导航

ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2014, Vol. 35 ›› Issue (9): 2559-2567.doi: 10.7527/S1000-6893.2014.0027

• Electronics and Control • Previous Articles     Next Articles

GNSS Vector Tracking Algorithm Based on Maximum Likelihood Estimator

CHENG Junren, LIU Guangbin, ZHANG Qian, FAN Zhiliang   

  1. Department of Control Engineering, The Second Artillery Engineering University, Xi'an 710025, China
  • Received:2013-11-11 Revised:2014-03-21 Online:2014-09-25 Published:2014-03-28
  • Supported by:

    National Natural Science Foundation of China (61201120); National High-tech Research and Development Program of China (2010AA7010213)

Abstract:

Vector tracking is an advanced algorithm combining the signal tracking with the navigation of global navigation satellite system (GNSS) receivers. Traditional vector delay/frequency lock loop (VDFLL) generally loses of lock under high dynamic conditions because the pseudo-range and range-rate are always calculated by the delay lock loop (DLL) and frequency lock loop (FLL) discriminators, which may cause an approximation error and a one-step delay effort. Therefore, from the point of view of estimating the signal parameters directly, this paper proposes a vector tracking algorithm based on maximum likelihood estimator (MLE). This algorithm constructs the cost function of code delay and Doppler shift based on incoming signals firstly, and then calculates and converts the estimation errors to measurements by the noniterative filter method. Finally, all the measurements are input to a Kalman filter to complete the vector tracking. Theoretical analysis and simulation results show that compared to the traditional VDFLL, the new algorithm takes both advantages of the MLE and vector tracking, overcomes the delay efforts of FLL and performs a more robust tracking during the periods of signal blockage under high dynamic conditions.

Key words: GNSS receiver, signal tracking, delay lock loop, frequency lock loop, vector tracking, maximum likelihood estimator

CLC Number: