Patent US4633999A successfully refreshed from Google Patents.
Patent US4219812A successfully refreshed from Google Patents.
US4219812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Range-gated pulse doppler radar system
Assignee: United States Department of the Army
•
Filing: 1978-12-26
•
Granted: 1980-08-26
•
Expires: 1998-12-26
Abstract
Abstract A range-gated radar system which includes a phase modulator that modulates an r.f. generator with a signal which may be binary coded. In a preferred embodiment, the binary signal is a periodic signal of 2N-1 bits per period. Starting at some arbitrary point in the sequence, K contiguous bits are transmitted then M contiguous bits are passed over, then K more bits are transmitted, and so on. The quantities M+K and 2N-1 have no primary factors in common. The radar system may be a doppler radar system using balanced digital processing which involves separating the upper and lower sideband components of modulation that exist in the return radar signal as a result of the motion of scatterers and subtracting them.
Inventors
- 👤 Otto E. Rittenbach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:50
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/64
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
109 words
A range-gated radar system including an antenna and transmit-receive device which comprises: a source of r.f. energy; a source of a coded binary signal; and means for phase-modulating said r.f. energy source with said coded binary signal; said coded binary signal source comprising means for generating a periodic bit sequence having 2 n -1 bits per period, where N is any integer greater than one; means for selecting K contiguous bits from said sequence starting at some arbitrary point in the sequence; means for passing over the next M contiguous bits in said sequence wherein 1≦K≦M and wherein (2 N -1) and (K+M) have no prime factors in common.
Claim 2
Dependent Claim
109 words
A range-gated radar system including an antenna and transmit-receive device which comprises: a source of r.f. energy; a source of a coded binary signal; and means for phase-modulating said r.f. energy source with said coded binary signal; said coded binary signal source comprising means for generating a periodic bit sequence having 2 n -1 bits per period, where N is any integer greater than one; means for selecting K contiguous bits from said sequence starting at some arbitrary point in the sequence; means for passing over the next M contiguous bits in said sequence wherein 1≦K≦M and wherein (2 N -1) and (K+M) have no prime factors in common.
Claim 3
Dependent Claim
93 words
A range-gated radar system according to claim 1 including a code delay line connected to the output of said coded binary signal source; a demodulator code gate responsive to the output of said code delay line; an in-phase r.f. demodulator coupled to said source of r.f. energy, the output of which is in phase with said source, and to the return signal from the transmit-receive device received by said antenna; and an in-phase code demodulator responsive to the output of said demodulator code gate and to the output of said in-phase r.f. demodulator.
Claim 4
Dependent Claim
26 words
A range-gated radar system according to claim 2 including an in-phase code frequency bandpass filter disposed intermediate said in-phase r.f. demodulator and said in-phase code demodulator.
Claim 5
Dependent Claim
23 words
A range-gated radar system according to claim 3 including an in-phase doppler bandpass filter coupled to the output of said in-phase code demodulator.
Claim 6
Dependent Claim
30 words
A range-gated radar system according to claim 4 including a noncoherent integrator coupled to the in-phase doppler bandpass filter, and a threshold detector in the output of said noncoherent integrator.
Claim 7
Dependent Claim
104 words
A range-gated radar system according to claim 4 further including an r.f. phase shifter coupled to said r.f. energy source the output of which is in phase quadrature with said r.f. energy source; a quadrature r.f. demodulator connected to the output of said r.f. phase shifter and to said return signal; a quadrature code frequency bandpass filter in the output of said quadrature r.f. demodulator; a quadrature code demodulator responsive to the output of said demodulator code gate and to the filtered output of said quadrature r.f. demodulator; and a quadrature doppler frequency bandpass filter coupled to the output of said quadrature code demodulator.
Claim 8
Dependent Claim
58 words
A range-gated radar system according to claim 6 further including a first noncoherent integrator coupled to the in-phase doppler bandpass filter; a first threshold detector in the output of said first noncoherent integrator; a second noncoherent integrator coupled to the quadrature doppler bandpass filter; and a second threshold detector coupled to the output of said second noncoherent integrator.
References Cited (Backward Citations)
US4124850A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-26 | 1984-02-25 | 1984-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-26 | 1988-02-25 | 1988-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-26 | 1992-02-25 | 1992-08-26 | $7700.00 | Window Closed / Lapsed |