Marine radar based on cylindrical array antennas with other applications
First Claim
1. A method of providing and operating a radar system for detecting moving targets comprising:
- providing a cylindrical array antenna with one or more layers of array elements equally spaced around a respective cylinder;
digitally controlling the array elements to activate a subset of the array elements at any given time;
generating waveforms that are common to all active transmit array elements, the waveforms having phase or frequency modulation to provide high resolution in range;
controlling amplitude and phase of the generated waveforms in each active transmit array element in the subset to collectively form and point the respective transmit beam;
receiving returns from scatterers illuminated by the transmit beam at each active receive array element;
controlling amplitude and phase of the received returns at the respective active receive array elements, and combining the results to form a receive beam;
digitizing the combined results to form a digital representation of the radar return in the receive beam;
processing the digitized radar returns to create a sequence of range samples;
coherently processing a sequence of digitized radar returns to obtain Doppler resolution represented by a sequence of Doppler samples, repeated in each receive beam for each range sample;
envelope detecting the range and Doppler samples;
comparing the envelope detected range and Doppler samples with at least one threshold for detection of the moving targets;
recording the receive beam positions corresponding to the spacing of the array elements of detected moving targets;
comparing detected moving targets with previously detected targets already in track,check for range ambiguities, and update track files;
displaying the detected moving targets on a computer monitor;
displaying received returns from stationary objects in a background mode;
repeating the above operations for a sequence of beam positions to scan a designated sector; and
changing a transmit repetition frequency on alternate scans to resolve range and Doppler ambiguities.
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Accused Products
Abstract
An all-solid-state marine radar technology based on a non-rotating cylindrical array antenna is described. Multiple transmit and receive modules are used to form the antenna beam, which allows the beam sequencing, the dwell time in each beam position, the resolution, and the beam shape to be varied in order to make best use of the available energy. Waveforms with a high duty ratio can be used on transmit in order to make efficient use of solid-state power amplifiers. High resolution in both range and Doppler provides high measurement accuracy and superior performance in clutter. Alternate embodiments, including continuous waveform embodiments are disclosed.
36 Citations
29 Claims
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1. A method of providing and operating a radar system for detecting moving targets comprising:
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providing a cylindrical array antenna with one or more layers of array elements equally spaced around a respective cylinder; digitally controlling the array elements to activate a subset of the array elements at any given time; generating waveforms that are common to all active transmit array elements, the waveforms having phase or frequency modulation to provide high resolution in range; controlling amplitude and phase of the generated waveforms in each active transmit array element in the subset to collectively form and point the respective transmit beam; receiving returns from scatterers illuminated by the transmit beam at each active receive array element; controlling amplitude and phase of the received returns at the respective active receive array elements, and combining the results to form a receive beam; digitizing the combined results to form a digital representation of the radar return in the receive beam; processing the digitized radar returns to create a sequence of range samples; coherently processing a sequence of digitized radar returns to obtain Doppler resolution represented by a sequence of Doppler samples, repeated in each receive beam for each range sample; envelope detecting the range and Doppler samples; comparing the envelope detected range and Doppler samples with at least one threshold for detection of the moving targets; recording the receive beam positions corresponding to the spacing of the array elements of detected moving targets; comparing detected moving targets with previously detected targets already in track, check for range ambiguities, and update track files; displaying the detected moving targets on a computer monitor; displaying received returns from stationary objects in a background mode; repeating the above operations for a sequence of beam positions to scan a designated sector; and changing a transmit repetition frequency on alternate scans to resolve range and Doppler ambiguities. - 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)
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Specification