There are many applications that can benefit from a view of GNSS signals – including the use of both a GPS repeater and a simulated signal – without being able to see the sky including testing GNSS systems in vehicle production or for aircraft maintenance, the ability to navigate in-car on an underground motorway and for the safety of personnel in underground metro systems and mines.
There are systems available that can repeat signals received from the sky into sky deprived settings or generate a GPS or other signal as if the location can indeed see the sky. A few simple criteria can determine which method is best for you – importantly bearing in mind that either type of system will radiate a signal that could interfere with the actual sky signals and impair your other systems as well as other users. In fact, it could also lead to legal problems with government radio spectrum managers!
GPS repeater signals from the sky is an ideal solution for test applications. With careful design and planning these systems will deliver a signal for use in testing GPS systems where the actual position from the satellite signals is less important than the reception of the signals themselves.
Typical applications we have delivered systems for include vehicle production lines and both military and commercial aircraft maintenance hangars. It is easy to see that the time and cost of simply moving a jet aircraft outside the maintenance hangar just to test onboard GPS systems makes using a GPS repeater an attractive option.
We’ve also delivered GPS repeater systems for Emergency Services and Rapid Response Aircraft to ensure vehicles avoid wasting precious response time acquiring GNSS signals for their on-board mapping systems; potentially a life-or-death situation where response time is paramount.
However, a GPS repeater will only fix the position of the antenna outside. In a sky-deprived setting, a simulated signal will provide an actual position.
In these cases, such as personnel safety in underground transport and mines, a simulated GPS signal can give meter accurate positions underground as if a view to the sky was possible.
For example, the SubWAVE solution that we have partnered with Syntony to deliver uses existing underground cable infrastructure to transmit a simulated GPS satellite signal that can be received by any device with GPS (including an iPhone) giving depth underground as well as surface position (e.g., 50m under Oxford Street rather than on Oxford Street).
You can then integrate this within current management platforms or deliver mapping solutions to end devices to ensure visibility of personnel in potentially dangerous solutions with the goal of guiding them to safe harbours should this be needed.
Both a GPS Repeater and a simulated GPS signal have their benefits and their shortcomings, so it’s important to evaluate your current setup and determine which timing solution is right for you. With decades of experience and expertise, Chronos is ready to provide the advice and the technology partnership you need to remain on the clock.
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