Abstract
In challenging environments such as forests, valleys and higher latitude areas, there are usually fewer than four visible satellites. For cases with only two visible satellites, we propose a dual-satellite alternate switching ranging integrated navigation algorithm based on the broadband low earth orbit (LEO) constellation, which integrates communication and navigation (ICN) technology. It is different from the traditional dual-satellite integrated navigation algorithm: the difference is that it can complete precise real-time navigation and positioning without an altimeter and continuous observation. First, we give the principle of our algorithm. Second, with the help of an unscented Kalman filter (UKF), we give the observation equation and state equation of our algorithm, and establish the mathematical model of multipath/non-line of sight (NLOS) and noise interference. Finally, based on the SpaceX constellation, for various scenarios, we analyze the performance of our algorithm through simulation. The results show that: our algorithm can effectively suppress the divergence of the inertial navigation system (INS), in the face of different multipath/NLOS interference and various noise environments it still keeps good robustness, and also has great advantages in various indicators compared with the traditional dual-satellite positioning algorithms and some existing 3-satellite advanced positioning algorithms. These results show that our algorithm can meet the real-time location service requirements in harsh and challenging environments, and provides a new navigation and positioning method when there are only two visible satellites.
Highlights
With the increasing demand for automatic driving and unmanned control systems, the accuracy of positioning technology must increase in urban, indoor and valley environments
Since broadband low earth orbit (LEO) satellites are communication satellites, their clock bias can be eliminated through a full-duplex (FD) communication system based on integrates communication and navigation (ICN) technology (ICNT) [19]
Due to the multipath effect, NLOS causes pseudorange measurement errors and carrier phase measurement errors, which affect the accuracy of satellite navigation and positioning, according to the reference [32], we model according to the direct signal relative to the multipath signal amplitude (Signal-to-Multipath Ratio, SMR), which is different from the reference [32]
Summary
With the increasing demand for automatic driving and unmanned control systems, the accuracy of positioning technology must increase in urban, indoor and valley environments. In [19], a single-satellite positioning scheme is proposed, based on LEO constellation clock error elimination, and detailed clock error elimination principles and methods is outlined This algorithm has high positioning accuracy and is suitable for navigation and positioning problems in extreme and challenging environments. One solution to the various problems associated with the algorithms described above, is the newly proposed dual-satellite integrated navigation positioning algorithm for broadband LEO constellations, which is low-cost, robust, operates in real-time, and, as an integrated navigation system, has anti-interference abilities It can meet real-time navigation and positioning requirements without the aid of an altimeter, continuous observation, or reliance on GNSS, and it can provide a real-time location service solution in harsh and challenging environments such as lush forests, canyons, and gullies. We provide a discussion, conclusions, and suggestions for future research
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