A fast position recovery approach for GPS receivers in jamming environments and a recommendation for future GPS signal structure

The GPS receiver operation in a jamming environment brings several challenging tasks. If the signal is lost for a certain period of time then a reacquisition delay can be undesirable for time critical applications. The delay is due to necessity to find the lost signal again and to determine the time stamp on this signal which is contained in the navigation message. While the signal can be found in sub-second intervals with state-of-the-art prediction and searching strategies the time-stamp reading from navigation message may take up to six seconds provided good signal conditions. This paper suggests an approach to get a position fix without this time stamp recovery. It is based on an iterated least squares method and uses an excessive number of satellites to perform positioning with partially available measurements. It has been suggested initially for indoor positioning but is equally valuable for jamming environments. The method is simulated with GPS LI C/A signals which provided an evidence of its potential