An Optimization Method of Ambiguity Function Based on Multi-Antenna Constrained and Application in Vehicle Attitude Determination

Abstract

The global navigation satellite system (GNSS)-based multi-antenna attitude determination method has the advantages of a simple algorithm and no error accumulation with time in long endurance operation. However, it is sometimes difficult to simultaneous obtain the fixed solutions of all antennas in vehicle attitude determination. If float or incorrect fixed solutions are used, precision and reliability of attitude cannot be guaranteed. Given this fact, a baseline-constrained ambiguity function method (BCAFM) based on a self-built four GNSS antennas hardware platform is proposed. The coordinates obtained by BCAFM can replace the unreliable real-time kinematic (RTK) float or incorrect fixed solutions, so as to assist the direct method for attitude determination. In the proposed BCAFM, the baseline constraint is applied to improve search efficiency (searching time), and the ambiguity function value (AFV) formula is optimized to enhance the discrimination of true peak. The correctness of the proposed method is verified by vehicle attitude determination results and baseline length difference. Experimental results demonstrate that the function values of error peaks are reduced, and the only true peak can be identified accurately. The valid epoch proportion increases by 14.95% after true peak coordinates are used to replace the GNSS-RTK float or incorrect fixed solutions. The precision of the three attitude angles is 0.54°, 1.46°, and 1.15°, respectively. Meanwhile, the RMS of baseline length difference is 3.8mm.

LSOS: An FG Position Method Based on Group Phase Ranging Ambiguity Estimation of BeiDou Pseudolite

“…Using the existing four GNSS antenna platforms, Dr. Zhao proposed a baseline-constrained ambiguity function method. This method can effectively improve the unreliable or inaccurate estimation solution of RTK localization, and further directly assist the estimation of altitude direction [12][13][14][15]. Professor Takuji Ebinuma of the Japanese Waseda University has been working on indoor pseudolite for many years and has extensive experience in rapid RTK positioning.…”

A simple method of searching for a fixed solution in a coordinate domain

“…A description of the MAFA method can be found in, for example, (Cellmer 2012(Cellmer 2013(Cellmer 2015Cellmer et al 2010Cellmer et al 2017Cellmer et al 2018Cellmer et al 2021Kwasniak et al 2016Kwasniak et al 2017Baselga 2010;Nowel et al 2018). Some researchers use the MAFA method foundations in recent research in airplane attitude determination (Wang et al 2007;Wang et al 2019;Wu et al 2019, Zhao et al, 2022. Nevertheless, we do not use the functional model of the MAFA method in the present contribution.…”