RUNWAY TRAFFIC SURVEILLANCE DEVICE

• US 3,760,416 A
• Filed: 11/24/1971
• Issued: 09/18/1973
• Est. Priority Date: 11/30/1970
• Status: Expired due to Term

• Current Assignee: Georges J.J. Barriere, Michel Rene J. Dalbera
• Original Assignee: Georges J.J. Barriere, Michel Rene J. Dalbera
• Inventors: Barriere, Georges J. J., Dalbera, Michel Rene J.
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US05/201,748
• Time in Patent Office: 664 Days
• Field of Search: 343/112CA,112TC,7ED,5PC
• US Class Current: 342/61
• CPC Class Codes: G01S 13/913 for landing purposes
• CPC Class Codes: G01S 7/046 using an intermediate storage device, e.g. a recording/reproducing device

Abstract

A radar surveillance device particularly adapted for airport surface monitoring, including a fixed pointing monopulse radar and tracking circuits for selected targets. Radar derived data such as data on range, azimuth (bearing) angle, speed in analog or digital form are continuously recorded in a transient (repetitive) recording as, for example, in a continuous belt magnetic tape recorder. A continuous comparison of radar derived data with built-in limits produces an alarm signal whenever one or more of said data items reaches its build-in limit. The alarm signal can alert tower personnel but also activates a transfer of recorded data from the transient (first) to more permanent (second) recording means. In one embodiment, the time retention capacity of the first recording means is used to hold data for one such period preceding an alarm signal, the recording being shifted to the second recorder during the presence of an alarm signal. In another embodiment, a read-out from the first recorder is activated by the alarm signal and the data read-out is recorded in the second recorder so that a complete second recorder record is extant including the data in the holding period of the first recorder one predetermined holding period prior to the alarm. A continuous record for accident investigations and airport traffic monitoring purposes is thus available.

Claims

1. A radar surveillance system for a predetermined area comprising:

a coherent monopulse Doppler radar having a fixed antenna pointing angle such that the radiation pattern thereof substantially covers said predetermined area for producing sum and difference video signals corresponding to substantially only moving targets;

means for tracking selected ones of the targets within said predetermined area for which video signals are supplied by said radar, said tracking means employing said sum and difference signals to derive selected data concerning said selected targets;

an alarm signal generator responsive to said tracking means and including preselected reference circuits to compare said selected data against corresponding preselected reference limits for generating an alarm signal when one item or more of said selected data reaches or exceeds a predetermined relationship with the corresponding reference limit;

first recording means for continuously recording said selected data from said tracking means, said first recording means being repetitive and adapted for retaining said selected data at least for a first predetermined holding period prior to any point of time during recording;

second recording means being non-repetitive and capable of providing a longer recording period than said first recording means; and

transfer control means responsive to said alarm signal for activating said second recording means to record said selected data during presence of said alarm signal.

2. Apparatus according to claim 1 further defined in that said transfer control means includes additional means for discontinuing the recording of said selected data in said first recording means and for causing said first recording means to retain data recorded therein during presence of said alarm signal.

3. Apparatus according to claim 2 in which said first recording means comprises at least one continuous-belt magnetic tape recorder having a writing head for recording said selected data and said additional means includes controllable erasing means for erasing recorded data after said first predetermined holding period from the time of recording, in the absence of said alarm signal, said erasing means being deactivated to retain said selected data during presence of said alarm signal.

4. Apparatus according to claim 3 in which said second recording means comprises a non-repetitive magnetic tape recorder adapted to record said selected data for a second predetermined period substantially greater than said first predetermined holding period.

5. Apparatus according to claim 4 in which said selected data are radar derived data including at least range, angular position, speed and acceleration.

6. Apparatus according to claim 1 in which additional mEans are provided within said transfer control means for continuously reading said selected data from said first recording means at a constant delay from the time of recording therein substantially equal to said first predetermined holding period, and for effecting recording of said data thereby read in said second recording means during presence of said alarm signal, said first recording means also including continuously operative erasing means for erasing said data after said reading but prior to recording of new selected data therein.

7. Apparatus according to claim 6 in which said first recording means comprises a continuous belt magnetic tape recorder having close-spaced reading, erasing and recording heads encountered in that order by any arbitrary point on the moving magnetic tape.

8. Apparatus according to claim 4 in which said first and second recording means include multi-track magnetic tape recorders having one track for recording each discrete data item of said selected data.

9. Apparatus according to claim 4 in which said first and second recording means are single track tape recorders and multiplexing means are included whereby all data items of said selected data may be recorded on a single track in a time sequence rapid compared to the rate of change of the fastest changing data item of said selected data.

10. Apparatus according to claim 7 in which said first and second recording means are single track tape recorders and multiplexing means are included whereby all data items of said selected data may be recorded on a single track in a time sequence rapid compared to the rate of change of the fastest changing data item of said selected data.