Patent ID: 8519886

Claim:
A method for determining a bending angle with an antenna and receiver system positioned onboard a moving vehicle, the method comprising: receiving a first GPS signal from a first GPS satellite, the first GPS satellite having an apparent position of less than 10 degrees above the horizon; determining a true position of the first GPS satellite from information encoded in the first GPS signal; receiving, by a first antenna and a second antenna positioned above the first antenna, GPS signals from a plurality of GPS satellites located at more than 15 degrees above the horizon; determining an orientation of a baseline between the first antenna and the second antenna based on a phase difference of a carrier frequency of the GPS signals received by the first antenna and the second antenna from the plurality of GPS satellites positioned at least 15 degrees above the horizon without reference to differential global position system or DGPS ground station signals; determining an apparent position of the first GPS satellite from the first GPS signal and the orientation of the baseline; wherein said determining the apparent position of the first GPS satellite and determining the true position of first GPS satellite is repeated over a time period of at least ten minutes as the first GPS satellite moves between a true position of −0.5 degrees and +2 degrees above the horizon at a rate of at least ten samples for every 0.01 degree change in actual satellite elevation; determining the bending angle by calculating the difference between the elevation angle of the apparent position and the elevation angle of the true position of the first GPS satellite; and using time series data analysis to track and remove corrupting interferometric motion.