GNSS.store provides a wide range of timing receivers used across industries requiring precise synchronization and frequency stability.
These receivers perform multiple tasks, including delivering exact time references, enabling synchronization between systems, and supporting reliable frequency control.
Precise Time Determination
A single-frequency receiver such as the NEO-M8T or LEA-M8F can establish time on the GPS or Galileo scale with a CEP50 accuracy of approximately 16 to 20 nanoseconds. Accuracy is limited by ionospheric and tropospheric delays, and proper configuration must account for antenna cable length as well as receiver and antenna delays. It is important to note that satellite constellations maintain their own reference times, which vary by about 10 nanoseconds. Additionally, offsets between a system and its reference introduce a further 5 to 10 nanosecond discrepancy.
Dual-frequency receivers, including the ZED-F9T or F10T, mitigate these effects by directly measuring and compensating for ionospheric delay. This provides greater accuracy, with a CEP50 of around 5 nanoseconds.
For applications requiring alignment to the UTC scale, each satellite system provides conversion methods. However, these are limited by the resolution of the coefficients broadcast from satellites, updated as frequently as twice daily or as infrequently as once per day. This constraint introduces an additional error of about 5 nanoseconds.
Synchronization Methods
Real-Time Kinematic (RTK) techniques, available with receivers such as the ZED-F9T, allow synchronization between two identical devices to within 100 picoseconds. This assumes identical antennas and precise compensation for cable length. In practice, fractional noise from the oscillator introduces about 4 nanoseconds, resulting in a documented standard deviation of 2.5 nanoseconds. A limitation of RTK is the operating range, which is typically restricted to several hundred kilometers.
Precise Point Positioning (PPP) services, such as PointPerfect integrated in the ZED-F9T, extend synchronization globally. PointPerfect delivers accuracy of around 200 picoseconds, though fractional noise again determines the overall performance at about 2.5 nanoseconds. Unlike RTK, PPP does not impose distance constraints.
Frequency Accuracy
Fractional noise also governs frequency precision. For example, the ZED-F9P achieves stability within ±4 nanoseconds, while the NEO-N8T typically provides ±11 nanoseconds.
Advanced Timing Receiver Capabilities
Dedicated timing receivers, such as the LEA-M8F, include features for generator frequency correction based on signals from satellite systems. This capability enables further enhancements:
- Reliable timekeeping: Critical in cases of antenna damage, satellite service disruptions, or malicious spoofing attempts. As spoofing attacks generally target GPS, incorporating Galileo and BeiDou adds resilience.
- Reliable frequency control: Ensures continued stability even under adverse conditions.
- External generator integration: Supports synchronization with more stable references such as atomic clocks.
- Frequency measurement: Provides additional monitoring and control functionality.
To find out more read SO Different Timing by GNSS.Store.
