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GATE 2016 CE (CE1) – Question 33

Geomatics Engineering · Principles of surveying: plane and geodetic surveying, errors and adjustment · 1 mark · Multiple choice

The minimum number of satellites needed for a GPS to determine its position precisely is

  1. 2
  2. 3
  3. 4
  4. 24

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Correct answer: (C) 4

Explanation

A receiver must solve for three spatial coordinates and its clock offset from satellite time. Each independent satellite pseudorange supplies one equation. Thus a minimum of **four satellites, C**, is required for the unconstrained three-dimensional fix; three would suffice only with an additional independent constraint.