Secondary surveillance radar and its interrogation transmission method

• US 7,408,498 B2
• Filed: 09/07/2005
• Issued: 08/05/2008
• Est. Priority Date: 09/14/2004
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Aoki, Yoshirou, Kuji, Yoshinori, Ootomo, Hisashi
• Primary Examiner(s): Gregory; Bernarr E
• Application Number:
  US11/219,725
• Publication Number:
  US 20060055586A1
• Time in Patent Office: 1,063 Days
• Field of Search: 342 29- 51, 342/175, 342/195, 701120-122
• US Class Current: 342/37
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/781 Secondary Surveillance Radar [SSR] in general

Abstract

An interrogation transmission method of a secondary surveillance radar compares prediction angle ranges for transmitting interrogations with a beam-width of an antenna, and transmits the interrogations at every roll-call period if the prediction angle ranges for transmitting interrogations are narrower than the beam-width of the antenna. In contrast, if the prediction angle ranges for transmitting the interrogations are wider than the beam-width of the antenna, the radar respectively sets a period to transmit the interrogations and a period not to transmit the interrogations until responses can be received, and transmits interrogations at every roll-call period after the responses can be received (even if a receiving error or downlink occurs).

Claims

1. A secondary surveillance radar, comprising:

transmitting means for repeatedly transmitting interrogation signals from a beam antenna;

receiving means for receiving response signals for the interrogation signals; and

management processing means for dividing each of interrogation repetition cycles into two time periods, which are an all-call period to perform transactions for a transponder of an air traffic control radar beacon system (ATCRBS) and a mode S and a roll-call period to perform selective transactions for a mode S transponder and varying azimuth angle ranges for transmitting interrogations in accordance with prediction angle ranges of targets in the roll-call period, wherein

the management processing means obtains and compares a beam-width of the antenna with the prediction angle ranges, performs selective interrogations at every roll-call period if the prediction angles ranges are narrower than the beam-width, and thins out the selective interrogations at every roll-call period by reducing transmission times of the interrogation by prescribed intervals if the prediction angle ranges are wider than the beam-width.

2. The secondary surveillance radar according to claim 1, wherein

the management processing means thins out the selective interrogations at every roll-call period in an initial state if the prediction angle ranges are wider than the beam-width and transmits interrogations at every roll-call period after confirming receptions of responses.

3. The secondary surveillance radar according to claim 1, wherein

the management processing means employs conditions, of (1) whether the prediction angle ranges are within the beam-width of the antenna and (2) a range of the targets, as priority information to schedule the transactions.

4. interrogation transmission method of a secondary surveillance radar for dividing each of interrogation repetition cycles into two time periods, which are an all-call period to perform transactions for a transponder of an air traffic control radar beacon system (ATCRBS) and a mode S and a roll-call period to perform selective transactions for a transponder of the mode S and having a function to vary angle ranges for transmitting the interrogations in accordance with prediction angle ranges of targets in the roll-call period, comprising:

comparing a beam-width of an antenna with the prediction angle ranges;

performing selective interrogations at every roll-call period if the prediction angle ranges are narrower than the beam-width in the comparison in the comparing; and

thinning out transmissions of selective interrogations at every roll-call period by reducing transmission times of the interrogations by prescribed intervals if the prediction angle ranges are wider than the beam-width in the comparison in the comparing.

5. The interrogation transmission method of the secondary surveillance radar according to claim 4, wherein

the thinning out thins out the transmission of the selective interrogations at every roll-call interval with the prescribed intervals in an initial state and transmits interrogations at every roll-call period after confirming receptions of responses.

6. The interrogation transmission method of the secondary surveillance radar according to claim 4, wherein

the thinning out employs conditions, of (1) whether the prediction angle ranges are within the beam-width of the antenna and (2) a range of the targets, as priority information to schedule the transactions.

7. A secondary surveillance radar, comprising:

a transmitter that repeatedly transmits interrogation signals from a beam antenna;

a receiver that receives response signals for the interrogation signals; and

a management processor that divides each of interrogation repetition cycles into two time periods, which are an all-call period to perform transactions for a transponder of an air traffic control radar beacon system (ATCRBS) and a mode S and a roll-call period to perform selective transactions for a mode S transponder and varying azimuth angle ranges for transmitting interrogations in accordance with prediction angle ranges of targets in the roll-call period, wherein

the management processor further obtains and compares a beam-width of the antenna with the prediction angle ranges, performs selective interrogations at every roll-call period if the prediction angles ranges are narrower than the beam-width, and thins out the selective interrogations at every roll-call period by reducing transmission times of the interrogation by prescribed intervals if the prediction angle ranges are wider than the beam-width.

8. The secondary surveillance radar according to claim 7, wherein

the management processor thins out the selective interrogations at every roll-call period in an initial state if the prediction angle ranges are wider than the beam-width and transmits interrogations at every roll-call period after confirming receptions of responses.

9. The secondary surveillance radar according to claim 7, wherein

the management processor employs conditions of (1) whether the prediction angle ranges are within the beam-width of the antenna and (2) a range of the targets, as priority information to schedule the transactions.