GPS Receivers and the Observables

  • Richard B. Langley

Abstract

We saw in Chapter 3 that at a sufficiently large distance from a transmitter, the electromagnetic waves that it emits can be considered to be spherical. We can represent the electric field intensity of a spherical electromagnetic wave of frequency ω and wave number k at some distance r from the transmitter as
$$E = {{{E_0}} \over r}{e^{i(\user2{\omega }t - kr)}}.$$
(4.1)
The signal from a GPS satellite when it arrives at a receiver can be taken to be such a wave and if we replace r by ρ, we can represent the signal in simplified form as
$$y\, = \,A cos(\omega t\, - \,kp\, + \,\phi ')$$
(4.2)
where A is the signal amplitude, t is the elapsed time measured from the start of transmission from the satellite, is the distance travelled from the satellite to the receiver, and ϕ′ is a phase bias term which is the phase of the wave at the satellite at t = 0.

Keywords

Quartz Microwave Attenuation Autocorrelation Azimuth 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Richard B. Langley
    • 1
  1. 1.Geodetic Research Laboratory, Department of Geodesy and Geomatics EngineeringUniversity of New BrunswickFrederictonCanada

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