Design And Implementation Of Multi-source And Multi-Vision Unmanned Vehicle Mobile GIS Data Acquisition System

At present, the construction of smart city is in full swing. How to fast, economically, accurately access to geospatial information, especially high-resolution and high-precision 3D geographic information is the important foundation of smart city. The traditional aerospace based remote sensing platforms are unable to get the complete geometry of buildings. While vehicle-borne mobile mapping system, as a land-based data acquisition platform, is able to quickly access the geospatial information on the ground, which can make up the shortage of observation from aerospace based remote sensing platforms. It has a positive role in advancing the process of digital earth construction, greatly improving the efficiency of digital 3D modeling. However, the current vehicle mobile mapping systems still have such problems as not high flexibility, low accuracy, difficult to calibration, adaptability is not strong, expensive, etc.Considering requirements of geospatial data acquisition to automotive mobile measurement hardware, we firstly research market in-depth. Meantime, taking scientific, stability, flexibility into account, we integrally use the theory and methods of photogrammetry and remote sensing, computer vision, systems integration to design and implement an multi-source and multi-vision unmanned vehicle mobile GIS data acquisition system, the one which is economic, applicable, efficient and reliable by using low-cost hardware material. On this basis, a three-dimensional mapping outdoor scene test and the analysis of accuracy evaluation has been done. The main contents are as follows:1) Overall design of multi-source and multi-vision unmanned vehicles GIS data acquisition systemPlan to use the mobile carrier pan-tilt (contain one unmanned remote control electric car, support system, and 360° multi-source multi-faceted array rotating pan-tilt), object imaging system (contain a single-lens reflex camera, three ordinary digital camera, and a RGB-D camera), attitude determination and positioning system (contain four GPS/IMU modules and upper computer module) and a power supply module (four solar mobile power) to design and implement an inexpensive, economical, efficient and convenient multi-source and multi-vision unmanned vehicle GIS data acquisition system.2) Design of 360° multi-source multi-faceted array rotating pan-tiltIn the design of 360° multi-source multi-faceted array of rotating pan-tilt, the photographic measurement precision and degree of automation are both taken into account. Meantime, the long baseline in the multi-vision is used to magnify intersection angle to improve the accuracy of mapping. The design structure has two parts, the lower part is the wooden rotary table, the upper part is the holder of pan-tilt imaging. Since the pan-tilt is designed considering the richness and completeness of object imaging, the wooden rotary table and pan-tilt imaging holder can rotate 360°freely within the region approximate hemisphere, which increases the flexibility and convenience of photography mode. About the upper pan-tilt imaging holder, it is made of aluminum alloy square tube and aluminum alloy plate, and contains four cameras placed platforms. Therefore, the pan-tilt provides imaging system and object positioning attitude determination system with a stable, secure, reliable platform foundation.3) Camera calibration and positioning and attitude calculation modelIn this part, the method of camera calibration and mathematical model of positioning and attitude is formulated, mainly on the camera calibration method based on DLT; Secondly, the collinearity equations of space triangulation positioning involved in positioning and attitude calculation is discussed, as well as the method of forward intersection and resection and self-calibrating based bundle adjustment theory is explored. Additional, the assessment criteria of accuracy is established.4) The test of three-dimensional mapping accuracy of outdoor scenesSelecting the outside buildings scenes, and through the form of laying control points artificially, we make use of the three-dimensional plane coordinates of control points measured with the total station. Then, combining the image information and data acquired by GIS data acquisition system of multi-sources and multi-vision unmanned vehicle, we verify the accuracy of the processed three-dimensional plane coordinates and evaluate by applying the photogrammetry relevant theories and methods.The result of experiment showed that:Comparing the data, which was obtained by the GIS data acquisition system of multi-source and multi-vision unmanned vehicle, with the real three-dimensional coordinate data which acquired by using digital total station in the method of laying points artificially, the real errors are got as:mx=0.721513894, my=0.577783803,mz=0.31332879.This result can verify that the GIS data collected by the data acquisition system is with high precision,and can meet the requirements of the construction of digital cities.Compared with the conventional vehicle mobile mapping systems, not only the hardware of GIS data acquisition system of the multi-source and multi-vision unmanned vehicle is low cost, this system also saves the Lidar laser scanner. Moreover, it is in scientific and flexible, high accuracy, fast calibration, adaptable, efficient and reliable, and in high performance. Design and development of the system can provide a suitable and efficient new ways for building digital earth and even the economic wisdom of the earth to get the target geospatial information.