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• 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.