What is the difference between the GLS-1000 and GLS-1500 laser scanner?
The GLS-1500 has all the innovative features of the GLS-1000 including onboard control, easy traversing, Precise Scan Technology etc, however the scan speed has been uprated to 30,000 points per second. Note that all our existing GLS-1000 owners can upgrade their instrument to the new scan rate making Topcon scanners the only manufacturer to be future proof.
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What is the accuracy of the GLS-1000 / GLS-1500 laser scanner?
An accuracy of 4mm is maintained throughout the 1-150 metre range. The maximum range of the instrument is 330m and the angular accuracy is 6 seconds vertical and horizontal (6” is equivalent to +/- 0.3mm at 10m or +/- 3mm at 100m). Point size at 100m is 1mm. Target detection accuracy is 3″ at 50m which is ideal for easy traversing around a site.
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What is the horizontal / vertical field of view of the GLS-1000 / GLS-1500 laser scanner?
360 degrees horizontally and 70 degrees vertically. The ability to scan directly overhead, on the occasions when this may be needed, can be achieved with an optional tilt mount or tripod floor spider. In most work environments the upper window of a scanner with vertical point scanning does not get used. The GLS can scan 7m above and below the horizontal straight ahead position for targets 10m away. For targets 100m away the vertical scan range is ±70m.
The scanner will cope with 10′ of tilt, however when inclined to scan overhead the tilt sensors need to be turned off. Data can be registered with other scans to geo-reference points using target or tie-point registration.
How is cloud point registration carried out?
The quickest method is to use the scanner like a total station: us the scanner to backsight onto a single target with known coordinates, and registration takes seconds in ScanMaster. Other methods include scanning 3 common targets visible in all scan positions, or creating tie points on common features in the point cloud. Future versions of Scanmaster will include automated cloud to cloud registration.
How portable is the GLS-1000 / GLS-1500 laser scanner?
The Topcon scanner is one of the most portable instruments on the market. At only 24×24x57mm and weighing 17.6kg, the internal (hot swappable) batteries and onboard software control mean that this is all you need to get scanning. A rugged backpack is available as an optional extra making trekking to remote survey locations very simple indeed.
What is the maximum operating time on internal batteries?
4-5 hours of scanning is possible using the 4 internal batteries. It is possible to hot swap 2 by 2 in order to continue work without interruption. The batteries are the same as those found in many Topcon survey instruments.
What type of laser beam source is in the Topcon laser scanner?
The GLS-1000/1500 is the only scanner available in its class that uses an eye-safe Class 1 laser. The invisible beam makes it completely acceptable to work in areas where there could be a risk to the public such as shopping centres, busy urban areas, academic institutions etc.
How portable is the GLS-1000 / GLS-1500 laser scanner?
The Topcon scanner is one of the most portable instruments on the market. At only 24×24x57mm and weighing 17.6kg, the internal (hot swappable) batteries and onboard software control mean that this is all you need to get scanning. A rugged backpack is available as an optional extra making trekking to remote survey locations very simple indeed (see our video section for a preview).
What is the advantage of having a built in camera?
The integrated 2MP digital camera is coaxially aligned with the laser aperture and records images from the scanning location. The camera lens uses the laser mirror for coexistent image and beam accuracy. It is also possible to take high resolution photographs with a digital camera and map the colours from this onto the point cloud using Imagemaster Photo.
Is the onboard SD card large enough to store high volume scan data?
Topcon has developed our own data format to create small file sizes for example:
Points: 10,000,000 pts-> 200MB
Images: 40 shots -> 10MB
Total: 210MB
The GLS-1000 / 1500 has been tested with 20 manufacturers’ cards and can work with up to 8GB capacity.
How does the GLS-1000 scan speed of 3000 points/sec compare to other instruments?
Note: The GLS-1000 can now be upgraded to 30,000 points per second, matching the specification of the new GLS-1500 scanner.
Some manufacturers have impressive speeds of many thousands of points per second. It is important to remember that scan speed is NOT proportional to scan time due to the fact that there are limits to how fast the servos and mirror mechanism can move. Scan speed refers to the number of pulsed light beams per second and is always faster in the vertical scan than the horizontal scan (due to the limitation of horizontal servo speed). Thus true acquisition speed is a function of the geometry of the subject being scanned; tall thin targets (e.g. towers) will be faster to survey than short wide (e.g. low walls) targets.
The overall scan time of the GLS-1000 is very competitive due to the considerable ease of setup and operation i.e. 8-10 scanner setups could be easily achieved in one day.
What is Precise Scan Technology?
The new technology not only uses “time of flight” measurement but also combines the innovative phase-based analysis technology, which results in unparalleled stable and precision accuracy measurement. The technological innovation also allows measurement over a wide area (up to 150 meters) by varying the focus of the transmitted laser beam.
In other words Digital Signal Processing, and combining Pulse and Phase data is used to improve the range timing information. It’s a bit like Ambiguity resolution for RTK GPS. Pulse information gives us good range information, phase comparison of the carrier enables us to get even better range information and so increased precision and consequently less noise.
What is the maximum scanning range?
330m at 90% reflectivity and 150m at 18% reflectivity (*see faq on reflectance intensity)
What is reflectance intensity or reflectivity?
Since reflectivity of targets can dictate the maximum range achievable with a scan as well as the quality of the data, it is important to have an understanding of this. There are a number of factors that affect laser scan “intensity”:
1. How much light was sent out?
2. Range to the target
3. Attenuation of beam by atmosphere
4. Reflectance of target (at the appropriate wavelength)
5. Incident angle of light on the target surface
6. Size of receiver aperture
7. Efficiency of receiver optics at focusing the return light onto receiver sensor
8. Specularity of the target surface
Items 1, 6, and 7 are the easiest – they are internal to the instrument. Item 2 should be known after the range calculation is complete. But items 3, 4, 5, and 8 are dependent on conditions remote from the instrument. Taken from http://lidarnews.com/intensity
What are the recommended computer specifications to run Scanmaster? Will it run on a Netbook?
ScanMaster will run on pretty much any moden laptop. The important item is having a discrete video card. The software will work with integrated cards, but generally you will not get full resolution. The best results we have found to date are with NVIDIA cards. It may also be worth considering that a lower specification PC may be used for acquiring scans if you have a favorite piece of hardware to use in the field, and another more powerful machine for using the point cloud processing facilities of Scanmaster. It will run on a Netbook, however we feel that once you have used onboard control, you will realise the benefit of lightweight, fast field operations.
What software do you recommend for processing point clouds?
There are many packages out there for working with and processing laser scan point clouds. Topcon ScanMaster is provided free with the GLS1000. If you are an establised Leica Cloudworx / Cyclone user then it is possible to export .PTX format files to import. We recommend the following excellent value packages and are a reseller for them also:
Pointools View Pro – point cloud visualisation, animation and sharing with customers (via the free viewer)
Kubit - work with millions of points in a familiar AutoCAD environment.
Topcon Imagemaster Pro – combine scanning and photogrammetry: ideal for filling in scan shadows
EdgeWise 3D – automated vectorisation of point clouds
Will the scanner operate at low subzero temperatures?
Yes – we have used it without problem at minus 10C, however if prolonged use in very cold places is anticiapted then a factory upgrade can be made.