Ground penetrating radar. Finds what EMF can’t.
Orbital operates dual-frequency Ground Penetrating Radar (GPR) across Brisbane, the Gold Coast and the Sunshine Coast. GPR finds the services that don’t show up under conventional EMF tracing — non-conductive utilities, services where there’s no available access point, and targets at depth in cohesive and non-cohesive South East Queensland soils.
When you need GPR specifically
EMF locating works by inducing or detecting a signal on a conductive utility. It is the right tool for most metallic and energised services. It is the wrong tool — or simply doesn’t work — in several common situations where GPR is the answer.
Non-conductive services
Polyethylene gas mains, fibre-optic conduits, stormwater pipes, plastic water services, ceramic sewer pipes. These don’t accept or carry an inducible signal. GPR locates them by detecting the disturbance their existence creates in the soil profile.
No safe access point for EMF tracing
Where the only access to a conductive utility is hot or otherwise off-limits, EMF tracing is impractical or unsafe. GPR is non-contact and works from the surface.
Unknown services on a private property
Private services rarely appear on DBYD records. They may not have surface access points. They may not be conductive. GPR scans the area regardless of any of that.
Deeper targets in suitable soil conditions
Where the target is beyond reliable EMF range but the soil profile permits radar penetration, GPR can identify deeper signatures. South East Queensland’s mix of cohesive and non-cohesive soils suits a dual-frequency GPR system, which adapts to the local conditions.
Concrete scanning
Pre-cut concrete slab scanning to identify post-tension cables, reinforcement and embedded services. Smaller scope than a full subsurface utility survey but the same equipment principle.
Our GPR equipment — Radiodetection RD1500 dual-frequency
Orbital operates the Radiodetection RD1500 dual-frequency GPR. The dual-frequency configuration is critical for the South East Queensland field environment:
- High-frequency channel — for shallow targets (under 1 metre), tight resolution, suitable for utility scanning in built-up areas, residential locates and concrete scanning.
- Low-frequency channel — for deeper signatures (beyond 3 metres in suitable soil), broader coverage, suitable for civil and infrastructure work.
- Combined output processed live by the operator on the unit’s display, with depth slicing and signature interpretation available on-site rather than back at the office.
- Survey wheel calibrated for accurate distance recording, integrated with our GNSS RTK survey capture so located features land on the CAD plan with survey-grade coordinates.
The equipment matters but the operator matters more. Our GPR operators have decades of combined experience interpreting radar signatures under real SEQ field conditions — clay overburden, saline coastal soils, paved surfaces, mixed fill. Knowing what a target looks like on a radar trace is a learned skill; we have it.
Where GPR fits in our wider locating service
On most commercial scopes, GPR is one tool inside an AS 5488 locating workflow rather than a standalone service. The typical sequence:
- Records review (QL-D) — pull DBYD and asset owner records to identify candidate utilities.
- Surface walk (QL-C) — locate visible features and correlate to records.
- EMF trace (QL-B) — locate conductive services with the Radiodetection RD8100M.
- GPR sweep (QL-B) — locate non-conductive services and confirm signal-less areas of the site.
- Survey capture — every located feature recorded to GDA2020 Zone 56.
- CAD deliverable — DWG + PDF with AS 5488 quality-level designation per feature.
- QL-A verification through our Vac2U alliance where the design demands it.
GPR is also bookable as a standalone service for jobs where the existing locator has already done the EMF work and just needs the non-conductive sweep, or for concrete scanning before slab cutting.
Where GPR has limits — what we will and won’t tell you
Most marketing pages skip this section. We don’t, because the limits matter for project planning.
- Soil moisture matters. Saturated clay attenuates radar signal — depth and clarity drop in waterlogged conditions. We’ll tell you up front if site conditions will compromise the survey, and we’ll often defer the work for a couple of dry days when feasible.
- Highly conductive or salt-affected soils absorb signal. Coastal sites and certain Logan / Redlands clay profiles can be challenging. We test on arrival and re-scope if conditions aren’t workable.
- Small-diameter plastics in noisy ground may not return a clear signature. We’ll tell you if a service is suspected but not confidently located, and recommend QL-A verification at that point.
- GPR is not magic. Where neither EMF nor GPR gives a confident response, the correct answer is vacuum excavation — coordinated through our Vac2U alliance, not pretending the radar saw something it didn’t.
Honesty about limits builds trust. Engineering buyers register the difference between an operator who will say “we can’t see this — let’s verify” and one who marks every service confident with no defensible basis.
Who buys GPR work from Orbital
Engineering consultancies
Non-conductive utility surveys, deeper target searches, integrated AS 5488 packages where GPR is part of the broader QL-B scope. Delivered in Orbital’s default CAD convention, designated by AS 5488 quality level.
Civil contractors and builders
Sites where the EMF locate hasn’t found the gas main, fibre route, or stormwater connection. Pre-pour concrete scanning. New civil works near unknown private services.
Council and asset owners
Asset condition surveys, locating retired or abandoned services, supporting build-over applications where private services aren’t on the asset register.
Specialised one-off scopes
Heritage building investigations (suspected hidden services), forensic location of services in dispute, pre-acquisition site due diligence.
Why Orbital for GPR
Twenty-three years locating in South East Queensland — and through that time, GPR has moved from a specialist tool used occasionally to a core part of every commercial locate. We’ve been operating dual-frequency radar through that transition. We know what targets look like in our local soils, we know what conditions to defer in, and we know when to recommend QL-A verification instead.
CERTLOC certified. NULCA member. Radiodetection authorised dealer — we run their equipment because we believe in it; that’s also why we sell it to other operators. Jamie Ware has trained a number of the GPR operators currently working across this market. Our GPR work is integrated with EMF locating, survey, CCTV and the Vac2U alliance — coordinated delivery in one engagement.
Frequently asked questions
Is GPR the same as EMF locating?
No. EMF locating induces and detects a signal on conductive utilities — it’s the right tool for energised cables and metallic pipes. GPR detects disturbance in the soil profile — it’s the right tool for non-conductive services and for areas where there’s no access point to induce an EMF signal. Most commercial locates use both methods together; that’s what AS 5488 quality level QL-B requires.
How deep can GPR find a service?
Depends on the soil profile, the size of the target, and the contrast between the target and the surrounding ground. In typical SEQ soils, dual-frequency GPR comfortably resolves targets to ~3 metres. Beyond that, signatures get less defined. In waterlogged or salt-affected ground the practical depth is shallower.
Can you scan a concrete slab before I cut?
Yes. Pre-cut concrete scanning is a smaller-scope GPR job — identifying post-tension cables, reinforcement, conduits and any embedded services before a saw cut or core drill. Quick to mobilise, quick to deliver, much cheaper than the cost of cutting the wrong thing.
Do you survey the located services or just mark them?
Both. Standard scope on a commercial GPR survey includes GNSS RTK or total station capture of every located feature, so the data exists in the CAD deliverable not just as paint on the ground. Quick standalone GPR sweeps (e.g. for a single suspected service) can be marking-only if that’s what the brief requires.
What’s the cost?
Per scope. The variables: site size, target depth, soil conditions, whether it’s a standalone GPR job or part of an AS 5488 package. Send us the site address and brief; we’ll come back with a fixed-price quote, usually within 24 hours.
Related services
- Underground service locating (EMF + GPR combined)
- AS 5488 Subsurface Utility Engineering
- Vacuum excavation through Vac2U alliance
- CAD drawings — DWG and PDF
Tell us what you’re looking for.
Specific target, suspected service, full site sweep, slab scan — the scope shapes the kit and the time on site. Send us the brief and the site address; we’ll come back with a fixed-price quote and a realistic mobilisation date.