What accuracy range can I expect with Differential GPS?

Question

It would be good if 40cm is a possibility.

Answer 1

I recall that 1-2 feet is what Raytheon claims for their marine differential GPS systems. That's 30.5 to 61 centimeters. In the real world (offshore) there are so few differential correction transmitters that the technology is somewhat impractical. Ordinary GPS can easily put you within 60.8 feet (0.01 nautical miles) and that's usually more than good enough for sailors and fishermen. Also, regular GPS generates a new position about once per second. The distance you move during that second effects the accuracy of your position. Furthermore, adding differential corrections greatly slows the process so that if you're moving the error is significantly increased. The type of differential GPS used by surveyors and geologists is accurate to less than an inch, but takes about 30 seconds to render a fix and the device must not move during the data acquisition period. So, the answer is more complicated than your question -- a sure sign you've got more reading to do. Try "Trimble Navigation." They make most of the high accuracy, high end, geographical survey gear used these days...................

Answer 2

As a surveyor, I use a very expensive GPS system that has sub centimeter accuracy. There are many systems available that are cheaper, but the ones we use have real time capability. Other less expensive systems use post processing, but are just as accurate. Exactly what application would you be using these measurements for? If 40cm is the accuracy you require, it would seem that the application would be for artillery.

Answer 3

We (me and fellow co-workers) used some commercial differential GPS equipment (but not surveyor 'grade') about 10 years ago that was specified to 2 cm accuracy.

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