Patent ID: 7692577

Claim:
A method for detecting an erroneous satellite measurement from a signal sent by a satellite and received by a receiver, comprising the steps of: (a) determining an approximate location of the receiver; (b) determining an elevation for each of a plurality of satellites from which the receiver receives a signal; and (c) for each one of the plurality of satellites: (i) determining an uncertainty value as a function of the satellite elevation; (ii) determining an expected range between the receiver and the satellite; (iii) measuring a range between the receiver and the satellite; (iv) determining a range difference between the expected range and the measured range; (v) determining a median value of the range differences; (vi) determining an offset value between the range difference and the median value; and (vii) comparing the offset value with a value that is the sum of the uncertainty value and a predetermined threshold to thereby detect an erroneous satellite measurement.