Klobuchar's Algorithm for Ionospheric Corrections
   Document Cover 0.768115942029

Date manufactured: September 25, 1975

Period/Dates when in use: 1975 - ?

Description: This document describes the development of the Klobuchar algorithm for ionospheric corrections. This algorithm was designed by John A. Klobuchar in the mid 1970's to provide ionospheric time delay corrections for single-frequency GPS/NAVSTAR users. The document describes the motivation for the development of the algorithm, provides a general overview of ionospheric time delay and details the calculations and coefficients that reduce the ionospheric time delay by approximately 50% rms for single-frequency GPS users.

Item History: The algorithm and coefficients described in this document were used in the earliest designs of GPS for ionospheric time delay corrections. The coefficients have been transmitted as part of the GPS message since the earliest satellites were launched. They are still in use today.

Supporting documentation:
Original Document (1688508 bytes)

Institute for Scientific Research (ISR)
Boston College
140 Commonwealth Avenue, Chestnut Hill, MA 02467

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Submission authored by:
Patricia Doherty
Boston College/ISR
140 Commonwealth Avenue
Chestnut Hill, MA 02467