UgCS for Ground Penetrating Radar (GPR) surveys
In most cases, GPR surveys are a hard work and can be very dangerous for field personnel due to harsh topographic environments and weather conditions.
This is where drones come into play. They are lightweight (compared to a manned airplane or a helicopter), easily transportable by car and capable of flying autonomously at low altitudes with high precision. Such approach assures delivery of accurate survey results, is also safer for personnel and more time-efficient.
A GPR mounted on a drone enables to see through the surface of ground, ice, rocks, freshwater, and buildings or through structures at unsafe and hazardous environments without compromising the safety of staff, providing an additional solution for more efficient surveying.
To enable a full integration of the radar and drone SPH Engineering has developed a lightweight onboard data logger and the support of GPR in the ground control software for drones - UgCS. The result of the integration - the radar status and its current trace is displayed on the screen of UgCS (see Fig.1); Data logging is started automatically at take-off and finished upon landing.
Figure 1. UgCS ground control software displaying GPR status.
SPH Engineering has made hundreds of test flights with the GPR-drone integrated system to make sure the system is optimized for real-world use.
Figure 2. The GPR-drone (DJI M600Pro) integrated system.
Technical specification
Currently, SPH Engineering provides two configurations for the GPR-drone integrated system setup. Both are using DJI M600 Pro drone and Radarteam Cobra Plug-In GPR, but the antenna is different in each setup:
- SUBECHO-70 (SE-70) antenna
- SUBECHO-150 (SE-150) antenna
Antennas differ in their frequency range and centre frequency.
SE-70 has a centre frequency of 80 MHz and can penetrate the ground more – up to 80 meters in good conditions (ice or dry sand).
SE-150 has a centre frequency of 124 MHz and penetration up to 40 meters in good conditions, however, the resolution is much better.
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COBRA PLUG-IN ANTENNAS |
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SUBECHO MODELS |
SE-70 |
SE-150 |
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Frequency range, MHz |
20-140 |
20-280 |
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Bandwidth, MHz |
120 |
260 |
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Centre frequency, MHz |
80 |
124 |
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Size (L x W x H), cm |
139 x 15 x 21 |
92 x 22 x 22 |
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Weight, kg |
3,7 |
3,5 |
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DJI M600 Pro drone with GPR |
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Take-off weight |
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with TB47S batteries, kg |
14,31 |
14,11 |
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with TB48S batteries, kg |
14,81 |
14,61 |
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Approximate flight time |
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with TB47S batteries, min |
15 |
16 |
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with TB48S batteries, min |
19 |
20 |
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Maximum length of survey line (speed 2m/s) |
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with TB47S batteries, m |
1800 |
1920 |
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with TB48S batteries, m |
2280 |
2400 |
Applications
Current the GPR-drone integrated system can be used in areas where deep ground penetration is required but a good resolution is not very important.
Examples of applications include:
- Bathymetry of fresh water
- Geological surveys for soil layer profiling
- Mapping of underground infrastructure
Bathymetry
The GPR-drone integrated system enables to measure the depth of water or profiling the bottom of freshwater rivers, lakes, ponds up to 15 meters in depth.
Benefits – possibility to do work even when the water is frozen or the surface of the water is partially covered with ice. Compared to bathymetry using a boat (equipped with echo sounders) the drone with a GPR provides better accuracy in following survey lines thanks to the inbuilt GPS and automated flight. Also, in most cases, a drone makes it a lot easier to deliver the necessary equipment to the desired area.
The results displayed in Figure 3 were gathered with the drone flying at an altitude of 20 meters above the water surface level to profile 8 meters deep frozen lake.
Figure 3. Profiling results of a frozen lake.
The 3D visualization of the lakes profile was created using GPR-Slice software (http://www.gpr-survey.com).
Geological surveys
Soil layer profiling is a standard task that needs to be done before any serious area development or construction works. The standard technique is drilling dozens of holes or conducting a GPR survey on carts.
GPR-drone integrated system delivers higher work productivity and enables safer work conditions for the personnel in cases of rough terrain.
GPR allows finding any potentially dangerous underground water streams or lakes.
Data gathered by GPR-drone integrated system flying at an altitude of 5 meters over an asphalt-covered car parking lot is displayed in Figure 4. The soil layers are clearly visible.
Figure 4. Layers of the soil below a parking lot measured up to a depth of 36m (screenshot of Prism2 www.radsys.lv).
Mapping of underground infrastructure
Mapping of underground infrastructure is an important task before starting any construction works on previously developed territories or in cases when actual documentation and maps for underground infrastructure is missing.
Please note that the current GPR-drone integrated system does not enable to map small or thin objects such as cables or thin pipes. It is capable of detecting objects with an approximate size of 5 - 10% of depth, such as concrete sewage channels, tunnels, bunkers, etc.
For more detailed information DOWNLOAD FULL ARTICLE (pdf)
"New Approach to use Ground Penetrating Radar (GPR) integrated with a drone (UAV)" or get in touch with us: ugcs@ugcs.com.