FOI Develops New Radio Channel Models

The Swedish Defence Research Agency (FOI) has, on behalf of the Swedish Armed Forces (Försvarsmakten), investigated how radio channel models for future military systems can be improved. By integrating new, high-resolution geodata from the Swedish Mapping, Cadastral and Land Registration Authority (Lantmäteriet), the models are expected to provide more accurate calculations of radio wave propagation. This work is considered important for assessing range and performance in the Armed Forces' communication systems.

– One wants to be able to calculate detection distances, communication ranges, and so on, and then one must know how radio waves propagate, says Eric Corrigan, a researcher at FOI's Electronic Warfare department in Linköping (southern Sweden).

According to information from FOI, the agency has chosen to conduct the studies and develop the models in-house. The alternative of purchasing commercial software was dismissed, as the department's operations are described as being strongly dependent on an internal understanding of wave propagation.

The researchers have, among other things, examined how forest height affects the attenuation and reflection of radio waves. Previous propagation models have relied on standard heights based on terrain type. Now, open geodata from Lantmäteriet is being evaluated instead, which is based on airborne laser scans with one to two measurement points per square metre.

To handle the detailed data, the project has tested a parabolic equation model that has previously been used to calculate radio wave propagation.

– That model seems to be compatible with this type of forest modelling, which means we can proceed with the studies and eventually compare with measurements, says Eric Corrigan.

According to the agency, the more accurate geodata also brings increased computational complexity. Future work will therefore focus on how FOI can balance the demand for precision with the Armed Forces' need for sufficiently rapid results.