Calibration considerations for the IGS/BIPM pilot time transfer project using carrier phase

摘要

During the spring of 1998 a pilot project was begun between the Bureau International des Poids at Mesures (BIPM) and the International GPS Service (IGS) to investigate the accuracy of time and frequency comparisons using GPS phase and code measurements. The IGS has established a cooperative network of stations around the world which gather GPS data, analysis centers that provide analysis products from these GPS data and other contributed data. The precision of the data and products has made major contributions to geodynamics and earth sciences and presents the possibility of highly precise time and frequency comparisons. To compare time information between two sites by whatever means requires the time of propagation of the signal through the equipment, cables, and space to be precisely and accurately known. IGS differential measurements with GPS carrier phase data are highly precise and must be accurately calibrated in order to provide time comparisons. This paper will address the problems and possible techniques for calibration for time comparison. Specialized equipment and GPS system simulators will be described that calibrate from signal reception in the antenna through receiver output.