  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.
