Patent ID: 6407700
Filing Date: 2002-06-18
Classification: G01S

Abstract:
A method for measuring, autonomously and substantially in real-time, an ionospheric delay of a GPS signal transmitted by a first satellite having an obliquity, the method comprising:receiving a code range, a carrier phase range and a satellite elevation angle for each of at least two satellites; for each of the at least two satellites, calculating: a code-phase divergence between the code range and the carrier phase range, a time derivative of the code-phase divergence, an obliquity from the satellite elevation angle, and a time-derivative of the obliquity; calculating a zenith delay from the obliquities, the time-derivatives of the obliquities and the time-derivatives of the code-phase divergences of the at least two satellites; and calculating the ionospheric delay by multiplying the obliquity of the first satellite and the zenith delay.