How are the weights assigned in OPUS-RS?
In OPUS-RS, the weight of an observation is the inverse of the square of the observation’s standard deviation. For one way phases observations, the standard observation of an L1 observation is 0.019 meter/sin(elevation angle), and the standard observation of an L2 observation is 0.0244 meter/sin(elevation angle). For one way range observations, the standard deviation is initially set at 0.05 meter/sin(elevation angle) for P1 and 0.064 meter/sin(elevation angle) for P2. However, the range observations are filtered to detect noisy data and multipath. Noisy range data may be downweighted by assigning a larger standard deviation. In addition, OPUS-RS contains a priori constraints on all the parameters. The assigned standard deviations are 0.4 meters for double difference ionospheric refraction delays, 0.025 meters for the correction to the nominal tropospheric delay, 1.44 meters for the correction to a priori value of an L1 double difference ambiguity, and 2.3 meters for the correction to
