21–30 of 75 posts
> When using BeiDou for car navigation, the receiver could theoretically transmit the car's location to a satellite in orbit, said Dean Cheng, a senior research fellow at the Heritage Foundation in Washington. Details on this? What does "theoretically" mean? Are there known protocols for this? Implementations? A lot of things could "theoretically" be done but aren't in practice.
> When using BeiDou for car navigation, the receiver could theoretically transmit the car's location to a satellite in orbit, said Dean Cheng, a senior research fellow at the Heritage Foundation in Washington. Details on this? What does "theoretically" mean? Are there known protocols for this? Implementations? A lot of things could "theoretically" be done but aren't in practice.
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!
This doesn't make sense. How can there be more satellites in the Eastern hemisphere than in the Western? Navigation satellites are in low earth orbit: they go around the earth every couple of hours. I could understand if one constellation had better polar coverage while another has better equatorial, but an east-west divide isn't physically possible (unless the Chinese are turning their satellites off when over the A…
This doesn't make sense. How can there be more satellites in the Eastern hemisphere than in the Western? Navigation satellites are in low earth orbit: they go around the earth every couple of hours. I could understand if one constellation had better polar coverage while another has better equatorial, but an east-west divide isn't physically possible (unless the Chinese are turning their satellites off when over the A…
This doesn't make sense. How can there be more satellites in the Eastern hemisphere than in the Western? Navigation satellites are in low earth orbit: they go around the earth every couple of hours. I could understand if one constellation had better polar coverage while another has better equatorial, but an east-west divide isn't physically possible (unless the Chinese are turning their satellites off when over the A…
Take a look at the orbits here : https://www.researchgate.net/figure/Ground-tracks-of-the-Bei...
Isn't the proliferation of multiple GNSS constellations actually quite positive thing? The smartphone geolocation chips seem to have no problem receiving signals from all constellations. So effectively this competition between the systems allows for denser coverage of location satellites. This in turn should enable more accuracy and faster location acquisition even with limited sky visibility. In security sense, it s…
Wouldn't it be nice instead of countries an open academic agency launch a series of open source satellites for locations. Hopefully likes of apple, Google, Microsoft, alibaba, benz, BMW, Toyota, Amazon, Qualcomm, European space agency can fund it. But I doubt it will happen as it's considered more strategic investment with military implications. But I am still hopeful like internet(which was designed for military pur…
Something SpaceX could consider? Given their ambition with Satellite Internet backbone.
Isn't the proliferation of multiple GNSS constellations actually quite positive thing? The smartphone geolocation chips seem to have no problem receiving signals from all constellations. So effectively this competition between the systems allows for denser coverage of location satellites. This in turn should enable more accuracy and faster location acquisition even with limited sky visibility. In security sense, it s…
Military depends on an encrypted signal. If you have the encryption key, you can decode it even with a very high level of interference.
Disadvantage is the key is shared for all users, and if it leaks to the adversary, then they can jam the signal.
Isn't the proliferation of multiple GNSS constellations actually quite positive thing? The smartphone geolocation chips seem to have no problem receiving signals from all constellations. So effectively this competition between the systems allows for denser coverage of location satellites. This in turn should enable more accuracy and faster location acquisition even with limited sky visibility. In security sense, it s…
Everyone sharing one system is excellent. Everyone sharing four increasingly redundant systems starts to look like a waste of money. We need a carpooling equivalent gps system. Still better than more bombs I guess.