Patent ID: 6424890
Filing Date: 2002-07-23
Classification: B64G

Abstract:
An apparatus for determining the position of a satellite at any instant of time between two sampling instants, based on information in one or more navigation messages provided by the satellite, the information allowing the computation of the satellite positions at the two sampling instants, each navigation message having a time of validity, the apparatus comprising:a) means for setting the first sampling instant; b) means for computing the satellite position at the first sampling instant using parameters provided in a first navigation message with a suitable time of validity; c) means for setting a next sampling instant later than the first sampling instant; d) means for computing the satellite position at the second sampling instant using parameters provided in the first navigation message if the first navigation message has a suitable time of validity, and otherwise using parameters in a second navigation message with a suitable time of validity; and e) means, for each of the three dimensions of motion, for constructing a polynomial of at least third degree by choosing the coefficients of the polynomial so that the polynomial interpolates the satellite position at each of the sampling instants.