3D Challenges in Antarctica
Merrick & Company has provided high definition scanning (HDS) for over 20 years. They recently scanned Scott’s Discovery Hut at Hut Point near McMurdo Sound on Ross Island. The data was to be used to help in the preservation of the hut which was assembled during the Discovery Expedition of 1901-1904. The hut was originally fabricated in New Zealand and shipped to Antarctica where it was assembled at its current location. This project displays how Merrick works with their clients to understand their problems and provide working solutions.
Here the scan is discussed in greater detail by James Wilder Young:
This scan presented a unique challenge with a specific solution based on environmental conditions and restrictions in a remote location.
After getting all the equipment to the hut by ATV and dragging it the rest of the way, it took roughly 4 hours to scan both the inside and outside of the hut. The total project started at about 6:00pm and was completed just after 10:00 pm.
The discovery Hut was scanned with a Zollar+Frohlich Imager 5010 3D laser scanner. This is an eye safe (laser class 1) scanner with a range of 187 meters (613.5 feet). It is resistant to dust and water and can operate at temperatures between -10 to +45 degrees Celsius (14 to 113 Degree Fahrenheit). The scan of the Discovery Hut was done in temperatures close to, or below, the lower end of the operating temperature. The 5010 laser scanner collects more than 1 million pixels/second (1.016 million) at maximum measurement rate.
The beam divergence is < 0.3 mrad (full angle) with a minimum distance of 0.3 meters. Range Noise in Black is 14%, grey 37% and white 80%. The vertical field-of-view is 320 degrees and the horizontal field-of-view is 360 degrees. The vertical resolution is 0.0004 degrees and the horizontal resolution of 0.0002 degrees. The vertical and horizontal accuracy is 0.007 degrees RMS and the rotation speed of the sensor is 3000 rpm maximum. Being a laser, it operates in all conditions including bright sun light to pitch darkness.
The targets used for the scanning were Leica black and white targets. They tied together the scans and calibrated the data. The target locations also provided locations for georeferencing the data to real world coordinates.
There were a total of eight targets being used and the targets were moved around for each scan. Four targets were required in each scan as well as at least two targets that were the same from scan to scan in order to tie the scans together. The targets are surveyed using a total station, the Leica 1800. Four scans were required to scan the outside of the Discovery Hut as well as Four scans for the inside of the hut.
Merrick and Company has decided to provide UAS services in the United States after developing the technology in Mexico over the past 3 years. This enhances their survey and mapping projects and provides a more cost effective process for some projects. Currently, Merrick & Co. Geomatics Group teams with their Civil Engineering group and Compass data/Compass Drone to perform the majority of their UAS projects. They are currently expanding their capabilities to include specialized solutions such as inspections, BIM, as-built and additional engineering projects.