Three-pulse MTI without blind speeds

DETAILED DESCRIPTION Briefly, the present invention comprises a moving-target indicator with no blind speeds which compensates for antenna scan modulation.
The MTI system comprises a circuit for generating a first, second, and third expanded doppler-tolerant FM consecutive pulses, wherein the first and third FM pulses have a given dispersion characteristic and wherein the second FM pulse has a dispersion characteristic which is the conjugate of the dispersion characteristic for the first and the third FM pulses.
Circuitry is also provided for transmitting these first, second, and third doppler-tolerant FM pulses, and for receiving the first, second, and third echo pulses from these transmitted first, second, and third FM pulses, respectively and compressing those echoes.
A processing circuit is then provided for effectively adding the first and third echo pulses and subtracting twice the second echo pulse therefrom to thereby detect moving targets while compensating for antenna scan modulation effects.
In a preferred embodiment of the present invention, the receiving and compressing circuitry comprises a single pulse compressor with a first dispersion characteristic having a first output port for providing compressed signal and a second output port for providing signals which are the conjugate of the signals from the first output port.
This embodiment further includes a switch for alternately switching in proper sequence the output signals from the first and second output ports to the processing circuit in order to compress the most recently transmitted expanded doppler FM pulse.
This preferred embodiment may also be implemented by utilizing a second pulse compressor with a dispersion characteristic which is the conjugate of the first dispersion characteristic.
This second pulse compressor would be used to provide the second output port conjugate signals.