UAV ground penetrating radar array
A GPR system the implements a modified multistatic mode of operation is provided. The GPR is suitable for mounting on an unmanned aerial vehicle. The GPR system has radar transceivers. The GPR system transmits transmit signal serially via the transceivers. For each transceiver that transmits a transmit signal, the GPR system receives a return signal acquired by each transceiver except for a return signal for the transceiver that transmits the transmit signal. The GPR system outputs of matrix of return signals that includes a null value for the return signals of the transceivers that transmit.
1. A signal system for controlling an array of transmitter and receiver pairs to operate in a modified multistatic mode, the signal system comprising:
a controller that, for each of the transmitter and receiver pairs in sequence, directs the transmitter of that transmitter and receiver pair to transmit a transmit signal and directs receivers of the other transmitter and receiver pairs to acquire a return signal from the transmit signal; and
an aggregator that,
for each of the transmit signals transmitted by a transmitter, receives a return signal acquired by the receivers of the transmitter and receiver pairs other than the transmitter and receiver pair to which that transmitter belongs; and
outputs a collective representation of the acquired return signals wherein the collective representation does not include a return signal for each receiver for which the transmitter paired with that receiver transmitted the transmit signal.
2. The signal system of claim 1 wherein the transmitter and receiver pairs are transceivers and when a transmitter of a transceiver transmits a transmit signal, the receiver for that transceiver is not directed to receive a return signal for that transmitted signal.
3. The signal system of claim 1 wherein the controller further directs the receiver for the transmitter and receiver pair that transmits the transmit signal to acquire a return signal and wherein the collective representation of the acquired return signals does not include the return signals acquired by the receivers of the transmitter and receiver pairs that transmit the transmit signal.
4. The signal system of claim 1 wherein the transmitter and receiver pairs include a separate transmit antenna and receive antenna, and wherein the aggregator receives the return signals of the receivers of the transmitter and receiver pairs that transmitted the transmit signal and does not include those return signals in the collective representation.
5. The signal system of claim 1 wherein the signal system includes a demultiplexer and, for each transmitter and receiver pair, a switch associated with that transmitter and receiver pair, wherein the demultiplexer inputs the transmit signals and directs the transmit signal to a switch for transmission by the transmitter of the transmitter and receiver pair associated with that switch as directed by the controller, wherein each switch controls the associated transmitter and receiver pair to transmit or receive as directed by the controller.
6. The signal system of claim 1 wherein the signal system is a ground penetrating radar system.
7. The signal system of claim 1 wherein the signal system is mounted on an autonomous vehicle.
8. The signal system of claim 1 wherein the signal system does not include precise timing electronics to switch an antenna of a transceiver that transmits a transmit signal to receive a return signal of that transmitted transmit signal.
9. A method performed by a ground penetrating radar system mounted on an unmanned aerial vehicle, the ground penetrating radar system having radar transceivers, the method comprising:
transmitting a transmit signal serially by each radar transceiver of the ground penetrating radar system; and
collecting, for each transceiver of the ground penetrating radar system that transmits a transmit signal, a return signal acquired by each transceiver of the ground penetrating radar system except for a return signal for the transceiver that transmitted the transmit signal.
10. The method of claim 9 wherein the return signal is acquired by the transceiver that transmitted the corresponding transmit signal but is not used in subsequent processing of the return signals.
11. The method of claim 9 wherein the ground penetrating radar system does not include precise timing electronics to switch an antenna of a transceiver that transmits a transmit signal to receive a return signal of that transmitted transmit signal.
12. A system for controlling an array of transceivers, each transceiver associated with an antenna, the system comprising:
a demultiplexer that, in response to a transceiver selection signal indicating a transceiver, directs an input to an output for that transceiver;
for each of the transceivers, a switch that
in response to a transmit mode signal indicating to transmit, directs an input connected to the output of the demultiplexer for that transceiver to a transmit output for the antenna of that transceiver, and
in response to a receive mode signal indicating to receive, directs an input from the antenna of that transceiver to a receive output; and
a controller to, for each transceiver,
send a transceiver selection signal for that transceiver to the demultiplexer, and
send a transmit mode signal to the switch for that transceiver and, for transceivers other than that transceiver, send a receive mode signal to the switches for those transceivers.
13. The system of claim 12 wherein the system and the array of transceivers is mounted on an unmanned aerial vehicle.
14. The system of claim 12 further comprising a signal generator to generate the transmit signals that are input to the demultiplexer.
15. The system of claim 14 wherein the signal generator generates multiple transmit signals for each transceiver and employs equivalent-time sampling of the transmit signals.
16. The system of claim 14 further comprising an amplifier and attenuator for tuning the generated transmit signal prior to input to the demultiplexer.
17. The system of claim 12 further comprising an aggregator that receives the return signals and provides a matrix of return signals with a return signal for each transceiver other than the transceiver that transmitted the corresponding transmits signal.