  An overview of the target echo strength (TS) modelling capacity at the
Swedish Defense Research Agency (FOI) is presented. The modelling methods
described range from approximate ones, such as raytracing and Kirchhoff
approximation codes, to high accuracy full field codes including boundary
integral equation methods and finite elements methods. Illustrations of the
applicability of the codes are given for a few simple cases tackled during the
BeTTSi II (Benchmark Target Echo Strength Simulation) workshop held in Kiel
2014.
