Patent US5502444A successfully refreshed from Google Patents.
US5502444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for improving the signal-to-clutter ratio of an airborne earth penetrating radar
Assignee: Mandex Inc
•
Filing: 1994-09-23
•
Granted: 1996-03-26
•
Expires: 2014-09-23
Abstract
Abstract The method improves the signal-to-clutter ratio of an airborne earth penetrating radar for distinguishing subsurface objects from surface clutter or above-ground objects. The method relies on the dispersive response of the signals returned from an subsurface object to distinguish these subsurface signals from the non-dispersive response signals returned by surface clutter. The electromagnetic response from a subsurface object is spread out over time in comparison to the response from surface clutter. A correlation coincidence detection methodology discriminates surface clutter based on the temporal persistence of a subsurface object. The correlation procedure produces a sequence of values which are used as the basis for detection. If the radar pulses detect a subsurface object, the sequence of values persists beyond the interval of integration containing the clutter response.
Inventors
- 👤 Ira Kohlberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:08
CPC Classifications
G; G01; G01S; G01S7/00; G01S7/02; G01S7/28; G01S7/285; G01S7/32; G01S7/292; G01V; G01V3/00; G01V3/15; G01V3/17; G01S13/00; G01S13/88
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
101 words
A method of detecting a subsurface object buried in a dispersive environment comprising the steps of: transmitting a radiant signal; receiving a returned reflection of the radiant signal, the returned reflection including a clutter response and a buried object response; dividing the returned reflection into time intervals; performing a correlation operation for the returned reflection to obtain a sequence of correlation voltages; determining the existence of correlation values in the sequence beyond the time interval containing the clutter response; indicating the presence of the buried object based on the existence of correlation values beyond the time interval containing the clutter response.
Claim 2
Independent Claim
101 words
A method of detecting a subsurface object buried in a dispersive environment comprising the steps of: transmitting a radiant signal; receiving a returned reflection of the radiant signal, the returned reflection including a clutter response and a buried object response; dividing the returned reflection into time intervals; performing a correlation operation for the returned reflection to obtain a sequence of correlation voltages; determining the existence of correlation values in the sequence beyond the time interval containing the clutter response; indicating the presence of the buried object based on the existence of correlation values beyond the time interval containing the clutter response.
Claim 3
Dependent Claim
60 words
The method of claim 1, wherein the step of performing a correlation operation further includes the steps of: computing the magnitude of the correlation voltage; and comparing the magnitude of the correlation voltages with a minimum threshold value to determine whether the correlation voltage is above the threshold value to be used in determining the existence of a non-surface object.
Claim 4
Dependent Claim
16 words
The method of claim 1, wherein the minimum threshold value corresponds to a signal noise level.
Claim 5
Dependent Claim
24 words
The method of claim 1, wherein the transmitted radiant signal has a frequency low enough to reach the subsurface object in the dispersive environment.
Claim 6
Dependent Claim
22 words
The method of claim 1 further comprising the step of determining the time intervals containing the clutter response from a ranging operation.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein the radiant signal is transmitted and received by an airborne radar platform.
Claim 8
Dependent Claim
117 words
A radar system for detecting non-surface objects comprising: a transmitting antenna emitting radiant signals; a receiving antenna receiving return signals reflected from a non-surface object and clutter; a correlation processing unit dividing the returned reflection into time intervals, performing a correlation operation for the returned reflection to obtain a sequence of correlation voltages, and determining the existence of correlation values in the sequence beyond the time interval containing the clutter response; said correlation processing unit producing a first detection signal when the existence of correlation values is detected beyond the time intervals containing the clutter response; and a display indicating the presence of the non-surface object based on said first detection signal from said correlation processing unit.
Claim 9
Dependent Claim
117 words
A radar system for detecting non-surface objects comprising: a transmitting antenna emitting radiant signals; a receiving antenna receiving return signals reflected from a non-surface object and clutter; a correlation processing unit dividing the returned reflection into time intervals, performing a correlation operation for the returned reflection to obtain a sequence of correlation voltages, and determining the existence of correlation values in the sequence beyond the time interval containing the clutter response; said correlation processing unit producing a first detection signal when the existence of correlation values is detected beyond the time intervals containing the clutter response; and a display indicating the presence of the non-surface object based on said first detection signal from said correlation processing unit.
Claim 10
Dependent Claim
20 words
The radar system of claim 7, wherein said correlation processing unit uses a Kronecker delta function in the correlation operation.
Claim 11
Dependent Claim
53 words
The radar system of claim 7, wherein said correlation processing unit computes the magnitude of the correlation voltage; and compares the magnitude of the correlation voltages with a minimum threshold value to determine whether the correlation voltage is above the threshold value to be used in determining the existence of a non-surface object.
Claim 12
Dependent Claim
17 words
The radar system of claim 7, wherein said transmitting antenna is an airborne earth penetrating radar platform.
References Cited (Backward Citations)
US4866446A
Cited
US4812850A
Cited
US4896116A
Cited
US4905008A
Cited
US4937580A
Cited
US5057846A
Cited
US5132691A
Cited
US5160931A
Cited
US5247302A
Cited
US5339080A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-26 | 1999-09-25 | 2000-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-26 | 2003-09-25 | 2004-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-26 | 2007-09-25 | 2008-03-26 | $7700.00 | Window Closed / Lapsed |