Method and apparatus for digitally determining the speed of a target vehicle while the radar platform vehicle is in motion
First Claim
1. A frequency discriminator for use in a doppler radar device operable to determine the speed of a target vehicle when the radar platform vehicle is moving, said doppler radar device having a receiving means operable to receive a composite doppler signal having frequency components relating to the speed of said target vehicle and the speed of said radar platform vehicle, said frequency discriminator comprising:
- means for frequency translating the received doppler signal to lock one of the frequency translated components to a preselected reference frequency;
means for separating the frequency translated doppler signal into a first frequency translated component and a second frequency translated component;
means for frequency translating said first frequency translated component to produce a signal suitable for a first speed measurement display.
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Accused Products
Abstract
A moving doppler radar unit capable of separating the incoming doppler signal into its respective frequency components by means of frequency translation techniques and fixed frequency filters is disclosed. When the radar platform vehicle and target vehicle are both moving, the received doppler signal is a complex wave having frequency components related to the ground speed of the platform vehicle and the relative speed of the platform and target vehicles with respect to each other. Separation of the received doppler signal into its respective frequency components is accomplished by frequency translating the received doppler signal to a preselected reference frequency, discriminating between the frequency translated platform speed and target speed frequency components by means of a narrow band filter and a band pass filter, and frequency translating the separated frequency components downward to provide speed signals representative of the ground speed of the radar platform vehicle and the ground speed of the target vehicle. These speed signals are then converted into digital speed information which can be conventionally displayed. A lock detection circuit is included to inhibit the speed computation if the received doppler signal is not properly frequency translated to the reference frequency.
51 Citations
35 Claims
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1. A frequency discriminator for use in a doppler radar device operable to determine the speed of a target vehicle when the radar platform vehicle is moving, said doppler radar device having a receiving means operable to receive a composite doppler signal having frequency components relating to the speed of said target vehicle and the speed of said radar platform vehicle, said frequency discriminator comprising:
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means for frequency translating the received doppler signal to lock one of the frequency translated components to a preselected reference frequency; means for separating the frequency translated doppler signal into a first frequency translated component and a second frequency translated component; means for frequency translating said first frequency translated component to produce a signal suitable for a first speed measurement display. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A doppler radar device for determining the speed of a target vehicle when the radar platform vehicle is moving, said device comprising:
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a means for receiving a composite doppler signal having frequency components relating to the speed of said target vehicle and the speed of said radar platform vehicle; means for frequency translating the received doppler signal so as to lock the frequency translated component resulting from the platform vehicle speed to a preselected reference frequency; means for separating the frequency translated doppler signal into a first frequency translated component and a second frequency translated component; means for frequency translating said first frequency translated component to provide a first speed component; means for converting said first speed component into speed information; and means for displaying said speed information of said first speed component. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method for separating the doppler signal received from a target vehicle by a moving platform having a doppler radar transceiver thereon into composite frequencies, said step comprising the steps of:
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frequency translating the received doppler signal so as to lock a frequency translated component thereof to a preselected reference frequency; filtering the received doppler signal into a first frequency translated component and a second frequency translated component; and frequency translating said first frequency translated component to provide a first signal suitable for displaying speed information. - View Dependent Claims (33, 34, 35)
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Specification