Vector tracking loop design for degraded signal environment

Abstract

This paper presents vector tracking algorithm for tracking the pseudorandom code of satellite navigation signals, which is suitable for degraded signal environment. The benefits of the vector tracking in comparison of scalar tracking are also explained. This vector tracking algorithm is based on the discriminator function. Conventional GPS receivers use scalar tracking methods and signals from each channel are processed independently. On the contrary, vector tracking loops process the signals in aggregate and can provide better tracking in degraded signal environment, since the channels are closely correlated in vector mode. In vector tracking approach the tracking control input is generated by the navigation filter. The vector tracking loops can operate in weak signal conditions and can rapidly reacquire the weak or attenuated signals. In this paper the ability of vector tracking loop to reacquire the signals is explored and is compared with conventional scalar tracking method.