Technologies

Wireless Spectrum Management

TIREM™ - Terrain Integrated Rough Earth Model™

TIREM

Alion’s Terrain Integrated Rough Earth Model (TIREM) enables DoD and commercial customers to forecast radio frequency propagation loss over irregular terrain and seawater for ground-based and air-borne transmitters and receivers. Alion scientists and engineers have been enhancing and maintaining TIREM since created in 1967.

TIREM is a set of physics-based, DoD standard algorithms, used to predict coverage for communication ranges for land mobile radios, point-to-point distances, sensor acquisition ranges, television and radio broadcast stations, etc. TIREM predicts median propagation loss from 1 MHz to 40 GHz. The techniques used to calculate these losses include:

  • Free-space spreading
  • Reflection
  • Diffraction
  • Surface-wave
  • Tropospheric-scatter
  • Atmospheric absorption

TIREM is the de facto propagation tool for the Federal Government. TIREM is used in hundreds of modeling and simulation (M&S) tools and tactical military radios for the DoD including:

  • SPECTRUM XXI
  • SPEED
  • INC1 WIN-T NETOPS
  • NPT
  • GIANT
  • GATE
  • EMPIRE
  • Joint-Tactical Network Toolkit (J-TNT)
  • Joint Communications Simulation System (formerly NETWARS)
  • OPNET Modeler
  • AGI Satellite Toolkit