Geolocation of frequency-hopping transmitters via satellite

An emitter-location technique which involves spaceborne interception of ground-to-satellite communication links is analyzed. In this scheme a number of interceptor satellites transpond the frequency band of interest to a terrestrial location for processing. The basic technique can be used on a variety of signal types: fixed-frequency, frequency-hopped, and pseudo-noise. The theoretical feasibility of geolocating terminals that are hopping in frequency is emphasized. The technique is applicable at any frequency, but, to simplify the formulation, it is assumed the ground terminals have narrow antenna beamwidths and, therefore, they operate in the higher satellite communication frequency bands. The general formulas for the interception accuracy are summarized and a strawman interceptor system is proposed. Interception regions for prototypical terminals and satellites are calculated, and the results are presented parametrically as a function of uplink signal-to-noise ratio (SNR)