A Selective Availability Anti-spoofing Module (SAASM) is used by military Global Positioning System receivers to allow decryption of precision GPS observations, while the accuracy of civilian GPS receivers may be reduced by the United States military through Selective Availability (SA) and anti-spoofing (AS).
[1] However, on May 1, 2000[2] it was announced that SA was being discontinued, along with a United States Presidential Directive that no future GPS programs will include it.
Those features are not available with the similar, but older, PPS-SM (Precise Positioning Service Security Module) system.
[citation needed] SAASM hardware is covered with an anti-tampering coating, to deter analysis of their internal operation.
[citation needed] Deployment of the next generation military signal for GPS, called M-code, commenced with the launch of IIR-M and IIF satellites, beginning in 2005.