Tilt compensation has made a large impact on surveying – especially the new ones introduced in the past few years. This new technology has made surveying easier and faster. How does tilt compensation work? What are some of the options for surveying when you want tilt compensation?

How Does Tilt Compensation Work?

The first equipment with tilt compensation relied on magnetic compass orientation. Magnetic compass orientation used three-axis accelerometer and a three-axis magnetometer to develop pitch and roll angle information. This was then used to correct the measurements.

Modern tilt compensation relies on an Inertial Measurement Unit (IMU), also called an inertial navigation system (INS). According to Trimble’s Help Center, “The IMU in the receiver uses information from acceleration sensors (accelerometers) and rotational sensors (gyroscopes) as well as GNSS to continuously determine its position, rotation, and degree of tilt, and correct for any amount of tilt.”

What this combination of accelerometers and gyroscopes allows for is correct positioning of the pole tip – regardless of the pole angle. This instrumentation calculates the tilt angle and the title distance and compensates for this using the software. Most of the options out there allow for a tilt of 15 degrees or less.

What Are the Benefits of Tilt Compensation?

The biggest advantage of tilt compensation is how efficient the surveyor becomes. You no longer have to make sure the pole in straight up and down, which allows you to go faster. There is a certain amount of “slope” that is accounted for and corrected, which speeds things up considerably. The surveyor also won’t get as tired as they would when having to level the pole with each point – meaning they can get more done in a day.

Tilt compensation also allows for the easy measurement of points that were previously very hard to collect. The side of a building, under thick foliage, pipe inserts, or under an overhang are all points that can now be collected easily.

There is also a safety factor. Surveyors can now collect points in locations like the edge of a busy road or on the edge of a cliff without getting as close to danger.

Lastly, the act of leveling the pole often created a lot of errors. Tilt compensation essentially removes this source of error. By using tilt compensation, surveyors actually get more accurate measurements.

What Are Some of The Options Available?

Back in 2013, Trimble announced that they were adding Tilt Compensation to their R10 GNSS Surveying System. This new rover was distinctly different that previous lines. It was compact, ready for harsh handling, and it included magnetic oriented tilt compensation. This was one of the very first surveying systems with tilt compensation included.

In 2020, Trimble announced the integration of calibration-free tilt compensation to the R12i. What really set this rover apart is the calibration-free aspect. Previous versions, using magnetic oriented tilt compensation, required fairly complex calibration.

In March of 2022, Leica Geosystems, part of Hexagon, announced the introduction of the Leica AP20 AutoPole. This is the world’s first title-compensated total station pole. In addition to the tilt compensation, the AP20 AutoPole also takes automatic pole height readings. Leica predicts the AP20 AutoPole will “transform how professionals measure with total stations” by making the process easier, faster, and safer.