Patent ID: 8089402

Claim:
An apparatus for calibrating a global navigation satellite system (GNSS) receiver for receiver or antenna hardware induced direct path signal errors in carrier phase measurements of GNSS transmitter direct path signals when tracking the GNSS transmitter direct path signals, the apparatus comprising: a controlled reception pattern antenna (CRPA) comprising a plurality of receiving elements and configured to sense a plurality of direct path signals from a GNSS transmitter; a digital sampler circuit configured to convert the plurality of sensed GNSS direct path signals to a plurality of sampled digital signals; and a digital processor configured to: access stored direct path phase calibration correction data for at least some combinations of the plurality of receiving elements and a plurality of transmitter orientations with respect to the CRPA; generate direct path beam steering control data using a transmitter orientation with respect to the CRPA; combine the accessed direct path phase calibration correction data specific to the transmitter orientation with respect to the CRPA and each of the plurality of receiving elements together with the direct path beam steering control data to generate corrected direct path beam steering control data; generate a composite corrected direct path digital signal by combining the sampled digital signals and the corrected direct path beam steering control data; and convert the composite corrected direct path digital signal into a corrected direct path GNSS carrier phase measurement.