3 results about "Clock correction" patented technology

The invention provides a method for determining a service range of a satellite-based augmentation system, which comprises the following steps of: selecting a target research area, resolving satellite augmentation orbit/clock correction and user difference ranging error information of a global navigation satellite system in a current epoch, calculating an orbit/clock correction comprehensive error of each satellite projected on a grid point in the current epoch, and determining the service range of the satellite-based augmentation system. Counting the UDRE envelope probability of grid points in a target area, calculating the delay error value of an ionosphere of the grid points and the vertical error information of the ionosphere of the grid, counting the GIVE envelope probability of the grid points in the target area, solving a union set for a public area under the integrity parameter envelope requirement, and determining a final SBAS service area. The union overlapped area is the final service area. On the basis of the requirement for avoiding the integrity risk event, the integrity parameter corrects the residual error of the corresponding correction with the 99.9% envelope probability to form the envelope, the processing method is reasonable, and the processing efficiency is high.

The invention provides a clock synchronization and fault feedback method, which comprises the following steps: after a slave clock receives a first message sent by a first master clock, calculating to obtain a first local clock correction value needing to be corrected by a local clock and a first maximum correction value needing to be corrected by the slave clock; after the slave clock receives a second message sent by the second master clock, calculating to obtain a second local clock correction value needing to be corrected by the local clock and a second maximum correction value needing to be corrected by the slave clock; the first local clock correction value is compared with the first maximum correction value, the second local clock correction value is compared with the second maximum correction value, and a fault identification result and a clock synchronization result of the slave clock are determined based on clock synchronization and fault identification criteria. According to the invention, whether the message sent by the master clock device is lost or has a wrong value is detected, and clock synchronization and fault positioning of the slave clock can be completed; in addition, a double-master-clock structure is adopted, so that the problem of transient failure of a single master clock is solved.