Re: [gpsd-users] Coding Question

[Gary E. Miller]

Yo Roger!

On Tue, 5 Feb 2019 08:15:02 +0000
Roger Oberholtzer <address@hidden> wrote:

> >> I need RTCM because I am working on Intelligent Transportation
> >> Systems and I need to have individual lane accuracy.  
> 
> > RTCM would only get you lane accuracy if the base station is
> > no more than a few kilometers from the rover.  
> 
> We have found that one also needs a system with an IMU, like
> something from Oxford Technical Solutions or Applanix.

Or the cheap u-blox/IMU combos sold for drones.  The problem is they
drift off center very fast.  Ok, for mementary underpasses, not much
more.

I have seen $70k IMU, and even they drift a bit.

> A GPS-only
> solution simply does not provide the needed accuracy.

Unless you have a very close base station, or do PPP.

> At least not in the real world.

Best I can do, L1 only, is around 1 meter.  But with a local
base station I can get to 1 centimeter.

> I consider GPS salesman to be the equivalent of used
> car salesmen. They will claim anything. The truth is in the fine
> print.

Well, salesman are another thing.  I'm talking about my real results.

> We measure vehicle location at driving speed and require sub-meter
> accuracy. We get it when we get it. And we don't when we don't.

Makes me feel real safe.  Not.

Some of the u-blox have wheel sensors to improve the fix.

> Oxford Technical Solutions do a lot with autonomous vehicles.

The death rate per mile for autonomous vehicles is 20x for manned
vehicles.  Not Ready For Prime Time.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can’t measure it, you can’t improve it." - Lord Kelvin

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