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Calculating position from raw GPS data (2017)

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Re: Calculating position from raw GPS data (2017)

#51

Post by toast0 »

namibj wrote: post #8

Android provides carrier phase access for a while now, and with that relative positioning between such devices in about the same neighborhood can be done with enough precision that you have to care about where in the device the GNSS antenna lurks. That alone isn't too fancy; it gets good once you throw in the accelerometer and gyroscope in each device. Because with that you get this not only in realtime, but also wit…

https://www.bestbuy.com/site/tracfone-blu-view-5-64gb-prepai...

Here's a GNSS receiver for $30. It comes with some other junk you don't really need though.

Re: Calculating position from raw GPS data (2017)

#52

Post by mbonnet »

nobodyknowin wrote: post #17
AlexanderTheGr8 wrote: post #15

Earlier quoted context omitted.

I never really thought of that. That's a pretty interesting restriction. Although any party with access to warheads that can fly 1000+ mph probably can bypass the GPS restriction, no?

Not if they buy an off-the-shelf solution.

correct. and the idea here is to put up at least some form of barrier to entry, because any good guidance is also nuclear warhead delivery guidance at a certain point.

Re: Calculating position from raw GPS data (2017)

#53

Post by slow_typist »

namibj wrote: post #48
slow_typist wrote: post #34

Earlier quoted context omitted.

Can‘t you? https://www.mouser.de/ProductDetail/u-blox/ZED-F9P-02B?qs=DP...

They are 114.62 USD each if you buy at least 100 of them. And you still need to add an active antenna and a good crystal. Considering those, this module is about 3x the price I asked.

The crystal is already included. Of course you need an antenna and several other parts and most importantly communication between base and rover for correction data. Integration is the elephant in the room here. Ready to use boards go for like US$ ~ 300 (without board to board communication).

Admittedly I misread your post - you asked for $ 100 a pair. But a few hundreds is possible - at least in costs.

Re: Calculating position from raw GPS data (2017)

#54

Post by namibj »

slow_typist wrote: post #53
namibj wrote: post #48

Earlier quoted context omitted.

They are 114.62 USD each if you buy at least 100 of them. And you still need to add an active antenna and a good crystal. Considering those, this module is about 3x the price I asked.

The crystal is already included. Of course you need an antenna and several other parts and most importantly communication between base and rover for correction data. Integration is the elephant in the room here. Ready to use boards go for like US$ ~ 300 (without board to board communication). Admittedly I misread your post - you asked for $ 100 a pair. But a few hundreds is possible - at least in costs.

I misread the block diagram. It indeed only needs power communications and an antenna.

Re: Calculating position from raw GPS data (2017)

#55

Post by solidsnack9000 »

AlexanderTheGr8 wrote: post #16
cmsj wrote: post #12

Earlier quoted context omitted.

GPS was built primarily for the military and the signals available for civilian use were crippled to reduce accuracy. GPS receivers that provided high accuracy fell under the ITAR rules (ie you needed proper licensing to trade them) Over time such restrictions have largely been lifted, but there are still US export controls on GPS receivers with particular features, such as those designed for use in high speed aircra…

> those able to decode the still-military-only encrypted signals How? I was under the impression that military-only signal was encrypted. And if someone breaks that encrpytion, blame should go to the poor handling of encryption rather than the person breaking it? Analogy : if you leave a classified document on the train and a passenger reads it, whose fault is it?

Well, consider another analogy: a person leaves their door unlocked and another person goes in their home. It is still trespassing, even though the physical barrier has been intentionally disabled.

I'm not sure even what section of US code to check but it is certainly plausible that you can (for example) find a surplus device that decodes the signals on EBay and it's actually illegal to do it. You can find radios on EBay that broadcast on bands that are unlawful to use (or unlawful without certain licenses, &c).

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