A METHOD FOR DETERMINING THE BASE LINE FOR A SYNTHETIC APERTURE OF A SAR USING GNSS

摘要

The present invention relates to a method for determining a synthetic aperture of a synthetic aperture radar, SAR, system using information from a global navigation satellite system, GNSS, which includes a plurality of satellites each transmitting a radio frequency signal comprising a unique pseudo random number, PRN. The method comprises: receiving the radio frequency signal from a group of satellites in the GNSS, determining a first maximum correlation peak of the PRN of the received radio frequency signal from each satellite in the group of satellites, determining the phase shift between the first determined maximum correlation peak and a second determined maximum correlation peak of a received PRN from the same satellite at a later time, for each satellite in the group of satellites, determining a line-of-sight, LOS, movement of the SAR system relative each of the satellites in the group of satellites by means of the determined phase shift for each satellite in the group of satellites, and determining a synthetic aperture using the LOS movement relative each satellite in the group of satellites.