4results about How to "Improve time synchronization" patented technology

The invention discloses an underwater electric explosion plasma source device, and the device comprises a pulse power device which is used for generating a large-current pulse, and transmitting the large current to a metal wire target; the metal wire target is connected with the pulse power device through a cable; the metal wire target is arranged in the water container and used for rapidly heating the metal wire target to perform wire explosion to generate plasma when large current passes through the metal wire target, and the plasma interacts with surrounding water to heat and gasify water near the metal wire target to form high-pressure bubbles; bubbles formed by the plasma and the water vapor generate pressure waves in the water body in the expansion and contraction process, and the bubbles serve as artificial focuses. Compared with an existing plasma source, large bubbles can be formed more easily; compared with an existing high-pressure air gun seismic source, the high-pressure air gun seismic source is short in bubble oscillation period, clean in signal, large in initial bubble ratio and capable of being used without a large water body, has the advantages of being simple in device design, convenient to operate, environmentally friendly and the like and can be widely applied to geological exploration.

A configurable multi-spectral remote sensing stereo imaging system and a design method relate to the field of multi-spectral oblique remote sensing imaging technology. In order to solve the problem of limited oblique image information acquisition capability in existing drone-based multi-spectral imaging systems, as well as the lack of acquisition synchronization and cumulative errors between multiple cameras. Aiming at the multi-angle and multi-spectral data acquisition requirements of complex remote sensing scenes, the present invention designs a configurable camera mounting structure, a synchronous trigger control module, and a camera internal and external parameter calibration method, adopts a hinge structure and a fixed latch to realize the camera quantity configuration and tilt angle adjustment functions, designs and develops a camera synchronous trigger module based on a microcontroller and pulse width modulation technology to realize data synchronization acquisition, and designs and develops a multi-camera calibration method to obtain accurate spatial transformation relationships between cameras, so as to realize the correction of multi-camera position and posture information.

The application discloses a time synchronization method based on low-orbit satellite and Beidou PPP-B2b, which comprises the following steps: 1) a central station and a client respectively acquire real-time PPP-B2b signals, pseudo distances, carrier phase observation values and broadcast ephemeris broadcast by a Beidou No. 3 satellite and low-orbit satellites through respective receivers; 2) the central station and the client respectively solve a clock difference of the central station receiver and a clock difference of the client receiver; 3) the client solves a difference value between a local time and a central station time; and 4) the time difference between the client and the central station is input into a digital frequency synthesis module of the client to adjust the clock difference of the client receiver. The application realizes real-time PPP time transmission through Beidou No. 3 precise point positioning service and low-orbit satellite positioning service, and the client can realize sub-nanosecond time synchronization without dependence on the Internet. Meanwhile, the application realizes time synchronization and communication through low-orbit satellite assistance, and enhances the time synchronization performance in interference, shielding and complex environments.

This invention discloses an algorithm for improving time synchronization accuracy in a master-slave network topology. The algorithm comprises the following steps: S1, establishing a master-slave network topology; S2, exchanging messages to obtain four timestamps and calculating the master-slave clock offset and average link delay, sending an Optimize_Req message to the master clock; S3, selecting the optimal master-slave clock offset from multiple offsets and calculating the asymmetric link delay ratio for each synchronization; S4, if the current link delay is approximately symmetrical, the master-slave clock offset is used to update the slave clock; S5, if the current link delay is asymmetric, the clock offset estimate is obtained using the maximum likelihood estimation algorithm, and an Optimize_Resp message is sent to the slave clock to update it. This invention improves the PTP time synchronization protocol by using the above algorithm, adding two message transmissions. The master clock receives the synchronization results from multiple slave clocks, further performs filtering and optimization, and then sends the updated results to the slave clocks, allowing the slave clocks to adjust themselves.