US4766436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radar device for measuring the distance of the device to a surface
Assignee: Thomson TRT Defense
•
Filing: 1987-06-23
•
Granted: 1988-08-23
•
Expires: 2007-06-23
Abstract
Abstract This radar device for measuring the distance h of the device to a surface (2) includes transmission means (5) for transmitting to the surface a frequency-modulated wave E(t) provided by an oscillator (14) having a frequency control, receiving means (7) for receiving this wave R(t) reflected from the surface, a mixer circuit (10) for producing a beat wave between the transmitted and received waves and a processing circuit (20) including a beat-wave-digitizing circuit (25) and a time-frequency transform operator (27) for supplying frequency components from which the distance h is determined. This processing circuit (20) further includes an auto-correlation operator for effecting an auto-correlation of the beat wave digitized by the circuit (25) and also spectrum processing means (32) for finally determining the distance h.
Inventors
- 👤 Hugues Crepin
- 👤 Serge Hethuin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:52
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/08; G01S13/32; G01S13/34; G01S13/343
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
173 words
A radar device for measuring the distance h of the device from a surface, said device comprising: a. transmitting means for transmitting a frequency-modulated wave toward the surface; b. receiving means for receiving a reflection of the wave from the surface; c. a mixer circuit electrically coupled to the transmitting and receiving means for producing a beat signal; and d. processing means for determining from the beat signal the distance h, said processing circuit including: (1) a digitizing circuit electrically coupled to the mixer circuit for producing digital samples of the beat signal; (2) auto-correlation means electrically coupled to the digitizing circuit for effecting auto-correlation of the digital samples of the beat signal; (3) time-frequency transform means electrically coupled to the auto-correlation means for producing from the auto-correlated samples components representative of the frequency spectrum of the reflection wave; and (4) spectrum processing means electrically coupled to the time-frequency transform means for operating on selected ones of the components having predefined amplitudes and determining a frequency f b representative of the distance h.
Claim 2
Dependent Claim
173 words
A radar device for measuring the distance h of the device from a surface, said device comprising: a. transmitting means for transmitting a frequency-modulated wave toward the surface; b. receiving means for receiving a reflection of the wave from the surface; c. a mixer circuit electrically coupled to the transmitting and receiving means for producing a beat signal; and d. processing means for determining from the beat signal the distance h, said processing circuit including: (1) a digitizing circuit electrically coupled to the mixer circuit for producing digital samples of the beat signal; (2) auto-correlation means electrically coupled to the digitizing circuit for effecting auto-correlation of the digital samples of the beat signal; (3) time-frequency transform means electrically coupled to the auto-correlation means for producing from the auto-correlated samples components representative of the frequency spectrum of the reflection wave; and (4) spectrum processing means electrically coupled to the time-frequency transform means for operating on selected ones of the components having predefined amplitudes and determining a frequency f b representative of the distance h.
Claim 3
Dependent Claim
63 words
A radar device as claimed in claim 1, characterized in that the spectrum processing means determines the frequency f b by performing the operation: ##EQU8## where c n are the amplitude values of the components produced by the time-frequency transform means and where f n are the frequency values with respect to these amplitudes, n being an integer varying from k to k+m.
Claim 4
Dependent Claim
124 words
A radar device as claimed in claim 1, characterized in that the spectrum processing means operates on amplitude values c n of the components produced by the time-frequency transform means for the frequencies f i , in accordance with the following method: a. that value i is determined which gives the maximum absolute value of c n -c n-1 , that is to say c i -c i-1 ; b. those components c i or c i-1 are determined which have the highest amplitude; and c. determining the frequency in accordance with the formula: f b =f i or f i-1 depending on whether c i >c i-1 or c i-1 >c i , respectively, n being an integer varying from k to k+m.
Claim 5
Dependent Claim
79 words
A radar device as claimed in claim 1, characterized in that the spectrum processing means operates on amplitude values c n of the components produced by the time-frequency transform means for the frequencies f n in accordance with the following method: a. f b 2 is calculated in accordance with the formula ##EQU9## b. the value h is determined by finding the square-root value f b of the preceding quantity, n being an integer varying from k to k+m.
Claim 6
Dependent Claim
76 words
A radar device as claimed in claim 1, characterized in that the spectrum processing means operates on amplitude values c n of the components produced by the time-frequency transform means for the frequencies f i to determine the value i such that c i is the highest of the components and the frequency f b from which h is determined then being f b =f i , n being an integer varying from k to k+m.
References Cited (Backward Citations)
US4078234A
Cited
US4107679A
Cited
US4205314A
Cited
US4568938A
Cited
US4599618A
Cited
US4620192A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |