Kosmos 2501, Russian space-based navigation system comparable to the American GPS system, which consists of Uragan spacecraft. The operational system contains 21 satellites in 3 orbital planes, with 3 on-orbit spares. GLONASS provides 100 meters accuracy with its C/A (deliberately degraded) signals and 10-20 meter accuracy with its P (military) signals. The spacecraft also carries instrumentation of the KOSPAS-SARSAT international search-and-rescue system