Performance enhancement of direction finding for multiple baseline interferometry

Novel digital phase detector (DPD) method using trigonometric function and moving average processor (MAP) is proposed to improve direction finding (DF) accuracy in dual baseline interferometry with limited baseline space such as small sized UAV. Main advantage of proposed DPD method is that the phase error can be reduced by applying MAP for improving SNR and also another advantage is that the received signal envelope corrupted by fading does not affect the estimation result of phase accuracy. The proposed DPD using low sampling frequency can measure the phase difference precisely and the structure of digital receiver using the proposed DPD is very simply implemented at low cost. Simulation results show that SNR 20 dB is required for 1° RMS of DF accuracy in limited antenna spacing but the required SNR of the proposed DPD is only 10 dB preserving the performance of DF accuracy under the same circumstance.