Common azimuth sector indicating system

Claim 2

A common azimuthal sector indicating system, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar (SSR) and reply signals transmitted by a transponder replying to the interrogation signals, for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. means for receiving said interrogation signals during the passage of the rotating main beam, b. means for receiving said transponder reply signals transmitted by said transponder as it is interrogated by the rotating main beam, c. means for producing a first signal for a predetermined length of time following reception of an interrogation signal, d. means for producing a second signal for a predetermined length of time following reception of a reply signal, and e. means for producing a common azimuth sector indicating signal in response to coexistence of said first and second signals.

Claim 3

The invention set forth in claim 1, further including means responsive to a side lobe suppression control signal transmitted by the SSR to change said predetermined length of time of at least one of said first and second signals.

Claim 4

The invention set forth in claim 1, wherein said means for receiving said interrogation signals also receives a side lobe suppression control pulse transmitted by the SSR before and after the passage of the main beam, further including: a. means for delaying said received side lobe suppression control pulse by an amount greater than the delay between the last pulse of a normal interrogation signal and the first pulse of a normal transponder reply signal, b. means for generating a third signal in response to the most recent delayed side lobe suppression control pulse for a predetermined length of time, p1 c. means responsive to coexistence of said third signal and a transponder reply signal to produce a range warning signal, d. an indicator, and e. means responsive to coexistence of said range warning signal and said common azimuth sector indicating signal to actuate said indicator.

Claim 5

The invention set forth in claim 1, wherein said indicating system is arranged on an own aircraft and the transponder is located on another aircraft, said invention further including means for decoding altitude reporting signals in the transponder reply signals from said other aircraft, means for producing similar own aircraft altitude reporting signals, means for comparing said altitude reporting signals to produce common altitude stratum signals, and co-altitude common azimuth sector indicator means responsive to simultaneous presence of said common altitude stratum signals and said common azimuth sector indicating signals.

Claim 6

The invention set forth in claim 3, wherein said indicating system is arranged on an own aircraft and the transponder is located on another aircraft, said invention further including means for decoding altitude reporting signals in the transponder reply signals from said other aircraft, means for producing similar own aircraft altitude reportiNg signals, means for comparing said altitude reporting signals to produce common altitude stratum signals, and indicator means responsive to simultaneous presence of said common altitude stratum signals and said range warning and common azimuth sector indicating signals.

Claim 7

A common azimuthal sector indicating system, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals,for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. first receiver means for receiving said interrogation signals during the passage of the rotating main beam, b. second receiver means for receiving said transponder reply signals transmitted by said transponder as it is interrogated by the rotating main beam, c. timing means, responsive to said first receiver means, for producing a signal when the rotating main beam is directed within a selected azimuth sector of its full rotation, and d. means, responsive to said second receiver means and to said timing means, for producing a common azimuth sector indicating signal.

Claim 8

A common azimuthal sector indicating system, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals,for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. first receiver means for receiving said interrogation signals during the passage of the rotating main beam, b. second receiver means for receiving said transponder reply signals transmitted by said transponder as it is interrogated by the rotating main beam, c. timing means, responsive to said first receiver means, for producing a signal when the rotating main beam is directed within a selected azimuth sector of its full rotation, and d. means, responsive to said second receiver means and to said timing means, for producing a common azimuth sector indicating signal.

Claim 9

A common azimuthal sector indicating system, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals, for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. means responsive to reception of said interrogation signals during passage of the main beam to produce a first signal during and for a predetermined length of time following reception of said interrogation signals; b. means responsive to reception of said transponder reply signals transmitted by said transponder as it is interrogated by the rotating main beam to produce a second signal during and for a predetermined length of time following reception of said reply signals; c. means for producing a common azimuth sector indicating signal in response to coexistence of said first and second signals.

Claim 10

A common azimuthal sector indicating system, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals, for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. means responsive to reception of said interrogation signals during passage of the main beam to produce a first signal during and for a predetermined length of time following reception of said interrogation signals; b. means responsive to reception of said transponder reply signals transmitted by said transponder as it is interrogated by the rotating main beam to produce a second signal during and for a predetermined length of time following reception of said reply signals; c. means for producing a common azimuth sector indicating signal in response to coexistence of said first and second signals.

Claim 11

A common azimuthal sector indicating system for a craft, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder in another craft replying to the interrogation signals, for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. means for receiving said interrogation signals during scanning of the craft by the rotating main beam, b. means for receiving said transponder reply signals transmitted by said transponder in the other craft as it is interrogated by the rotating main beam, c. means for producing a first signal in response to interrogation signals received during the scanning of the craft, the first signal being maintained for a time interval equal to that required for the main beam to rotate through the angle that said wider sector extends beyond the leading edge of the main beam, d. means for providing a second signal in response to reply signals received during scanning of the other craft, said second signal being maintained for an interval equal to that required for the main beam to rotate through the angle that such wider sector extends beyond the trailing edge of the main beam, and e. means for producing a common azimuth sector indicating signal in response to coexistence of said first and second signals.

Claim 12

A common azimuthal sector indicating system for a craft, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder in another craft replying to the interrogation signals, for monitoring an azimuth sector wider than the rotating main beam of the radar, comprising: a. means for receiving said interrogation signals during scanning of the craft by the rotating main beam, b. means for receiving said transponder reply signals transmitted by said transponder in the other craft as it is interrogated by the rotating main beam, c. means for producing a first signal in response to interrogation signals received during the scanning of the craft, the first signal being maintained for a time interval equal to that required for the main beam to rotate through the angle that said wider sector extends beyond the leading edge of the main beam, d. means for providing a second signal in response to reply signals received during scanning of the other craft, said second signal being maintained for an interval equal to that required for the main beam to rotate through the angle that such wider sector extends beyond the trailing edge of the main beam, and e. means for producing a common azimuth sector indicating signal in response to coexistence of said first and second signals.

Claim 13

A common azimuthal sector indicating method, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals, for monitoring an azimuthal sector wider than the rotating main beam of the radar, comprising the steps of producing a first signal during and for a predetermined length of time following reception of the interrogation signals during Passage of the main beam, producing a second signal during and for a predetermined length of time following reception of the reply signals transmitted by the transponders and producing a common azimuth sector indicating signal in response to coexistence of the first and second signals.

Claim 14

A common azimuthal sector indicating method, utilizing interrogation signals transmitted by a standard azimuthally scanning secondary surveillance radar and reply signals transmitted by a transponder replying to the interrogation signals, for monitoring an azimuthal sector wider than the rotating main beam of the radar, comprising the steps of producing a first signal during and for a predetermined length of time following reception of the interrogation signals during Passage of the main beam, producing a second signal during and for a predetermined length of time following reception of the reply signals transmitted by the transponders and producing a common azimuth sector indicating signal in response to coexistence of the first and second signals.

Claim 15

A common azimuthal sector indicating method to monitor the existence of an intruding craft, comprising the steps of receiving at one location interrogation signals during scanning of the location by a rotating main beam transmitted by a standard azimuthally scanning secondary surveillance radar; receiving at the one location transponder reply signals transmitted by a transponder on an intruding craft when the transponder is interrogated by the rotating main beam; producing a first signal during and for a predetermined length of time following reception of the interrogation signals; producing a second signal during and for a predetermined length of time following reception of the reply signals; and producing a common azimuth sector indicating signal in response to coexistence of the first and second signals.

Claim 16

A common azimuthal sector indicating method to monitor the existence of an intruding craft, comprising the steps of receiving at one location interrogation signals during scanning of the location by a rotating main beam transmitted by a standard azimuthally scanning secondary surveillance radar; receiving at the one location transponder reply signals transmitted by a transponder on an intruding craft when the transponder is interrogated by the rotating main beam; producing a first signal during and for a predetermined length of time following reception of the interrogation signals; producing a second signal during and for a predetermined length of time following reception of the reply signals; and producing a common azimuth sector indicating signal in response to coexistence of the first and second signals.