Open day considers UAVs and gravity flow

February 2nd, 2015, Published in Articles: PositionIT


At Afgen’s recent open day it was clear that UAVs are on everyone’s minds. This disruptive technology drew interest from the 87 attendees at the event which took place at the company’s Kyalami office on 23 January 2015. The audience predominantly consisted of land and mine surveyors, and attendees also had a chance to ask questions, and test the different total stations on display.

Derek Gouws, Afgen’s managing director, discussed two UAV case studies and pointed out that UAVs are 95% accurate within 14 mm horizontally and 68 mm vertically, with a 10 mm ground sample distance.  Research, he said, indicates that UAV photogrammetry has a similar practical accuracy to RTK GPS, making it suitable for cadastral, topographic and engineering survey work with a 1:200 map scale accuracy requirement. UAVs are very useful for detailed work over larger areas, he said, but will not replace GPS technology, as some applications e.g. manhole surveys are impossible without it. GPS is also needed to set up GCPs and to make spatial corrections.

Alfred Leuta (Afgen) hands Lappies Labuschagne his prize.

Alfred Leuta (Afgen) hands Lappies Labuschagne his prize.

Gouws explained to the audience that when buying a UAV, survey ranges should be a key factor in the decision as the data processing times can make them inefficient for areas less than 5 km2. Data processing for a 5 km2 project can take approximately three days, he said, making UAVs most optimal for areas between 10-15 km2. Calibrating the camera and UAV is also crucial for accurate surveys, he added, as is constant ground speed and at least 60% image overlap.

In terms of computer processing power required to process UAV data, Afgen recommends a configuration of a 64-bit operating system (Windows XP or later; Mac OS X Snowleopard or later; Debian/Ubuntu), with an Intel Core i7 processor, 12 GB RAM and a graphics card (Nvidia Geforce 8xxx series or later, or ATI Radeon HD 5xxx or later).

Afgen’s Ben Honiball also spoke about the Pentax R2500N reflectorless total station’s features, and Gouws concluded with a presentation on a test-of-gravity-flow scanner providing details on how a Swedish mine measures its gravity flow in order to positively influence recovery and waste dilution. The day concluded with a lunch and a lucky draw, with the lucky winner, Lappies Labuschagne, taking home an Agatape laser distance meter.

View the photo gallery here.

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