Cosmos 2181 was a Russian navigation satellite launched from the Plesetsk cosmodrome aboard a Kosmos 11 rocket. It was positioned in plane 13 of the constellation. It was used for testing of components and equipment of a space navigation system being set up to determine the position of civil aircraft and ships of the USSR merchant marine and fishing fleet at any point on the oceans and seas.
Development of this second generation Soviet navigation satellite system represented a collaboration between the Navy, Academy of Sciences, and Ministry of Shipping. The basis was the Parus / Tsiklon-B doppler navigation system, but allowing asynchronous operation of on-board equipment with only essential equipment receiving a timer interrupt. Development began in 1974 with some preliminary work already accomplished. The Tsikada system provided global navigation for both the Soviet Navy and commercial shipping. Prime contractor was KBPM/Reshetnev. PO Polyot, A S Klinyshkov provided synchronisation equipment. NII Radiopribor under N Ye Ivanov provided cryptography and spacecraft navigation systems. Flight trials began in 1976 under Admiral A I Rassokho. The system was accepted into military service in 1979.
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