Starlink A Possible GPS Alternative?
Fri, 10/21/2022 - 8:49pm
How researchers at the University of Texas hacked the signal sufficiently to determine its potential application as a navigation system:
I predict that the current accuracy will improve as soon as Elon Musk figures out a way to monetize the data...
Gee, I don’t get this. Is Musk (I find it difficult to key in his name without editorializing) going to retroctively install rubidium clocks in some of his >3,000 satellites? Is there another solution? Speaking of “an accuracy of about 98 feet” for all I know might be true but I’d need more to find a reason to believe it.
lot of conspiracy recent days and he earns a lot of it despite whatever you just said
lot of things cover underneath and you just see the tip of iceberg only. Enjoy before it last!
Additional Info Sources
It hasn't yet been peer reviewed, but Humphreys' lab has published a paper on their work.
As described in part at MIT Technology Review:
The UT Austin researchers did not try to break Starlink’s encryption or access any user data coming down from satellites. Instead, they sought out synchronization sequences—predictable, repeating signals beamed down by the satellites in orbit to help receivers coordinate with them. Not only did Humphreys find such sequences, but “we were pleasantly surprised to find that they [had] more synchronization sequences than is strictly required,” he says.
Each sequence also contains clues to the satellite’s distance and velocity. With the Starlink satellites transmitting about four sequences every millisecond “that’s just wonderful for dual use of their system for positioning,” says Humphreys.
If the terrestrial receiver has a good idea of the satellites’ movements—which SpaceX shares online to reduce the risk of orbital collisions—it can use the sequences’ regularity to work out which satellite they came from, and then calculate the distance to that satellite. By repeating this process for multiple satellites, a receiver can locate itself to within about 30 meters, says Humphreys.
If SpaceX later decided to cooperate by including additional data on each satellite’s exact position in its downlinks, that accuracy could theoretically improve to less than a meter—making it competitive with GPS.