Ch 16. Vector Processing

Overview:

Vector processing combines the two tasks of waveform parameter estimation and position/velocity/time (PVT) estimation into a single, quasi‐optimal algorithm. Unlike conventional scalar tracking loops where each satellite signal is treated as an independent entity, vector processing tracks all the available signals in unison. This is accomplished by directly controlling the local oscillators based on the receiver’s PVT state vector. Vector processing is a paradigm of receiver operation based largely upon the Kalman filter.

Vector tracking has many advantages over scalar tracking. The most commonly cited advantage is increased immunity to interference and jamming. The minimum carrier‐to‐noise power density ratio (C/N0) at which the receiver can operate is lowered by processing the signals in aggregate instead of processing them separately. Vector tracking algorithms also have the ability to bridge signal outages and immediately reacquire blocked signals. Moreover, vector tracking loops have a greater immunity to receiver dynamics than scalar tracking loops. A final advantage: The vector tracking architecture allows the receiver’s motion to be constrained in different dimensions, which can be exploited by the receiver whose motion occurs primarily in one or two directions, such as ships or automobiles.