SHADER Satellite-Haps Airborne Datalink as an Extension for RPAS (Broadband Satellite Communications to Remote Piloted Aircraft Systems –RPAS- Using High Altitude Pseudo-Satellites)

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Small RPAS cannot afford to carry heavy payload, hence limiting the possibility of broadband, satellite-based, datalink.

The project’s main objective is to propose a preliminary design of a HAPS (High-Altitude Platform System) layer in a SATCOM-based communication network that would foster the use of small RPAS in new domains.

In parallel, a field experiment – limited in scope – is setup to gather data and validate key assumptions.


The project aims to reuse as much existing technologies as possible. However, this concept demands some specific solutions due to the specific constraints:

  • It shall be possible to accommodate for multiple and simultaneous radio connections.
  • Both the HAPS and the RPAS are in motions.
  • The HAPS trade a very long endurance against a somewhat limited payload capacity compared to regular aircraft, hence constraining the mass budget.

This HAPS layer is intended to provide a wide area coverage for broadband datalink to RPAS beneath it. Removing the need for the RAPS to carry a dedicated SATCOM payload allow them to extend their mission endurance, or even be used where it was not previously possible.

Some practical examples include deep-sea scientific missions, maritime surveillance, and firefighting.


At system level, the key feature is the HAPS. High Altitude Platform System that is design to have a very long endurance thanks to its mission altitude in the low stratosphere.

On the hardware side, the key feature is steerable antennas, for both the radio link (HAPS <-> drone) and SATCOM link. In particular, the need to handle simultaneous connections with many RPAS imposes the use of radio smart antennas, in a similar fashion as 5G base station.

System Architecture

The core concept of the architecture is an intermediate layer of HAPS (High Altitude Platform System) that acts as a SATCOM link relay for drones.

On board the HAPS are all the necessary equipment to implement a communication network node: radio antenna, modems, router, and SATCOM antenna.

The key hardware aspect is the antennas’ directivity, in order to maximize data transmission efficiency over a long distance.


The project plan is to go step by step toward a system preliminary design:

  • State-of-the art review & trade-off analysis
  • System Preliminary architecture
  • System preliminary design

In parallel is prepared and executed the flight test campaign based on a manned aircraft. This campaign is intended to validate key parameters and mitigate the main technological risks.

All these steps are verified through a V&V process inspired by aeronautical development process.

Current status

The program started on 07/09/2020 and the activities are presently in progress.

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