DGPS Kinematic Carrier Phase Signal Simulation Analysis for Precise Velocity and Position Determination

ABSTRACT This paper describes the differential GPS and signal simulator equipment, procedures, and simulated aircraft trajectories used to analyze carrier phase measurements in estimating velocities and 3D positions. A differential GPS simulator system was used to generate C/A‐code, P‐code, and carrier phase signals from segments of the actual GPS constellation. Two pairs of dual‐frequency receivers from different manufacturers were tested. These units have the capability of tracking the P‐code (L1/L2 for one of the receivers and L2 for the other). An aircraft trajectory with accelerations up to 5 g was simulated, and analysis is performed in terms of the resulting velocity errors and dynamics. Two methods for estimating the 3D velocities were tested, namely carrier phase with fixed‐integer and real‐number (float) ambiguities. Both raw Doppler measurements and a number of carrier‐phase‐derived Doppler measurements were tested. As a by‐product, the 3D positions could also be determined using various carrier phase approaches. The estimated quantities were compared with the reference quantities known a priori to determine the performance of the receivers under the various conditions simulated.