GPS Distance measurement and relative positioning

[tjaartv]

I want to use a two GPS receivers, one moving and one static, measure the distance between the static and moving to obtain the relative position of the moving GPS receiver with relation to the static one. Does anyone know what type of accuracy can be expected from such a system?

Alternatively 3 static receivers and one moving may be used, and the distance from the moving to each of the static receivers being calculated and thus determining the relative position of the moving receiver. I want to use it for a robotic application where the robot must know it's position within a 3000 square meter area with about 10 cm accuracy.

Any advice on the method proposed here and whether I will be able to achieve 10 cm accuracy will be very much appreciated.

 

[IRstuff]

Depends on how much money you are willing to spend. There are already existing RTK (real-time kinematic) GPS systems with cm-accuracy. Likewise, differential GPS receivers are also commercially available for this type of application.


Most of these systems involve some sort of real-time correction of the GPS data by locating a base station with known position that broadcasts corrections to the local GPS solution.

TTFN

 

[AlWingy]

all depends on the antennas you use and the way you have your experiment setup. If you used unbalanced antennas the if you hold one of the receivers then you'll affect the radiation patterns and match of your antenna and therefore affect the accuracy.

 

[VEBill]

How does antenna match and pattern affect GPS accuracy (assuming that it isn't so bad that the system simply stops working)? I'm trying to envision where the GPS information in the time domain would be 'stored' in order to cause an error.

 

[IRstuff]

The only issue might be if the DOP got affected because one or more satellites were no longer visible or receivable.

TTFN