Re:China's version of GPS now has more satellites than US or...
by lolc on Tuesday August 20, 2019 @08:30AM
(#20746139)
Interesting, thanks! I was wondering how two-way communication would work at scale. I often talk to people who are worried about being tracked and a recurring topic is the one-way property of GPS.
Re:China's version of GPS now has more satellites than US or...
by throw0101a on Tuesday August 20, 2019 @08:07AM
(#20745937)
It should be noted that BeiDou-1 and -2 are/were regional systems. The BeiDou-3 currently being deployed is global.
Beidou-1 used a two-way link, because it used two satellites in the same orbit. This means the satellite can track all users.
But Beidou-2 supports a one-way link - the same operating principle as GPS, GLONASS and Galileo - where the satellites can't track users. The downside to this design is it needs a lot more satellites, and they have to be in different orbits.
Beidou-2 retains some backwards-compatibility with the two-way link, but if your cell phone's GPS chip supports Beidou, it'll be the one-way link. You'd notice the 20cm antenna and poor battery life if you had the two-way link!