Coherent, frequency multiplexed radar

Claim 1

A continuous wave, frequency-multiplexed radar system, comprising: transmitter means for transmitting, against a target, a continuous output signal having successive cycles, each of said cycles including N mutually coherent, contiguous segments, wherein said output signal has a respective predetermined frequency during each of said segments; receiver means for receiving a return signal produced by reflection of said output signal from said target, while said output signal is being transmitted; separation means connected to said receiver means for, during each cycle, separating said return signal into N respective frequency components corresponding to said predetermined frequencies; means for successively obtaining quadrature samples from said separated frequency components for each of the segments of a return signal cycle, said samples being obtained in a predetermined order during each of a plurality of range times following transmission of said signal cycle in said output signal; and matched filter processing means for combining quadrature samples obtained from a succession of return signal cycles during a respective one of said range times to produce indications of the range and velocity of a target having a range corresponding to said range time.

Claim 6

A method for measurement of target range and velocity by a continuous wave, frequency-multiplexed radar system including a transform processing means for combining signal samples to produce predetermined target indicia, comprising the steps of: generating a continuous periodic output signal having successive periods, wherein each of said periods includes N contiguous, mutually coherent time segments in each of which said output signal has a respective predetermined frequency; continuously transmitting said output signal against a remote target to generate a continuous reflection of said output signal from said target; continuously receiving said reflected signal while said output signal is being transmitted; separating N frequencies from said received signal; obtaining quadrature samples from said separated frequencies for each of the periods of a received signal cycle, said samples being obtained in a predetermined order during each of a plurality of range times following transmission of said period in aid output signal; for each of said predetermined frequencies, accumulating quadrature samples obtained from a succession of received signal cycles during a respective one of said range times; and combining all quadrature samples accumulated during said range time to produce indications of the range and velocity of a target having a range from said radar system corresponding to said range time.

Claim 7

A method for measurement of target range and velocity by a continuous wave, frequency-multiplexed radar system including a transform processing means for combining signal samples to produce predetermined target indicia, comprising the steps of: generating a continuous periodic output signal having successive periods, wherein each of said periods includes N contiguous, mutually coherent time segments in each of which said output signal has a respective predetermined frequency; continuously transmitting said output signal against a remote target to generate a continuous reflection of said output signal from said target; continuously receiving said reflected signal while said output signal is being transmitted; separating N frequencies from said received signal; obtaining quadrature samples from said separated frequencies for each of the periods of a received signal cycle, said samples being obtained in a predetermined order during each of a plurality of range times following transmission of said period in aid output signal; for each of said predetermined frequencies, accumulating quadrature samples obtained from a succession of received signal cycles during a respective one of said range times; and combining all quadrature samples accumulated during said range time to produce indications of the range and velocity of a target having a range from said radar system corresponding to said range time.

Claim 11

A method for measurement of target range and velocity by a continuous wave, frequency-multiplexed radar system including a transform processing means for combining signal samples to produce predetermined target indicia, comprising the steps of: generating a continuous periodic output signal having successive periods, wherein each of said periods includes N contiguous, mutually coherent time segments in each of which said output signal has a respective predetermined frequency; continuously transmitting said output signal against a remote target to generate a continuous reflection of said output signal from said target; continuously receiving said reflected signal while said output signal is being transmitted; separating N frequencies from said received signal; obtaining quadrature samples from said separated frequencies for each of the periods of a received signal cycle, said samples being obtained in a predetermined order during each of a plurality of range times following transmission of said period in said output signal; for each of said predetermined frequencies, accumulating quadrature samples obtained from a succession of received signal cycles during a respective one of said range times; pulse-compressing the accumulation of quadrature samples for each of said predetermined frequencies by further sampling each said sample during each of a plurality of fine range times occurring during said time; progressively phase-shifting accumulated, pulse-compressed quadrature samples obtained during said fine range times and combining phase-shifted quadrature samples to obtain respective Doppler frequency accumulations; and successively combining all of said respective Doppler frequency accumulations with each of said fine range accumulations to produce indications of the range and speed of a target having a range from said radar system corresponding to a respective one of said fine range times.

Claim 12

A method for measurement of target range and velocity by a continuous wave, frequency-multiplexed radar system including a transform processing means for combining signal samples to produce predetermined target indicia, comprising the steps of: generating a continuous periodic output signal having successive periods, wherein each of said periods includes N contiguous, mutually coherent time segments in each of which said output signal has a respective predetermined frequency; continuously transmitting said output signal against a remote target to generate a continuous reflection of said output signal from said target; continuously receiving said reflected signal while said output signal is being transmitted; separating N frequencies from said received signal; obtaining quadrature samples from said separated frequencies for each of the periods of a received signal cycle, said samples being obtained in a predetermined order during each of a plurality of range times following transmission of said period in said output signal; for each of said predetermined frequencies, accumulating quadrature samples obtained from a succession of received signal cycles during a respective one of said range times; pulse-compressing the accumulation of quadrature samples for each of said predetermined frequencies by further sampling each said sample during each of a plurality of fine range times occurring during said time; progressively phase-shifting accumulated, pulse-compressed quadrature samples obtained during said fine range times and combining phase-shifted quadrature samples to obtain respective Doppler frequency accumulations; and successively combining all of said respective Doppler frequency accumulations with each of said fine range accumulations to produce indications of the range and speed of a target having a range from said radar system corresponding to a respective one of said fine range times.