Journal of Systems Engineering and Electronics ›› 2020, Vol. 31 ›› Issue (3): 612-625.doi: 10.23919/JSEE.2020.000037

• Control Theory and Application • Previous Articles     Next Articles

Fine Doppler shift acquisition algorithm for BeiDou software receiver by a look-up table

Wenqi QIU1,2,3(), Qingxi ZENG1,2,3,*(), Chang GAO3(), Chade LYU3()   

  1. 1 State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun 130012, China
    2 Non-destructive Detection and Monitoring Technology for High-speed Transportation Facilities Key Laboratory of Ministry of Industry and Information Technology, Nanjing 211106, China
    3 College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China
  • Received:2019-08-19 Online:2020-06-30 Published:2020-06-30
  • Contact: Qingxi ZENG E-mail:qwqnrc@nuaa.edu.cn;jslyzqx@nuaa.edu.cn;zmknfqa@163.com;lvchade2008@163.com
  • About author:QIU Wenqi was born in 1993. He received his B.S. degree from Nanjing Institute of Technology, Nanjing, in 2016, and M.S. degree from Nanjing University of Aeronautics and Astronautics, Nanjing, in 2019. He is currently a Ph.D. candidate at Navigation Research Center, College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, China. His research interests include digital signal processing, GNSS software receiver systems, and guidance navigation and control. E-mail: qwqnrc@nuaa.edu.cn|ZENG Qingxi was born in 1980. He received his B.S. degree from Harbin Institute of Technology, Harbin, in 2002 M.S. degree from Northeast Electric Power University, Jilin, in 2006, and Ph.D. degree from Southeast University, Nanjing, in 2009. In 2018, he was a visiting scholar in the Robotics Institute Carnegie Mellon University, USA. He is currently an associate professor with the School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, China. In 2017, he was the leader of two research projects. Both projects were completed. His research interests include positioning and navigation of unmanned ground vehicles, multi-sensor fusion systems, and GNSS software receiver. E-mail: jslyzqx@nuaa.edu.cn|GAO Chang was born in 1996. She received her B.S. degree from Harbin Institute of Technology, Harbin, in 2017. She is currently working toward her M.S. degree at Electronic Technology Center, College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, China. Her research interests include BeiDou software receiver systems, integrated navigation and positioning systems, and visual inertial odometry systems. E-mail: zmknfqa@163.com|LYU Chade was born in 1996. He received his B.S. degree from Nanjing University of Information Science & Technology, Nanjing, in 2018. He is currently working toward his M.S. degree at Electronic Technology Center, College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, China. His research interests include BeiDou software receiver systems, template matching and location technique, and unmanned vehicle indoor and outdoor positioning. E-mail: lvchade2008@163.com
  • Supported by:
    the Open Project of State Key Laboratory of Automotive Simulation and Control, Jilin University(20161108);the National Natural Science Foundation of China(51505221);the Fundamental Research Funds for the Central Universities(NS2019022);This work was supported by the Open Project of State Key Laboratory of Automotive Simulation and Control, Jilin University (20161108), the National Natural Science Foundation of China (51505221), and the Fundamental Research Funds for the Central Universities (NS2019022)

Abstract:

The BeiDou software receiver uses the fast Fourier transform (FFT) to perform the acquisition. The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking loop. Since the frequency step is usually 500 Hz or larger, the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking state. The straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the FFT. However, these solutions intensify the complexity and amount of computation. The contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm, which achieves fine acquisition by a look-up table. After coarse acquisition using the parallel frequency acquisition (PFA) algorithm, the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing load. When the Doppler shift is within the queryable range of the table, the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.

Key words: fine acquisition, fast Fourier transform (FFT), table look-up, parallel frequency acquisition (PFA), BeiDou