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Positioning Application: Can I get a Dilution Of Precision (DOP) value of less than 1?

  • PosApp (SimREPLAY, SimREPLAY+, SimGEN)
  • SimPLEX


  • Usually the minimum value of DOP is 1 if you are looking at the best 4 satellites.
  • However this may not necessarily be the case if you are considering all satellites in view.
    • The nominal error in the calculated position is a function of the relative satellite geometry and the satellite pseudorange errors.
    • The DOP calculation assumes a one unit error (one metre) in the pseudorange.
    • So you wouldn't expect the net positional error to be less than this using just four satellites.
    • If you include a large number of satellites in the DOP calculation then the accuracy of the calculated position will improve correspondingly.
    • So it is possible the DOP may be reduced to less than 1 in this case.
    • Situations where this could be true would be:
      • High elevation vehicles.
      • Multiple constellations enabled.
      • Multiple SV's in view.
  • Figure 1 Shows an example of a GDOP value less than 1 in a scenario with Multiple constellations and High elevation vehicle.
  • See SOL10131 for further details on DOP.


Figure 1 - Example GDOP value less than 1. 


Product : SimPLEX,SimREPLAYplus,SimREPLAY,SimGEN,PosApp,DOP,Scenario,Receiver