scholarly journals Sensitivity of the Gravity Model and Orbital Frame for On-board Real-Time Orbit Determination: Operational Results of GPS-12 GPS Receiver

2019 ◽  
Vol 11 (13) ◽  
pp. 1542
Author(s):  
Eunhyouek Kim ◽  
Seungyeop Han ◽  
Amer Mohammad Al Sayegh
Keyword(s):  
Real Time ◽  
Gravity Model ◽  
Orbit Determination ◽  
Low Earth Orbit ◽  
Observation Data ◽  
Gps Receiver ◽  
Champ Satellite ◽  
Earth Gravity ◽  
Earth Gravity Model ◽  
Gravity Recovery

This paper describes the sensitivity of both the orbital frame domain selection and the gravity model on the performance of on-board real-time orbit determination. Practical error sources, which affect the navigation solution of spaceborne global positioning system (GPS) receivers, are analyzed first. Then, a reasonable orbital frame (radial, in-track, cross-track (RIC)) is proposed to clearly represent the characteristics of the error in order to improve the performance of the orbit determination (OD) logic. In addition, the sensitivity of the gravity model affecting the orbit determination logic is analyzed by comparison with the precise orbit ephemeris (POE) of the Challenging Minisatellite Payload (CHAMP) satellite, and it is confirmed that the Gravity Recovery And Climate Experiment (GRACE) Gravity Model 03 (GGM03) outperforms the Earth Gravity Model 1996 (EGM96). The effects of both proposed orbit frames and the gravity model on the orbit determination logic are verified using a GPS simulator and observation data from the CHAMP satellite. Moreover, the practical performance of on-board real-time orbit determination logic is verified by updating the software of the spaceborne GPS receiver, GPS-12, on DubaiSat-2 operating at low Earth orbit (LEO). The results show that the position accuracy of on-board real-time orbit determination logic in GPS-12 is improved by 59%, from 12.6 m (1 σ) to 5.1 m (1 σ), after applying the proposed methods. The velocity accuracy is also improved by 57%, from 13.7 mm/s (1 σ) to 5.9 mm/s (1 σ).

Real-time orbit determination of Low Earth orbit satellite based on RINEX/DORIS 3.0 phase data and spaceborne GPS data

2020 ◽  
Vol 66 (7) ◽  
pp. 1700-1712
Author(s):  
Chongchong Zhou ◽  
Shiming Zhong ◽  
Bibo Peng ◽  
Jikun Ou ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Orbit Determination ◽  
Low Earth Orbit ◽  
Gps Data ◽  
Earth Orbit ◽  
Orbit Satellite ◽  
Low Earth Orbit Satellite ◽  
Phase Data

scholarly journals GPS based onboard orbit determination system providing fault management features for a LEO satellite

2013 ◽  
Vol 66 (4) ◽  
pp. 539-559 ◽  
Author(s):  
H. Bolandi ◽  
M. H. Ashtari Larki ◽  
M. Abedi ◽  
M. Esmailzade
Keyword(s):  
Orbit Determination ◽  
Equations Of Motion ◽  
Fault Management ◽  
Time Intervals ◽  
Earth Gravity ◽  
Earth Gravity Model ◽  
Determination Process ◽  
Position Data ◽  
Determination System ◽  
Leo Satellite

This paper presents accurate orbit determination (OD) of the Iran University of Science and Technology Satellite (IUSTSAT) from Global Positioning System (GPS) data. The GPS position data are treated as pseudo-measurements within an onboard orbit determination process that is based on the numerical integration of the equations of motion using an earth gravity model and applying an Extended Kalman Filter for the data processing. In this paper, through accurate tuning of GPS duty cycle and on/off time intervals, a solution is suggested to achieve the desired OD accuracy despite power constraints. Moreover, a new scheme for automatic fault management in the orbit determination system is derived that provides fault detection and accommodation features.

scholarly journals Real Time On-board Orbit Determination Performance Analysis of Low Earth Orbit Satellites

2015 ◽  
Vol 43 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Eun-Hyouek Kim ◽  
Dong-Wook Koh ◽  
Young-Suk Chung ◽  
Sung-Baek Park ◽  
Hyeun-Pil Jin ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Real Time ◽  
Orbit Determination ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Low Earth Orbit Satellites

scholarly journals Random Optimization Algorithm on GNSS Monitoring Stations Selection for Ultra-Rapid Orbit Determination and Real-Time Satellite Clock Offset Estimation

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xu Yang ◽  
Qianxin Wang ◽  
Shuqiang Xue
Keyword(s):  
Real Time ◽  
Optimization Algorithm ◽  
Orbit Determination ◽  
Observation Data ◽  
Satellite Clock ◽  
Real Time Clock ◽  
Random Optimization ◽  
Earth Rotation Parameters ◽  
Clock Offset ◽  
Monitoring Stations

Geographical distribution of global navigation satellite system (GNSS) ground monitoring stations affects the accuracy of satellite orbit, earth rotation parameters (ERP), and real-time satellite clock offset determination. The geometric dilution of precision (GDOP) is an important metric used to measure the uniformity of the stations distribution. However, it is difficult to find the optimal configuration with the lowest GDOP when taking the 71% ocean limitation into account, because the ground stations are hardly uniformly distributed on the whole of the Earth surface. The station distribution geometry needs to be optimized and besides the stability and observational quality of the stations should also be taken into account. Based on these considerations, a method of configuring global station tracking networks based on grid control probabilities is proposed to generate optimal configurations that approximately have the minimum GDOP. A random optimization algorithm method is proposed to perform the station selection. It is shown that an optimal subset of the total stations can be obtained in limited iterations by assigning selecting probabilities for the global stations and performing a Monte Carlo sampling. By applying the proposed algorithm for observation data of 201 International GNSS Service (IGS) stations for 3 consecutive days, an experiment of ultra-rapid orbit determination and real-time clock offset estimation is conducted. The distribution effects of stations on the products accuracy are analyzed. It shows that (1) the accuracies of GNSS ultra-rapid observed and predicted orbits and real-time clock offset achieved using the proposed algorithm are higher than those achieved with the traditional method having the drawbacks of lacking evaluation indicators and being time-consuming, corresponding to the improvements 17.15%, 19.30%, and 31.55%, respectively. Only using 30 stations selected by the proposed method, the accuracies achieved reach 2.01 cm (RMS), 4.93 cm (RMS), and 0.20 ns (STD), respectively. Using 60 stations, the accuracies are 1.47 cm, 3.50 cm, and 0.17 ns, respectively. (2) With the increasing number of stations, the accuracies of the Global Positioning System (GPS) orbit and clock offset improve continuously, but more than 60 stations, the improvement on the orbit determination becomes more gradual, while for more than 30 stations, there is no appreciable increase in the accuracy of the real-time clock offset.

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