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US3889261A
Expired / Lapsed
US
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Range measurement pulse radar system
Assignee: Thales SA
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Filing: 1973-09-20
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Granted: 1975-06-10
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Expires: 1993-09-20
Abstract
Abstract A multifrequency measurement pulse radar system transmits at least two series of pulses of a same repetition frequency but of different carrier frequencies. The reflected signals are demodulated by a single reference signal and filtered in at least one Doppler filter bank. Each object of the space is characterized by at least two signals, which are picked off separately at the corresponding outputs of the Doppler filters. These signals are compared in pairs in a phase comparator which delivers the range data.
Inventors
- 👤 Jacques Sirven
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:47
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/36; G01S13/10; G01S13/24
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
160 words
A pulse radar system designed to provide range data, comprising a transmitter for transmitting at least two series of pulses of the same recurrence periodicity but having different carrier frequencies and a receiver comprising: means for demodulating all the received signals by a single reference signal, in order to yield Doppler signals; at least one bank of n Doppler filters each receiving said Doppler signals and supplying at n separate outputs, separate signals depending upon their particular Doppler frequencies, the interval between the centre frequencies of the filters in each bank being constant and equal to a sub-multiple of each difference between two emitted frequencies; switching means respectively connected to each of the filter outputs, in order to succesively pick off pairs of signals to pairs of outputs whose Doppler frequency difference is equal to the difference between two of said transmitted frequencies; and a phase-comparator for comparing the signals of each pair picked off and producing said range data.
Claim 2
Dependent Claim
160 words
A pulse radar system designed to provide range data, comprising a transmitter for transmitting at least two series of pulses of the same recurrence periodicity but having different carrier frequencies and a receiver comprising: means for demodulating all the received signals by a single reference signal, in order to yield Doppler signals; at least one bank of n Doppler filters each receiving said Doppler signals and supplying at n separate outputs, separate signals depending upon their particular Doppler frequencies, the interval between the centre frequencies of the filters in each bank being constant and equal to a sub-multiple of each difference between two emitted frequencies; switching means respectively connected to each of the filter outputs, in order to succesively pick off pairs of signals to pairs of outputs whose Doppler frequency difference is equal to the difference between two of said transmitted frequencies; and a phase-comparator for comparing the signals of each pair picked off and producing said range data.
Claim 3
Dependent Claim
49 words
A radar system as claimed in claim 1, wherein selector means are arranged between said switching means and said comparator, for transmitting the pairs of signals picked off, solely in the case where each of said signals of said pair has an amplitude in excess of a predetermined threshold.
Claim 4
Dependent Claim
121 words
A radar system as claimed in claim 2, emitting pulses at a high recurrence frequency, the carrier frequency of the pulses alternately having a first value F1 and a second value F2, comprising two identical filter banks and a switch for applying the demodulated signals alternately to the first and to the second filter banks, with the same recurrence frequency as exhibited by the emitted pulses; and wherein said switching means comprise a first series of gates connected to the outputs of the first filter bank for successively picking off the first signals of each pair, and a second series of gates connected to the outputs of the second filters bank for successively picking off the second signals of each pair.
Claim 5
Dependent Claim
126 words
A system as claimed in claim 3, wherein said filter banks are of the type constituted by devices for calculating the Fourrier transform, and are supplied with two demodulated signals, in quadrature, possessing furthermore n pairs of outputs, wherein each series of gates of the switching means comprises n pairs of gates, the outputs of the first gates of each pair of the first series being connected in parallel to a first output terminal, the outputs of the second gates of each pair being connected in parallel to a second output terminal, and the first and second gates of each pair of the second series being connected in parallel respectively to a third and fourth output terminal, these output terminals being coupled to said selector means.
Claim 6
Dependent Claim
95 words
A system as claimed in claim 4, further comprising a device for controlling the gates, in order to simultaneously operate the two gates coupled to the output of order j (j 1, 2 . . . n) of the first filter bank on the one hand, and the two gates coupled to the output of order j + or - k of the second filter bank, on the other, the difference of order k corresponding to a Doppler frequency difference between the demodulated signals, equal to the difference between the emitted frequencies F1 and F2.
Claim 7
Dependent Claim
131 words
A system as claimed in claim 5, wherein said selector means comprise a first device for converting cartesian coordinates into polar coordinates, connected to the two first output terminals of the switching means receiving the first picked off signal, a second identical device for converting coordinates, connected to the third and fourth output terminals of such switching means, each of said converters having an output for the modulus and one for the argument, two threshold detectors connected to the ''''modulus'''' outputs of said converters, and AND-gate with two inputs connected to the outputs of two detectors, and two gates connected respectively to the ''''argument'''' outputs of said converters, each having a control input connected to the output of said AND-gate and the outputs of said gates being coupled to the phase-comparator.
Claim 8
Dependent Claim
25 words
A system as claimed in claim 5, further comprising a phase-correcting circuit for storing predetermined phase-shift values, connected between said switching means and the phase-comparator.
Claim 9
Dependent Claim
79 words
A system as claimed in claim 1, further comprising a range computer circuit coupled to the output of the phase comparator, a set of coupling elements between the transmitter and the receiver, for performing the simulation of a zero range echo, and a calibrating circuit for storing the range signal received during said simulation; and wherein said computer circuit comprises a subtractor circuit for deducting from any range measurement, the value of the signal stored in said calibrating circuit.
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) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |