Performance Evaluation of the Early CNAV Navigation Message

摘要

The GPS Directorate initiated a pre-operational routine generation and transmission of the Civil Navigation Message (CNAV) starting on 28 April 2014. CNAV data of the Block HR-M and IIF satellites have been collected with a small set of globally distributed receivers. Starting in 2015, CNAV uploads are performed on a daily basis. Since then, the Signal-in-Space Range Error (SISRE) amounts to roughly 0.6 m, which is essentially identical to the LNAV SISRE for the same satellites. The new broadcast Inter-Signal Corrections (ISCs) agree with differential code biases derived in the frame of the IGS Multi-GNSS Experiment and DCBs from the Center for Orbit Determination in Europe on the 0.1-2 ns level depending on the ISC type. Use of these ISCs enables, for the first time, a consistent point positioning based on the exclusive use of civil L1C/A and L2C observations.