Reading Orbit Data Provided with Doris

Doris (Doppler Orbitography and Radiopositioning Integrated by Satellite) is a high-precision orbit determination and positioning system developed by the French Space Agency (CNES), widely used for satellite orbit data processing. For ENVISAT satellite DOR_VOR files, the core functionality of the orbit data reading program involves parsing raw binary data, extracting valid orbit information, and converting it into structured records.

The primary processing workflow includes: first identifying metadata in the file header (such as satellite ID, time range, and data version) to verify file integrity; then parsing orbit data blocks which typically contain timestamps, position vectors (XYZ coordinates), and velocity components; finally performing coordinate system transformations or interpolation based on application requirements to generate standardized orbit data records. Code implementation typically involves binary file reading operations, endianness conversion for cross-platform compatibility, and filtering algorithms for outlier detection.

This data processing is particularly critical in fields like satellite altimetry and geodesy, providing fundamental input for subsequent precise orbit determination or geophysical parameter retrieval. The program must handle technical details such as direct binary reading, byte order conversion, and abnormal value filtering, while adhering to the DORIS system data format specifications provided by CNES. Key functions often include header parsing routines, binary data structure mapping, and coordinate transformation algorithms using rotation matrices or quaternion calculations.