Loro antenna and pulse pattern detection system

• US 5,247,311 A
• Filed: 06/10/1992
• Issued: 09/21/1993
• Est. Priority Date: 06/10/1992
• Status: Expired due to Fees

• Current Assignee: Richard S. Sobocinski
• Original Assignee: Richard S. Sobocinski
• Inventors: Sobocinski, Richard S.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US07/896,338
• Time in Patent Office: 468 Days
• Field of Search: 342/386, 342/398, 342/450, 342/453, 342/458, 342/137, 342/47, 342/408, 342/195, 342/189, 342/428
• US Class Current: 342/453
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
• CPC Class Codes: G01S 3/58 Rotating or oscillating beam systems using continuous analysis of received signal for determining direction in the plane of rotation or oscillation or for determining deviation from a predetermined direction in such a plane G01S3/14 takes precedence
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals

Abstract

A passive surveillance method and system, capable of operation in conjunction with both non synchronous and synchronous pulse pattern rotating ground radars. Received signal scan modulated pulses are deinterleaved and correlated with a previously selected repetitive portion of an interrogation signal source base pulse pattern. A single receiver channel, sequential lobe on receive only (LORO) direction finding antenna is employed in the system to modulate received signals to extract target object relative bearings for the correlated signals. The system makes use of all available data to determine the best estimate of the target object position.

Claims

1. A method for determining the relative position of an observer object from at least one set of target object transponder replies by measuring bearing and range from said observer object in an environment having at least one rotating pulsed synchronous or non synchronous interrogation signal source, said method comprising:

(a) receiving said interrogation signal source and said target object reply signals with a multi element antenna,

(b) varying the attenuation of each of said multi element antenna received signal paths with time to result in a rotating shaped antenna pattern in space,

(c) controlling said shaped antenna pattern rotation rate to be at least one revolution during each said interrogation signal source beam passage over said target object,

(d) generating an antenna rotation reference signal each time said shaped antenna pattern maximum received signal position passes a specified reference direction angle,

(e) summing said multi element antenna signal paths onto a single microwave receiver channel,

(f) determining a base pulse repetition pattern on at least one set of said interrogation signal source signals by a pulse deinterleaving process,

(g) determining a target pulse repetition pattern by a pulse deinterleaving process on at least one said target object transponder reply,

(h) determining a matched pulse pattern for at least one said target pulse repetition pattern that correlates with said base pulse repetition pattern of said interrogation signal source,

(i) determining at least one target object relative bearing angle BT by measuring the phase of the amplitude modulation envelope on said matched pulse pattern with respect to said antenna rotation reference signal,

(j) determining at least one interrogation signal source relative bearing angle BR by measuring the phase of the amplitude modulation envelope on said base pulse repetition pattern with respect to said antenna rotation reference signal,

(k) determining at least one interrogation signal source object range r by use of signal strength versus range transformation calculations for said base pulse repetition pattern signal pulse amplitudes,

(l) determining the speed of rotation of said interrogation signal source antenna by measuring the time interval between successive sweeps past said observer object,

(m) determining an inscribed angle BS from said speed of rotation by measuring a time between said target pulse repetition replies and said interrogation signal source antenna illumination of said observer object,

(n) calculating at least one target object range t by using said representations BT, BR, r and BS,

(o) calculating the relative position of the observer object from at least one said target object using said representations BT and t.

2. A method for determining the relative position of an observer object from at least one set of target object transponder replies by measuring bearing and range from said observer object in an environment having at least one rotating pulsed synchronous interrogation signal source, said method comprising:

(a) receiving said interrogation signal source and said target object reply signals with a multi element antenna,

(b) varying the attenuation of each of said multi element antenna received signal paths with time to result in a rotating shaped antenna pattern in space,

(c) controlling said shaped antenna pattern rotation rate to be at least one revolution during each said interrogation signal source beam passage over said target object,

(d) generating an antenna rotation reference signal each time said shaped antenna pattern maximum received signal position passes a specified reference direction angle,

(e) summing said multi element antenna signal paths onto a single microwave receiver channel,

(f) determining a base pulse repetition pattern on at least one set of said interrogation signal source signals by a pulse deinterleaving process,

(g) determining a target pulse repetition pattern by a pulse deinterleaving process on at least one said target object transponder reply,

(h) determining a matched pulse pattern for at least one said target pulse repetition pattern that correlates with said base pulse repetition pattern of said interrogation signal source,

(i) determining at least one target object relative bearing angle BT by measuring the phase of the amplitude modulation envelope on said matched pulse pattern with respect to said antenna rotation reference signal,

(j) determining at least one interrogation signal source object range r by use of signal strength versus range transformation calculations for said base pulse repetition pattern signal pulse amplitudes,

(k) determining the speed of rotation of said interrogation signal source antenna by measuring the time interval between successive sweeps past said observer object,

(l) determining an inscribed angle BS from said speed of rotation by measuring a time between said target pulse repetition replies and said interrogation signal source antenna illumination of said observer object,

(m) generating a continuous synchronous predicted interrogation signal source pulse repetition pattern between successive sweep updates of said interrogation signal source antenna past said observer object,

(n) determining a time difference in arrival between receipt of said target pulse repetition pattern pulses and the receipt of said synchronous predicted interrogation signal source pulse repetition pattern pulses,

(o) calculating del, the sum of the distance from said interrogation signal source to said target object plus the distance from said target object to said observer object minus the distance r from said interrogation signal source to said observer object from said time difference in arrival,

(p) calculating at least one target object range t by using said representations r, BS and del,

(q) calculating the relative position of the observer object from at least one said target object using said representations BT and t.

3. A method for determining the relative position of an observer object from at least one set of target object transponder replies by measuring bearing and range from said observer object in an environment having at least one rotating pulsed synchronous or non synchronous interrogation signal source, said method comprising:

(a) receiving said interrogation signal source and said target object reply signals with a multi element antenna,

(b) varying the attenuation of each of said multi element antenna received signal paths with time to result in a rotating shaped antenna pattern in space,

(c) controlling said shaped antenna pattern rotation rate to be at least one revolution during each said interrogation signal source beam passage over said target object,

(d) generating an antenna rotation reference signal each time said shaped antenna pattern maximum received signal position passes a specified reference direction angle,

(e) summing said multi element antenna signal paths onto a single microwave receiver channel,

(f) determining a base pulse repetition pattern on at least one set of said interrogation signal source signals by a pulse deinterleaving process,

(g) determining a target pulse repetition pattern by a pulse deinterleaving process on at least one said target object transponder reply,

(h) determining a matched pulse pattern for at least one said target pulse repetition pattern that correlates with said base pulse repetition pattern of said interrogation signal source,

(i) determining at least one target object relative bearing angle BT by measuring the phase of the amplitude modulation envelope on said matched pulse pattern with respect to said antenna rotation reference signal,

(j) calculating at least one target object range t by use of signal strength versus range transformation calculations for said matched pulse pattern target object pulse repetition pattern pulse amplitudes,

(k) calculating the relative position of the observer object from at least one said target object using said representations BT and t.