The Saab Sensis Radar Environmental Simulator (RES) is a scenario-based radar stimulator that provides detailed engineering design verification, test and debug of a host radar's signal and data processor. The RES monitors a radar's commands to determine its waveform type, beam steering angle, thresholds and antenna configuration, and then provides a true waveform response. Actual radar performance can be achieved by using terrain data for desired latitude/longitude placement.

The RES also enables ideal wartime scenario simulation. It non-invasively interfaces with a radar while synchronously injecting Intermediate Frequency (IF) or digital signals containing target, clutter and Electronic Counter Measure (ECM) returns associated with pre-scripted scenarios. These scenarios can be stored for playback at any time. The RES is designed to participate in Distributed Interactive Simulation (DIS) events such as Missile Defense System Exerciser (MDSE), as well as customized scenarios.

The RES simulation supports all test phases (development and integration, system stress and loading, requirements verification and acceptance, etc.) in the radar lifecycle, which significantly reduce program cost and risks. It is a complete end-to-end test and evaluation tool.