Calibrating Your Optical Equipment to NIST

Many tools are included in a surveyor's toolkit, from devices that measure distances to angles and custom optical equipment. And for these tools to provide accurate readings, two things are important: first, you should know how to use the tool properly, and second, the instrument itself must be calibrated.

What is Calibration?

Calibration is the process of determining the accuracy of your instrument before using it to measure something. Your instrument will then be configured so that it can provide results that fall within the standard range.

The National Institute of Standards and Technology (NIST) is an organization that aims to advance measurement science in an effort to foster innovation and industrial competitiveness. They provide standards for instrument calibration services for optical equipment like video boresights, observational theodolites, pilot balloon theodolite, a compass for land Surveying and other surveying tools so that users can achieve the highest level of measurement quality.

A business that offers NIST traceable calibration means that they’re capable of calibrating instruments based on the set measurement standards by the NIST.

The Why, The When, and The How

Having accurate measuring tools, especially optical surveying devices is fundamental to being a competent and responsible surveyor. However, for several reasons, surveying tools become inaccurate over time. This can be caused by overuse or mishandling, exposure to corrosive substances, electrical/mechanical shock, or simply natural wear and tear, especially if the tool is frequently used.

This phenomenon is called "gauge drift." And subjecting your tool to calibration is key to addressing this drift.

Without proper calibration, you’ll get errors in your readings. And with inaccurate readings, you’ll analyze the wrong data and will produce inaccurate models, which will serve as the basis of a bigger project. In the long run, this can compromise the durability and the safety of the final output — and the users of that final output (e.g., motorists using a bridge, employees working a commercial building, families residing in a home).

This is why apart from the annual servicing of your tools, calibrating them every two weeks is advised (this frequency depends on how often you’re using the tool). Calibration must also be done when your tool has been exposed to harsh conditions such as electrical/mechanical shocks, and extreme changes in the environment.

But how do you calibrate optical equipment and other surveying tools such as the measuring instruments for nautical applications? The easiest and most cost-effective way is to take them to professionals who offer calibration services that use NIST standards.

The calibration procedure may vary from tool to tool. But in essence, it entails using the tool to test samples of at least one calibrator — the result of which will then be used to establish a relationship between the measuring method of the tool being tested and that of the calibrator. If significant discrepancies are found, the tool will be configured to produce more accurate results, i.e., those that are within the acceptable range.

When looking for a provider of NIST traceable calibration services, confirm that they do conform to industry measurement standards and that they calibrate the specific tools you have. It’s also ideal to tap a provider that offers a quick turnaround time and performs repairs as well.