Direction of Arrival Estimation for High Frequency Source in the Presence of Three-dimensional Sensor Position Errors

The double spiral line array (DSLA) has sufficient three-dimensional sampling ability. It can estimate direction of arrival (DOA) for both the elevation and the azimuth angle via beamforming methods. However, in the presence of sensor position errors, the array manifold which actually exist is different from the one based on the nominal array geometry, which degrades the performance of DOA estimation. When involving high frequency signals, the sensor position errors even cause unsuccessful source DOA estimation. Here this problem is mitigated through a frequency downshift by applying frequency difference beamforming. Both the simulation and tank data analysis suggest that the frequency-difference beamforming can be more robust against three-dimensional sensor position errors than the conventional beamforming. Root Mean Square Error (RMSE) of the estimated source directions with sensor position errors are simulated using the conventional and frequency difference beamforming.