Ground probing radar method and apparatus

• US 4,967,199 A
• Filed: 05/26/1989
• Issued: 10/30/1990
• Est. Priority Date: 05/27/1988
• Status: Expired due to Fees

• Current Assignee: British Gas Trading Limited (Centrica PLC)
• Original Assignee: British Gas Trading Limited (Centrica PLC)
• Inventors: Stansfield, Michael P., Cordes, Paul B., Scott, Howard F., Ashworth, Roger P., Gunton, David J.
• Primary Examiner(s): Barron, Jr., Gilberto
• Application Number:
  US07/357,532
• Time in Patent Office: 522 Days
• Field of Search: 342/22, 342/158
• US Class Current: 342/22
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/885 for ground probing prospecting or detecting using electromagnetic waves G01V3/12
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: G01V 3/15 specially adapted for use during transport, e.g. by a person, vehicle or boat

Abstract

A wheeled support assembly 10 is manually pushed over the ground and has a motor 22 rotating an antenna assembly 60 about a vertical axis 24. Encoders 28 on the antenna shaft 20 and on a wheel axle encode antenna angular position and position over the ground. Transmitted pulses and received data pass through a rotary microwave connector 26. For example, 400 sets of pulses are emitted at equal angular intervals in each revolution of the antenna assembly. The interval between pulses is e.g. 12 microseconds, with 256 pulses per set. Noise reduction is achieved by processing the received data accordingly. In a modification the rotary connector 26 is single channel with some electronic stages mounted on the rotating antenna assembly. Power is coupled to them via the microwave cable. An umbilical connects the assembly 10 to a support facility including a computer. Alternatively, battery power is used with data transferred radiatively.

Claims

1. Ground probing radar apparatus comprising a support assembly which can be moved over the ground, an antenna assembly comprising transmit and receive elements and mounted on the support assembly so as to be rotatable about an axis directed into the ground, a drive motor mounted on the support assembly and connected to the antenna assembly so as to be able to rotate it about said axis, and means operable in response to rotation of the antenna assembly about said axis to produce data representative of the angular position of the antenna assembly about said axis, the support assembly carrying an impulse generator feeding pulses to the transmit elements of the antenna assembly, a sampling unit, a low-pass filter for receiving the output from the sampling unit, an analogue-to-digital converter for receiving the output from the filter, a digital signal processor receiving the output from the converter, a ramp voltage generator and a pulse train generator, said data being fed to the digital signal processor and to the ramp voltage generator, the output from the pulse train generator being fed to the impulse generator and to the sampling unit, and the sampling unit receiving the output data from the receive elements of the antenna assembly via a delay line and the output from the ramp voltage generator being fed to the sampling unit.

4. Apparatus according to claim 1 the support assembly being supported on ground-engaging wheels.

5. Apparatus according to claim 1 said means being an encoder operable in response to rotation of the antenna assembly.

6. Apparatus according to claim 1, the antenna assembly comprising a cylindrical drum supported at the lower end of a hollow support shaft, said antenna elements being carried on a support sheet extending across the drum, the shaft extending to a rotary microwave connector, a microwave conductor extending through the hollow shaft at least from said receive elements of the antenna assembly to a microwave rotary connector connected to the shaft, a drive motor and drive means coupling the motor to the shaft.

2. Ground probing radar apparatus comprising a support assembly which can be moved over the ground, an antenna assembly comprising transmit and receive elements and mounted on the support assembly so as to be rotatable about an axis directed into the ground, a drive motor mounted on the support assembly and connected to the antenna assembly so as to be able to rotate it about said axis, and means operable in response to rotation of the antenna assembly about said axis to produce data representative of the angular position of the antenna assembly about said axis, the support assembly carrying an impulse generator feeding pulses to the transmit elements of the antenna assembly, a sampling unit, a low-pass filter for receiving the output from the sampling unit, an analogue-to-digital converter for receiving the output from the filter, a digital signal processor receiving the output from the converter, a ramp voltage generator and a pulse train generator, said data being fed to the digital signal processor and to the ramp voltage generator, the output from the pulse train generator being fed to the impulse generator and the sampling unit receiving the output data from the receive elements of the antenna assembly via a delay line and the output from the ramp voltage generator being fed to the sampling unit.

3. Ground probing radar apparatus comprising a support assembly which can be moved over the ground, an antenna assembly comprising transmit and receive elements and mounted on the support assembly so as to be rotatable about an axis directed into the ground, a drive motor mounted on the support assembly and connected to the antenna assembly so as to be able to rotate it about said axis, and means operable in response to rotation of the antenna assembly about said axis to produce data representative of the angular position of the antenna assembly about said axis, the support assembly carrying a sampling unit, a low-pass filter for receiving the output from the sampling unit, an analogue-to-digital converter for receiving the output from the filter, a digital signal processor receiving the output from the converter, and a ramp voltage generator, said antenna assembly carrying a pulse train generator and impulse generator the output from the pulse train generator being fed directly to the impulse generator of the antenna assembly and the sampling unit receiving the output data from the receive elements of the antenna assembly via a delay line and a trigger take-off, a trigger pulse output from said trigger take-off being fed to the sampling unit and to the ramp voltage generator, the output from said ramp voltage generator being also fed to the sampling unit.