Possibilities of Higher Order Range Error Correction in Real-time Precise Positioning

Abstract

With the increasing number of precise navigation and positioning applications by using Global Navigation Satellite Systems (GNSS) such as GPS, the ionospheric higher order effects and their correction become more and more important. Whereas the first-order error can be completely eliminated by a linear combination of dual frequency measurements, the second- and third-order residual effects remain uncorrected in this approach. To quantify the second-order residual effect, a simple formula has been derived for GNSS users in Germany. Our proposed correction algorithm reduces the second order effects to a residual error of fractions of one millimeter up to 2 mm at a high vertical TEC level of 10¹⁸ electrons/m² (100 TECU) depending on user azimuth and elevation angles. It is expected that the correction will enable a more accurate positioning by using carrier phase measurements.