[FOSS-GPS] Introduction

John Morris john at coyotebush.net
Mon Sep 22 11:33:24 EDT 2008

Another introduction ...

I'm John Morris, living in Menlo Park California. I'm a software engineer
with a passion for maps, and I may someday hang out my shingle as a GIS
consultant. Meanwhile, I'm working on database performance, playing with GPS
and taking the occasional GIS class.

I'm very interested in low cost DGPS.  I've written non-working
post-processing software. I've pretty much decided kinematic "float"
solutions aren't practical (can't handle cycle slips), so I'm planning on
starting over.  (www.precision-gps.org)

I'm thinking of simple static positions through a cell-phone service. The
goal would be to get almost real-time positions with extremely inexpensive
hardware. This would involve
  O Cell-phone GIS software, similar to cybertracker. 
  O 30 seconds of pseudo-ranges, sent off to a central server
  O A software service to process the position and return it immediately
  O A network of base stations, starting with 1
  O Server to store and distribute data

For the low end user, Sirf III pseudoranges and an external patch antenna
might do the job. A better solution would use the AC12 or ublox receivers
with a compact dome antenna. Cost to the user? $100 for Sirf and $300-400
for the AC12+compact dome. Plus the cell phone and data plan. 

As part of my earlier failure, I have code for interfacing to a variety of
receivers. In addition I have a quickie NTRIP broadcaster, some RTCM and
Community Base Station code.

  - John

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