Abstract:This paper introduces the structure and decoding principle of data stream in BINEX format that are received by the Trimble BD970 OEM board. The corresponding observation and navigation files are acquired, implying that the mission of decoding to the measured data is accomplished successfully. In addition, indicators and methods of GNSS observation data quality evaluation are described in this paper. The research conducts data analysis based on decoded data of the BD970 OEM board and eventually acquires relevant indicators on the quality of observational data, providing reliable data for the subsequent product applications.