WP4-18

Transponder for drone-rover cooperation

ID	WP4-18
Contributor	TEKNE
Levels	System functions
Require	UWB transceivers
Provide	Guidance for the drone positioning with respect to the landing pad.
Input	Autopilot GPS and intertial navigation data Distances measured using the UWB system
Output	Guidance commands
C4D building block	Coordination — Drone and Rover
Input Interface	PX4, serial link
Output Interface	PX4, serial link
TRL	5
Tasks	T4.1, T4.2
Use Case	UC5 - Agriculture
Demonstrator	D1 - Crop monitoring
Contact	c.tiere@tekne.it

Description

The WP4-18 component estimates the still UGV (Unmanned Ground Vehicle) position with respect to the UAV on the basis of the autopilot navigation data and of the distance between the two vehicles. The distance is computed from the measurements of Time of Flight (ToF — time of electromagnetic propagation) measured by the UWB transceivers which both vehicles are equipped with. The WP4-18 component drives the UAV towards a certain target position that is given relatively to the UGV (on the vertical, at a certain height). To land on the UGV, the UAV moves by navigating on the basis of GPS data. At the end of this approaching manoeuvre, due to the limited GPS accuracy, it may happen that the UGV (the landing pad) is not in the field of view of the UAV dedicated video camera that controls the landing. The WP4-18 component, which doesn’t require optical visibility, executes the positioning manoeuvre to bring the UAV to a position such that the autonomous landing manoeuvre can start.

Usage Example

The WP4-18 component can be used for autonomous UAV landing on the UGV during missions that the vehicles carry out cooperatively. When the two vehicles are far from each other and from the Ground Control Station WP5-05-TEK “LPWAN for identification, tracking, and emergency messages” component (work package WP5) can provide long-range communication for monitoring the positions and for commanding the UAV to execute the manoeuvre (approaching + positioning + landing).

Improvements

While the autonomous landing of a UAV on a UGV is a mature technique, the approaching manoeuvre, which brings the UGV in the field of view of the UAV landing camera, depends on the availability and the quality of GPS signals. The WP4-18 component solves this issue by using UWB distance measurement sensors for positioning the UAV with respect to the UGV.