Alion’s Terrain Integrated Rough Earth Model (TIREM) enables DoD and commercial customers to forecast radio frequency (RF) 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 creating it 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 1 THz. The techniques used to calculate these losses include:

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

As 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: