I see a lot of BS is spewing in this thread Every commercial ship carry transponder to identify themselves That is the insurance requirement So the Chinese can clearly see who is on the ocean. They even have web based Automatic ship identification system
The Chinese has built an automatic system to identify, track carrier. How do we know it?. Because the lead scientist was publicly commended and given award for scientific and engineering achievement. Some of the member here maybe can dig it . It is buried somewhere under the missile thread.
They system probably not depend on visual or SAR only. But it also track electromagnetic etc . So Carrier op doing CAP with aircraft launch and retrieve periodically is tell tale sign of Carrier
The Indian did some simulation not too long ago and their conclusion is here
For detail here it is
China’s Constellation of Yaogan Satellites & the Anti-Ship Ballistic Missile: October 2015 Update
Authors: S. Chandrashekar and Soma Perumal
To read the complete report in PDF click
With the recent launches of the Yaogan 26 and Yaogan 27 satellites China has demonstrated its ability to routinely identify, locate and track an Aircraft Carrier Group (ACG) on the high seas. This space capability is an important component of an Anti-Ship Ballistic Missile (ASBM) System that China has set up.
The current operational satellite constellation consists of ELINT satellites, satellites carrying Synthetic Aperture Radar (SAR) sensors as well as satellites carrying optical imaging sensors.
Based on the orbit characteristics, their local time of equatorial crossing and other related parameters, these satellites can be grouped into different categories that perform the various functions for identifying, locating and tracking the ACG.
Yaogan 9 (Yaogan 9A, 9B, 9C), Yaogan 16 (16A, 16B, 16C), Yaogan 17 (17A, 17B, 17C), Yaogan 20 (20A, 20B, 20C) and Yaogan25 (25A, 25B, 25C) are the five triplet cluster equipped with ELINT sensors that provide broad area surveillance over the Oceans. With a coverage radius of about 3500 Km, they provide the first coarse fix for identifying and locating an ACG in the Pacific Ocean. Yaogan 20 and Yaogan 25 may be replacements for the Yaogan 9 and the Yaogan 16 that may be nearing the end of their lives.
Yaogan 23, Yaogan 10, Yaogan 18, Yaogan 14 and Yaogan 21 are the current operational satellites carrying a SAR sensor. With Local times of crossing of 02 00, 06 00, 10 00, 14 00 hours and 1730 hours, they provide all weather as well as day and night imaging capabilities over the regions of interest.
The Yaogan 26 which had replaced the Yaogan 12 which in turn had replaced the Yaogan 5 has the orbital characteristics of a SAR mission but its local time of crossing is 10 30 AM. This is very close to the 10 00 hours crossing time of the Yaogan 18 SAR satellite. This could therefore be either a SAR mission or a high resolution optical imaging mission. From the orbit characteristics this may possibly carry a SAR.
Yaogan 11, Yaogan 4, Yaogan 24 and Yaogan 7 constitute the high resolution optical satellites in the current constellation. The sensors they carry may have resolutions of between 1 to 3 m. Their local times of crossing of 09 00, 11 00, 13 30, and 15 00 hours respectively ensure favourable illumination conditions for their imaging missions.
Yaogan 27, Yaogan 19, Yaogan 22 and Yaogan 15 satellites with local times of crossing of 09 30, 10 30, 13 30 and 14 30 hours respectively are optical imaging satellites with medium resolution (3 to 10 m) capabilities. They act as a broad area coverage complement for the SAR as well as the high resolution optical imaging satellites. Yaogan 27 is a replacement for the Yaogan 8 that may be nearing the end of its life.
Using typical sensor geometries and the two line orbital elements available from public sources the ability of the current constellation to identify, locate and track the ACG was simulated.
Assuming that any three of the ELINT clusters are operational at any given point in time the ELINT satellites typically make 18 contacts in a day with the moving target. The maximum period for which the target remains outside the reach of the ELINT satellites is about 90 minutes in a day.
The SAR and the optical imaging satellites together typically provide 24 satellite passes over the target. About 16 targeting opportunities, during which the uncertainty in the target’s location is less than 10 km, are available in a day.
The analysis and the simulation results suggest that China has in place an operational ASBM system that can identify, locate, track and destroy an Aircraft Carrier in the Pacific Ocean. This seems to be an important component of a larger Chinese Access and Area Denial Strategy focused around a conflict over Taiwan.
