ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4pSP9. Aeroacoustic wideband array processing for detection and tracking of ground vehicles.

Tien Pham

Brian M. Sadler

Army Res. Lab., Adelphi, MD 20783

Wideband array processing using a steered covariance matrix (STCM) [H. Wang and M. Kaveh, IEEE Trans. ASSP 33, 823--831 (1985)] was implemented and evaluated with experimental data from a small baseline aeroacoustic sensor array. The nonstationary character of acoustic signatures from maneuvering vehicles requires harmonic association and adaptive selection of an operating-frequency set for the STCM on a data-block by block basis. The sensor outputs are processed so that all selected frequencies with the same direction of arrival (DOA) have the same rank-one representation in the steered covariance matrix. This matrix was used in the steered minimum variance (STMV) method [J. Krolik, in Advances in Spectrum Analysis and Array Processing, Vol. II, Chap. 6 (Prentice-Hall, Englewood Cliffs, NJ, 1991)] to accomplish adaptive direction finding. Processing gain and corresponding improvement of accuracy in the DOA estimates was observed when compared to narrow-band subspace methods such as ESPRIT. The STMV DOA estimates are more stable and more reliable than the narrow-band methods. This is especially evident in the multivehicle case with a nearby vehicle much louder than more distant ones.