Precise Velocity Estimation Using a Stand-Alone GPS Receiver

Abstract

ABSTRACT: Stand-alone GPS receiver velocity algorithms and flight test results are presented. A dual-frequency GPS receiver was subjected to aircraft dynamics of up to 1 g (9.8 m/s2), with aircraft bank angles of up to 45 deg. Velocity errors were determined for static and in-flight conditions. In-flight results were evaluated against a postprocessed, differential kinematic GPS solution and by an assessment of the velocity estimation residuals. Differences between the stand-alone velocity solution and the postprocessed differential velocity solution were found to be at the 2–4 mm/s level (1 s̀) for horizontal velocity components and 9.7 mm/s (1 s̀) for vertical velocity. Since these differences include noise contributions from three GPS receivers, stand-alone velocity errors are expected to be smaller than the results reported here. This is also indicated by the stand-alone velocity residual biases, which were found to be on the order of 0.1 mm/s or less, while residual standard deviations ranged from 0.8 to 3.2 mm/s.