Advanced Adaptive Beamforming/Nullsteering CRPA with Robust Bias Compensation for Rotorcraft Precision Navigation

Lightning Ridge Technologies advances the state of the art of Controlled Reception Pattern Antennas (CRPAs) for rotorcraft by developing an adaptive beamsteering technology to significantly mitigate hostile jamming while estimating and cancelling GPS signal variations that plague rotorcraft operations. These variations include but are not limited to rotor interference, manufacturing variability and electronic mutual coupling in the antennas, and airframe and environmental changes that alter signal scattering, diffraction, and reflection. Most problematic for precision navigation and adaptive CRPA processing, the main rotor states contributing to rotor blade modulation (RBM) are currently not measured in real-time on operational helicopters (e.g., the MH-60). The proposed architecture utilizes a two part estimation scheme to account for the biases. Carrier-phase biases are quickly varying, and should be calibrated in real-time. Pseudorange errors can be smoothed over longer periods, and these biases cause less effect on the sensitive beamsteering algorithms; thus pseudorange biases should be calibrated off-line. Lightning Ridge Technologies"experts have designed CRPA systems to land jets on aircraft carriers (Navy JPALS Program); this prior knowledge enables us to create a feasible approach providing significant benefits to rotorcraft aviation.