| 摘要 |
A method is described which enables the location of a radio frequency emitting target in absolute or relative GPS coordinates from a single airborne platform within a few seconds. The method uses a signal processing technique which emulates an antenna moving at very high velocities to induce a Virtual Doppler shift on signals incident upon a linear antenna array. The Virtual Doppler shift is directly proportional to the signal direction of arrival as measured by its direction cosine. The method is shown to prevent single and multiple GPS jammers from being able to jam conventional GPS signals. Also disclosed is a means and method for developing virtual Doppler shifted signals to determine the angle-angle bearing of emitting targets to high resolution. This in turn, allows the position of the emitter to be determined in a GPS reference frame to be located to a high degree of accuracy from a single platform in extremely short times. The ultra-high precision direction-find capability requires the ability to determine the direction cosines of GPS satellite signals incident upon the detecting air vehicle and provides GPS anti-jam capability as a derivative of the definition of the direction finding.
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