Setup review: ArduPilot Rover for autonomous tow-rope retrieval

Hardware Rovers and boats
1

Hi all,
We’re a hang gliding + paragliding club and we operate an electric towing winch on a 1200 m grass airstrip. The winch has two drums and is remote-controlled, so no one is standing at the winch during operation.

After two tows, we need to retrieve the tow ropes using a car. To reduce downtime between tows, we’d like to build an autonomous rover that can:

  1. Drive from the winch/start area to the far end of the strip (take-off area)

  2. Pick up the tow ropes there (mechanical gripping solution will be developed later)

  3. Return and drop off the ropes at the winch/start area again

I’ve attached a simple sketch of the layout (winch at one end, rover route along the strip).

IMG_20260225_180206
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Environment

  • Grass field / airstrip, ~1200 m long

  • Mostly flat, but can be uneven / bumpy

  • Outdoor conditions: wind, rain/humidity, temperature changes

Performance requirements

  • Cruise speed to avoid delaying operations: ~15–20 km/h

  • Accuracy while driving along the strip: ~1 m is OK

  • High accuracy only near the winch / rope pickup/drop-off point: ~2–5 cm desired

    • The rover can slow down significantly for the final approach / docking maneuver

Current hardware concept

We’re considering using a large 4WD RC car platform (possibly with extra battery capacity), e.g. Kraken KV5TTE Ultra 2 Electric (KT7707) or similar.

Kraken
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For the autopilot/navigation/telemetry stack we’re currently looking at:

  • The Cube Orange+ autopilot set (ArduPilot Rover)

  • Holybro PM07 V2 power module (14S capable)

  • ArduSimple long-range RTK base + rover GNSS kit (cm-level RTK, incl. radio link)

  • RFD 868x telemetry radio pair (EU 868 MHz)

What we’re asking for feedback on

We’d really appreciate a candid assessment of:

  1. Overall complexity & risk

    • How hard is this to get reliable in real life (not just “it moves once”)?

  2. Navigation / accuracy strategy

    • Is RTK alone typically sufficient to achieve 2–5 cm repeatable docking accuracy in the last meters?

    • Would you recommend adding something for the final approach (e.g., fiducial marker + camera, lidar/rangefinder, wheel odometry, etc.)?

  3. Component choices

    • Are the Cube Orange+, PM07, RTK kit, and 868 MHz telemetry choices reasonable for this use case?

      Any alternatives you’d strongly recommend (especially for GNSS/RTK robustness on a ground vehicle and for high-speed driving on grass)?

Notes / constraints

  • Rope gripping mechanism is not the focus right now; we mainly want to validate the feasibility and the autopilot/navigation setup.

  • The rover is intended to run along a defined corridor (the airstrip), not complex off-road navigation.

Thanks in advance for any guidance!

2
  1. Not too complex. Getting that vehicle up and running with ArduRover is straight forward.
  2. See Dock Mode which answers the 2nd point.
  3. The kit components sound good. Others may comment on the choices for RTK.
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3

If you’re intending to use optical markers for final guidance, and the area is otherwise an open airfield, RTK GPS may not be necessary at all.

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4

Yea, I suppose that with a big enough April tag it will be well within standard GPS precision.

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5

Here’s another cheap way to set up an RTK base:

It integrates directly into mission planner for the NTRIP data. This might not give you exactly the same precision as the ardusimple gear, but we’re still talking about cm.

You’d still need an RTK receiver on the car. A here4 (or 3) will do that.

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6

Thanks for the feedback. Regarding DOCK mode:

Can DOCK mode be entered automatically as part of a mission in Mission Planner, or does the mode change need to be triggered by e.i. the companion computer / OpenMV device? This could complicate things for us.

7

Someone else asked that on the forum and didn’t get an answer. There is a DO_AUX_FUNCTION mission command which includes many functions and most Modes but not Dock. Which was the question asked. So within a Mission I think not.

I bet you could use a Lua script to monitor for Mission Complete and then switch to Dock Mode.

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