Direct Determination, of Vehicle Acceleration Using GPS Phase Observables

Christopher Jekeli and Ramon Garcia

Abstract:	For airborne gravimetry using INS and GPS, the accelerations from both systems are differenced to yield the gravity acceleration. Usually, the GPS acceleration is determined by first solving for the position of the vehicle relative to a base station and subsequently taking two time derivatives of the vertical component. An alternative method is to time-differentiate the observed phases directly thus avoiding the cycle ambiguity problem that must be solved for positioning and that is fraught with (certainly not insurmountable) difficulties in the event of a cycle slip. With quadratically varying satellite and receiver clock errors (bias, drift, drift rate) this method would also eliminate the spatial differencing of signals that is done when determining accurate positions. However, tests show that the receiver clock in some geodetic receivers behaves considerably unlike this ideal model. This fact together with the imposition of the Selective Availability degradation obliges us to doubly difference (in space) the phase accelerations to obtain the relative vehicle accelerations. Test results for stationary and aribome receivers and double difference model development for direct (relative) vector acceleration determination are given in this paper.
Published in:	Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996) June 19 - 21, 1996 Royal Sonesta Hotel Cambridge, MA
Pages:	647 - 655
Cite this article:	Jekeli, Christopher, Garcia, Ramon, "Direct Determination, of Vehicle Acceleration Using GPS Phase Observables," Proceedings of the 52nd Annual Meeting of The Institute of Navigation (1996), Cambridge, MA, June 1996, pp. 647-655.
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