Leveraged fault identification method for receiver autonomous integrity monitoring

Receiver autonomous integrity monitoring (RAIM) provides integrity monitoring of global positioning system (GPS) for safety-of-life applications. In the process of RAIM, fault identification (FI) enables navigation to continue in the presence of fault measurement. Affected by satellite geometry, the leverage of each measurement in position solution may differ greatly. However, the conventional RAIM FI methods are generally based on maximum likelihood of ranging error for different measurements, thereby causing a major decrease in the probability of correct identification for the fault measurement with high leverage. In this paper, the impact of leverage on the fault identification is analyzed. The leveraged RAIM fault identification (L-RAIM FI) method is proposed with consideration of the difference in leverage for each satellite in view. Furthermore, the theoretical probability of correct identification is derived to evaluate the performance of L-RAIM FI method. The experiments in various typical scenarios demonstrate the effectiveness of L-RAIM FI method over conventional FI methods in the probability of correct identification for the fault with high leverage.