DGPS High Accuracy Aircraft Velocity Determination Using Doppler Measurements

This paper describes the results of a series of differential GPS tests conducted for the purpose of high accuracy aircraft velocity determination. Velocities were determined through the use of Doppler measurements obtained either through the raw receiver output or the application of carrier phase-derived Doppler measurements. Static and kinematic tests were performed using two sets of GPS receivers, specifically two NovAtel MiLLennium™ dual frequency receivers and two NovAtel single frequency PowerPack OEM2 with special high accuracy velocity software. The first static test was a short baseline test (< 10 m) in a moderate to high multipath environment and served as the best case scenario for velocity determination. The second static test was conducted during an aircraft static initialization with inter-antenna distance of about 1 km. The kinematic test was a flight conducted for the purpose of collecting gravity data. Inter-antenna distances of up to 90 km were obtained. Receiver performance for each test was assessed by differencing epoch-by-epoch between receiver raw Doppler and carrier phase derived velocities.