High-resolution Direction-finding Systems For Long-range Position Location of HF/VHF Transmitters Using Meteor Scatter

The objective of this program is to develop, analyze, and assess the performance of a system for locating the position of HF and VHF transmitters using energy from these transmitters that incidentally scatters from metor trails. The proposal presented a candidate algorithm for meteor scatter position location (MSPL), which requires only angle of arrival data (both azimuth and elevation) for a number of scattered signals from several different receiving locations. The Phase I effort includes: evaluating this and other candidate algorithms for their capability to perform the MSPL mission; designing and evaluating the performance of systems for implementing these algorithms; selecting the best algorithm based on its estimated error performance and on the practiciality of its implementation; detailing the system design, specifying the performance of its critical components, and determining the minimum antenna baseline; and estimating the system's error statistics as a function of basic measurement errors, emitters ERP, range, propagation variances, etc. MSPL systems require extremenly accurate measurement of a signal's angle of arrival. Novel Difference-of-Time-of-Arrival Receivers for Direction Finding, developed by the proposing firm under U.S. Government sponsorship, have demonstrated angular resolution of 0.03 milliradian. These will be evaluated as key elements of the MSPL system. ANTICIPATED BENEFITS: MSPL systems can locate an emitter (hostile or friendly) when all normal communication channels are closed. MSPL systems candetermine both the location and the axis of meteor trails, and may be configured to generate statistical data of these meteor events, a capability which may be of interest to atmospheric physicists and other in the scientific community.