R
Rick C
Guest
On Sunday, July 21, 2019 at 5:46:43 AM UTC-4, DecadentLinux...@decadence.org wrote:
I hope no one takes any of these erroneous comments seriously, but then I likely don't need to explain that considering the source.
Limiting GPS devices by decree is not a very good way to accomplish whatever that would be intended to accomplish so they have always done it by technical means, i.e. Selective Availability which was turned off in 2000.
There is one limitation that is legally imposed on GPS receivers. They can not operate above some altitude and/or speed of travel to prevent them being used in ICBMs. With the various soft GPS receivers, this is not so effective since the code can be modified to remove this limitation.
I have worked with GPS receivers at several points in my career and I have never been told of any other "legal" limitations on receivers. In fact, they use GPS for surveying work where they use long averages to determine location to a wavelength of the GPS carrier, a few inches.
The military now gets better accuracy by using a different signal and modulation that aren't available to anyone else. Also, there are at least two other GPS-like systems and we have no control over how they are received. WAAS was added specifically to improve the accuracy of GPS for civilian use.
--
Rick C.
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Rick C <gnuarm.deletethisbit@gmail.com> wrote in
news:5eb5abc1-1f18-4d6e-9dd1-4c8c735f5604@googlegroups.com:
On Saturday, July 20, 2019 at 8:43:14 AM UTC-4,
DecadentLinux...@decadence.org wrote:
Sylvia Else <sylvia@email.invalid> wrote in
news:gpfkr2Fgv0jU1@mid.individual.net:
On 18/07/2019 3:44 pm, John Larkin wrote:
At work, we signed up with MonkeyBrains for microwave internet
service. We ordered the 50+50 mbit plan. It's actually speed
testing about 350+350.
And at home, a guy from Comcast (our local cable TV pirates)
knocked on the door and proposed to upgrade us for free,
faster internet and more cable TV (including HBO) for about
half our current price. They swapped out the modem today and
the internet here is now running about 450+50 mbits. AT&T and
Sonic keep leaving flyers on the doorknob offering us a
gigabit.
Sounds like mad competition to give away bandwidth. The
backbone fiber links must be moving astronomical amounts of
data. Each county around here might need a petabit per second.
Marketing numbers has always been a thing, whether it's
bandwidth, the output torque of a car engine, or the battery
voltage on a portable drill.
People think higher is better, so that's what the marketers
give them. Sometimes it has some real theoretical significance
even if the user won't notice the difference. Sometimes not.
It's all part of the standard ploy of deceiving the ignorant
punter.
Sylvia.
Look at the GPS accuracy levels when it entered the market.
At first all a consumer could get is maybe 10 yard diameter
resolution and don't even think about getting a reading indoors,
while the mil boys enjoyed full, 'current' accuracy.
Now, folks do not even think about it, they pop up their map
app on
their 'smart' phone and their little blue blip pings their
location even if they are tooling down the street in a car.
A lot of that is improvements in the receiver sensitivity and
throwing more hardware at the problem to facilitate reception.
Nope. Initially it was not permitted for consumer level GPS
receivers to resolve to 'mil levels'.
After it was OKd it was simply a matter of the chip makers to make
a single chip solution needing onlt a single receive antenna device.
Then there was the addition of WAAS which can bring the location
error to as low as 10 feet with a bit of averaging.
It was an 'addition' to the spectrum of what consumers were allowed
to access.
BTW, before
all this the error was a lot more than 30 feet.
On CONSUMER devices.
I recall plotting
the location of a stationary receiver and seeing it wander nearly
100 feet from the starting reported location overnight.
Back then, it would report a differing location points with each
check, every whatever seconds. It did not matter. The military
gear, however, did not have this problem.
NIST used to ping your PC from Boulder Colo with a time setting
timestamp. It would even make up for latencies in your seral port.
Depending on your modem's ISP connection quality, you might see a
different time set timestamp every time you check. Mine got down to
less than a ms of change each test. Some vary more than a second
each time.
It's still not accurate enough to tell you which lane your car is
in. At least, not with a reasonable level of certainty.
A standing test (no motion) is most accurate and repeatable. A
moving test relies on 'old data', even if it is only a couple
milliseconds old and that causes errors.
Lane position determination is and or should be a purely optical
thing.
I hope no one takes any of these erroneous comments seriously, but then I likely don't need to explain that considering the source.
Limiting GPS devices by decree is not a very good way to accomplish whatever that would be intended to accomplish so they have always done it by technical means, i.e. Selective Availability which was turned off in 2000.
There is one limitation that is legally imposed on GPS receivers. They can not operate above some altitude and/or speed of travel to prevent them being used in ICBMs. With the various soft GPS receivers, this is not so effective since the code can be modified to remove this limitation.
I have worked with GPS receivers at several points in my career and I have never been told of any other "legal" limitations on receivers. In fact, they use GPS for surveying work where they use long averages to determine location to a wavelength of the GPS carrier, a few inches.
The military now gets better accuracy by using a different signal and modulation that aren't available to anyone else. Also, there are at least two other GPS-like systems and we have no control over how they are received. WAAS was added specifically to improve the accuracy of GPS for civilian use.
--
Rick C.
+-+ Get 1,000 miles of free Supercharging
+-+ Tesla referral code - https://ts.la/richard11209