Joint Navigation and Synchronization Using SOOP in GPS-Denied Environments: Algorithm and Empirical Study

We consider the problem of tracking a receiver using signals of opportunity (SOOP) from beacons and a reference anchor with known positions and velocities, and where all devices have asynchronous local clocks or oscillators. Based on an extended Kalman filter, we propose a sequential estimator to jointly track the receiver location, velocity, and its clock parameters using time- difference-of-arrival and frequency-difference-of-arrival measurements obtained from the SOOP samples collected by the receiver and reference anchor. Field experiments are carried out using a software defined radio testbed, and Iridium satellites as the SOOP beacons. Experiment demonstrate that our measurement model has a good fit, and our proposed estimator can successfully track both the receiver location, velocity, and the relative clock offset and skew with respect to the reference anchor with good accuracy.