Angular shift determining apparatus for determining angular shift of central axis of radar used in automotive obstacle detection system
First Claim
1. An angular shift determining apparatus for determining an angular shift of a central axis of radar wave radiation from a radar device used in an automotive obstacle detection system designed to determine a distance to and angular direction of a target tracked by the radar device comprising:
- an object identifying circuit that determines a relative position and a relative speed of the target with respect to a system vehicle equipped with the automotive obstacle detection system in cycles based on the distance to and the angular direction of the target determined by the automotive obstacle detection system and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; and
an angular shift determining circuit that determines the angular shift of the central axis of radar wave radiation from a longitudinal center line of the system vehicle based on an angular component of the relative position of the moving object as represented by polar coordinates, said angular shift determining circuit also determining an offset of a distribution of relative positions of the moving object, determined by said object identifying circuit in cycles for a preselected period of time when the system vehicle is substantially traveling straight, from the central axis of radar wave radiation in a width-wise direction of the system vehicle to determine an error component of the angular shift of the central axis of radar wave radiation caused by a lateral offset of the moving object from the longitudinal center line of the system vehicle to correct the angular shift of central axis of radar waver radiation by removing the error component therefrom.
1 Assignment
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Accused Products
Abstract
An angular shift determining apparatus is provided which may be employed in an automotive obstacle detection system designed to determine a distance to and angular direction of a target tracked by a radar. The angular shift determining apparatus determines an angular shift of the central axis of radiation of radar waves from the longitudinal center line of a vehicle equipped with the obstacle detection system based on a relative position of the target and removes from the determined angular shift an error component produced when a preceding vehicle traveling with a lateral offset from the system vehicle is tracked as the target and an error component produced when a stationary object located on a curved road is tracked by the radar as the target to mathematically project an actual angular shift of the central axis of radiation of radar waves.
84 Citations
27 Claims
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1. An angular shift determining apparatus for determining an angular shift of a central axis of radar wave radiation from a radar device used in an automotive obstacle detection system designed to determine a distance to and angular direction of a target tracked by the radar device comprising:
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an object identifying circuit that determines a relative position and a relative speed of the target with respect to a system vehicle equipped with the automotive obstacle detection system in cycles based on the distance to and the angular direction of the target determined by the automotive obstacle detection system and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; and an angular shift determining circuit that determines the angular shift of the central axis of radar wave radiation from a longitudinal center line of the system vehicle based on an angular component of the relative position of the moving object as represented by polar coordinates, said angular shift determining circuit also determining an offset of a distribution of relative positions of the moving object, determined by said object identifying circuit in cycles for a preselected period of time when the system vehicle is substantially traveling straight, from the central axis of radar wave radiation in a width-wise direction of the system vehicle to determine an error component of the angular shift of the central axis of radar wave radiation caused by a lateral offset of the moving object from the longitudinal center line of the system vehicle to correct the angular shift of central axis of radar waver radiation by removing the error component therefrom. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An angular shift determining apparatus for determining an angular shift of a central axis of radar wave radiation from a radar device used in an automotive obstacle detection system designed to determine a distance to and angular direction of a target tracked by the radar device comprising:
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an object identifying circuit that determines a relative position and a relative speed of the target to a system vehicle equipped with the automotive obstacle detection system in cycles based on the distance to and the angular direction of the target determined by the automotive obstacle detection system and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; and an angular shift determining circuit that determines the angular shift of the central axis of radar wave radiation from a longitudinal center line of the system vehicle based on a direction of the relative speed of the target determined as the stationary object, when the system vehicle is traveling on a curve in a road, said angular shift determining circuit also determining the degree of the curve to determine an error component of the angular shift of the central axis of radar wave radiation caused by the traveling of the system vehicle on the curve to correct the angular shift of central axis of radar waver radiation by removing the error component therefrom.
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13. An angular shift determining apparatus for determining an angular shift of a central axis of radar wave radiation from a radar device used in an automotive obstacle detection system designed to determine a distance to and angular direction of a target tracked by the radar device comprising:
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an object identifying circuit that determines a relative position and a relative speed of each target traced by the radar device to a system vehicle equipped with the automotive obstacle detection system in cycles based on the distance to and the angular direction of the target determined by the automotive obstacle detection system and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; and an angular shift determining circuit that determines an angular shift of the central axis of radar wave radiation from a longitudinal center line of the system vehicle as a first angular shift based on the relative position of the target determined as the moving object, said angular shift determining circuit also determining an offset of a distribution of relative positions of the moving object, determined by said object identifying circuit in cycles for a preselected period of time when the system vehicle is substantially traveling straight, from the central axis of radar wave radiation in a width-wise direction of the system vehicle to determine a first error component included in the first angular shift caused by a lateral offset of the moving object from the longitudinal center line of the system vehicle to remove the first error component from the first angular shift to determine a first error-removed angular shift, said angular shift determining circuit determining an angular shift of the central axis of radar wave radiation as a second angular shift based on a direction of the relative speed of the target determined as the stationary object, when the system vehicle is traveling on a curve in a road, said angular shift determining circuit also determining the degree of the curve to remove an error component caused by the traveling of the system vehicle on the curve from the second angular shift to determine a second error-removed angular shift, said angular shift determining circuit mathematically projecting an actual angular shift of the central axis of radar wave radiation based on the first and second error-removed angular shifts. - View Dependent Claims (14, 15, 16, 17, 18)
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19. An automotive obstacle detection apparatus comprising:
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a radar device that transmits a radar wave over a given detection range across a central axis at given angular intervals; a distance determining circuit that determines a distance to a target within the given detection range based on a time interval between transmission of the radar wave and reception of the radar wave reflected from the given detection range; a storage device that stores a relation between the distance to the target determined by said distance determining circuit and an angular direction of the radar wave transmitted by said radar wave; an object identifying circuit that determines a relative position and a relative speed of the target to a subject vehicle equipped with the obstacle detection apparatus in cycles based on the distance to and the angular direction of the target stored in said storage device and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; an angular shift determining circuit that determines an angular shift of the central axis of radar wave radiation from a longitudinal center line of the subject vehicle based on the relative position of the moving object, said angular shift determining circuit also determining an offset of a distribution of relative positions of the moving object, determined by said object identifying circuit in cycles for a preselected period of time when the subject vehicle is substantially traveling straight, from the central axis of radar wave radiation in a width-wise direction of the subject vehicle to determine an error component of the angular shift of the central axis of radar wave radiation caused by a lateral offset of the moving object from the longitudinal center line of the system vehicle to mathematically project an actual angular shift of central axis of radar waver radiation by removing the error component therefrom; and an angular direction correcting circuit that corrects the angular direction of the target by modifying the relation between the distance to the target and the angular direction of the radar wave transmitted by said radar wave stored in said storage device so as to eliminate the actual angular shift of the central axis of radar waver radiation. - View Dependent Claims (20, 21)
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22. An automotive intervehicle distance control apparatus comprising:
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an automotive obstacle detection apparatus including (a) a radar device that transmits a radar wave over a given detection range across a central axis at given angular intervals, (b) a distance/angle determining circuit that determines a distance to and an angular direction of a target within the given detection range based on a signal derived by reflection of the radar wave from the given detection range, and (c) an object identifying circuit that determines a relative position and a relative speed of the target to a vehicle controlled by the automotive intervehicle distance control apparatus in cycles based on the distance to and the angular direction of the target and that determines whether the target is a moving object or a stationary object based on the relative speed of the target; an angular shift determining circuit that determines an angular shift of the central axis of radar wave radiation from a longitudinal center line of the controlled vehicle based the relative position of the moving object, said angular shift determining circuit also determining an offset of a distribution of relative positions of the moving object determined by said object identifying circuit in cycles for a preselected period of time from the central axis of radar wave radiation in a width-wise direction of the controlled vehicle to determine an error component of the angular shift of the central axis of radar wave radiation caused by a lateral offset of the moving object from the longitudinal center line of the system vehicle to mathematically project an actual angular shift of central axis of radar waver radiation by removing the error component from said angular shift of the central axis of radar wave radiation; a correcting circuit that corrects the distance to and the angular direction of the target so as to eliminate the actual angular shift of the central axis of radar wave radiation; and an intervehicle distance control circuit that determines whether the target tracked by said radar device is a preceding vehicle traveling ahead of the controlled vehicle or not based on the distance to and the angular direction of the target corrected by said correcting circuit when an intervehicle distance control mode is entered, when it is determined that the target is the preceding vehicle, said intervehicle distance control circuit controlling speed of the controlled vehicle at a target change rate to bring a distance between the preceding vehicle and the controlled vehicle into agreement with a target distance. - View Dependent Claims (23, 24, 25, 26, 27)
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Specification