Luftburna kommunikationsnoder i marknät. Analys av helikopterscenario


  • Sara Örn Tengstrand

Publish date: 2013-12-31

Report number: FOI-R--3820--SE

Pages: 41

Written in: Swedish


  • ad hoc networks
  • helicopter
  • communication range


Today, helicoptersmay be without communicationwith the base and close ground units after leaving the base. This may cause the helicopter to avoid flying close to own units, due to the risk of friendly fire. It also makes it hard to get updated information, and to send back information before landing. It is desireable to have radio commnication before the helicopter is in visual range. We have calculated ranges of communication between the helicopter and nodes on the ground. The ground nodes in our case are units using a modern tactical radio. The radio system uses the frequency 50 MHz or 300MHz, and for these frequencies has a bandwidth of 25 kHz or 1 MHz, respectively, and a transmit power of 50Wor 44W.We also discuss demands put on the time it takes to establish a link. The calculations show that the range varies depending on the terrain, for all combinations of flight and antenna heights. At lower flight heights, the range is short. At a flight height of 20 m, the range is between 1,25 and 10 km, even if a 25 m mast is used. At 1000 m flight height, the range is larger, 7-55 km at 3 m antenna height and 9-103 km with a 25 m mast. If 64 ground nodes are used, and the helicopter may connect to the best one, the range is up to doubled. However, it is not as good as using one 25 m mast. At the frequency 50 MHz, range is larger. At 20 m flight height and a 25 m mast, the range is 4-32 km, and at 1000 m with a three meter antenna 24-117 km. If the link is used by the helicopter to idintify itself to the ground nodes, the link needs to be established and the information sent before the helicopter is seen. In this case, the range is in most cases only long enough when using the highest studied flight height, 1000 m.