Land mobile satellite channel model for autonomous GPS positioning estimation

TL;DR

This paper evaluates the performance of vector delay-locked tracking loops in GPS receivers over land mobile satellite channels with multipath fading, comparing Kalman filter variants and proposing integrity monitoring techniques.

Contribution

It introduces a combined approach of vector tracking loops with RAIM and FDE algorithms to improve GPS lock stability in multipath land mobile satellite environments.

Findings

UKF outperforms EKF in multipath conditions

RAIM and FDE reduce signal loss incidents

Vector tracking maintains lock during outages

Abstract

The performance of GPS receivers with vector delay-locked tracking loop (VDLL) structure over a land mobile satellite (LMS) channel model for the simulation of multipath fading transmission is investigated. We apply vector delay-locked tracking loop receiver for GPS signal transmitting over LMS multipath fading situations. The adeptness of the vector tracking loop is to incessantly position when satellite GPS signal outage occurred. However, miscarriage tracking in one channel may overspread into the whole system originated the entire loss of locking on all satellites for vector tracking loop algorithm. To moderate this locking-loss situation, the VDLL system is carried with receiver autonomous integrity monitoring (RAIM) and fault detection and exclusion (FDE) algorithm to avoid signal unlocked incidence. The satellite signal to GPS receiver designs with two different Kalman filters (EKF: Extended Kalman Filter and UKF: Unscented Kalman Filter) are established to compare their performance over LMS multipath fading channel model simulations.