Highway vehicle guidance system
First Claim
1. A radar vehicle guidance apparatus for use in guiding a land vehicle along a roadway and comprising:
- (a) a backward looking, lateral position sensing, tracking first radar guidance apparatus mounted to the vehicle and operating at a radar frequency; and
(b) an elongated stripe distributed along the roadway in the direction of vehicle travel, the stripe comprising a frequency selective surface having a substantially uniform series of scattering antenna elements formed by electrically conductive material for generating a retro-reflective grating lobe extending from behind the vehicle at an operating frequency of the tracking radar.
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Accused Products
Abstract
A radar highway motor vehicle guidance apparatus for guiding a land vehicle along a roadway using a backward looking and a forward looking, lateral position sensing, monopulse tracking radar guidance apparatus which transmits radar pulses backward and 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.
52 Citations
15 Claims
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1. A radar vehicle guidance apparatus for use in guiding a land vehicle along a roadway and comprising:
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(a) a backward looking, lateral position sensing, tracking first radar guidance apparatus mounted to the vehicle and operating at a radar frequency; and (b) an elongated stripe distributed along the roadway in the direction of vehicle travel, the stripe comprising a frequency selective surface having a substantially uniform series of scattering antenna elements formed by electrically conductive material for generating a retro-reflective grating lobe extending from behind the vehicle at an operating frequency of the tracking radar. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for guiding a vehicle along a roadway comprising:
radar tracking and steering the vehicle by radiating radar waves in the forward direction and in the rearward direction and detecting retro-reflections from an elongated frequency selective surface ahead of and from an elongated frequency selective surface behind the vehicle, the frequency selective surface including a stripe along a roadway formed of a series of antenna elements formed by a conductive material with spacings between the elements to generate retro-reflective grating lobes from incident radar waves. - View Dependent Claims (13, 14, 15)
Specification