[OSGeo-Discuss] Mobile GPS data collection, summary of sorts.

[Bob Basques]

All,

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 
though.

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 
certainties.

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?

bobb


pmarc wrote:
> 2006/8/1, Bob Basques <bob.basques at ci.stpaul.mn.us>:
>> All,
>
>>         * 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 [1] 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.
>
> [1] http://gpsd.berlios.de (it should change addresses in near future.