Dual frequency long-short baseline ambiguity resolution for GNSS attitude determination

Carrier phase Ambiguity Resolution (AR) is the key to GNSS attitude determination. The baseline length is a readily available and widely used constraint. The traditional long-short baseline AR method resolve the integer ambiguity using the baseline length constraint on condition that the short baseline length is shorter than half of the carrier wavelength. In this contribution, we propose the Dual Frequency Long-Short Baseline (DFLSB) AR method for GNSS attitude determination. The dual frequency integer ambiguity is resolved by combining the restriction of short baseline constraint, Wide Lane (WL) integer ambiguity and the relationship of the dual frequency carrier phase. The main advantage of DFLSB method is increasing the short baseline length limit from 0.0951m to 0.431m compared to the traditional long-short baseline AR method. We analyze the error characteristic on the short baseline length and the dual frequency carrier phase relationship in numerical to find the maximum short baseline length limit of DFLSB method and the maximum tolerance of carrier phase measurement error. Both static open sky and dynamic land vehicle experiments were carried out to demonstrate the proposed algorithm and evaluate its performance. As a comparison, the performance of single epoch C-LAMBDA was recorded. In static open sky environment, the integer ambiguity resolution success rate of both DFLSB and C-LAMBDA method can reach 100% due to the good geometry and data quality. In dynamic urban environment, the integer ambiguity resolution success rate of DFLSB method is about 15% higher than C-LAMBDA at a price of an additional antenna. The mean computational time of DFLSB method is two orders of magnitude lower than that of C-LAMBDA method.