An INS-assisted vector tracking receiver with multipath error estimation for dense urban canyons

Reliable, sustainable, and precise positioning in dense urban canyons is emerging as an important problem for global navigation satellite system-derived (GNSS-derived) applications due to the harsh propagation environments. Challenged by various and troublesome factors, such as weak signal and multipath, the tracking loop of GNSS receiver is heavily overburdened making the measurements deteriorated or even unavailable. But the dynamic short-delay multipath that is frequently encountered in dense urban areas is not well addressed. The existing multipath mitigation technologies are either unable to cope with the short-delay multipath, or computationally expensive with complex structures. To solve this problem, a vector tracking loop aided by inertial navigation system and enhanced by a multipath error estimator is proposed. This slope-based estimator creates nearly no extra structure and computation cost. The vector tracking is naturally bonded with the estimator for their common needs for modeling and estimating the errors contained in measurements. Then, to flexibly apply this estimator and remove the bias, a detection–estimation–mitigation method is provided. Finally, the superiority of the proposed method is proved by theoretical simulation, GNSS simulator-based experiments, and a vehicle experiment in an urban canyon, in which the improvements in measurement, tracking robustness, and positioning precision are verified.