Module 2 : Global Positioning System
  Lecture 12 : GPS Measurements Techniques
Table 12.2 summarizes characteristics of code based positioning method assuming that C/A code has been used..
 
Table 12.2 Summary of code based positioning techniques* (GPS Guide, 1995)
Method
Basic Concepts
Min.# receivers Obs. Time
Accuracy
(at 95% prob.)
Comments
Single Point
(static or kinematic)
  • need at least four satellites
  • instantaneous position
1
1-10 s
100 m horizontally 156 m vertically
simplest, lowest cost
Differential
(static or kinematic)
  • need at least four satellites
  • apply corrections measured at reference to rover
2
1-50 s
3 to 12 m horizontally and vertically
simple, low cost

 

Referring to Lachapelle et al. (1991), the GPS Positioning Guide (1995) reports horizontal and vertical accuracies using kinematic code differential techniques as follows (at 95% probability with PDOP < 3.0):

  • over 50 km at 4-9 m horizontally and 5-11 m vertically
  • over 500 km at 6-11 m and 7-12 m for the same components
 
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