Robust altitude estimation for over-the-horizon radar using a state-space multipath fading model

• Published in: IEEE transactions on aerospace and electronic systems Vol. 39; no. 1; pp. 192 - 201
• Main Authors: Anderson, R.H., Kraut, S., Krolik, J.L.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2003; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aging aircraft; Air traffic control; Airborne radar; Aircraft; Altitude; Degradation; Dwell; Estimates; Fading; Mathematical models; Maximum likelihood estimation; Phase transformations; Predictive models; Recursive estimation; Robustness; State estimation; Studies; Uncertainty
• ISSN: 0018-9251; 1557-9603
• DOI: 10.1109/TAES.2003.1188903

In previous work, a matched-field estimate of aircraft altitude from multiple over-the-horizon (OTH) radar dwells was presented. This approach exploits the altitude dependence of direct and surface reflected returns off the aircraft and the relative phase changes of these micro-multipath arrivals across radar dwells. Since this previous approach assumed high dwell-to-dwell predictability, it has been found to be sensitive to mismatch between modeled versus observed micro-multipath phase and amplitude changes from dwell-to-dwell. A generalized matched-field altitude estimate is presented here based on a state-space model that accounts for random ionospheric and target-motion effects that degrade the dwell-to-dwell predictability of target returns. The new formulation results in an efficient, robust recursive maximum likelihood (ML) estimation of aircraft altitude. Simulations suggest that the proposed technique can achieve accuracy within 5,000 ft of the true aircraft altitude, even with relatively high levels of uncertainty in modeling of dwell-to-dwell changes in the target return. A real data result is also presented to illustrate the technique.