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Why do some people view it as a with-us-or-against-us problem? Combining beidou with GPS gives a better accuracy. Some competition and collaboration in the GPS field can benefit us as a whole.
So China has the technology to destroy satellites [1], and is developing alternatives to US satellites. Does this make anyone else nervous? Maybe Trump has a point when he says we should stop letting China steal our technology. [1] https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mi...
Any country/company who has launch vehicles can destroy satellites. SpaceX could just as easily destroy satellites.
Earlier quoted context omitted.
Due to COCOM limits, GPS was never an option for China to use on their missiles. https://en.wikipedia.org/wiki/CoCom#Legacy Edit: I'm wrong.
COCOM is a non issue when building your own devices from scratch. GPS satellites are transmit only so they can’t impose such limits directly it’s device manufacturers that implement COCOM.
The new military M code transmitted from the latest satellites is encrypted with a frequently changing key, so in the event of a war the DOD can disable the civilian signal as the M code will work standalone, hence a third party nation cannot rely on GPS.
The previous P(Y) code was also encrypted, but is theorised to need the civilian C/A code as well to work.
It’s interesting and odd to me that Beidou requires two-way communication, as opposed to other satellite tracking systems where the receivers are purely passive and satellites only transmit, not receive. Is there an explanation for why this was done?
I am highly skeptical of this claim, it's either for higher accuracy of military stuff, or an internet connexion to get a key or the ephemerides or something. But nobody is sending signal to a satellite 21000km from the surface straight from a watch-sized device.
The current Breitling Emergency (a bulky men's watch, but it wouldn't look out of place on some big out-of-doors type guy's wrist) is a working PLB transmitter.
So that means signals from it can be received not just 21000km up, but 36000km up where Geostationary birds live.
If you activate it, that watch will transmit the digital signal with its unique ID in it, and assuming you filled all the paperwork out soon after somebody from the relevant local emergency response (maybe a coastguard, mountain rescue, that sort of thing) will be phoning your emergency contacts
"Hi, do you know nraynaud? They went flying today? OK, do you know where they were headed? We have an emergency transmission from their beacon so we're going to send somebody to take a look and check they're OK. We'll let you know, thanks".
A "real" beacon would be better, more robust, better battery life, easier and more obvious for random strangers to operate if you're unconscious, not to mention much cheaper. But the Emergency has the advantage that you'll actually have it when shit goes wrong, because it's your watch.
So China has the technology to destroy satellites [1], and is developing alternatives to US satellites. Does this make anyone else nervous? Maybe Trump has a point when he says we should stop letting China steal our technology. [1] https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mi...
>So China has the technology to destroy satellites [ Any country that can launch a satellite has a technology to destroy one. It's called a missile. You don't even need to go to orbit - just intersect the orbit of the target and dump a bucket of nails in its path.
Earlier quoted context omitted.
>So China has the technology to destroy satellites [ Any country that can launch a satellite has a technology to destroy one. It's called a missile. You don't even need to go to orbit - just intersect the orbit of the target and dump a bucket of nails in its path.
Aren't GPS satellites geostationary?
So China has the technology to destroy satellites [1], and is developing alternatives to US satellites. Does this make anyone else nervous? Maybe Trump has a point when he says we should stop letting China steal our technology. [1] https://en.wikipedia.org/wiki/2007_Chinese_anti-satellite_mi...
>So China has the technology to destroy satellites [ Any country that can launch a satellite has a technology to destroy one. It's called a missile. You don't even need to go to orbit - just intersect the orbit of the target and dump a bucket of nails in its path.
It's easier to put something in orbit than to knock something out of orbit.
Note you can buy off-the-shelf GPS modules today that will work across all four GNSS: https://www.u-blox.com/en/product/neo-m8-series
Sidenote: the ublox M8 chips are a pleasure to work with, and there are variants that have IMUs (gyros and accelerometers) on board for sensor fusion. All for <10$. What an exciting time we live in!
"We are likely to see an increased bifurcation of the world into two camps - 'pro-China' and 'pro-US'", says Blaine Curcio, founder of Orbital Gateway Consulting Why do some people view it as a with-us-or-against-us problem? Combining beidou with GPS gives a better accuracy. Some competition and collaboration in the GPS field can benefit us as a whole.
http://fortune.com/2018/08/28/china-has-been-withholding-bir...
https://www.wired.com/story/australias-ban-on-huawei-is-just...
https://nypost.com/2018/09/19/chinas-social-credit-system-is...