Printer FriendlyEmail Article Link

Can I combine / integrate two (or more) GNSS simulators that were originally only provided as standalone units?


Yes, you can combine GNSS simulators, that were originally only provided for standalone use, in order to create a new multibox system. But you should first consider the following points to ensure you are thinking about combining simulators that will support a multibox configuration:-

  1. The following GNSS simulator models do not support multibox configurations : GSS4100    GSS4200    STR4500    GSS6100    GSS6300    GSS6300M
        - One small exception is that a GSS6300M can be combined with a GSS5300; though for a different purpose, i.e. to add GNSS signals to a Multi-Radio Test set-up, rather than enhancing GNSS signal capability
  2. In general you can only combine simulators of the same model series. So you cannot, for example, combine a GSS6700 with a GSS8000
  3. There are just a few exceptions to the rule in point 2, which relate to the 'high-end' GNSS simulator models only, i.e. STR47xx / GSS7xxx / GSS8000.
        - An STR4760 and STR4780 can be combined with a GSS7700 or GSS7800
        - A GSS7700 (variant B) or GSS7800 can be combined with a GSS8000
        - Please refer to the hardware user manual, DGP00703AAA, interconnection diagrams for example of standard, supported multibox configurations

However, even with the above points understood, for the new system to be correctly configured the simulators needs to be formally integrated by Spirent. When simulators are combined the following must be considered:-

  1. A new set of interconnection cables is required so that all auxillary units are fed by timing signals from the master unit
        - NOTE : For 'high-end' simulator models (STR47xx / GSS7xxx / GSS8000) when more than two units are being combined a "Distribution Unit" is additionally required
  2. If the new system requires that RF signals from each unit are combined so as to provide a single antenna output, then a new Multibox Combiner Unit (MCU) is required
        - NOTE : If the user already has an MCU which can be used for the new system configuration, the new MCU signal path(s) will still need to be measured for path delay and loss at each required RF frequency
  3. The new system configuration will require new alignment data to be measured and appropriate offsets programmed to the unit
  4. The sig_gen.txt file, stored on the host PosApp PC, needs to be updated with the new system configuration 
  5. New hardware key(s) will need to be loaded on the host PosApp PC in order to ‘authenticate’ the simulators for use in a master/auxillary set-up

As you can see, combining simulators is not simply a case of, for example, creating your own set of interconnection cables, combining the units, and expecting to be able to run scenarios:-

  • Taking care to re-measure signal levels and delays will ensure that the new, designated RF output port provides the required, aligned GNSS signal.
  • Any uncertainty in signal level or delay will affect receiver performance and results
  • Without correctly programming CONF (configuration) data to the simulators, and representing those CONF selections in the sig_gen.txt file, PosApp or the simulator will either report an error when trying to start a scenario or the scenario might run but the simulator is in the wrong CONF state
  • Without providing the necessary hardware keys PosApp will warn you that one or more units are not licenced for use (see article FAQ10737)

For these reasons Spirent highly recommend contacting our global sales team to discuss your requirements and what integration options Spirent can offer (please see the details below or visit and select [About Us-->Contact Us] to find the details for your regional sales contact).

Spirent Communications, Aspen Way, Paignton, Devon TQ4 7QR, UK
T: +44 1803 546325
US Government & Defense: Spirent Federal Systems Inc. 22345 La Palma Avenue, Suite 105, Yorba Linda, CA 92887
T: +1 714 692 6565

Product : MCU,GSS5060,STR4500,GSS4150,GSS4100,GSS4200,GSS6100,GSS6300,GSS6560,GSS6700