High speed 3D Ground Penetrating Radar

Our patented High speed 3D GPR trailer and antenna array

Ground Penetrating Radar (GPR) is used to determine the presence of subsurface objects or features.

Our patented 3D NM-GPR comprises of a trailer and antenna system with 4 electronically deployable pods.

Utilising 3 GPR modules, the 46 antenna array can scan upto 1.2 metres deep and 2.5 metres across at 100km/h.

Designed with rough roads in mind, each pod has air ride suspension allowing the unit to negotiate large objects while hugging the road surface.

Overview

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Ground Penetrating Radar (GPR) is a technique where an ultra wideband electromagnetic signal is transmitted into the ground and the returned reflections measured to determine the presence of subsurface objects or features. For road pavements, GPR is used for locating and measuring:

  • Pavement layer depths - asphalt, granular, and concrete.
  • "As constructed" information and pavement changes / homogeneity.
  • Services
  • Anomalies - e.g. voids, rock, and buried objects.
  • Moisture ingress and inclusions
  • Calibrating deflection measurements to determine pavement material properties.

The PaveScout patented NM-GPR system, is unique. There is no other system in the world that has high real sample rate receivers in the one system (46 profiles across the 2.5 meter width of the system), which enables full 3D imaging of the road subsurface at 100km/h. There is no other system that can see as deep as 1.2 meters at 100km/h on all of the antennas, all at the same time. There is no other system that also performs common midpoint (CMP) dielectric compensation at the same time as data collection allowing calibration of subsurface layer depths and estimation of moisture within pavement layers. There is no other system that has been customized to reliability operate in difficult road conditions.

The 3D GPR system comprises of a trailer/antenna system, which then houses three GPR modules. The GPR modules are housed within the trailer, while the antennas, are housed within the radar pods. Each pod houses two transmitters and 5 receivers. There are three stages of protection, allowing reliable operation of the ground coupled antennas on the road surface.

  1. Each pod has 4 high speed wheels, with rims made from milled aluminium and heavy duty tread, allowing the antennas to glide over the road surface.
  2. The antennas have a thick 10mm replaceable nylon skid plate to protect the antenna from the road surface. Grooves on the skid plate indicate plate wear. The nylon skid plates are designed to be low cost, and easy to replace. Expected life of a skid plate is around 5000km (depending on road conditions).
  3. Finally each pod is individually suspended, with a tuned air ride suspension system, allowing the unit to move out of the way of larger object, while still hug the road surface.

When in operation the pods automatically deploy down onto the road surface, via a rugged motor/gearbox system. All elements of the system are designed with rough roads in mind. The RPS radar system is designed to last.

The 3D Ground Penetrating Radar (GPR) system is comprised of four electronically deployable pods. The results of the transmitters and receivers for the system are combined to produce a 46 wide antenna array. The result is a very high density 3D array image, with a data density of 50mm across the road, and 50mm along the road, down to a depth of 1.2 meters, all at 100km/h.

Trailer specifications

Ground Penetrating Radar Trailer with pods up
  • Number of Virtual Signals over the Trailer Width: 46 (sample every 52mm across).
  • Number of GPR modules required: 3
  • Number of Radar Pods: 4
  • Average Power Consumption (with 3 modules): 160W (90W for GPR modules and antennas, 70W to recharge of batteries after use of lifting motor or suspension air pump).
  • Peak Power consumption when lifting motor is in operation: 820W (This is levelled off via the internal 24V sealed deep cycle lead acid battery). Relay control on battery output to ensure no drop in radar voltage when motors are operating.
  • External connector: 1 x waterproof Gigabit Ethernet connector. 1 x Power and trigger cable (milspec), 1 x standard trailer plug (for trailer lights).
  • Dimensions: Length: 3.8 meters (when pods are down), Width: 2.5 meters, Height: 1 meter.
Ground Penetrating Radar Trailer

The trailer is designed to be used with a four wheel drive tow ball, but can be built with a standard tow ball. If the system is used in combination with a 3D laser triangulation sensor (e.g. INO scanner, or RPS laser scanner) then it is possible to having the tow ball mounted higher to stop the trailer arm from affecting the laser measurements for normal forward vehicle movements (normal turning circle of a vehicle).

Software Systems

RPS provide custom software solutions to process and analyse the masses of data the NM-GPR can produce.

 

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