The sensor and server disagree about the time
An environmental sensor records a reading at 10:00, but the gateway clock is several minutes ahead. When data from multiple locations are compared, timing errors can create misleading patterns. Clock synchronisation protects the integrity of observations.
Identify the relevant clocks
Sensors, gateways, processing servers and client systems may each record time.
Use suitable time sources
Synchronisation methods should match accuracy needs and operational constraints.
Record time zones clearly
A UTC timestamp and Singapore local time can describe the same instant differently.
Monitor clock drift
Devices can lose synchronisation through outages, configuration errors or ageing components.
Preserve event and processing times
The time a reading occurred differs from the time it reached an API.
Flag uncertain timestamps
Do not silently replace unreliable observation times with publication time.
Break-test: a gateway reconnects with an incorrect clock
Can the pipeline detect the offset and protect downstream time-series analysis?
Connected knowledge
See Observation Timestamp Integrity, Data Freshness Monitoring and NEA.