Yaogan Naval Ocean Surveillance Satellites
These remote sensing reconnaissance satellites are similar to the US DoD NOSS triplet launches. Each main spacecraft is accompanied by a pair of smaller payloads flying in formation with the main spacecraft. The Yaogan Weixing Satellite Fleet consists of remote sensing spacecraft that carry optical, Synthetic-aperture radar (SAR) or electronic intelligence payloads. According to Chinese Officials, the Yaogan Satellite Constellation is used for scientific experiments, land survey, crop yield assessment, and disaster monitoring. However, it is believed that the satellite system serves military purposes.
Yaogan 9A, Yaogan 9B, and Yaogan 9C, Chinese observation satellites, were launched on a Long March 4C rocket from Jiuquan on 05 March 2010 at 04:55 UT. Yaogan 16A, Yaogan 16B, and Yaogan 16C, Chinese observation satellites, were launched on a Long March 4C rocket from Jiuquan on 25 November 2012. Yaogan 17A, Yaogan 17B, and Yaogan 17C, Chinese observation satellites, were launched on a Long March 4C rocket from Jiuquan on 01 September 2013.
Ocean surveillance is the systematic observation of surface and subsurface sea areas by all available and practicable means primarily for the purpose of locating, identifying and determining the movements of ships and other vehicles, friendly and enemy, proceeding on the surface of the world's seas and oceans. Ocean surveillance systems provide near real-time, netted command and control support to commanders, afloat and ashore. It receives, processes, and disseminates timely all-source surveillance information on mobile targets of interest on the oceans, as well as on selected high interest fixed and mobile ground targets.
Radio interferometry dates back to the mid-1940s when the first radio interferometric observations were performed on the Sun. McCready, Pawsey1 & Payne-Scott used a single antenna iocated on a high coastal cliff in Australia to point east as the Sun rose. A fringe pattern was recorded from the interference between the direct signal and that reflecting £rorn the ocean surface below. An interferometer is composed of two or more antennas (presumed identical) separated by a distance. In general, the plane wave incident on the interferometer arrives at one antenna ?rst, and then at the other. The time delay between the two is calied the geometrical delay. The signais from the antennas pass through ampli?ers and ?lters which select the frequency of interest.
The multiple target ocean surveillance contact correlation problem can be decoupled roughly into two parts. The first, extensively treated in the literature, involves geolocation information only, and is normally analyzed through use of a bank of Kalman filters. The second is concerned with non-geolocation attribute information. Typically, the latter includes all data obtained through linguistic or discrete valued numerical sources.
Space systems provide systematic observations of surface areas and things by passive electronic means that provide commanders with situational awareness within a given area. Surveillance from space does not imply that a single satellite or capability must be continuously collecting. Satellites that are able to provide a snapshot in time can be augmented by additional capabilities collecting in the same or even different areas of the EMS. There will be short gaps in collection (minutes or a few hours), but capabilities will be concentrating on a target, which, over time, constitutes surveillance. These “following” capabilities can continue collecting on a target as the previous satellite moves out of the area of access in its orbit. Satellites may also be a contributor to an overall surveillance effort consisting of space, terrestrial, and airborne systems that together provide continuity in surveillance when space systems alone do not have continuous access or are unavailable.
The prime advantage of space-based ISR capabilities is their global and wide-area coverage over denied areas where little or no data can be obtained from ground and airborne sources. Other advantages these systems possess include mission longevity and reduced vulnerability to adversary action. Space-based ISR is limited by advanced denial and deception techniques.
China successfully sent Yaogan-30 07 group satellites into planned orbit on 26 October 2020. The satellites will "mainly be used for electromagnetic environment detection and related technological tests".
|Yoagan-9A/B/C||March 5, 2009||Long March-4C||Jiuquan|
|YG-16 Yaogan Weixing-16A/B/C||25 Nov 2012||CZ-2C||Taiyuan LC9|
|YG-17 Yaogan Weixing-17A/B/C||01 Sep 2013||CZ-4C||Taiyuan|
|YG-25 Yaogan Weixing-25A/B/C||10 Dec 2014||CZ-4C||JSLC LC43|
Some Western analysts were surprised by the launch of the YG-30-01 Yaogan Weixing-30-01 triplet on September 29, 2017 (and subsequent similar missions on November 24, 2017; December 25, 2017 and January 25, 2018). The successful launch of 3 Chinese military satellites YG-30 came at 11:43 am Beijing time 24 March 2020. This 6th triplet of satellites intended for wiretapping, like the first 5 launched between 2017 and 2019, was put into low orbit by a CZ-2C rocket, at the Xichang space center.
At 2:11 on 07 May 2021, the Long March 2C carrier rocket ignited at the Xichang Satellite Launch Center, sending remote sensing 30 group 08 satellites into space. Remote Sensing 30th Group 08 satellites adopt a multi-satellite networking mode, mainly used to "carry out electromagnetic environment detection and related technical tests". The satellites successfully entered the scheduled orbit, and the launch mission was a complete success. The mission, equipped with rocket fairing on a combination altimeter to measure the height of the fairing separation and then changes the atmosphere in the process and some attitude information, continue to promote "Based on the fairing debris falling area of the parachute control technology" research, to provide a reference for the subsequent design and improvement of the rocket landing zone control plan.
China successfully sent a new remote-sensing satellite group into orbit from the Xichang Satellite Launch Center in southwest China's Sichuan Province on 18 June 2021. The satellites were launched by a Long March-2C carrier rocket at 2:30 p.m. Beijing time. This is the ninth group belonging to the Yaogan-30 family. Also aboard was Tianqi-14, a satellite belonging to the Tianqi constellation. It was the 375th mission of the Long March rocket series.
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