Apparatus for estimating direction of arrival of signal
First Claim
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1. An apparatus for estimating direction of arrival of a signal comprising:
- an array sensor having first and second sensor elements located at outermost ends and one or more third sensor elements located inward thereof;
switch means for selecting either one of the first and second sensor elements for transmission and one of the first, second, and third sensor, elements for reception;
switch control means for causing the switch means to select the first sensor element for transmission in a first period and to select at least the second and third sensor elements for reception in time division fashion, and for causing the switch means to select the second sensor element for transmission in a second period and to select at least the first and third sensor elements for reception in time division fashion, wherein the first and second periods are two periods alternating one after the other in cyclic fashion; and
direction-of-arrival estimating means for estimating the direction of arrival of the signal from a received signal obtained at the sensor element selected for reception.
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Abstract
An apparatus for estimating direction of arrival of signal is provided that has excellent performance in terms of angular resolution and the number of signals that can be identified. In an array sensor comprising a plurality of sensor elements, the two outermost sensor elements are alternately selected by a switch for use as a transmitting sensor, and the other sensor elements are selected in time division fashion as receiving sensors. With this arrangement, the effective aperture is increased to about twice the physical aperture, to improve angular resolution in a direction-of-arrival estimator.
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Citations
10 Claims
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1. An apparatus for estimating direction of arrival of a signal comprising:
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an array sensor having first and second sensor elements located at outermost ends and one or more third sensor elements located inward thereof; switch means for selecting either one of the first and second sensor elements for transmission and one of the first, second, and third sensor, elements for reception; switch control means for causing the switch means to select the first sensor element for transmission in a first period and to select at least the second and third sensor elements for reception in time division fashion, and for causing the switch means to select the second sensor element for transmission in a second period and to select at least the first and third sensor elements for reception in time division fashion, wherein the first and second periods are two periods alternating one after the other in cyclic fashion; and direction-of-arrival estimating means for estimating the direction of arrival of the signal from a received signal obtained at the sensor element selected for reception. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A calibration method for an apparatus for estimating direction of arrival of a signal comprising an array sensor having first and second sensor elements located at outermost ends and one or more third sensor elements located inward thereof, switch means for, selecting either one of the first and second sensor elements for transmission and one of the first, second, and third sensor elements for reception, switch control means for causing the switch means to select the first sensor element for transmission in a first period and to select at least the second and third sensor elements for reception in time division fashion, and for causing the switch means to select the second sensor element for transmission in a second period and to select at least the first and third sensor elements for reception in time division fashion, wherein the first and second periods are two periods alternating one after the other in cyclic fashion, and direction-of-arrival estimating means for estimating the direction of arrival of the signal front a received signal obtained at the sensor element selected for reception, said method comprising the steps of:
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determining a correction value of a direction vector; and calibrating said apparatus using said correction value so that a direction-of-arrival estimate computed from the received signals obtained at the second and third sensor elements when the first sensor element is selected as a transmitting sensor agrees with a direction-of-arrival estimate computed from the received signals obtained at the first and third sensor elements when the second sensor element is selected as a transmitting sensor.
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Specification