[OSGeo-Discuss] Mobile GPS data collection, summary of sorts.
bob.basques at ci.stpaul.mn.us
Wed Aug 2 12:00:13 PDT 2006
Ok, I took a look at GPSD, it looks to be fairly comprehensive for GPS
listening. I didn't read everything so some comments here might be
based on my mis-information.
I worked on a listener a few years back that did something simialr, but
we were also recording AVL info as well as the GPS data. Now maybe
these should be considered two different capbilities, but most AVL
hardware reports GPS data as well.
Our basic architecture was like so:
Listener (working through IP of remote device) listens for the GPS
stream and pipes this to a database, we used MySQL, could be any
database. Each different type of hardware we used for data capture (and
believe me, there are a lot of them) had it's own Comm Lib for talking
to the listener, this worked exceptionally well as the DB handler was a
one time shot. All we ever need to do with it was add a few columns of
extra info that a new piece of hardware might support. The listener
were all handled with their own respective Comm library, this enable
old/new as well as different manufactures of collection devices to be
used in the same fleet operations. This was all a standalone
operation, worked all by itself, all points received were stored (I
know, it sounds like a lot of data, but it was easily manageable).
Now we were working this through a Office interface, didn't require the
field folks to see a display of the map with points on it. But the same
process would work with our described system so far. Once you have a
Database to query from that's how we had our Application work, it just
queried the database with an AJAX (BTW, this was before it was called
AJAX :c) request handler. This operated in the background
automatically. The interface we used was built to use raster images for
the backgrounds, and SVG animation sprites to control the point
tracking. since everything was stored, a user could replay any tracked
action at any time just by using a couple of Time indexes to qurey the
database by. Worked very slick, I think we were a bit before our time
This whole set up had a 7-10 lag for real time tracking in the described
configuration, (office mapping with Field GPS/AVL collection only)
Building this all into the portable device was a planned product, but we
just went in other directions and never got back to it. Running this
all on the portable device will also allow the users to see where they
and anyone else in their fleet are at any point in time.
Now, while the GPSD does the GPS collection very well, I'm not sure how
to approach also supporting AVL, I would suspect that some flexibility
lay in it's architecture for such things, but I would need to talk it
over more with a Tech person from the DEV team before giving out any
with the described operation of the system you can see how each
component becomes it's own beast and can be updated and enhanced
seperately from any of the other components. It also lends itself to
only building what needs to be built, while relying on opensource stacks
that already exist just as easily. The trick is to define the
specifications nicely, so that all components come up to spec once the
system is set in motion.
Am I making any sense yet?
> 2006/8/1, Bob Basques <bob.basques at ci.stpaul.mn.us>:
>> * Daemon (listener) to monitor GPS (could be a wrapper around
>> any of the options already available for reading GPS devices.)
>> coordinate locations, and other digital devices, Compass, etc.
> Please take a look at gpsd  it has all these funcionalities, is
> actively supported, and is already being used at embedded devices.
> It may fulfill all the current needs, and could be extended/modified
> to accomodate for future needs.
>  http://gpsd.berlios.de (it should change addresses in near future.
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