91–100 of 191 posts
Down to 30cm - good! Now all we need is a GPS-enabled app for urban pedestrians that reminds them to look left or right just before they step off a curb into oncoming traffic.
As a runner I’d appreciate the corresponding app to remind drivers to look both ways before turning right.
>will give the next generation of smartphones 30-centimeter accuracy instead of today’s 5-meters Didn't the US scramble the civilian signals specifically so it wouldn't be too accurate? And they're just okay with civilians having access to ultra accurate GPS receivers?
Why would consumers want this type of accuracy ?
I guess I'd reverse the question. Why wouldn't you want the greatest level of accuracy you can get? Maybe you want to track your property lines? Maybe you want to accurately mark where your access point is for your septic tank? Maybe you just want to hide Easter eggs or buried treasure?
I'm not sure why anyone would want a tool that is less accurate than it can be, assuming it is also reasonably affordable.
>will give the next generation of smartphones 30-centimeter accuracy instead of today’s 5-meters Didn't the US scramble the civilian signals specifically so it wouldn't be too accurate? And they're just okay with civilians having access to ultra accurate GPS receivers?
Why would consumers want this type of accuracy ?
Earlier quoted context omitted.
Nothing at all: http://www.aholme.co.uk/GPS/Main.htm
How do these folks do the math? Do they understand general relativity? Or do they just pull the equations from somewhere?
Earlier quoted context omitted.
But that's client side right? What's preventing someone from implementing a GPS receiver using a SDR that doesn't have those restrictions?
Copenhagen Suborbitals has a blog-post about those limits: By default all GPS units have some built-in limits (so-called COCOM limits) that prevents them from providing any data if the velocity exceeds 515 m/s at altitudes above 18 km. These artificial limits are built into GPS receivers to prevent bad guys from using them in missiles and other nasty stuff. ... and proceed to figure out a way around ... https://copen…
Earlier quoted context omitted.
Things have changed since the 90s. > In May 2000, at the direction of President Bill Clinton, the U.S. government ended its use of Selective Availability in order to make GPS more responsive to civil and commercial users worldwide. > The United States has no intent to ever use Selective Availability again. The military has better precision, only because they buy better hardware. Similar hardware is used in commercial…
>The military has better precision, only because they buy better hardware. That's not true. Military receivers can use the Y Code which is encrypted for military use only. There are some really fancy civilian receivers out there that can leverage Y code to a limited extent without knowing the encryption key but full accuracy is only possible on a military receiver that can decrypt and use the Y code.
>will give the next generation of smartphones 30-centimeter accuracy instead of today’s 5-meters Didn't the US scramble the civilian signals specifically so it wouldn't be too accurate? And they're just okay with civilians having access to ultra accurate GPS receivers?
Why would consumers want this type of accuracy ?
As an avid hiker and runner I'm more excited to see what this will do for things like Garmin smart watches. I run through downtown Boston a few times a week and the accuracy is very bad at times making you look like you run much farther than you do.
It also has the potential to greatly increase the accuracy of the instant pace, which is a lot more volatile than the total distance
As an avid hiker and runner I'm more excited to see what this will do for things like Garmin smart watches. I run through downtown Boston a few times a week and the accuracy is very bad at times making you look like you run much farther than you do.
The multipath in urban environments probably limits the accuracy, unfortunately.
With the existing L1 signal the multipath signals overlap each other and its hard to find out which the original signal was.
The newer L5 signal is much shorter, so multipath signals will show up as individual peaks, and the receiver can simply pick the first signal, cause that will be the direct one.
Down to 30cm - good! Now all we need is a GPS-enabled app for urban pedestrians that reminds them to look left or right just before they step off a curb into oncoming traffic.