Track extension for use with ATCRBS surveillance procedures

• US 5,208,591 A
• Filed: 04/19/1991
• Issued: 05/04/1993
• Est. Priority Date: 09/29/1989
• Status: Expired due to Term

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Stayton, Gregory T., Ybarra, Kathryn W.
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US07/687,965
• Time in Patent Office: 746 Days
• Field of Search: 340/961, 364/439, 364/461, 364/429, 342/29, 342/30, 342/32, 342/36, 342/37, 342/38
• US Class Current: 340/961
• CPC Class Codes: G01S 13/781 Secondary Surveillance Radar [SSR] in general
• CPC Class Codes: G01S 7/2923 based on data belonging to a number of consecutive radar periods

Abstract

During ATCRBS surveillance procedures, a multiplicity of target aircraft are typically detected through target replies from interrogation signals. However, the nature of the target acquisition procedures are such that positive identification of the target aircraft is not available. Rather than ordering the target tracks with increasing range and correlating the target replies with tracks based on the ordering of the target tracks, the tracks are prioritized, based on confidence in the reliability of the identification of each track, into groups. An attempt to correlate the tracks of each group with the set of target replies is performed for the groups in order of decreasing priority. A target reply is assigned to a track when a correlation between a track and a target reply is determined.

Claims

1. A method of processing aircraft traffic target replies provided in response to interrogation signals from a monitoring aircraft for traffic in a vicinity of said monitoring aircraft, wherein positions of target aircraft traffic are represented by target reply signals in aircraft processing apparatus, said method comprising the steps of:

accumulating sets of target replies, each target reply including a time and a distance parameter, wherein said sets of target replies can include missing and inaccurate target replies;

based on a predetermined criterion for correlation between target reply parameters for a plurality of unassigned target replies, assigning unassigned correlated target replies to a target aircraft track;

based on a preselected relationship between parameters for each correlated target reply of a target aircraft track, determining a priority level for each target aircraft track;

providing an additional set of target replies along with parameters for each additional set of target replies;

assigning an unassigned additional set target reply to a target aircraft track when said additional set target reply has said predetermined criterion for correlation with target replies of said target aircraft track, wherein said assigning an unassigned additional set target reply step is performed in order of priority level of said target aircraft tracks;

accumulating unassigned additional set target replies with sets of target replies previously accumulated; and

returning to said providing an additional set of target replies step.

2. The method of claim 1 further comprising the step of including a calculated target reply in a processed target aircraft track when unassigned additional set target replies does not include a correlated target reply prior to said returning step, a target aircraft track being discarded when a preselected number of calculated target replies are included therein.

3. The method of claim 1 further comprising the step of providing with each target reply a bearing parameter.

4. The method of claim 2 wherein said determining step includes a step of associating a priority level with each target aircraft track group selected from the set of groups consisting of an established track group, an image track group, a potential image track, and a potential track.

5. The method of processing tracks for target aircraft in a vicinity of a surveillance aircraft, each track represented by target reply signals provided by target aircraft in response to interrogation signals by said surveillance aircraft, said method comprising the steps of:

periodically acquiring a set of target reply signals, each target reply signal indicating a position of a target aircraft relative to said surveillance aircraft, wherein a set of said target reply signals can include inaccurate target reply signals and can have missing target reply signals;

determining when a first predetermined correlation between unassigned target reply signals of different sets of target reply signals is present;

assigning each of unassigned target reply signals having said first predetermined correlation to a first group correlated track, each first group correlated track having a first level of priority;

repeating said assigning unassigned target reply signals having said first predetermined correlation for unassigned target reply signals until unassigned target reply signals no longer meet said first predetermined correlation;

performing said assigning step and said repeating step for a second predetermined correlation to provide second group correlated tracks having a second priority level;

for each new set of target reply signals, assigning an unassigned new set of target reply signals to a first group correlated track for each first group correlated track when said first predetermined correlation condition is present therebetween, said unassigned new set target signal and said first group correlated track forming an updated new first group correlated track;

after all first predetermined conditions have been identified between said unassigned new set target reply signals and said first group correlated tracks, assigning an unassigned new set target reply signal to a second group correlated track for each second group correlated track when said second predetermined correlation exists therebetween to form an updated second group correlated track; and

returning to said assigning an unassigned new set of target reply signals step.

6. The method of claim 5 further comprising the steps of:

prior to said returning step, assigning unassigned target reply signals and a unassigned new set target reply signal having said first predetermined correlation to a new first group correlated track until said first predetermined correlation is no longer present; and

after all said first predetermined conditions have been satisfied, assigning unassigned target reply signals and a unassigned new set target reply signal having said second predetermined correlation to a new second group correlated track until said second predetermined correlation is no longer present.

7. The method of claim 6 further comprising the steps of:

for first and second group correlated tracks which have not been updated, providing updated first and second group correlated tracks by assigning extrapolated target reply signals thereto; and

for said updated first and said updated second group correlated tracks, determining a group designation from said first and said second predetermined correlation conditions.

8. The method of claim 7 further comprising the step of discarding first and second group correlated tracks having a predetermined number of consecutive extrapolated target reply signals included therein.

9. The method of claim 8 further including the step of:

treating said updated and said new first group correlated tracks as first group correlated tracks;

treating said updated and said new second group correlated tracks as second group correlated tracks; and

returning to said for each new set of target reply signals step.

10. The method of claim 9 further including the step of providing third group correlated tracks determined by a third predetermined correlation with a third priority level, each new set target reply signals for said third group correlated tracks processed in a manner similar to said first and said second group correlated tracks in an order determined by said third priority level.