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Intended Use and Operating Principle

DANGER! If the equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.

Spectracom GSG-Series Signal Generators and GNSS Simulators are used to test GNSS receivers by generating GNSS signals, as they are transmitted by GNSS satellites. The signals are transmitted via air (using an antenna; see Signal Power Level Considerations), or via an RF cable.

Depending on the model, and the options installed in a GSG unit, generated/simulated signals, as well as user position, time and output power can be manipulated by the user either:

  • during the test, i.e. in real-time, via the GSG front panel, or
  • before beginning the test, by saving the programmed signal data (as well as trajectory data, if the receiver is to be tested under virtual movement conditions) in scenario files, using the optional StudioView™ software.

In addition to GNSS, other signals such as interference and multi-path can be generated to test the sensitivity to various disruptions.

The number of channels installed in a GSG unit determines how many signals can be generated. If more channels are required than available, two or more GSG units can be synchronized to generate 128, 256, or more signals.

Built-in trajectories (static, configurable circle, and rectangular as defined in 3GPP TS 25.171) or user-designed trajectories (in NMEA standard format) can be run on GSG simulators. Users can upload their own ephemeris data in standard RINEX format or re-use the default data for any time periods. The GSG-6 Series is capable of automatically downloading historical RINEX, WAAS and EGNOS data from official websites, as needed.

The GSG-6 Series can be controlled via an Ethernet network connection, or USB or GPIB. A built-in web interface allows remote operation of the instrument. With the optional GSG StudioView™ PC Software, you can build, edit, and manage the most complex scenarios, including building trajectories via Google Maps, independent of the GSG unit, for later upload.

Besides the variety of built-in navigation/positioning tests, GSG units are also suited for accurate testing of timing GNSS-receivers. The GSG-6 is equipped with an ultra-high-stability OCXO timebase for precision timing of the satellite data, or use external synchronization from a 10 MHz reference from e.g. a Cesium or Rubidium clock. A built-in 1PPS output, synchronized to the generated satellite data, allows comparison with the 1PPS signal from the timing receiver under test.