FM/CW surveillance radar system with range gating

Claim 2

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal and for receiving a received signal; an FM/CW channel coupled to said antenna for receiving said received signal and including means for converting from said received signal a doppler signal above a threshold level to an FM/CW channel alarm signal; a range channel coupled to said antenna for receiving said received signal and including: means for frequency shift key (FSK) processing a CW signal, which is to be transmitted by said antenna, only during a range blanking period; range gate blanking means for inhibiting said received signal from being processed by said range channel only during said FSK process; and, means for converting from said received signal a range doppler signal above a threshold level to a range channel alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said FM/CW channel and said range channel alarm signals are concurrently coupled thereto.

Claim 3

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal and for receiving a received signal; oscillator means coupled to said antenna for generating an FM/CW signal of a frequency f c ± f m ; an FM/CW channel coupled to said antenna for receiving said received signal and including: means for passing only the doppler signal of a frequency f d from said received signal that is above a threshold level; means for converting said passed doppler signal to an alarm signal; a range channel coupled to said antenna for receiving said received signal and including: means for frequency shift keying (FSK) and FM/CW signal of a frequency f c ± f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; range gate blanking means for inhibiting any received signals from being processed by said range channel during said FSK pulse duration; means for generating a range doppler signal from said received signal; means for passing only a range doppler signal that is above a threshold level; means for converting said passed range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 4

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal and for receiving a received signal; oscillator means coupled to said antenna for generating an FM/CW signal of a frequency f c ± f m ; an FM/CW channel coupled to said antenna for receiving said received signal and including: means for passing only the doppler signal of a frequency f d from said received signal that is above a threshold level; means for converting said passed doppler signal to an alarm signal; a range channel coupled to said antenna for receiving said received signal and including: means for frequency shift keying (FSK) and FM/CW signal of a frequency f c ± f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; range gate blanking means for inhibiting any received signals from being processed by said range channel during said FSK pulse duration; means for generating a range doppler signal from said received signal; means for passing only a range doppler signal that is above a threshold level; means for converting said passed range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 5

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; oscillator means coupled to said antenna for generating a carrier signal of a frequency f c ; modulator means coupled to said oscillator means for frequency modulating said carrier signal by a frequency modulating signal of a frequency f m ; an FM/CW channel coupled to said antenna for receiving a received signal and including: means for selecting the J l component signal of a frequency f d + f m of said received signal; means for FM demodulating said J l component signal; means for passing only a selected doppler signal of a frequency f d from said FM demodulated J l component signal; means for converting said doppler signal to an alarm signal; a range channel coupled to said antenna for receiving a received signal and including: means for frequency shift keying (FSK) and frequency modulating signal of a frequency f m by a pulsed FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed by said range channel during the FSK pulse duration; means for generating a range doppler signal from said FSK signal of a frequency f k ; means for converting said range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 6

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; oscillator means coupled to said antenna for generating a carrier signal of a frequency f c ; modulator means coupled to said oscillator means for frequency modulating said carrier signal by a frequency modulating signal of a frequency f m ; an FM/CW channel coupled to said antenna for receiving a received signal and including: means for selecting the J l component signal of a frequency f d + f m of said received signal; means for FM demodulating said J l component signal; means for passing only a selected doppler signal of a frequency f d from said FM demodulated J l component signal; means for converting said doppler signal to an alarm signal; a range channel coupled to said antenna for receiving a received signal and including: means for frequency shift keying (FSK) and frequency modulating signal of a frequency f m by a pulsed FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed by said range channel during the FSK pulse duration; means for generating a range doppler signal from said FSK signal of a frequency f k ; means for converting said range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 7

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal of a frequency f.sub.trans = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.rec = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = dopper signal frequency f k = frequency shift keyed signal frequency; an FM/CW channel coupled to said antenna for receiving said received signal and including; means for selecting the J l component signal of a frequency f d = f m of said receiving signal; means for FM demodulating said J l component signal; means for passing only the doppler signal from said FM demodulatued J l component signal that is above a threshold level; means for converting said passed doppler signal to a digital signal; a range channel coupled to said antenna for receiving said received signal and including; means for frequency shift keying (FSK) said frequency modulated signal of a frequency f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed by said range channel during the FSK pulse duration time; means for generating a range doppler signal from said digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 8

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal of a frequency f.sub.trans = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.rec = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = dopper signal frequency f k = frequency shift keyed signal frequency; an FM/CW channel coupled to said antenna for receiving said received signal and including; means for selecting the J l component signal of a frequency f d = f m of said receiving signal; means for FM demodulating said J l component signal; means for passing only the doppler signal from said FM demodulatued J l component signal that is above a threshold level; means for converting said passed doppler signal to a digital signal; a range channel coupled to said antenna for receiving said received signal and including; means for frequency shift keying (FSK) said frequency modulated signal of a frequency f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed by said range channel during the FSK pulse duration time; means for generating a range doppler signal from said digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 9

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna for directing the transmitted signal to said antenna and for directing the received signal from said antenna to the receiver; oscillator means for generating a CW signal of a carrier frequency f c that is coupled to said antenna for continuous transmission therefrom; control means coupled to said oscillator means for frequency modulating said CW signal of a frequency f c by a frequency modulating signal of a frequency f m and generating an FM/CW signal of a frequency f c ± f m ; an FM/CW channel coupled to said circulator for receiving a received signal and including; filter means for selecting the J l component signal of a frequency f d + f m of said received signal; demodulator means for FM demodulating said J l component signal; filter means for passing only the doppler signal of a frequency f d from said FM demodulator J l component signal that is above a threshold level; detector means for comparing said doppler signal to a threshold level for passing only a doppler signal that is above said threshold level; means for converting said passed doppler signal to an alarm signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said control means for frequency shift keying (FSK) said FM/CW signal of a frequency f c ± f m by an FSK signal of a frequency f k and of a given pulse duration; filter means for passing only the FSK signal of a frequency f k from a received signal; sample-and-hold means for storing the peak amplitude of said passed FSK signal received during a specified range gate width; range gating means for gating ON said sample-and-hold means only during said specified range gate width; means for generating a range doppler signal from said peak amplitude stored in said sample-and-hold means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 10

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna for directing the transmitted signal to said antenna and for directing the received signal from said antenna to the receiver; oscillator means for generating a CW signal of a carrier frequency f c that is coupled to said antenna for continuous transmission therefrom; control means coupled to said oscillator means for frequency modulating said CW signal of a frequency f c by a frequency modulating signal of a frequency f m and generating an FM/CW signal of a frequency f c ± f m ; an FM/CW channel coupled to said circulator for receiving a received signal and including; filter means for selecting the J l component signal of a frequency f d + f m of said received signal; demodulator means for FM demodulating said J l component signal; filter means for passing only the doppler signal of a frequency f d from said FM demodulator J l component signal that is above a threshold level; detector means for comparing said doppler signal to a threshold level for passing only a doppler signal that is above said threshold level; means for converting said passed doppler signal to an alarm signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said control means for frequency shift keying (FSK) said FM/CW signal of a frequency f c ± f m by an FSK signal of a frequency f k and of a given pulse duration; filter means for passing only the FSK signal of a frequency f k from a received signal; sample-and-hold means for storing the peak amplitude of said passed FSK signal received during a specified range gate width; range gating means for gating ON said sample-and-hold means only during said specified range gate width; means for generating a range doppler signal from said peak amplitude stored in said sample-and-hold means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal to an alarm signal; alarm means coupled to the alarm signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two alarm signals are concurrently coupled thereto.

Claim 11

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna directing signals from the transmitter to said antenna and from said antenna to the receiver for transmitting a transmitted signal of a frequency f.sub.t = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.r = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = doppler signal frequency f k = frequency shift keyed signal frequency; a mixer coupled to said antenna for mixing said transmitted signal and said received signal; a gunn-effect oscillator that is varactor tuned for frequency modulation of a CW output signal of a carrier frequency f c that is coupled to said antenna and that is continuously transmitted therefrom; a varactor supply coupled to said gunn-effect oscillator for frequency modulating said CW output signal of a frequency f c by a frequency modulating signal of a frequency f m ; an FM/CW channel coupled to said mixer for receiving said received signal and including; means for selecting the J l component signal of a frequency f d + f m of said received signal; means for FM demodulating said J l component signal; means for passing only the doppler signal of a frequency f d from said FM demodulated J l component signal; means for comparing said doppler signal to a threshold level for passing only a doppler signal above said threshold level; means for converting said passed doppler signal to a digital signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said varactor supply for frequency shift keying (FSK) said frequency modulating signal of a frequency f m by a pulsed FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any signals from being processed during said FSK pulse duration; sample-and-hold means for storing the peak amplitude of the signal received during a specified range gate width as established by successive FSK signals; means for generating a range doppler signal from said sample-and-hold-means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal to a digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 12

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna directing signals from the transmitter to said antenna and from said antenna to the receiver for transmitting a transmitted signal of a frequency f.sub.t = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.r = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = doppler signal frequency f k = frequency shift keyed signal frequency; a mixer coupled to said antenna for mixing said transmitted signal and said received signal; a gunn-effect oscillator that is varactor tuned for frequency modulation of a CW output signal of a carrier frequency f c that is coupled to said antenna and that is continuously transmitted therefrom; a varactor supply coupled to said gunn-effect oscillator for frequency modulating said CW output signal of a frequency f c by a frequency modulating signal of a frequency f m ; an FM/CW channel coupled to said mixer for receiving said received signal and including; means for selecting the J l component signal of a frequency f d + f m of said received signal; means for FM demodulating said J l component signal; means for passing only the doppler signal of a frequency f d from said FM demodulated J l component signal; means for comparing said doppler signal to a threshold level for passing only a doppler signal above said threshold level; means for converting said passed doppler signal to a digital signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said varactor supply for frequency shift keying (FSK) said frequency modulating signal of a frequency f m by a pulsed FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any signals from being processed during said FSK pulse duration; sample-and-hold means for storing the peak amplitude of the signal received during a specified range gate width as established by successive FSK signals; means for generating a range doppler signal from said sample-and-hold-means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal to a digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 13

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna directing the signal from the transmitter to said antenna and the received signal from said antenna to the receiver for transmitting a transmitted signal of a frequency f.sub.trans = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.rec = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = doppler signal frequency

Claim 14

An FM/CW surveillance radar system with range gating, comprising: a transmit-receive antenna; a circulator coupled to said antenna directing the signal from the transmitter to said antenna and the received signal from said antenna to the receiver for transmitting a transmitted signal of a frequency f.sub.trans = f.sub.c ± f.sub.m ± f.sub.k and for receiving a received signal of a frequency f.sub.rec = f.sub.c ± f.sub.m ± f.sub.d ± f.sub.k where f c = carrier signal frequency f m = frequency modulating signal frequency f d = doppler signal frequency

Claim 15

f k = frequency shift keyed signal frequency; a gunn-effect oscillator that is varactor tuned for frequency modulation of a CW output signal of a carrier frequency f c that is coupled to said antenna for continuous transmission therefrom; a varactor supply coupled to said gunn-effect oscillator for frequency modulating said CW output signal of a frequency f c by a frequency modulating signal of a frequency f m ; a gunn-effect oscillator supply coupled to said gunn-effect oscillator for generating said CW output signal of a carrier frequency f c; an FM/CW channel coupled to said circulator for receiving said receiving signal and including; means for selecting the J l component signal of a frequency f d + f m of said receiving signal; means for FM demodulating said J l component signal; means for passing only the doppler signal of a frequency f d from said FM demodulated J l component signal that is above a threshold level; means for comparing said doppler signal to a threshold level for passing only a doppler signal that is above said threshold level; means for converting said passed doppler signal above said threshold level to a digital signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said varactor supply for frequency shift keying (FSK) said frequency modulating signal of a frequency f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed during the FSK pulse duration; sample-and-hold means for storing the peak amplitude of the FSK signal received during a specified range gate width; means for generating a range doppler signal from said peak amplitude stored in said sample-and-hold means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal above said threshold level to a digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 16

f k = frequency shift keyed signal frequency; a gunn-effect oscillator that is varactor tuned for frequency modulation of a CW output signal of a carrier frequency f c that is coupled to said antenna for continuous transmission therefrom; a varactor supply coupled to said gunn-effect oscillator for frequency modulating said CW output signal of a frequency f c by a frequency modulating signal of a frequency f m ; a gunn-effect oscillator supply coupled to said gunn-effect oscillator for generating said CW output signal of a carrier frequency f c; an FM/CW channel coupled to said circulator for receiving said receiving signal and including; means for selecting the J l component signal of a frequency f d + f m of said receiving signal; means for FM demodulating said J l component signal; means for passing only the doppler signal of a frequency f d from said FM demodulated J l component signal that is above a threshold level; means for comparing said doppler signal to a threshold level for passing only a doppler signal that is above said threshold level; means for converting said passed doppler signal above said threshold level to a digital signal; a range channel coupled to said circulator for receiving said received signal and including; means coupled to said varactor supply for frequency shift keying (FSK) said frequency modulating signal of a frequency f m by an FSK signal of a frequency f k in which said FSK signal is of a pulse duration 1/f.sub.k ; means for selecting only the FSK signal of a frequency f k from said received signal; range gate blanking means for inhibiting any received signals from being processed during the FSK pulse duration; sample-and-hold means for storing the peak amplitude of the FSK signal received during a specified range gate width; means for generating a range doppler signal from said peak amplitude stored in said sample-and-hold means; means for comparing said range doppler signal to a threshold level for passing only a range doppler signal above said threshold level; means for converting said passed range doppler signal above said threshold level to a digital signal; a logic gate coupled to the digital signals generated by said FM/CW channel and said range channel for generating an alarm signal only when said two digital signals are concurrently coupled thereto.

Claim 17

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal and for receiving a received signal; a CW channel coupled to said antenna for receiving said received signal and including means for converting said received signal to a CW channel alarm signal; a range channel coupled to said antenna for receiving said received signal and including; Fsk means for frequency shift keying, only over a range gate blanking period, a CW signal that is to be transmitted by said antenna; range gate blanking means for enabling said received signal to be processed by said range channel only if said received signal is received between successive ones of said range gate blanking periods; and, means for converting said processed received signal to a range channel alarm signal; alarm means coupled to the alarm signals generated by said CW channel and said range channel for generating an alarm signal only when said CW channel alarm signal and said range channel alarm signal are concurrently coupled thereto.

Claim 18

An FM/CW surveillance radar system with range gating, comprising: an antenna for continuously transmitting a transmitted signal and for receiving a received signal; a CW channel coupled to said antenna for receiving said received signal and including means for converting said received signal to a CW channel alarm signal; a range channel coupled to said antenna for receiving said received signal and including; Fsk means for frequency shift keying, only over a range gate blanking period, a CW signal that is to be transmitted by said antenna; range gate blanking means for enabling said received signal to be processed by said range channel only if said received signal is received between successive ones of said range gate blanking periods; and, means for converting said processed received signal to a range channel alarm signal; alarm means coupled to the alarm signals generated by said CW channel and said range channel for generating an alarm signal only when said CW channel alarm signal and said range channel alarm signal are concurrently coupled thereto.

Claim 19

The radar system of claim 8 including oscillator means coupling said CW signal that is to be transmitted to said antenna, said oscillator means responsively coupled to said FSK means for frequency modulating said CW signal only over successive ones of said range gate blanking periods, said successive ones of said range gate blanking periods being separated by a range signal processing period.

Claim 20

The radar system of claim 9 in which: said CW channel includes a threshold detector for converting said received signal to said CW channel alarm signal only if above a preset level indicative of a preset target size; said range channel includes a threshold detector for converting said received signal to said range channel alarm signal only if within said range signal processing period.