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Why use a GNSS Simulator?

Why would I use a GPS / GNSS simulator, if I want to do any testing I just stick my antenna out of the window, attach it to my receiver and away I go. Well that’s all good and well but for those requiring a rigorous GPS test environment, live sky testing has some serious limitations including a lack of repeatability, control and scalability. Not to mention the fact that you can’t test future signals in space e.g. GPS L2C and L5, partially deployed constellations or constellations that don’t yet exist.

Testing with GPS / GNSS simulators is the widely-accepted best practice for validating the performance of GNSS receivers and systems in many different scenarios and operating conditions in a controlled laboratory environment. Simulators are used extensively in academia and industry, in virtually all GNSS receiver manufacturing and major system integration, and in many different application fields, including navigation, positioning, telecommunications, aviation, automotive, and space, for both civilian and military applications. Using simulators facilitates several stages of research and product development, including requirements analysis, design and development, integration, production, maintenance, and support.

GNSS simulators provide many benefits, including

  • Control. Simulators allow complete control over all aspects of test scenarios, including GNSS constellation signals and environmental conditions.
  • Flexibility. Users can easily define different scenarios for different testing needs.
  • Completeness. Equipment can be tested under different operating conditions, ranging from nominal to extreme, including conditions that are impractical or impossible to produce in live testing.
  • Repeatability. Test scenarios are the same every time they are executed.
  • Reliability. Because all test conditions are controlled, test results are reliable, and equipment performance can be evaluated against known truth data.
  • Cost. Tests are conducted in the laboratory, without extra expenses for field tests and test vehicles.
  • Efficiency. Many different tests can be completed in the same laboratory test bed, without reconfiguring or relocating equipment. New test scenarios can be created and executed quickly.
  • Realism. The performance of GNSS receivers and systems are tested using the actual hardware. Simulators with real-time control capabilities support advanced hardware-in-the-loop (HWIL) testing.
  • Future. Simulators provide effective means of testing new and future GNSS capabilities that are not yet supported by actual constellations, such as the GPS L2C and L5 signals and the Galileo system.

A summary of the advantages of testing with GNSS simulators, compared to live testing with actual GNSS constellations, is shown in the table below.

Live Testing with Actual GNSS Constellations Laboratory Testing with GNSS Simulators
No control over constellation signals Complete control over constellation signals
Limited control over environmental conditions Complete control over environmental conditions
Not repeatable; conditions are always changing Fully repeatable
Unintended interference from FM, radar, etc. No unintended interference signals
Unwanted signal multipath and obscuration No unwanted signal effects
No way to test with GNSS constellation errors Easily test scenarios with GNSS constellation errors
Expensive field testing and vehicle trials Cost-effective testing in laboratory
Limited to signals available in GNSS constellations Testing of present and future GNSS signals
Competitors can monitor field testing Testing conducted in secure laboratory

If ensuring final product quality, whilst also meeting tight project timescales is important to you then you require the capability to simulate realistic, repeatable and controlled GNSS signals that our single-channel and multi-channel test platforms offer.

If you want more information on how we can help, contact globalsales@spirent.com or download our Application Note: Benefits, challenges and test considerations for GNSS Technology Developers.

 

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