Object detection and location system
First Claim
1. A millimeter wave object detection and location system, comprising:
- an array of oscillators for emitting a beam of millimeter wave radiation the frequency of which varies according to a predetermined function of time;
means for directing said radiation onto a detector array as a local oscillator signal, and for transmitting said radiation into a field of view;
a detector array for detecting said emitted time-varying radiation having been reflected from one or more objects in the field of view, wherein said detector array comprises a two-dimensional array of detectors, each of said detectors being capable of forming a signal responsive to mixing of millimeter-wave radiation reflected from an object in the corresponding portion of said field of view with said local oscillator signal;
wherein said array of oscillators each direct radiation into a particular portion of said field of view and onto a corresponding portion of said detector array; and
means for processing the signals formed by each of said detectors in order to detect the presence of any said objects in the field of view and to indicate their locations.
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Accused Products
Abstract
A millimeter wave object detection and location system is disclosed comprising a source generating a millimeter wave signal which is divided into an illumination beam, directed onto a field of view, and a local oscillator portion, mixed with radiation reflected from objects in the field of view. The mixing is performed in a staring array of mixer/detector elements which need not be mechanically or electronically scanned to generate signals responsive to the entire field of view. The detected signal from each element is directly responsive to a portion of the field of view. The oscillator signal is preferably linearly polarized, and a polarizing grid is used to separate the local oscillator signal and illumination beam and direct them in a simple and efficient manner. A twist reflector may also be used to rotate the polarization of a portion of the beam to direct it onto the mixer/detector array for mixing with the received signal from the field of view.
Improved constructions of millimeter wave source and mixer/detector elements are also disclosed, which greatly simplify construction of the device.
90 Citations
64 Claims
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1. A millimeter wave object detection and location system, comprising:
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an array of oscillators for emitting a beam of millimeter wave radiation the frequency of which varies according to a predetermined function of time; means for directing said radiation onto a detector array as a local oscillator signal, and for transmitting said radiation into a field of view; a detector array for detecting said emitted time-varying radiation having been reflected from one or more objects in the field of view, wherein said detector array comprises a two-dimensional array of detectors, each of said detectors being capable of forming a signal responsive to mixing of millimeter-wave radiation reflected from an object in the corresponding portion of said field of view with said local oscillator signal; wherein said array of oscillators each direct radiation into a particular portion of said field of view and onto a corresponding portion of said detector array; and means for processing the signals formed by each of said detectors in order to detect the presence of any said objects in the field of view and to indicate their locations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A millimeter wave object detection, location and velocity indicating system, comprising:
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means for emitting a beam of millimeter-wave radiation, the frequency of which is varied in a predetermined manner as function of time; means for directing said beam onto a field of view; an array of detectors for detecting radiation reflected from objects in said field of view; an array of sources of millimeter wave radiation, arranged to evenly illuminate said array of detectors with a local oscillator signal; said detectors each further comprising means for mixing said local oscillator signal with radiation reflected from objects in the field of view and means for providing an output signal responsive to said means for mixing; and signal processing means, for; determining the direction of said objects with respect to said array of detectors, responsive to identification of the ones of said detectors providing said output signals; determining the distance of said objects from said array of detectors, responsive to measurement of the time elapsed between emission of the reflected radiation and its detection; and determining the velocity of said objects by determining the relative frequency shift of the reflected radiation. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. Method for generating a millimeter-wave image responsive to objects in a field of view, comprising the steps of:
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employing an array of oscillator sources to generate a beam of millimeter-wave energy, the frequency of which is varied according to a predetermined function of time, transmitting a first minor portion of said beam toward an array of mixer/detector elements, such that individual ones of said oscillator sources illuminate corresponding portions of said array, directing a second major portion of said beam onto the field of view, such that individual ones of said oscillator sources illuminate corresponding portions of the field of view, focusing energy from said major portion of said beam reflected from objects in the field of view onto the array, mixing the reflected energy with the minor portion of the beam individually in the elements of said array, detecting difference-frequency signals resulting from said mixing step with respect to each of the elements of said array, analyzing said detected difference frequency signals to determine the relative direction and distance of said objects with respect to said array of elements, and generating an image of said objects responsive to said analyzing step. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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Specification