ISSSP Reflections No.1, September 29, 2013
Authors: Professor S. Chandrashekar and Professor Soma Perumal
On September 1, 2013 at 19:16 UTC a Chinese Long March 4 C rocket placed a new ELINT constellation of Yaogan satellites into an 1100 km 63.4 degree inclination orbit.
The three satellites Yaogan 17A, 17 B and 17 C fly in a stable triangular formation. This arrangement of satellites made possible by the inclination of the orbit helps in the location of electronic emission signals over a very large area.
Modern naval ships are constantly emitting electronic signals as part of their regular activities. Capabilities to sense these emissions and then locate the sources of these emissions are critical for anti-access and area denial strategies over the oceans.
The Yaogan 17 triplet joins the Yaogan 9 and Yaogan 16 constellations of ELINT satellites. All of them are launched from the Jiaquan Satellite Launch Centre and fly in similar 1100 km 63.4 degree inclination orbits. The Yaogan 17 constellation would complement the Yaogan 9 constellation (which may be nearing the end of its life) and the more recently launched Yaogan 16 triplet of satellites to provide a near continuous global update on the location of high value naval targets such as aircraft carriers.
Though the Chinese media reported the purpose of new satellites as remote-sensing/scientific applications, land survey, crop yield assessment and disaster monitoring it is clear from the orbit characteristics that this is a part of the operational Anti-Ship Ballistic Missile (ASBM) System that China has put in place as a part of its anti-access and area denial strategy.
In addition to the Yaogan 9, Yaogan 16 and Yaogan 17 ELINT constellations, a number of other Yaogan satellites carry high resolution optical imaging and Synthetic Aperture Radar (SAR) sensors. These work in tandem with the ELINT satellites to provide more precise location information on potential high value targets. The ELINT satellites cover a large area of the sea within which the target is identified and located coarsely.
The orbits and launch times of the SAR and optical imaging satellites are chosen in such a way as to pass over the same areas covered by the earlier ELINT passes.