Angle width discriminator/altitude line detector radar

• US 4,540,985 A
• Filed: 06/02/1978
• Issued: 09/10/1985
• Est. Priority Date: 05/23/1978
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Corporation
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Clancy, Steven J., Whatley, James F., Heinke, Dennis
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US05/911,867
• Time in Patent Office: 2,657 Days
• Field of Search: 343/5 DP, 343/5 VQ
• US Class Current: 342/90
• CPC Class Codes: G01S 7/2923 based on data belonging to a number of consecutive radar periods

Abstract

A pulse radar for acquiring a target while rejecting the altitude line is described wherein a plurality of target reports from a scanning antenna are examined and rejected if the pattern of target reports at an apparent range extends along a scanning angle too large to be a valid target and selected if the pattern of target reports at a range extends along a limited scanning angle indicative of a target having a valid target size. Target reports rejected during a prior scan may be used as a basis for rejecting target reports of a current scan.

Claims

1. A method for operating a pulse radar for acquiring a target comprising the steps of:

transmitting a sequence of signals from an antenna, said antenna radiating most of the electromagnetic energy in a narrow beam having a predetermined beam width;

scanning said antenna to direct said beam along a predetermined path represented by a plurality of path increments, connected in series;

receiving reflected signals emanating from said antenna;

integrating a plurality of said reflected signals arriving at said antenna at a predetermined time interval corresponding to a range cell and path increment for said directed beam to provide an output signal;

thresholding said output signal to provide a target report at times when the amplitude of the output signal is greater than a predetermined value;

repeating the steps of receiving and thresholding for a plurality of time intervals for each of a plurality of path increments for said directed beam;

storing said target reports;

comparing the occurrence of said target reports as a function of said plurality of path increments and range cell location with a plurality of predetermined target report patterns; and

selecting target reports having an occurrence matching one of said predetermined target report patterns indicative of a target having a valid target size.

2. The method of claim 1 wherein said steps of transmitting, scanning, receiving, integrating, thresholding, repeating and storing are performed a second time;

storing rejected target reports of said first scan;

rejecting target reports stored during a second scan when said target reports of said second scan occur within a predetermined distance of said range cell and path increment of said rejected target reports of said first scan;

comparing the occurrence of said target reports from said second scan as a function of said plurality of path increments and range cell location with a plurality of predetermined target report patterns; and

selecting target reports having an occurrence matching one of said predetermined target report patterns indicative of a target having a valid target size.

3. A method for operating a pulse radar for acquiring a target comprising the steps of:

transmiting a sequence of signals from an antenna, said antenna radiating most of the electromagnetic energy in a narrow beam having a predetermined beam width;

scanning said antenna to direct said beam along a predetermined path represented by a plurality of path increments, connected in series;

receiving reflected signals emanating from said antenna;

integrating a plurality of said reflected signals arriving at said antenna at a predetermined time interval corresponding to a range cell and path increment for said directed beam to provide an output signal;

thresholding said output signal to provide a target report at imes when the amplitude of the output signal is greater than a predetermined value;

repeating the steps of receiving and thresholding for a plurality of time intervals for each of a plurality of path increments for said directed beam;

storing said target reports;

comparing the occurrence of said target reports as a function of said plurality of path increments and range cell location with a plurality of predetermined target report patterns;

rejecting target reports which within at least one range cell extends over a plurality of path increments that is too large to be a valid target; and

selecting target reports having an occurrence matching one of said predetermined target report patterns indicative of a target having a valid target size.

4. The method of claim 3 wherein said steps of transmitting, scanning, receiving, integrating, thresholding, repeating and storing are performed a second time;

storing rejected target reports of said first scan;

rejecting target reports stored during a second scan when said target reports of said second scan occur within a predetermined distance of said range cell and path increment of said rejected target reports of said first scan;

comparing the occurrence of said target reports from said second scan as a function of said plurality of path increments and range cell location with a plurality of predetermined target report patterns;

rejecting target reports from said second scan which over at least one range cell extends over a plurality of path increments that is too large to be a valid target; and

selecting target reports having an occurrence matching one of said predetermined target report patterns indicative of a target having a valid target size.