A Doppler Based Navigation Algorithm

This algorithm uses the GPS satellite system for navigation. It is an innovative algorithm, because it employs only the Doppler measurements and starts with a known initial location of the receiver. Initially, this algorithm was developed for fixed point GPS transmitters. In the paper we have successfully attempted to adapt this algorithm for moving satellites. This algorithm appears to perform far better than the pseudorange conventional least square algorithm (LSA), due to the small standard deviation of the Doppler measurement noise. While we have already developed and tested this algorithm with simulated data, we will attempt to provide test results with live satellites. Introduction The Doppler based navigation idea is not new. In the late 50s Guier and Weiffenbach proposed a Doppler Satellite Navigation system, which could provide navigation accuracy of about one-half mile provided that proper use of the full Doppler measurement is made [1]. At that time both the navigation scientists and engineers were faced with challenge of designing an end-to-end system, which as we know is one of the predecessors of the GPS system. About the same time Guier and Weiffenbach proposed a techinique for measuring the Doppler shift of radio transmissions from satellites, thus enabling navigation based on their algorithm [1-2]. Applications of Doppler measurements were also found in relativity, space probe tracking, and geodesy [3]. In the late 1960s, R. R. Newton, trying to persuade the space community, argued that it is feasible to build a system of navigation by measuring the Doppler shift in the radio transmissions from a near-Earth satellite and a simple equipment for conducting the measurements [4]. By considering a particular case, R. R. Newton, described in detail that the calculations required to produce a navigation solution accurate to about 500 m, once the measurements are recorded, can be performed even by hand within 10-15 min [4]. In the early 1970s J. Glish, proposed a closed form solution for a Doppler Satellite Navigation system [5], based on the early work proposed by R. R. Newton [4]. However, J. Glish does not present the expected accuracy of his approach. The Doppler measurements were also combined with the range measurements to yield an instantaneous positioning with a single satellite [6]. This same idea is used by N. Levanon to produce user terminal position instantly by a two-communication system between a user terminal on the earth surface and a single low earth orbit (LEO) [7]. Since the Doppler measurements are less noisy, an algorithm, which would produce the user's position based only on Doppler, would be very desirable. In [8] we have proposed an alternative algorithm that uses the Doppler measurements for fixed pseudolites. A O B Range rate or Doppler