Extended angular resolution in sensor arrays using secondary echoes
View Patent ↗A reflector is used to extend an aperture of an omni-directional, single-point remote-sensing echo-system utilizing secondary round-trip reflections of a transmitted sensor signal. The reflector is spatially displaced from a transmission element to contribute a secondary reflection whose echo from the target object provides additional information used to triangulate both azimuthal and elevation angles of the target object.
1. A method for resolving an angular direction of an object, the method comprising:
transmitting a signal towards an object from a transmitter at transmission time, t 0 ;
receiving a first echo of the signal from the object at a receiver at receipt time t 2 ;
directing the first echo of the signal towards the object from a reflector displaced from the receiver;
receiving the second echo of the signal from the object at the receiver at second receipt time t 5 ; and
using a processor configured to triangulate an azimuthal angular direction of the object based on a delay between the times t 2 and t 5 , the azimuthal angular direction relative to a line defined by the transmitter and the receiver.
2. The method of claim 1 , wherein the transmitter and the reflector are mounted on a vehicle.
3. The method of claim 2 , wherein the directing the first echo comprises reflecting the first echo.
4. The method of claim 2 , wherein the directing the first echo comprises actively repeating the first echo.
5. The method of claim 1 , wherein the signal is implemented as an acoustic signal.
6. The method of claim 1 , wherein the azimuthal angular direction of the object includes an elevation component.
7. An apparatus for resolving an angular direction of an object, the apparatus comprising:
a signal transmission element operative to transmit a signal towards the object at a transmission time, t 0 ;
a signal reception element operative to receive a first echo of the signal from the object at a first receipt time, t 2 ;
a signal retransmission device displaced from the transmission element, the retransmission device operative to direct the first echo of the signal towards the object such that the signal receiver receives a second echo of the signal from the object at a second receipt time, t 5 ; and
a processor operative to triangulate an azimuthal angular direction of the object relative to the transmission element based on a delay between the times t 2 and t 5 , the azimuthal angular direction relative to a line defined by the transmitter and the receiver.
8. The apparatus of claim 7 , wherein the signal is implemented as an acoustical signal.
9. The apparatus of claim 8 , wherein the signal retransmission device is implemented as a passive signal reflector.
10. The apparatus of claim 8 , wherein the signal retransmission device is implemented as an active signal repeater.
11. The apparatus of claim 7 , wherein the signal retransmission device and the reflector are mounted on a vehicle.
12. The apparatus of claim 7 , wherein the azimuthal angular direction of the object includes an elevation component.