Abstract
As a newly developed satellite positioning system, the Chinese Area Positioning System (CAPS) is a typical direct sequence spread spectrum ranging system like GPS. The positioning precision of such navigation signals depends on many factors, including the pseudo-code rate, the signal to noise ratio, the processing methods for tracking loops and so on. This paper describes the CAPS link budget, the solution approach for CAPS positioning, focusing on the autocorrelation function feature of C/A code signals. The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution. Because the conventional Delay Lock Loop (DLL) is vulnerable to the impact of noise, a narrow correlator and multiple correlators as well as the corresponding discrimination methods of phases are proposed, which improves the robustness of DLL and the code-phase resolution of the measurement. The results show that the improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution. Theoretical analysis and experimental results show that a CAPS receiver could reach a 20-m positioning precision by using three satellites with a supported height from an altimeter.
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References
Kaplan E D. Understanding GPS, Principles and Applications. Boston: Artech House, 1996
Bian S F, Li W K. An Introduction to Satellite Navigation System (in Chinese). Beijing: Electronics Industry Publishing House, 2005
Liu J Y. GPS Satellite Navigation and Positioning Theory and Methods (in Chinese). Beijing: Science Press, 2003
Ai G X, Shi H L, Wu H T. Transponder satellite communications navigation and positioning system (in Chinese). PRC Patent, 200410046064, 2004-06-30
Shi H L, Sun X Y. Principle of transponder satellite navigation (in Chinese). Technical Report, National Astronomical Observatories. 2005
Shi H L, Pei J. The solutions of navigation observation equations for CAPS. Sci China Ser G-Phys Mech Astron, 2009, 52(3): 434–444
Psiaki M L. Block acquisition of weak GPS signals in a software receiver. In: Proceedings of ION GNSS-2001, Salt Lake City, 2001. Washington D. C.: Institute of Navigation, 2001. 2838–2850
Tsui J B. Fundamentals of Global Positioning System Receivers: A Software Approach. New York: Wiley, 2000
Van Dierendonck A J, Fenton P, Ford T. Theory and performance of narrow correlator spacing in a GPS receiver. Navigation, 1992, 39(3): 265–283
Cannon M E, Lachapelle G. Performance analysis of a narrow correlator spacing receiver for precise static GPS positioning. In: Proceedings of PLANS94, IEEE, Las Vegas, 1994. Washington D. C.: Institute of Navigation, 1994. 2994–2999
Braasch M S, McGraw G. GNSS multipath mitigation using gated and high resolution correlator concepts. In: Proceedings of the Institute of Navigation National Technical Meeting, San Diego, CA, 1999. Washington D. C.: Institute of Navigation, 1999. 333–342
Garin L, Rousseau J. Enhanced strobe correlator multipath rejection for code and carrier. In: Proceedings of ION GPS-97, 1997. Washington D. C.: Institute of Navigation, 1997. 559–568
Zhao Y, Zhang Q S. Architecture of software GPS receiver and implementation of its acquisition algorithm. J Beijing Univ Aeronaut Astronaut, 2006, 32(1): 53–56
Tang B, Dong X R, Liu S S, et al. Research of software GPS receiver in dynamic environments. J Syst Simul, 2007, 19(8): 1807–1810
Zhang Y, Lin B J, Xv Z H. Study on simulation of signal search and acquisition in software GPS receiver. J Syst Simul, 2006, 18(9): 2646–2649
Jin J K, Wu S L, Li J. Implementation of a new fast PN code-acquisition using radix-2 FFT. Syst Eng Electron, 2005, 27(11): 1957–1970
Li Y H, Kou Y H, Zhang Q S. Study on acquisition algorithm of weak GPS signals. J Telem Tracking Comm, 2005, (7): 61–65
Han Y B, Ma L H, Qiao Q Y, et al. Selection of satellite constellation framework of CAPS. Sci China Ser G-Phys Mech Astron, 2009, 52(3): 458–471
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Supported by the National Key Basic Research and Development Technology Plan (Grant No. 2007CB815500) and the National Natural Science Foundation of China (Grant No. 60802018)
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Ji, Y., Sun, X. Analysis on the positioning precision of CAPS. Sci. China Ser. G-Phys. Mech. Astron. 52, 328–332 (2009). https://doi.org/10.1007/s11433-009-0051-z
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DOI: https://doi.org/10.1007/s11433-009-0051-z