China launches experimental satellites to improve BeiDou network’s accuracy
- The new satellites will be designed to test technology that will allow the network to offer more precise positioning around the globe
- The applications could also help improve the technology used in driverless cars or in agricultural drones
The CentiSpace-1 S5 and S6 satellites are designed to test technology that will pave the way for a constellation of 160 satellites, known as the BeiDou Low Earth Orbit Navigation Augmentation System.
The technology is designed to improve the accuracy of the system, which operates in a similar way to the American GPS, and improve its coverage all around the globe.
This will help support a wide range of applications from autonomous driving to agriculture, for example by allowing drones to be used to spray crops.
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Systems such as BeiDou are not accurate enough by themselves to do things such as help land an aeroplane, so ground-based devices have been used to correct the navigation signals and improve their accuracy from a few metres to a few centimetres, according to a scientist with the China Satellite Navigation Office in Beijing.
However, ground-based augmentation relied on a dense network of reference stations and communication lines, which became impossible on the sea or in near-Earth space, the scientist, who asked not to be named, said.
Using low-Earth orbit satellites for space-based augmentation will help address this disadvantage by taking over the functions previously performed by the ground-based devices and also further improve the accuracy down to the millimetre level.
But it will also help expand the network’s coverage around the globe – its ground-based devices were largely confined to China, meaning it did not work so well in some parts of the world – and reduce the time needed to obtain optimal accuracy because most BeiDou satellites operate from a medium-Earth orbit.
Other satellite-based augmentation systems have already been established by the United States, Europe, Japan and India.
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China launches last piece of BeiDou Navigation Satellite system into orbit
The new satellites, each weighing about 100kg (220lbs) and developed by the Beijing-based company Future Navigation, will test new technologies including broadcasting equipment and electric propulsion devices that help correct a satellite’s orbit, according to the Dazhong Daily newspaper.
They would connect with CentiSpace-1 S3 and S4, which were launched last month, the newspaper added.
The pair will also carry out intersatellite laser link experiments, a communication technology similar to that used on SpaceX’s Starlink satellites.
Following the launch of CentiSpace-1 S5 and S6, the assembly of the BeiDou Satellite Navigation Augmentation System will start next year and is expected to be finished in about three years’ time.
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The satellites were launched using a platform off the coast of Shandong province. Sea launches have the advantage of being cheaper and safer than land launches, Zhang Ming, a member of the team behind the Long March 11 rocket used in the launch, told state broadcaster CCTV.
China is developing a satellite and rocket centre on the coast of Shandong to facilitate sea launches and offer a new route into space, in addition to its three inland launch centres and the coastal Wenchang spaceport on Hainan island.
