US4316191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low angle radar processing means
Assignee: Bendix Corp
•
Filing: 1980-04-14
•
Granted: 1982-02-16
•
Expires: 2000-04-14
Abstract
Abstract The elevation angle of a low angle target is accurately measured by subtracting from the received radar signal signals derived from an estimated value of target elevation which reduces the resulting signal to a minimum. The estimated value is an accurate measure of target elevation.
Inventors
- 👤 Takeo Sawatari
- 👤 Patrick N. Keating
- 👤 Ronald F. Steinberg
- 👤 Rolf K. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:25
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S3/00; G01S3/02; G01S3/04; G01S3/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
153 words
Radar equipment for processing electromagnetic signals from a low elevation target including radar means for receiving said electromagnetic signals from said low elevation target directly and via ground bounce comprising: an N element array antenna for receiving said electromagnetic signals; a set of N detectors of the received electromagnetic signals, each said detector being arranged in a separate channel; demodulator means for converting the detected electromagnetic signals into a set of N complex electrical signals X m , one said electrical signal being contained in each said channel; a matrix of complex weights M mn responsive to said set of N complex electrical signals X m for generating a set of N complex electrical signals X n ' where: ##EQU8## means for determining the total power represented by said set of N complex electrical signals X n '; and, means for iteratively adjusting said complex weights M mn to minimize said total power.
Claim 2
Dependent Claim
153 words
Radar equipment for processing electromagnetic signals from a low elevation target including radar means for receiving said electromagnetic signals from said low elevation target directly and via ground bounce comprising: an N element array antenna for receiving said electromagnetic signals; a set of N detectors of the received electromagnetic signals, each said detector being arranged in a separate channel; demodulator means for converting the detected electromagnetic signals into a set of N complex electrical signals X m , one said electrical signal being contained in each said channel; a matrix of complex weights M mn responsive to said set of N complex electrical signals X m for generating a set of N complex electrical signals X n ' where: ##EQU8## means for determining the total power represented by said set of N complex electrical signals X n '; and, means for iteratively adjusting said complex weights M mn to minimize said total power.
Claim 3
Dependent Claim
167 words
The equipment of claim 1 wherein: ##EQU9## where r and s correspond to the elevation angles of two signals from said low elevation target, respectively the direct-path signal (r, s=1) and the ground multipath signal (r, s=2) so that the set of H rs values (H 11 , H 12 , H 21 , H 22 ) forms a 2×2 matrix H, the inverse of which is: ##EQU10## and wherein: ##EQU11## λ=the wavelength of the electromagnetic signals A n is the position of the n th detector, and the normalized complex amplitude of the electromagnetic signals incident on the n th detector due to said low elevation target at an angle θ s is defined as d sn where: ##EQU12## and, wherein said complex weights are factorable into a real weighting factor W mn and a real phase shift φ mn , said matrix being comprised of means for weighting said complex electrical signals by W mn and for shifting the phase thereof by φ mn .
Claim 4
Dependent Claim
66 words
The equipment of claim 1 or 2 wherein said means for determining the total power represented by said set of N complex electrical signals X n ' comprises: means for squaring each of the signals X n ' to produce a set of power signals, each of which represents the power content of its parent signal X n '; and, means for summing said power signals.
Claim 5
Dependent Claim
54 words
The equipment of claim 1 or 2 wherein said means for determining the total power represented by said set of N complex electrical signals X n ' comprises: means for summing said N complex electrical signals X n '; and, means for squaring the sum of said N complex electrical signals X n '.
References Cited (Backward Citations)
US3189900A
Cited
US3229283A
Cited
US3720941A
Cited
US3757326A
Cited
US4005421A
Cited
US4084160A
Cited
US4060807A
Cited
US4163975A
Cited
FR2408843A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-02-15 | 1985-08-17 | 1986-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-15 | 1989-08-17 | 1990-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-15 | 1993-08-17 | 1994-02-16 | $7700.00 | Window Closed / Lapsed |