미국, 제3세대 GPS III 위성 23일(일) 발사 예정 VIDEO: What is GPS III and how will it stand apart?

What is GPS III and how will it stand apart?

By Shilpi Chakravarty -  12/18/2018

SpaceX Falcon 9 rocket will herald a new chapter in the GPS world. Whether it is locating an unknown street on Google Maps or tracking a fleet, GPS has become a lifeline to many. About 4 billion people worldwide use this system. To further boost its accuracy, the US Air Force is slated to launch the first of a new generation GPS III-SV01 on a SpaceX Falcon 9 rocket. Designed to be more secure and versatile and built by Lockheed Martin, the GPS III satellites will supersede the existing GPS constellations.

올해 2월 발사된 팔콘 로켓 모습/via youtube

미국, 제3세대 GPS III 위성 23일(일) 발사 예정 GPS 블록 IIIA은 첫 3세대 이자 통산 10번째 GPS III 위성 미국의 대북 추적 능력도 월등 개선 SpaceX Falcon 9 로켓은 GPS 세계의 새로운 시대를 예고하고 있다. 구글 지도에서 미지의 거리를 찾든, 함대를 추적하는 것이든, GPS는 많은 사람들의 생명선이 되었다. 전세계 약 40억 명의 사람들이 이 시스템을 사용한다. 정확도를 높이기 위해 미 공군은 신형 GPS III-SV01을 SpaceX Falcon 9 로켓으로 발사할 예정이다. 보다 안전하고 다재다능하게 설계되고 록히드 마틴에 의해 건설된 GPS III 위성은 기존의 GPS 별자리를 대체할 것이다. *Block-IIIA Satellite(지피에스) 블록-IIIA GPS III라고도 하며, GPS위성의 차세대의 위성으로서 2018년 12월 23일 발사될 예정이다. 민간용 L2C, L1C 신호, 군사용 M 코드 및 L5 반송파가 송신될 예정이다. 기술의 발전과 새로운 수요의 발생에 따라서 GPS 체계를 더욱 개량할 필요가 대두되었다. 1998년 미국 부통령과 백악관의 공표에 따라서 GPS 현대화 계획이 시작되었고, 미국 의회는 2000년 GPS III로 명명하면서 이 계획을 인가하였다. GPS 현대화 계획은 모든 사용자에 대해 정확도와 사용성을 향상하는 것을 목표로 하며, 새로운 지상국, 새로운 위성 및 4개의 추가적인 GPS 신호 대역을 포함한다. 민간용의 새로운 신호 대역은 L2C, L5와 L1C이며, 군용의 새로운 신호 대역은 M-Code이다. L2C1 신호는 상업적 용도를 만족시키도록 설계되었으며, 전리층 보정을 통하여, 정확도를 증진시켰으며, 2005년부터 GPS IIR-M에서 처음 적용되었으며, 2016년 까지 총 24개의 위성이 계획되었다. GPS IIIA에서는 정확도와 Earth coverage power를 증진시키고, 민간용 신호 L1C를 추가한다. 또한 Galileo, Compass, QZss 등과의 호환성(Interoperability)를 갖도록 개발되며, IIIB, IIIC에 대한 Bus capacity를 포함한다. GPS IIIB는 실시간으로 명령 및 통제가 가능한 cross-link를 적용함으로써, 위성에 upload가 가능하도록 하고, constellation 정확도를 증진시킨다. GPS IIIC는 고출력 spot beam을 적용함으로써, 군용 anti-jamming 능력을 제공하며, 무결성이 개선될 예정이다. GPS IIIB의 경우, 약 20cm 정도로, 기존 IIR-M 위성 보다 15배까지 정확도가 향상되었다. 설계수명은 12년에서 15년으로 개선되며, 4번째 민간용 신호인 L1C을 적용한다. GPSIII에서는 차세대 제어부분(Operational Control Segment:OCX)이 적용되며, OCX는 L2C와 L5신호를 이용한 모든 기능을 제공할 예정이다. [네이버 지식백과]  황기철 콘페이퍼 에디터 큐레이터 Ki Cheol Hwang, conpaper editor, curator

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You might wonder as to what happened to its other series. Well, you will be surprised to know that GPS III is one of its kind and has nothing to do with its numeric description. It is the third generation of GPS system that is considered the most powerful GPS satellites ever on orbit. It will have three times better accuracy and up to eight times improved anti-jamming capabilities, and maybe that’s why the numeric III mentioned with it.

Also what makes it class apart is that GPS III will boast a 15 year design life, twice as long as some of the current GPS satellites. They can even be launched two at once, making them less expensive to launch and maintain.

GPS systems in the United States have gone through six major iterations since 1978. The latest block of satellites, called IIF, launched between 2010 and 2016. The 12 satellites are all designed to last 12 years. Some of their notable features include the ability to receive software uploads, better jamming resistance and doubling accuracy.

The GPS Block IIIA set of satellites — the seventh set of GPS satellites, and the first set of the third generation — is manufactured by Lockheed Martin. The block was originally supposed to start launching in 2014. However, technical delays pushed the first projected launch to May 2018. The series is expected to launch 10 satellites, with the last one scheduled for the second quarter of 2023.

What will GPS III do?

For the first time, the Air Force is assigning nicknames to the GPS III satellites. The first one is Vespucci, after Amerigo Vespucci, the Italian navigator whose name was adopted by early mapmakers for the continents of the Western Hemisphere.

The new satellites are expected to provide location information that’s three times more accurate than the current satellites.

Current civilian GPS receivers are accurate to within 10 to 33 feet (3 to 10 meters), depending on conditions, said Glen Gibbons, the founder and former editor of Inside GNSS, a website and magazine that tracks global navigation satellite systems.

With the new satellites, civilian receivers could be accurate to within 3 to 10 feet (1 to 3 meters) under good conditions, and military receivers could be a little closer, he said.

GPS III’s new L1C civil signal also will make it the first GPS satellite to be interoperable with other international global navigation satellite systems.

However, jamming-resistant military signal will be available until a new and complex ground control system is available, and that is not expected until 2022 or 2023, said Cristina Chaplain, who tracks GPS and other programs for the Government Accountability Office.

How expensive it is?

The US Air Force awarded Lockheed Martin a contract worth more than $1.3 billion for two GPS III satellites, according to an announcement from the Department of Defense September 26.

The price of the first 10 satellites is estimated at $577 million each, up about 6% from the original 2008 estimate when adjusted for inflation, Chaplain said.

The Air Force said in September it expects the remaining 22 satellites to cost $7.2 billion, but the GAO estimated the cost at $12 billion.

First Lockheed Martin-built GPS III satellite packed/shipped for launch

How was GPS III contract awarded?

The Air Force controls a constellation of 31 GPS satellites from a high-security complex at Schriever Air Force Base outside Colorado Springs.

An interesting article by NASA says, the award for the first GPS III satellite contract traces its roots back to the day when the current Global Positioning System (GPS) reached full operational capability on 17 July 1995.

While the original GPS goals were met on that day, significant advances in technology as well as user demands on the newly-completed system resulted in an effort to modernize the GPS.

This initiative gained full support from the White House and President Bill Clinton’s Administration in 1998, which initiated the GPS III program in conjunction with the US Congress’ official authorization in 2000.

On 26 April 2016, the Air Force officially announced SpaceX’s selection to launch the second GPS III satellite.

Since then, the third, fourth, fifth, and sixth GPS III satellites have undergone competitive launch bids, with SpaceX winning all of them with their Falcon 9 rocket.

Ground testing and check out for GPS III-SV01 was successfully completed throughout 2017, and refinements to the SpaceX launch manifest brought the mission’s launch into alignment for December 2018.

https://www.geospatialworld.net/blogs/what-is-gps-iii-and-how-will-it-stand-apart

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