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Environment models

Environmental Models allow GSG to simulate signal obscuration. (This feature is supported as of software versions 6.1 and higher).

Scenarios utilizing signal obscuration simulate the blocking of GNSS signals by objects placed along the trajectory route. Typical use cases are the simulation of urban "canyons", tunnels, etc.

Environmental models in GSG simulators are supported through compressed keyhole markup language files (kmz), popularized by Google Earth™. A simple way to create these files is by using the 3D drawing tool SketchUp™, available from Trimble Navigation Limited:

Two kinds of models can be configured in a scenario, Vehicle model and Environment model:

If a satellite is blocked by an object from either environment or vehicle model, i.e. it is not visible by the receiver antenna, its power will be set to OFF.

GSG can successfully handle vehicle models with up to 130 triangles. Models should be optimized for a low polygon count. The triangle count is limited to a total of 300 for the combined environment and vehicle models.

For additional information, see the Spectracom Technical Note Vehicle Modeling.