Clock synchronization and time keeping are crucial in distributed applications like smart city sensor networks, manufacturing systems, data centres, etc. The various distributed elements like the sensors and actuators within the system should have tight clock synchronization to make sense of the collected data and provide timely controls. State of the art techniques include using GPS receivers and network based protocols like Network Time Protocol (NTP) and Precision Time Protocol (PTP). However, all existing techniques have certain drawbacks which may cause intentional or unintentional failures that could lead to clock synchronization error. And aclock synchronization error caused unintentionally or by a malicious entity could destabilize the system and lead to safety and security incidents, such as wrong data log, control disorder of hardware actuation. Our novel patent pending clock synchronization technique makes use of unique frequency signatures present in the power line voltage signal to synchronize time across various distributed devices. We calltheseunique frequency signatures as powerline forensic time. It has distinct advantages over existing clock synchronization techniques in terms of security and robustness.
Utilize powerline voltage signal as a universal clock source Low requirement hardware with small form factor, which is easy to integrate into legacy devices Necessary algorithms can be easily ported to end devices. Can work in 2 different modes -plug-in sensing mode and wireless sensing mode Plug-in sensing mode: connect with the powerline outlet directly to measure powerline frequency fluctuations, suitable for AC powered devices Wireless sensing mode: sense the electromagnetic radiation generated from powerlines and appliances to measure powerline frequency fluctuations, suitable for battery/DC powered device. Time synchronization accuracy: < 1 milliseconds using plug-in sensing mode, 50 ~ 500 milliseconds using wireless sensing mode Powerline signals are difficult to tamper with, thus the approach is very secure and resilient to failures.
Clock synchronization - Provide secure and robust clock synchronization for various distributed scenariosincluding, smart metering solutions, data centres, industrial automation and internet of things Clock verifier -Can be deployed as a clock verifier to existing setups that deployhigh precision clock synchronization protocols like PTP. This would provide additional security to the system and quickly identify system failures. Powerline phase identification -Power line frequency signatures can also be used to identify the phase of the grid that a particular power outlet belongs to. Time stamping -A maintenance-free time stamping technique for data loggers installed in remote locations with limited or nonetwork access for time keeping. Data logger with forensic event timestamping
Secure and robust clock synchronization Reliable event timestamping Fast and easy deployment with minimalhardware and software Maintenance free Small form factor & low cost Secure time synchronization infrastructure with full control