February 25, 2009 -- OxTS’s RT3002 and Riegl’s Q120 scanner are perfect for cost effective mobile mapping applications. Mobile mapping, where a 2D LIDAR is fitted to a vehicle, is a very efficient method of surveying. An inertial and GPS navigation system, like the RT3002, is an essential part of a mobile mapping system.
In this setup, the Q120 was fitted to a truck with the RT3002. As the truck is driven the laser scans the view out of the side of the truck. By driving up and down each street the left and right sides of the street can be captured. The RT3002 is used to directly geo-reference each individual laser point. The resulting image cloud accurately represents the real-world. Data from LIDAR can be imported in to CAD packages, combined with visual imagery or viewed directly in software packages like RiSCAN. To see a video of the data on YouTube, click here...
The Q120 scanner is one of the most economical, yet accurate scanners on the market. With up to 10,000 points per second and a range of 150m, it is ideal for mobile mapping. At 30mph this scanner can capture one point every 14cm, which is perfect for getting an overview of the environment.
The RT3002 is an inertial navigation system, aided by GPS, which measures position accurate to 2cm, roll and pitch to 0.03 degrees and heading to 0.1 degrees. At a range of 30m this equates to a horizontal accuracy of about 6cm and a vertical accuracy of about 3cm. The RT3002 can output real-time data or it can be post-processed, combining the raw GPS with CORS reference stations. The RT3002 provides an accurate timing pulse and an NMEA time reference signal to the Q120 so that the Q120’s data can be tagged to GPS time.
For a more economical package the Inertial+ from OxTS can be combined with customer’s own GPS receiver, saving the cost of purchasing the GPS from the total system cost. The Inertial+ can still deliver high accuracy measurements when connected to a high accuracy GPS, like the Trimble 5700.
Data from the Q120 can be processed using Riegl’s RiPROCESS software. This software combines the time-stamped data from RT3002 with the time-stamped data from the laser and geo-references all the data points. The data can be exported into other formats and viewed with software, such as RiSCAN.
Aligning the laser and the inertial navigation system accurately is an important part of the installation. By combining a Q120 with the inertial navigation system in a fixed frame, like this one from LaserSurvey Aps, the alignment can be computed once and then reused many times. The RT3002 and Inertial+ products can operate in any orientation so the frame can be mounted down on aircraft or pointing sideways on vehicles.
Overall the combination of the Q120 and the RT3002 gives a very cost-effective mobile mapping system. Processing the data is simple with software tools from Riegl. Installing the system in a compact frame means that there are no calibration issues for each installation.
To find out more about how the RT products can help you please contact us.