GPS Multireceiver Direct Position Estimation for Aerial Applications

Modern aviation safety increasingly depends on reliable GPS services, while signal degrading effects such as multipath and masking often occur during critical flight phases, such as takeoff and landing. In this regard, we propose multireceiver direct position estimation (MR-DPE), which operates a network of DPE receivers to enhance GPS accuracy under degraded signal conditions. A DPE receiver directly estimates navigation solutions in the position-velocity-time domain with a maximum-likelihood approach, bypassing the intermediate range measurements. Whereas prior works have shown the enhanced accuracy of DPE with weak signals, MR-DPE provides further improvement by leveraging the information redundancy and the geometric diversity provided by the network of receivers and antennas. We implemented MR-DPE using software-defined radio and tested it with simulated GPS signals to show improved GPS accuracy under degraded environments. We conducted comprehensive, full-scale flight experiments, a first for DPE-related works. A wide range of flight profiles was explored and analyzed, especially those prone to signal multipath and masking, thus validating the claimed benefits of MR-DPE in GPS accuracy.