly available datasets that researchers can use to develop, evaluate, and compare fingerprint-based positioning solutions constitutes a high entry barrier for studies. As an effort to overcome this barrier and foster new research efforts, this paper presents OutFin, a novel dataset of outdoor location fingerprints that were collected using two different smartphones. OutFin is comprised of diverse data types such as WiFi, Bluetooth, and cellular signal strengths, in addition to measurements from various sensors including the magnetometer, accelerometer, gyroscope, barometer, and ambient light sensor. The collection area spanned four dispersed sites with a total of 122 reference points. Each site is different in terms of its visibility to the Global Navigation Satellite System and reference points’ number, arrangement, and spacing. Before OutFin was made available to the public, several experiments were conducted to validate its technical quality.

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