US3803602A
Expired / Lapsed
US
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Digital range rate computer
Assignee: RCA Corp
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Filing: 1972-07-07
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Granted: 1974-04-09
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Expires: 1992-07-07
Abstract
Abstract A computer for determining range rate in knots of a target being tracked by a radar system. The range rate is determined from any change in target range that occurs during a tracking period. Statistical smoothing is used to increase accuracy of the calculated range rate. This is achieved by summing and storing the target range count for a first and third portion of a full track period and interrupting the summing and storing step for an intermediate second portion of the track period. The difference of the first and third range count is divided by an appropriate conversion factor to determine the range rate and also the polarity relation indicating an approaching or departing target. Particularly suitable for a midair collision avoidance system such as SECANT.
Inventors
- 👤 B Case
- 👤 J Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:50
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/66; G01S13/72; G01S13/70; G01S13/74; G01S13/79; G01S13/88; G01S13/93; G01S13/933
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
290 words
A digital range rate computer for determining the range rate of a remote station relative to an interrogation station, said remote station providing reply pulses to interrogation pulses from said interrogation station, said interrogation pulses having a predetermined repetition rate during a tracking period comprising: probe counter means for counting the interrogation pulses, first means responsive to a first predetermined count value in said probe counter means producing a first output signal indicative of a first selected interval of a tracking period of predetermined length, second means responsive to a second predetermined count value in said probe counter means for producing a second output signal indicative of a second selected interval of said tracking period, third means responsive to a third predetermined count value in said probe counter means for producing a third output signal indicative of a third selected interval of said tracking period, pulse means for generating clock pulses having a period substantially less than said tracking period, range counter means responsive sequentially to said first, second, and third output signals, said clock pulses and said reply pulses for providing a count of clock pulses during said first and third selected intervals of said tracking period representing the respective accumulated range values between said interrogation and remote stations during said intervals, said range counter means being responsive to said first output signal to be inhibited thereby from counting said clock pulses during said second selected interval and being further responsive to said second output signal to be enabled thereby to count said clock pulses during said third selected interval, and means for determining the difference between the respective range values accumulated during said first and third intervals, said difference being proportional to the range rate between said stations.
Claim 2
Dependent Claim
290 words
A digital range rate computer for determining the range rate of a remote station relative to an interrogation station, said remote station providing reply pulses to interrogation pulses from said interrogation station, said interrogation pulses having a predetermined repetition rate during a tracking period comprising: probe counter means for counting the interrogation pulses, first means responsive to a first predetermined count value in said probe counter means producing a first output signal indicative of a first selected interval of a tracking period of predetermined length, second means responsive to a second predetermined count value in said probe counter means for producing a second output signal indicative of a second selected interval of said tracking period, third means responsive to a third predetermined count value in said probe counter means for producing a third output signal indicative of a third selected interval of said tracking period, pulse means for generating clock pulses having a period substantially less than said tracking period, range counter means responsive sequentially to said first, second, and third output signals, said clock pulses and said reply pulses for providing a count of clock pulses during said first and third selected intervals of said tracking period representing the respective accumulated range values between said interrogation and remote stations during said intervals, said range counter means being responsive to said first output signal to be inhibited thereby from counting said clock pulses during said second selected interval and being further responsive to said second output signal to be enabled thereby to count said clock pulses during said third selected interval, and means for determining the difference between the respective range values accumulated during said first and third intervals, said difference being proportional to the range rate between said stations.
Claim 3
Dependent Claim
78 words
A computer according to claim 1 including means for determining the direction of movement of said remote station relative to said interrogAtion station, said means including means for comparing the clock pulse count during said first selected interval to the clock pulse count during the third selected interval, wherein a larger count for said first group is indicative of an approaching remote station and a larger count for said third group is indicative of a departing remote station.
Claim 4
Dependent Claim
37 words
A computer according to claim 1 including normally opeative means for jittering said interrogating pulses, and means responsive to said probe counter means for rendering inoperative said jittering means for a predetermined period of said tracking period.
Claim 5
Dependent Claim
26 words
A computer according to claim 1 wherein said selected intervals of the tracking period of each of said first, second and third intervals is substantially equal.
Claim 6
Dependent Claim
62 words
A computer according to claim 1 wherein said range counter means includes means for increasing the resolution of the spacing between a predetermined number of said interrogation pulses and their corresponding reply pulses, said means including means for generating a second pulse for each of said reply pulses, and means for determining the range of said remote station from said second pulse.
Claim 7
Dependent Claim
174 words
A digital range rate computer comprising: interrogation pulse means for producing interrogation pulses at periodic intervals for a given tracking period, detecting means for detecting reply pulses generated by a remote station in response to said interrogation pulses, first counter means for counting interrogation pulses, interval timing means responsive to the count value in said first counter means for generating output signals representative of a plurality of intervals during said tracking period, clock pulse means for generating clock pulses having a period substantially less than said tracking period, second counter means responsive respectively to said output signals of said interval timer means, said interrogation pulses, said reply pulses, and said clock pulses for incrementing a count value during a first interval of said tracking period and decrementing said count value during a subsequent interval of said tracking period, said first and subsequent intervals of said tracking period being equal, whereby the remaining count value in said second counter means is proportional to the range rate between said interrogation pulse means and said remote station.
Claim 8
Dependent Claim
174 words
A digital range rate computer comprising: interrogation pulse means for producing interrogation pulses at periodic intervals for a given tracking period, detecting means for detecting reply pulses generated by a remote station in response to said interrogation pulses, first counter means for counting interrogation pulses, interval timing means responsive to the count value in said first counter means for generating output signals representative of a plurality of intervals during said tracking period, clock pulse means for generating clock pulses having a period substantially less than said tracking period, second counter means responsive respectively to said output signals of said interval timer means, said interrogation pulses, said reply pulses, and said clock pulses for incrementing a count value during a first interval of said tracking period and decrementing said count value during a subsequent interval of said tracking period, said first and subsequent intervals of said tracking period being equal, whereby the remaining count value in said second counter means is proportional to the range rate between said interrogation pulse means and said remote station.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-08 | 1977-10-08 | 1978-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-08 | 1981-10-08 | 1982-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-08 | 1985-10-08 | 1986-04-09 | $7700.00 | Window Closed / Lapsed |