High level goal

The purpose of this task is to develop protocol and implementation for avoiding collisions with other aircrafts.

Communication layer

Two kind of communication modems will be used for the task

  1. ADS-B (for specification see appendix 1)
  2. WiFi (for specification see appendix 2)

Each qualified team will receive 4 ADS-B like transponders from aerobits.pl, 4 WiFi transponders from uspace.aero and Bluetooth beacons from kontakt.io.

Buffer zone

Each aircraft has to create a virtual sphere around itself, which will be treated as an unbreachable security zone. A sphere is defined mathematically as a set of points that are all at the same distance R (radius) from a given point, in three-dimensional space. The radius of the sphere will be a derivative of the momentum p (the product of the mass and velocity of an object). However, limits have been set on the minimum and maximum radius, as following:

Rmin = 5 m      Rmax = 25 m

Sphere Radius calculation

R [m] = m [kg] * v [m/s]


MTOM = 1,5kg

Vmax = 10m/s

R= 15 m

Mission altitude

Flight altitude must be determined using a barometric sensor, calibrated to starting point. Both units (ADS-B and WiFi) will be equipped with GPS and barometric sensor and will automatically calibrate to 0m height at starting position.

During the BEACON search mission, all aircrafts are obliged to maintain altitude of 90ft AGL.  Flight altitude change is possible only in the three following cases:

  1. Collision avoidance. Aircraft may climb or descend, but not lower than MSA and not higher than NOT EXCEEDING ALTITUDE
  2. When entire area has been flown and Beacon signal were not found, flight altitude can be reduced to 60ft AGL
  3. Descend is approved when the beacon is detected during search mission
Krakow Aviation Club outline
Krakow Aviation Club outline.

Communication layer

Each aircraft must broadcast the following information via two communication modems (WiFI & ADS-B):

  1. Position (Lat Lon DDD.DDDDDD direction, DD.DDDDDD direction)
  2. GPS Course (0-360° CW, north direction – 0°)
  3. Altitude
  4. Vertical speed
  5. Sphere Radius (R)
  6. ID (drone registry). Each communication modem will be equipped with unique number.


Teams will receive link with geofencing information in geojson format. Take-off position is located within geofencing border. It is only allowed to cross the border defined by geofencing, to avoid collision. The maximum crossing distance is set to value of 2R.

Avoiding collision rules

The moment of launching the collision avoidance protocol is the virtual touch of the spheres.

The moment of launching the collision avoidance protocol is the virtual touch of the spheres.


Caution! During the task, there may be n drones in designated area flying at the same time

Each aircraft must support, following collision avoidance scenarios. xxx

Aircraft on same track (Overtaking) Aircraft on reciprocal tracks (passage) Aircraft on crossing tracks (bypassing) 
 Collision avoidance scenarios1 Collision avoidance scenarios Collision avoidance scenarios2
Faster aircraft must give priority to the slower one.

No action needed by slower aircraft.

All aircrafts turning rightAircraft on the right has priority

The beginning of mission

Teams will receive the exact take-off time in UTC. Take-off must be performed within a maximum of 30s from the designated time.

Mission logger

Each flight must be logged with an 0,1s interval.

The use of the collision avoidance function must be registered with the decision information.

All unchanged logs must be available to the Jury on request, immediate after flight.

UAV WiFi Identification and Location Set  —>  pdf file
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