Synthetic aperture radar
First Claim
1. A method of operating a synthetic aperture radar (SAR) system which is comprised of a pulse generator, an SAR antenna for receiving and transmitting pulses from the pulse generator, and a filter for processing pulses received by the antenna which have been reflected from a target, comprising the steps of generating alternating pulses of upward frequency sweeping and downward frequency sweeping chirps, and simultaneously changing parameters of the filter from pulse to pulse to match either the upwardly frequency sweeping or downwardly frequency sweeping characteristics of the pulses generated by the pulse generator.
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Abstract
A method of operating a SAR system comprised of emitting a sequence of pulses toward a target, alternating characteristics of pairs of successive pulses, receiving reflected pulses from the target, passing the received reflected pulses through a filter, modifying parameters of the filter in step with the transmitted pulses to match the characteristics of the successive pulses in the event a time delay between pulse transmission and reception of a pulse reflected from a target is a fraction greater than an even multiple of a pulse period, and modifying the parameters of the filter in anti-synchronism with the successive pulses in the event a time delay between pulse transmission and reception of a pulse reflected from a target is less than a fraction greater than an even multiple of a pulse period.
44 Citations
20 Claims
- 1. A method of operating a synthetic aperture radar (SAR) system which is comprised of a pulse generator, an SAR antenna for receiving and transmitting pulses from the pulse generator, and a filter for processing pulses received by the antenna which have been reflected from a target, comprising the steps of generating alternating pulses of upward frequency sweeping and downward frequency sweeping chirps, and simultaneously changing parameters of the filter from pulse to pulse to match either the upwardly frequency sweeping or downwardly frequency sweeping characteristics of the pulses generated by the pulse generator.
- 9. A method of operating a SAR system comprising emitting a sequence of pulses toward a target, alternating characteristics of pairs of successive pulses, receiving reflected pulses from the target, passing the received reflected pulses through a filter, modifying parameters of the filter in step with the transmitted pulses to match the characteristics of the successive pulses in the event a time delay between pulse transmission and reception of a pulse reflected from a target is a fraction greater than an even multiple of a pulse period, and modifying the parameters of the filter in anti-synchronism with the successive pulses in the event a time delay between pulse transmission and reception of a pulse reflected from a target is less than a fraction greater than an even multiple of a pulse period.
- 12. A synthetic aperture radar (SAR) system comprising a pulse generator for generating pulses to which successive pulses have alternating characteristics, an antenna for transmitting pulses generated by the pulse generator and for receiving pulses reflected from a target, a filter for translating the received pulses, means for changing characteristics of each of successive pulses, and means for changing parameters of the filter in step with the pulses for translating the received pulses.
Specification