
NavSpark: Arduino Compatible with GPS GNSS Receiver - mpweiher
http://www.indiegogo.com/projects/navspark-arduino-compatible-with-gps-gnss-receiver
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zwieback
Title is misleading - as far as I know centimeter accuracy is only possible
with an RTK base station in the area where you're using the GPS, e.g. in a
survey. I'm guessing the chipset allows capturing of raw data that can be
post-processed.

[http://en.wikipedia.org/wiki/Real_Time_Kinematic](http://en.wikipedia.org/wiki/Real_Time_Kinematic)

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jlgaddis
Yep, even WAAS is only considered to be accurate to 3m, IIRC.

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fr0sty
According to the wikipedia page on WAAS[0], regular GPS is accurate (95% of
measurements) < 2.5m horizontal and with WAAS is is .9m horizontal.

There is also an FAA graph of GPS measurement accuracy[1] which I'm guessing
is the source of various "accurate to 2.2m" claims I have seen.

[0][http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#C...](http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#Comparison_of_accuracy)

[1][http://www.gps.gov/systems/gps/performance/accuracy/histogra...](http://www.gps.gov/systems/gps/performance/accuracy/histogram.png)

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jwcooper
Arduino compatible is misleading in a lot of these cases. It usually means it
works with the standard library included with the Arduino IDE, but most of the
3rd party external libraries (note...interesting and useful, and almost always
necessary when connecting devices/screens, etc) don't end up working without
changes to the libraries themselves.

Take a look at the amount of work that the Teensy3 community has done to make
Arduino (atmel) specific libraries compatible with the ARM chip on the
Teensy3. They're one of the few communities that have wide-ranging support
with an ARM chip, but have put in a lot of time and effort to get it there.

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zellyn
“Arduino compatible” is often also used to refer to the structure of the pins.
This one claims to be “Breadboard compatible.”

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veemjeem
is it? the attiny85 is still marketed as being arduino compatible, but with
only 6 i/o pins, it is nothing like any other arduino product.

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tyw
is centimeter accuracy even _possible_ with GPS?
[http://www.gps.gov/systems/augmentations/](http://www.gps.gov/systems/augmentations/)
cites 10-15 centimeter accuracy under their NDGPS modernization efforts, but
don't even say they've gotten there yet.

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chrissmithuk
It's not possible, even with pretty ideal conditions.

Edit: I excluded RTK stuff in that comment :)

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stefantalpalaru
It is, using RTK (real time kinematic) and 2 different receivers:
[http://www.kickstarter.com/projects/swiftnav/piksi-the-
rtk-g...](http://www.kickstarter.com/projects/swiftnav/piksi-the-rtk-gps-
receiver)

~~~
chrissmithuk
Yes but that somewhat limits the practicality because you need two receivers,
a clear signal path between them and one has to be relatively static.

It's fine for surveying but for dynamic applications which are far more
common, it's a pain.

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toomuchtodo
You can receive RTK corrections over IP (via a cellular connection).
Government bodies across the US push the data over IP to you if you register
for a free account.

[http://igs.bkg.bund.de/ntrip/index](http://igs.bkg.bund.de/ntrip/index)

[http://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via...](http://en.wikipedia.org/wiki/Networked_Transport_of_RTCM_via_I)
nternet_Protocol

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sanj
I don't see any reference to "centimeter accurate" in this description.

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nrp
The datasheet for the Venus838FLPx used on it actually specifies 2.5m
accuracy.

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ChuckMcM
Cheap GPS, cheap pocket tri-copters, fun fun fun!

I really don't care about taco service but it would be nice if I could call
someone at home and say "I forgot my under 8 oz item at home" they could
attach it to the copter and send it to my 15 miles away at work.

Soon, if not already, that will be an off the shelf capability.

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return0
I know I have a twisted mind, but I envisioned a quad copter delivering a
grenade, a bomb or a shot to the head. Creepy me, I know.

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ricardobeat
The ability to do the same with a RC car has existed for a couple decades.

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ChuckMcM
True, just not as flexibly. Most targets that might be threatened in this way
have various barriers between them and a would be RC car assasin. Although the
sequence in the move "The Dead Pool" tried to envision this threat with
respect to an actual vehicle target.

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bri3d
The CPU component of this is a synthesis of LEON3, which is a GPL
implementation of the SPARC V8 ISA. Seems pretty neat, especially with the
presence of a hard FPU.

[http://www.gaisler.com/index.php/products/processors/leon3](http://www.gaisler.com/index.php/products/processors/leon3)

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marktangotango
Positioning is a really huge concern in robotics; how do you know where your
robot is? Just because you told it to move doesn't mean it did, or that it got
there. So that's why this is really cool. Millimeter accuracy would be better,
I don't even know if that's possible with GPS at all.

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dublinben
It isn't possible in real-time, but surveying grade GPS receivers can approach
that level of accuracy with long collection times and post-processing.

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Nrsolis
See my above post.

There are self-contained systems that do this in real-time.

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revelation
You can already get a $20 GPS module, Arduino compatible. Just take any random
GPS mouse, they will be talking NMEA over some serial line.

Of course you don't get "centimeter accurate", but that's a lie anyway, so
nothing lost.

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beagle3
GPS mouse? Unless you mean module (DYAC), can you please give a pointer?

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j_s
[http://gpstracklog.com/2007/08/whats-a-gps-
mou.html](http://gpstracklog.com/2007/08/whats-a-gps-mou.html)

 _The term "GPS mouse" refers to the shape and size of the device, and has
come to mean any wired or wireless GPS receiver that doesn’t come with any
sort of interface. It merely outputs position data to a laptop, cell phone,
etc._

~~~
vonmoltke
Huh, I have always referred to them as "pucks".

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arjie
I funded hoping for a couple. I imagine the centimetre accuracy will be hard
yo achieve,but what sort of accuracy is required to calculate average speed
over 200 m to within 2 km/h?

Suppose you smooth the input will it be sufficient or does 2 m accuracy mean
that it oscillates so wildly within that circle that it's only worth it for
positioning alone?

~~~
Someone
In general, assuming a perfect clock, t seconds over 200m with an independent
measuring error of x/2 at both ends will measure as t seconds over (200 +/\-
x) m [1], for a speed of

    
    
      200/t +/- x/t   m/s
    

So, for a given x, the error grows as 1/t. The longer t (= the slower your
movement), the lower the _absolute_ error.

For a snail, you don't even need a GPS; just say "2 km/h" and you will be
within 2 km/h.

However, things are better, as measuring errors for GPS for nearby (in time
and place) positions aren't independent. If your position is of by x meters in
direction D now, chances are it will still be more or less of by x meters in
direction D in a few seconds.

Back to your question: I wouldn't know, but I think you want to rephrase it in
terms of relative error or specify at what speed you want to know the answer.

[1] the math is the other way around, but that doesn't matter much.

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mng2
>Source code of the customized Arduino IDE will also be made available; the
GPS / Beidou / GLONASS navigation kernel library integrated will remain in
library file format.

Sounds like the guts are in a binary blob.

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angersock
So, the most interesting thing is that this is a Sparc V8 32-bit arch, with
floating-point support.

It can run a real operating system, I think.

Jolly good show!

