Radar system

A method of removing leakage in a continuous wave radar system, comprising:

• a. subtracting a stored leakage signal from a down-converted radar return signal so as to form a resultant signal, wherein said down-converted radar return signal comprises a repetitive sequence of frequencies;
• and
• b. performing a leakage calibration every N.sup.th occurrence of said repetitive sequence of frequencies, wherein said leakage calibration comprises:
• i). calculating an average of successive resultant signals by averaging respective elements of said repetitive sequence across successive repetitive sequences so as to generate associated averaged leakage signal;
• ii). calculating at least one variance waveform associated with said averaged leakage signal;
• iii). comparing at least one measure of said at least one variance waveform with a corresponding at least one threshold;
• iv). combining said stored leakage signal with said averaged leakage signal in accordance with a Kalman Filter so as to form an updated leakage signal if said at least one measure of said at least one variance waveform is less than said corresponding at least one threshold;
• and
• v). storing said updated leakage signal as said stored leakage signal.

A method of removing leakage in a continuous wave radar system, comprising:

• a. converting a stored leakage signal from digital to analog form so as to form an analog leakage signal;
• b. subtracting said analog leakage signal from a down-converted radar return signal so as to form a resultant signal;
• c. sampling the in-phase and quadrature-phase components of said resultant signal, each said component comprising an associated waveform comprising a repetitive sequence of frequencies;
• and
• d. performing a leakage calibration every N.sup.th occurrence of said repetitive sequence of frequencies, wherein said leakage calibration comprises:
• i). calculating an average of successive said in-phase waveforms of said down-converted radar return signal by averaging respective elements of said repetitive sequence across successive repetitive sequences so as to generate associated averaged in-phase waveform;
• ii). calculating an average of successive said quadrature-phase waveforms of said down-converted radar return signal by averaging respective elements of said repetitive sequence across successive repetitive sequences so as to generate associated averaged quadrature-phase waveform, said in-phase waveform and said quadrature-phase waveform constituting an averaged leakage signal;
• iii). calculating at least one variance waveform associated with said averaged leakage signal;
• iv). comparing at least one measure of said at least one variance waveform with a corresponding at least one threshold;
• and
• v). replacing said stored leakage signal with a signal from said averaged leakage signal if said at least one measure of said at least one variance waveform is less than said corresponding at least one threshold.

A system for removing leakage in a CW radar system, comprising:

• a. a differential amplifier, the input of said differential amplifier operatively coupled to a down converted radar signal within the CW radar system;
• b. a signal processor;
• c. a memory operatively connected to said signal processor for storing a leakage signal;
• d. a digital to analog converter operatively connected to said signal processor;
• e. a gain controlled amplifier, whereby the input of said gain controlled amplifier is operatively connected to the output of said differential amplifier and the gain control of said gain controlled amplifier is operatively connected to said signal processor;
• f. a first analog to digital converter, the input of said first analog to digital converter operatively connected to the output of said gain controlled amplifier, the output of said first analog to digital converter operatively connected to said signal processor, whereby said first analog to digital converter provides an in-phase signal to said signal processor;
• g. a quadrature phase shifter, the input of said quadrature phase shifter operatively connected to the output of said gain controlled amplifier;
• and
• h. a second analog to digital converter, the input of said second analog to digital converter operatively connected to the output of said quadrature phase shifter, the output of said second analog to digital converter operatively connected to said signal processor, whereby said second analog to digital converter provides a quadrature-phase signal to said signal processor, said signal processor calculates a leakage calibration signal from said in-phase and said quadrature phase signals, said signal processor outputs said leakage calibration signal to said digital to analog converter, and said differential amplifier subtracts the signal at the output of said digital to analog converter from said down converted radar signal.