Real-Time Estimation and Calibration of GLONASS Inter-Frequency Phase and Code Bias

The frequency division multiple access (FDMA) strategy used in GLONASS causes inter-frequency phase bias (IFPB) and inter-frequency code bias (IFCB) between receivers from different manufacturers. The existence of IFPB and IFCB significantly increases the difficulties of fixing GLONASS ambiguity and limits the accuracy and reliability of GLONASS positioning. Moreover, the initial value of IFPB and IFCB may be unavailable or unreliable with the increasing number of receivers from different manufacturers in recent years. In this study, a real-time and reliable calibration algorithm of IFPB and IFCB based on multi-GNSS assistance is proposed by providing a fixed solution. Real-time IFPB rate and IFCB can be obtained using this algorithm without the initial IFPB and IFCB. The IFPB rate for all GLONASS satellites and IFCB for each GLONASS satellite are estimated due to different characteristics of IFPB and IFCB. IFPB calibration can be divided into constant and real-time IFPB calibrations to meet the different positioning requirements. Results show that constant IFPB rate has only 2 mm difference from the mean value of real-time IFPB rate. The IFPB rate and IFCB estimated by this algorithm have excellent stability, and the change in reference satellite cannot affect the results of IFPB rate and the stability of IFCB. The centimetre-level positioning results can be obtained using two calibration methods, and the positioning results with real-time calibration method are 10%–20% better than those with the constant calibration method. Under satellite-deprived environments, the improvements of multi-GNSS positioning accuracy with constant inter-frequency bias calibration gradually increase as the satellite cut-off elevation angle increases compared with GPS/BDS, which can reach up to 0·9 cm in the vertical direction.

[1]  Lambert Wanninger,et al.  Combined Processing of GPS, GLONASS, and SBAS Code Phase and Carrier Phase Measurements , 2007 .

[2]  Paul Collins,et al.  GLONASS ambiguity resolution of mixed receiver types without external calibration , 2013, GPS Solutions.

[3]  Lambert Wanninger,et al.  GLONASS Inter-frequency Biases and Their Effects on RTK and PPP Carrier-phase Ambiguity Resolution , 2011 .

[4]  Xiangdong An,et al.  A new method for GLONASS inter-frequency bias estimation based on long baselines , 2017, GPS Solutions.

[5]  Jinling Wang,et al.  An approach to GLONASS ambiguity resolution , 2000 .

[6]  M. Pratt,et al.  Single-Epoch Integer Ambiguity Resolution with GPS-GLONASS L1 Data , 1997 .

[7]  Sergey Revnivykh,et al.  GLONASS Status and Modernization , 2011 .

[8]  Yidong Lou,et al.  Impact of GLONASS pseudorange inter-channel biases on satellite clock corrections , 2014, GPS Solutions.

[9]  Nobuaki Kubo,et al.  Evaluation and Calibration of Receiver Inter-channel Biases for RTK-GPS/GLONASS , 2010 .

[10]  Yibin Yao,et al.  GLONASS inter-frequency phase bias rate estimation by single-epoch or Kalman filter algorithm , 2017, GPS Solutions.

[11]  Qingquan Li,et al.  Calibration of GLONASS Inter-Frequency Code Bias for PPP Ambiguity Resolution with Heterogeneous Rover Receivers , 2018, Remote. Sens..

[12]  Lambert Wanninger,et al.  Carrier-phase inter-frequency biases of GLONASS receivers , 2012, Journal of Geodesy.

[13]  Sergey Karutin.  GLONASS Program Update , 2015 .

[14]  Lou Yidong,et al.  GLONASS pseudorange inter-channel biases and their effects on combined GPS/GLONASS precise point positioning , 2013, GPS Solutions.

[15]  Maorong Ge,et al.  Improvements on the particle-filter-based GLONASS phase inter-frequency bias estimation approach , 2018, GPS Solutions.

[16]  Ren Ye,et al.  Calculation and accuracy evaluation of TGD from IFB for BDS , 2015, GPS Solutions.

[17]  C. Rizos,et al.  An enhanced calibration method of GLONASS inter-channel bias for GNSS RTK , 2013, GPS Solutions.

[18]  Jian Wang,et al.  An Approach to Improve the Positioning Performance of GPS/INS/UWB Integrated System with Two-Step Filter , 2017, Remote. Sens..

[19]  Maorong Ge,et al.  Particle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution , 2015, Journal of Geodesy.