TABLE OF CONTENTS Since individual GPS manufacturers have their own proprietary formats for storing GPS measurements, it can be difficult to combine data from different receivers. A similar problem is encountered when interfacing various devices, including the GPS system. To overcome these limitations, a number of research groups have developed standard formats for various user needs. This chapter discusses the most widely used standard formats, namely, RINEX, NGS-SP3, RTCM SC-104, and NMEA 0183.
To save storage space, proprietary formats developed by GPS receiver manufacturers are mostly binary, which means that they are not directly readable when displayed [1]. This creates a problem when combining data (in the postprocessing mode) from different GPS receivers. To overcome this problem, a group of researchers have developed an internationally accepted data exchange format [1]. This format, known as the RINEX format, is in the standard ASCII format (i.e., readable text). Although a file in the ASCII format is known to take more storage space than a file in the binary format, it provides more distribution flexibility.
A RINEX file is a translation of the receiver's own compressed binary files. A draft version of the RINEX format was introduced in 1989 followed by a number of updates to accommodate more data types (e.g., GLONASS data) and other purposes [1]. The current RINEX version 2.10 defines six different RINEX files; each contains a header and data sections: (1) observation data file, (2) navigation message file, (3) meteorological file, (4) GLONASS navigation message file, (5) geostationary satellites...
