From the earliest days of the GPS program, the US government intentionally degraded the civil signal to prevent full accuracy. This practice was referred to as Selective Availability (SA), and could be overcome by acquiring and processing the military signal. SA was officially discontinued on May 1, 2000 by presidential directive and is no longer a requirement for newly launched GPS satellites.

In contrast, Anti-Spoofing (AS) is still applied to the military signal to guard against fake transmissions of satellite data by encrypting the P-code to form the Y-code. Authorized Precise Positioning Service (PPS) receivers acquire and track the Y-code by using the SAASM security architecture. Test and evaluation of PPS receiver functions requires SAASM-capable simulation equipment.
Spirent Solves Your Critical Test Challenges

Spirent Federal Systems provides all of the following products for SA/A-S testing:
  • Intentional Satellite Clock Noise (ISCN) - unclassified SA testing may be performed using open literature models such as a first or second order Gauss Markov model. This does not require authorization from US government.
  • SA/A-S functions - all SAASM functions are fully supported
  • Embedded Auxiliary Output Chip (AOC) design
  • Authorized keys can be loaded through fill port on simulator PC
  • Simulator classification can be upgraded or downgraded with removable hard drives
Why Test with Spirent?
  • SimSAAS software has been granted GPS Wing security approval
  • Flexible software allows full control over SA/A-S functions
  • Spirent Federal's personnel are able to support all testing needs
  • Spirent Federal can identify the right product(s) for your unique testing requirements

Request a Quote Request a quote
Contact us Contact us


Need help finding the product that's right for your business?

Contact us