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NavVis improves SLAM precision indoors

February 7, 2018  - By

NavVis, a mobile indoor mapping, visualization and navigation company, released new mapping software that significantly improves the accuracy of simultaneous localization and mapping (SLAM) technology in indoor environments, such as long corridors, the company said.

The software update will be available for users of the NavVis M3 Trolley and will significantly improve the accuracy of the resulting maps and point clouds. NavVis’ mobile mapping system, the M3 Trolley, builds upon SLAM to increase speed and efficiency when scanning buildings.

The images below demonstrate the impact of NavVis Precision SLAM technology. The left image depicts a long corridor mapped with a conventional SLAM system where the above-mentioned drift error has occurred. The green outline shows how the map deviates from the true structure. The image on the right shows the significantly improved map accuracy obtained when mapping the same area using the M3 Trolley with the new Precision SLAM technology.

Image: NavVis

Image: NavVis

Here is a closer look:

Image: NavVis

Image: NavVis

SLAM is a technique originally developed by the robotics industry that is now increasingly being used in surveying and autonomous driving technologies. It solves a core problem that long plagued robotics engineers by enabling a device to determine its location while simultaneously mapping an unknown environment. This is done by chaining millions of measurements into a trajectory estimate.

However, even when a device captures highly accurate individual measurements, chaining them will result in an accumulation of noise and tiny measurement uncertainties. Over time, the estimated motion will start to deviate from the true motion (drift error). This can often be observed as a slight bending of long corridors that are actually straight. All available SLAM systems — regardless of whether these use LIDARs or other sensors — are inherently affected by this phenomenon.

The NavVis Precision SLAM technology significantly reduces drift error and improves the SLAM accuracy. This is particularly evident in cases where complementary techniques such as loop closures cannot be deployed, if, for example, the building’s layout does not allow for it.

Precision SLAM even improves accuracy when SLAM anchors are used to incorporate ground control points into the mapping process.

“I am very excited about our new Precision SLAM technology,” said Stefan Romberg, head of mapping and perception at NavVis. “We are always striving for the highest possible map and point-cloud accuracy and improving SLAM is a critical component to being successful. It is widely known among SLAM developers and users that complementary approaches such as loop closures or ground control points are needed to achieve a high accuracy.

“However, with the Precision SLAM technology we have developed an approach that not only nicely complements the former techniques but is especially evident when these have little effect or cannot be used.”

About the Author: Tracy Cozzens

Senior Editor Tracy Cozzens joined GPS World magazine in 2006. She also is editor of GPS World’s newsletters and the sister website Geospatial Solutions. She has worked in government, for non-profits, and in corporate communications, editing a variety of publications for audiences ranging from federal government contractors to teachers.