Question

Satellite Positioning Material

Statement: When we are calculating a user location with pseudo-range measurements for 10 satellites, and we exclude tropospheric or Ionospheric error correction, while utilizing the initial approximate user location of center of earth equals to (0, 0, 0).

In this case, will the accuracy of a user position location be affected if initial approximation user location is modified?

Answer 1

In case of satellite positioning, the initial approximate user location is always kept fixed with respect to a reference value and geographical coordinates. This is the base position which remains fixed, and the current location of the user is calculated with respect to this initial positioning. The other calculative parameters are set and calculated with respect to this initial positioning. So, if the initial approximation user location is modified, the entire programmed structure needs to change, or it should be made flexible, so that the modification doesn't affect the result. Otherwise, the accuracy will differ. The calculated or measured position from the satellite, would differ quite significantly from the actual position of the object. So, the satellites should be programmed in such a way,so as to make the calculations more flexible. In that way, even if the initial user coordinates are modified, we will be receiving a near accurate location of the user.