US5684490A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Highway vehicle guidance system
Assignee: The Ohio State University
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Filing: 1995-03-01
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Granted: 1997-11-04
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Expires: 2015-03-01
Abstract
Abstract A radar highway motor vehicle guidance apparatus for guiding a land vehicle along a roadway using a forward looking, lateral position sensing, monopulse tracking radar guidance apparatus which transmits radar pulses forward of the vehicle. The pulses are reflected back to the vehicle by a stripe distributed along the roadway. The stripe is a frequency selective surface which generates retro-reflective grating lobes at an operating frequency of the tracking radar. Operating the radar at two frequencies allows the radar to look at regions spaced at two different distances from the front of the vehicle. Highway related information may be encoded in the frequency selective surface by variations in the shape or dimensions of the frequency selective stripe morphology in order to modulate the reflected signal with highway information which is then also detected at the radar receiver. Target discrimination is enhanced by using pseudo random codes and matching antenna polarization with stripe polarization.
Inventors
- 👤 Jonathan D. Young
- 👤 Lee W. Henderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:59
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/06; G01S13/42; G01S13/44; G01S13/88; G01S13/93; G01S13/931; G01S7/00; G01S7/02; G01S7/024; H; H01; H01Q; H01Q1/00; H01Q1/27; H01Q1/32; H01Q1/3208; H01Q1/3233; H01Q15/00; H01Q15/0006; H01Q15/0013; G01S13/08; G01S13/10; G01S13/106; G01S13/24; G01S13/4454; G01S13/4463; G01S2013/9318; G01S2013/9327; G01S2013/93271; G01S2013/93272; G01S2013/9329; G01S7/03; G01S7/032
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
129 words
A radar vehicle guidance apparatus for use in guiding a land vehicle along a roadway and comprising: (a) a forward looking, lateral position sensing, tracking radar guidance apparatus mounted to the vehicle wherein the radar radiates and detects at least two frequencies, the two frequencies being selected to generate a retro-reflected grating lobe at two angles above the roadway and corresponding to two different distances from the vehicle; and (b) an elongated stripe distributed along the roadway in the direction of vehicle travel, the stripe comprising substantially laterally aligned antenna elements substantially uniformly spaced at least one-half the wavelength of the radar frequency, formed of electrically conductive material and spaced to provide a frequency selective surface generating retro-reflective, non-specular grating lobes at the operating frequencies of the tracking radar.
Claim 2
Dependent Claim
129 words
A radar vehicle guidance apparatus for use in guiding a land vehicle along a roadway and comprising: (a) a forward looking, lateral position sensing, tracking radar guidance apparatus mounted to the vehicle wherein the radar radiates and detects at least two frequencies, the two frequencies being selected to generate a retro-reflected grating lobe at two angles above the roadway and corresponding to two different distances from the vehicle; and (b) an elongated stripe distributed along the roadway in the direction of vehicle travel, the stripe comprising substantially laterally aligned antenna elements substantially uniformly spaced at least one-half the wavelength of the radar frequency, formed of electrically conductive material and spaced to provide a frequency selective surface generating retro-reflective, non-specular grating lobes at the operating frequencies of the tracking radar.
Claim 3
Dependent Claim
18 words
An apparatus in accordance with claim 1 wherein the radar guidance apparatus comprises a monopulse radar guidance apparatus.
Claim 4
Dependent Claim
25 words
An apparatus in accordance with claim 1 wherein the radar apparatus comprises a chirp radar transmitting pulses across a frequency band including said two frequencies.
Claim 5
Dependent Claim
72 words
An apparatus in accordance with claim 1 wherein polarization, frequency response and grating lobe angle parameters of the stripe are determined by the size, shape and orientation of said antenna elements, wherein at least one of said parameters is spatially varied along the stripe to modulate incident radar waves and generate waves reflected from the stripe containing roadway related information, and wherein the radar includes a detector for demodulating the reflected signals.
Claim 6
Dependent Claim
39 words
An apparatus in accordance with claim 1 wherein the radar has a transmitter which modulates the transmitted radar pulses with a selected pseudo-random code and also has a receiver which discriminates the reflections from said transmitter using correlation techniques.
Claim 7
Dependent Claim
19 words
An apparatus in accordance with claim 1 wherein said elements are covered by a weather resistant protective synthetic resin.
Claim 8
Dependent Claim
23 words
An apparatus in accordance with claim 1 wherein a ground plane is spaced below said elements for increasing the reflectivity of said stripe.
Claim 9
Dependent Claim
36 words
An apparatus in accordance with claim 1 wherein said stripe comprises a series of parallel, substantially equidistantly spaced wires spaced in excess of one half wavelength of said radar operating frequency and less than one wavelength.
Claim 10
Dependent Claim
18 words
An apparatus in accordance with claim 1 wherein the antenna elements comprise a series of spaced conductor elements.
Claim 11
Dependent Claim
26 words
An apparatus in accordance with claim 1 wherein the antenna elements comprise a conductive sheet material having a pattern of non-conducting slots forming slot antenna elements.
Claim 12
Independent Claim
124 words
A method for guiding a vehicle along a roadway comprising: directing radar waves at a radar frequency toward the roadway and radar tracking and steering the vehicle to follow retro-reflections from an elongated frequency selective surface formed as a stripe along a roadway by a series of substantially laterally aligned antenna elements formed by a conductive material with substantially uniform spacings between the elements at least one-half wavelength of the radar frequency to generate retro-reflective, non-specular grating lobes from incident radar waves, the radar tracking comprising radiating radar waves at a plurality of frequencies which generate retro-reflecting grating lobes reflected from said stripe at different angles above the roadway, and detecting the waves at said different frequencies corresponding to different distances from the vehicle.
Claim 13
Independent Claim
124 words
A method for guiding a vehicle along a roadway comprising: directing radar waves at a radar frequency toward the roadway and radar tracking and steering the vehicle to follow retro-reflections from an elongated frequency selective surface formed as a stripe along a roadway by a series of substantially laterally aligned antenna elements formed by a conductive material with substantially uniform spacings between the elements at least one-half wavelength of the radar frequency to generate retro-reflective, non-specular grating lobes from incident radar waves, the radar tracking comprising radiating radar waves at a plurality of frequencies which generate retro-reflecting grating lobes reflected from said stripe at different angles above the roadway, and detecting the waves at said different frequencies corresponding to different distances from the vehicle.
Claim 14
Dependent Claim
45 words
A method in accordance with claim 11 and further comprising varying the physical configuration of said elements in a pattern modulating an incident radar wave from a moving vehicle with roadway related information and demodulating the information in a receiver circuit mounted to the vehicle.
Claim 15
Dependent Claim
25 words
A method in accordance with claim 11 and further comprising modulating radiated radar waves with a pseudo-random code and discriminating reflected waves by cross correlation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-11-03 | 2001-05-05 | 2001-11-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-03 | 2005-05-05 | 2005-11-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-03 | 2009-05-05 | 2009-11-04 | $7700.00 | Window Closed / Lapsed |