ABSTRACT
This chapter discusses the velocity errors mainly come from the receiver noise and errors of the carrier-phase-derived Doppler. In the Comprehensive Method for Velocity Estimation (CMVE), the central difference of the carrier phase is used to generate the carrier-phase-derived Doppler, which is fused with the raw Doppler by comparing and selecting. The CMVE can reduce the influence of cycle slips and the receiver clock jumps. There are three methods of GPS velocity estimation: the method using the raw Doppler observations, the method using the time-differenced positions, and the Time-Differenced Carrier-Phase method. The data quality of the raw Doppler observations can be evaluated with the Doppler residual vectors after velocity estimation using the raw Doppler observables. Big cycle slips and the receiver clock jumps will result in peaks in the difference between the Carrier-Phase-Derived Doppler and the raw Doppler, thus their influence can be reduced by the selection of the threshold.
