Contents
Context
Long-range flights need a ground antenna pointed at the aircraft the whole time, and a link that holds over the distance.
Constraints
- Range: designed for ~20 km.
- Link options: direct RF, 4G and WiFi.
- Beyond line of sight: a satellite link, designed for it.
Architecture
Components and flows
Components
- Aircraft
- Aircraft (MAVLink telemetry)
- Links
- Long-range radio link
- 4G
- WiFi
- Satellite (designed for BLOS)
- Ground station
- Ground control station
- Tracker controller (embedded C++)
- Directional antenna (custom tracker hardware)
Flows
- Aircraft to Long-range radio link
- Aircraft to 4G
- Aircraft to WiFi
- Aircraft to Satellite (designed for BLOS)
- Long-range radio link to Ground control station (telemetry)
- Ground control station to Tracker controller (aircraft position)
- Tracker controller to Directional antenna (pointing)
- Telemetry in: the aircraft's live position over MAVLink, relayed through the ground control station.
- Tracker controller: embedded C++ that turns that position into where the antenna must point.
- Directional antenna on custom tracker hardware, kept locked on the aircraft.
- Links: direct RF, 4G modems and WiFi, with a satellite link designed for beyond-line-of-sight.
Key decisions
-
The tracker points from the aircraft's own telemetry, relayed through the ground control station, rather than sweeping 360° for signal strength.
-
In the field we flew on a single long-range radio link. For longer routes I designed a relay chain (a radio link tower roughly every ~10 km) and tested it in the lab; it was not fielded.
My role
As CTO of the engineering company I co-founded, I designed the tracker and the link architecture and wrote much of the tracker's code.
Outcome
Designed for ~20 km and field-tested to just under that range on a single long-range radio link. A relay chain for longer routes, with a tower roughly every ~10 km, was designed and tested in the lab; it was not fielded.
Stack
Each links to its entry on the stack page
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How did the antenna tracker stay locked on the aircraft at long range?
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