Experience with low cost RTK

I'm looking to put together the following:

GPS receiver system with at least 5Hz updates and 1 meter max 3d error.

Unobstructed view of the sky in an area of low density and few RF sources.

If I can do this with a standalone WAAS system fine,

If I need to provide a base/rover setup I can include the update data
link to the rover as part of what I'm already doing.

The differential baseline would be short, less than 1000 meters.

What is the lowest cost solution that will do this?

I'd like feedback from anyone that has actually done this.


Paul

You can certainly do it for under $5K. How much under $5K really
depends on your exact skills and needs. Any size, weight, power, or
data output limitations/requirements?

Without knowing more I'd suggest OEM boards with L1 carrier phase
"float" RTK processing. On short baselines, say under 5K meters,
meeting or exceeding your accuracy requirement of 1 meter (3D)
will be easy IF the system can "warm up" for a few minutes before
it is put into action. This means that the receivers are powered up,
tracking sats, and the base is sending corrections to the (preferably
static) rover receiver for a few minutes before you need the most
accurate data.

You can also get the accuracy you need with high-end code
receivers (typically carrier phase smoothed) , but they won't be
any cheaper and they won't be as accurate as a L1 float solution.

As an example here is a potential OEM solution:

http://www.navtechgps.com/supply/crescent.asp

There are many manufacturers to choose from depending on just
how you need things packaged.

pbreed@netburner.com wrote:

Some other choices:
Thales AC12,
($169 at www.navtechgps.com)
u-blox Antaris 4T,
($350 evaluation kit from www.u-blox.com)
($169 surface mount module)

Some I haven't tried but should work:
u-blox Antaris 4S,
(<$100 gps mouse from Conrad Electronics)
($129 OEM board from www.u-blox.com)
Furuno gt8032 (testing in progress)
Novatel SuperStar II

There are some inexpensive radio modems
Aerocomm 900Mhz 1W
($80 per module)

With the GPS receivers, the AC12 has particularly good carrier phase
and the Antaris 4T outputs 10hz raw measurements. I'm intrigued by the
Conrad mouse, but Conrad doesn't ship to the US.

Software is going to be your challenge. I'd get something working
postprocessed before considering RTK. For an idea of the issues, take a
look at Sam's website or at my partially working code -
www.precision-gps.org.

- John Morris
Menlo Park, CA

John wrote:


Is that a good address?
I get a page indicating it is a place holder for an expired domain.

Works OK for me !

Sam (at http://home-2.worldonline.nl/~samsvl/ )