What it is, why it matters, and how it affects measurement accuracy
In the world of distributed fiber optic sensing (DFOS), precision is everything. Whether you’re monitoring structural health in aerospace components, strain along a wind turbine blade, or temperature gradients in oil wells, the value of your data is only as good as the resolution with which you can capture it. One of the most critical—and sometimes misunderstood—performance parameters in DFOS systems is spatial resolution.
In this post, we’ll break down what spatial resolution really means in the context of fiber optic sensing, why it matters, and how it impacts the quality and reliability of your measurements.
What is Spatial Resolution in DFOS?
Spatial resolution defines how closely spaced the sensing points are placed along the fiber.
In distributed sensing using Optical Frequency Domain Reflectometry (OFDR)—the high-precision technique used in Sensuron’s instruments—spatial resolution can reach as low as 1.6mm. That means you can capture incredibly fine details of how strain or temperature changes along a structure.
This is different from point sensors (like FBGs), where discrete sensor elements are spaced apart along the fiber. With distributed sensing, the entire fiber becomes a continuous sensor, and spatial resolution tells you how “continuous” that sensor really is.
Why Spatial Resolution Matters
Here are a few key reasons why spatial resolution is a crucial parameter:
-
Detecting Localized Events
High spatial resolution allows you to identify short, localized changes in strain or temperature—such as cracks forming in a composite material or a thermal hotspot in a power cable. Lower resolution sensing systems miss these events entirely.
-
Mapping Complex Structures
Many applications involve structures with intricate geometries—think aerospace parts, pipelines with weld joints, or layered composite materials. To accurately map and monitor these, high spatial resolution is essential to avoid missing small but important changes.
-
Reducing Measurement Uncertainty
When spatial resolution is too coarse, closely spaced variations in the signal can blur together, leading to ambiguous or averaged data. This undermines the accuracy of your measurements and can make diagnostics less reliable.
How Spatial Resolution Affects Measurement Accuracy
With OFDR, extremely high spatial resolution is achievable. However, there’s a trade-off: pushing spatial resolution to the limit can affect the signal-to-noise ratio (SNR) and measurement range. That’s because the system must process smaller signal segments, which can be more sensitive to noise.
High spatial resolution improves your ability to locate and quantify subtle changes, but achieving it requires sophisticated optics, advanced signal processing, and carefully engineered interrogators—like the ones Sensuron builds.
Choosing the Right Spatial Resolution for Your Application
So, how much spatial resolution is enough?
- For civil structures (bridges, tunnels), a resolution of 10–50 mm may suffice to monitor overall strain behavior.
- In aerospace and advanced composites, where microcracks or delaminations are a concern, resolution of 10 mm or less is often required.
- In energy and pipelines, moderate spatial resolution is useful for detecting leaks or strain from ground movement.
Ultimately, the appropriate spatial resolution depends on your sensing goals. It’s about balancing detail with range, and precision with practicality.
Conclusion
Spatial resolution is not just a technical specification—it’s a defining feature that determines the quality and detail of your distributed fiber optic sensing data. With the right resolution, you gain deeper insight into your structure’s behavior, improve predictive maintenance, and make better-informed decisions.
Sensuron’s OFDR-based sensing systems are designed to deliver industry-leading spatial resolution without compromising measurement accuracy — empowering engineers and researchers to see what other systems miss.
Want to learn more about how spatial resolution can elevate your sensing capabilities? Contact us today.