Do it Yourself Differential GPS

[murrdpirate0]

I'm working on a robotics project that I believe could greatly benefit from the use of differential GPS. The robot will be navigating within a known 100m by 100m area and will need to have a positional accuracy of about 25cm. These two things lead me to believe that DGPS is a good fit.

I know that with DGPS, I need a receiver that let's me see the pseudoranges to the visible satellites. These receivers tend to be expensive, but I'm not sure why. I was looking at the u-blox LEA-6T as a potential candidate, but I'm definitely open to other suggestions.

Will I need pseudorange-outputting units for both the base station and rover, or just the base station? If I at least know which satellites the rover unit is calculating its position with, then that should be enough, right? Is knowing that information available in cheaper units?

As you might guess, I'm pretty much just starting my research on this, and I'd appreciate any thoughts and recommendations. Thanks.

 

[chingkui]

I don't have the experience that could help u, though I am also interested to get a GPS receiver that could let me do something interesting sometime in the future. I saw this website, not sure if this is useful to you:

http://home-2.worldonline.nl/samsvl/oemtable.htm

 

[murrdpirate0]

I encountered that website myself while trying to find suitable GPS units. It appears that it's a bit old and the models are no longer available, but there might be similar, next generation, versions of some of them.