How SPH Engineering's SkyHub Integrates Complex Drone Payloads on DJI Platforms

What SkyHub Is and Why It Matters for Sensor Integration

SkyHub is a drone onboard computer that, in SPH Engineering's words, "extends the capabilities of commercial-off-the-shelf UAVs for industrial sensing and automation." In practical terms, it sits between the aircraft's flight controller and your survey payload, acting as the central hub that fuses sensor readings with positioning data, logs everything locally, and controls how the drone flies relative to the surface below it.

For survey firms adding a non-camera sensor to a DJI airframe, this matters because most specialized payloads were never designed to talk to a DJI drone. A ground-penetrating radar, an echo sounder or a methane analyzer each speaks its own protocol and needs accurate position and altitude data to produce usable results. SkyHub provides the hardware bridge and the software logic that turn a stock enterprise drone and a third-party sensor into a single, coordinated survey instrument. The full range is available through our SPH Engineering integrated systems collection, and the True Terrain Following Kit for DJI drones is the component that delivers the low-altitude capability described below.

Synchronizing Specialized Sensors

SkyHub supports a broad set of survey payloads, and the integration challenge is similar across all of them: capture the sensor reading, stamp it with an accurate position and time, and record it offline in a format the manufacturer's processing software expects. According to SPH Engineering, supported payloads include:

• Ground Penetrating Radar (GPR) for mapping cavities, voids, utilities and archaeological features
• Echo sounders for drone bathymetry and water-depth mapping
• Methane detectors for pipeline, tank and landfill emissions surveys
• Magnetometers for fast magnetic and metal-detection surveys
• Gamma-ray spectrometers, metal detectors and side-scan sonar for specialized geophysical work

Geotagging and Offline Logging

SkyHub fuses payload output with autopilot telemetry to geotag each measurement using the drone's positioning, which removes the need for a separate GNSS receiver on the sensor itself. The onboard computer can also output an NMEA stream to feed coordinates directly to sensors that expect a GPS feed. All mission data is recorded locally in standard formats, so no internet connection is required in the field. SPH Engineering lists support for common survey outputs including CSV, SEG-Y and NMEA-0183, which means GPR traces, bathymetry logs and detector readings arrive ready for established post-processing workflows. For a deeper look at the survey applications themselves, see our pillar guide on advanced drone surveying with SPH Engineering.

True Terrain Following for Low-Altitude Data Capture

Most subsurface and emissions sensors only produce clean data when they are flown at a consistent, low height above the surface. A GPR loses penetration and resolution if its standoff distance varies; a methane analyzer needs to be in the plume; an echo sounder needs a stable height above the water. Standard DJI flight modes hold a barometric or GNSS altitude relative to takeoff, not the ground, so a mission over rolling terrain will drift dangerously close in some spots and uselessly high in others.

SkyHub's True Terrain Following (TTF) solves this by using a downward-facing rangefinder, such as a laser or radar altimeter, to measure the real distance to the surface in flight and continuously adjust the drone's height. SPH Engineering states TTF can maintain altitudes "as low as 0.5 m" above the ground or water, which is the regime these sensors require. A related Grasshopper mode enables point-based descents to predefined heights for targeted spot measurements.

Why This Changes the Survey

True terrain following is what makes airborne GPR and drone bathymetry practical rather than theoretical. It lets a crew fly tight, repeatable lines over hilly, vegetated or hazardous ground while keeping the sensor in its optimal window. For surveying hazardous or inaccessible sites, this means data without putting people on the surface, as illustrated in our case study on surveying tailings ponds with UAV bathymetry.

DJI Platform Compatibility and Power

On the DJI side, SkyHub connects to enterprise platforms through the DJI PSDK connector and draws 12 to 24V from the drone battery. SPH Engineering lists compatibility with the DJI M400, M350 RTK and M300 RTK, and the system also supports a wide range of Pixhawk and Cube-based airframes over MAVLink for operators outside the DJI ecosystem.

SkyHub also provides a software-controlled power output (9/12/15/18V at up to 5A) plus multiple serial, UART, Ethernet and USB interfaces, so a single onboard computer can power and communicate with the payload directly. This consolidation is a large part of why the platform reduces integration overhead for firms standardizing on DJI enterprise drones.

Choosing the Right Sensor for the Job

Because SkyHub is sensor-agnostic, the integration decision usually comes down to which payload fits the application. For subsurface mapping, GPR frequency selection drives both depth and resolution, a trade-off we cover in comparing drone GPR frequencies for different soil types and in our overview of airborne GPR mapping with ZondAero. For water work, see drone bathymetry with the Surveyor 240-16 MBES, and for emissions work, rapid methane leak detection with the Laser Falcon. Whichever sensor you select, SkyHub and UgCS provide the common integration, flight-planning and terrain-following backbone. If you are scoping a build, request a quote and our team can confirm the right kit for your aircraft and payload.