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Tactical Data Links

Objective

To model, simulate and analyze the performance of a tactical data link for a national aerospace company

Network Model - Air Defence Scenario

  • A Ground Station (GS) is connected to the Early Warning Radar (EWR), via ground network infrastructure.
  • The GS starts up the network, does the time slot assignment, generates the crypto key and the frequency hopping pattern
  • GS then broadcasts the Air Picture to all friendly aircraft
  • Friendly aircraft broadcast their positions periodically to one another and to the GS
  • When enemy aircraft is detected by the EWR it transmits information to the GS
  • GS in turn broadcasts the updated Air Picture to friendly aircraft, which then engage the enemy

Performance Analysis

A set of simulation runs covering a wide range of input parameters were run to study the system performance. Some of the observations discovered after an in-depth analysis of the simulation results were -

  • With the low bit rates available and with RF propagation losses too many Air Picture packets
  • Time slots were not immediately available for the GS given the round robin slot allocation

Some of the recommendations to the customer were

  • Reduce the Recognized Air Picture (RAP) packet size
  • Move from a round robin to demand based slot allocation
  • Layer 3 routing could be added in the future for communication between nets
ParameterValue
Grid Length 300x300 kmSlot Duration 50 ms
EncryptionAES256
Bits per slot2500 bits
RF Power20 W
ModulationQPSK
RX Sensitivity-108 dbm