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СИСТЕМА МОБИЛЬНОГО КАРТОГРАФИРОВАНИЯ В КИТАЕ
Чаншэн Тэн
Leador Spatial Information Technology Corporation, Китай, Пекин, менеджер по продукции, магистр фотограмметрии и дистанционного зондирования, тел. +86-10-6261-7985, факс: +86 10 6261 7985, e-mail: tengchangsheng@leador.com.cn
Шэн Го
Leador Spatial Information Technology Corporation, Китай, Пекин, менеджер по продукции,
бакалавр фотограмметрии и дистанционного зондирования, тел. +86-10-6261-7985, факс: +86 10 6261 7985, e-mail: leader3s@leador.com.cn
Возрастающее проникновение на рынок интернет-картографирования и персональной навигации в Китае открыло большие возможности для гео-сообществ в области научных исследований и бизнеса. Уже признано, что геоданные лежат в основе любого геопространственного применения. Следовательно, своевременный сбор и обновление карты, информации об изображении и точное представление стали более важны, чем когда-либо. Мобильная система картографирования со встроенным мультидатчиком является хорошим средством быстрого сбора геоданных. Такая система широко используется в навигации по карте, управлении городом, аварийно-спасательной службе и пожарной охраны, дорожном патруле, административно-хозяйственном управлении, железнодорожном патруле и интернет-приложений.
Ключевые слова: мобильная система картографирования, управление городом, PPOI, дорожный патруль, административно-хозяйственное управление.
MOBILE MAPPING SYSTEM IN CHINA
Changsheng Teng
Leador Spatial Information Technology Corporation, China, Beijing, Product Manager, Master degree on photogrammetry and remote sensing, tel. +86-10-6261-7985, fax. +86-10-6261-7985, e-mail: tengchangsheng@leador.com. cn
Sheng Guo
Leador Spatial Information Technology Corporation, China, Beijing, Product Manager, Bachelor degree on photogrammetry and remote sensing, tel. +86-10-6261-7985, fax. +86-10-6261-7985, e-mail: leader3s@leador.com.cn
In China, the growing market penetration of internet mapping and personal navigation has opened up great research and business opportunities to geospatial communities. It has been recognized that geospatial data is at the heart of any geospatial application. Consequently, collecting and updating map and image information in a timely, accurate fashion has become more important than ever so. MMS (Mobile Mapping System) which integrates multi-sensor has clearly established a trend towards fast geospatial data acquisition. Such system is widely used in the fields of navigation map surveying, urban management, emergency response, road patrol, facility management, railway patrol, and Internet applications.
Key words: MMS, urban management, PPOI, road patrol, facility management.
1. INTRODUCTION
MMS is the system of collecting geospatial data from a mobile platform. Such systems are composed of an integrated array of time synchronized GNSS (Global Navigation Satellite System), IMU (Inertial Measurement Unit), DMI (Distance Measurement Instrument), imaging sensors , laser scanning sensors and onboard computer mounted on a mobile platform. The primary output from such systems includes GIS data, digital maps, and georeferenced images and video.
MMS basically consists of two subsystems, each comprising a variety of sensors:
1) Trajectory subsystem: PPOI (Precise Positioning and Orientation Instrument) as the core, and aiding sensors like digital odometer and inclinometer;
2) Object data subsystem, currently with image sensor and laser scanner.
The whole system is managed by a central controller, which logs all sensor data to a hard disk for performing real-time integrity checks and post-processing. The GNSS-PPS (Pulse Per Second) - signal, generated by the GNSS receiver, together with GNSS time information is used to synchronize all sensors and to time-tag the data with an uncertainty of less than one millisecond (Graefe, 2003).
In China, as a new way of geo-spatial data acquisition, the main navigation data producers see MMS as its primary means of data collection and updating and mobile mapping technology as the company's core technology. Thus, mobile mapping technology has become the best solution for geospatial data acquisition, playing an increasingly key role in the geo-information data-updating.
Research in mobile mapping technology started in 1990s, the field in multiple-sensor integration, system error calibration, direct geo-referenced technology. Up to now, LD2000 MMS, LD2011, LD2014 has been successfully developed Leador Spatial Information Technology Corporation (Abbreviation: Leador Spatial) and used in all walks of life, its hardware and software have been exported to Korea, and Italy, and Iran, and other countries.
Figure 1: LD2000 MMS (left) is developed in 2004 and L D2011 MMS (right) is developed in 2011
Figure 2:LD2014 MMS is developed in 2014
2. KEY TECHNOLOGIES
MMS is a multi-sensor integrated digital mapping system, which generally composes the mobile vehicle, multi-sensor, on-board computer and data acquisition software. Development and application of MMS is mainly dependent on the development of the following key technologies:
1) Direct georeferencing
GNSS coverage is affected by topography, e.g. trees close to the road, houses etc. It is a key to determine the position and orientation of MMS with frequent GNSS outages. On this basis, we can obtain the coordinates of the target features, without using ground control points and photogrammetric triangulation method. PPOI-L61 developed by Leador Spacial is a system which is very accurate, and is compatible for GPS, GLONASS, Galileo, BDS; its specifications are shown in Table 1.
Table 1
PPOI-M60 specifications
SPS PP
Horizontal position (m) 3-5 0.02
Vertical position(m) 5-10 0.05
Heading (deg) 0.02 0.005
Roll & Pitch (deg) 0.005 0.0021
Velocity (m/s) 0.03 0.005
Physical dimensions (mm) PCS:340x200x105 IMU:180x172x130
Weight (kg) PCS<3.5 IMU<5.6
For achieving a full accuracy a local gravity model is required. 2) Multi-Sensor Integration
MMS use variety of spatial data collection tools, although the multi-sensor system as compared with a single sensor system has many advantages but introduces a
series of new problems, such as performance of new sensors and software, multisensor consistency problems, systemic error calibration technology.
The overall calibration technology is important for ensuring the systematic errors. Calibration technology comprises a relative calibration and absolute calibration. Firstly, the relative calibration means solving the intrinsic parameters of each sensor respectively, so as to assure the relation between the sensor and a group of sensors and the own center. Relative calibration includes multi-image sensor, PPOI, laser scanning sensor and lever arm calibration, foresight calibration. Absolute calibration means assuring the relative relationship between the sensors and the object coordinates. The specifications of LD2000, LD2011 and LD2014 are shown in Table 2.
Table 2
The specifications of LD2000, LD2011 and LD2014
LD2000 LD2011 LD2014
Laser max range(m) \ 500 920
Laser max FoV (vertical) (deg) \ 300 360
Panoramic Photo Max FoV(deg) \ 360x270 360x270
Panoramic photo resolution (MP) \ 12 30
DMI Max range (m) 40 40 40
Absolute accuracy (RMS)(m) 1.0 0.3 0.1
Relative accuracy (RMS)(m) 0.1 0.1 0.05
Max. speed (km/h) 80 80 80
3. FLOW OF DATA ACQUISITION AND PROCESSING
Flow of data acquisition and processing includes data acquisition, Determination of positon and orientation, georeferencing and mapping. Flow chart is shown in Fig 3.
Fig 3: Flow chart of data acquisition and processing
1) Data acquisition
Use acquisition system of MMS to collect GNSS/IMU, image and other original data in target area. Data collection is drove to collection area. The system will automatically collect the track of traveling route, the position and attitude observation data of GNSS/IMU, CCD image, panoramic images, laser point cloud and POI when MMS driving along the route.
2) Determination of positon and orientation
Use LIONET (Leador INS/GNSS Orientation and Navigation Enhanced Technology) post-processing software to compute an optimal integrated inertial navigation solution by processing the raw IMU, GNSS data ,DMI data collected from PPOI amounted on vehicle(other platform), along with GNSS observables recorded form base station receiver(s). It computes a carrier phase GNSS solution and then blends it with the inertial data using forward and reverse time processing.
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Figure 4: Interface of LIONET software
3) Georeferencing and mapping
Direct digital image georeferencing using coMapper implies the direct measurement of position and orientation of each single image frame at the moment of data acquisition. In principal, this allows immediate map production using the photo-grammetric unit (a stereopair of images, or a single image+DEM). Ultimately, this approach totally bypasses the aerotriangulation step with no ground control point requirement. Fig. 5 below shows the georeferencing concept.
Figure 5: Interface of coMMapper software
Use coMapper to measuring objectives, extract attribute, mapping and building database by stereoscopic image of georeferenced and laser point data. Then output DLG, digital measurable image, navigation map and panoramic laser data, etc.
4. APPLICATIONS
Mobile Mapping Solution brings you omnidirectional information via its images and laser points. It is widely used in the field of local search, navigation, urban & industry planning, homeland security, emergency response, roadway management, street map, etc.
4.1. AERIAL MOBILE MAPPING
Traditional techniques of geo-referencing aerial photography, ground profiling radar, or Lidar are prohibitively expensive, particularly in inaccessible areas, or where the type of data collected makes interpretation of individual features difficult. Image direct georeferencing, simplifies the mapping control for large scale mapping tasks.
Figure 6: Oblique camera pod (left) and 3D model Jiujiang, China (right)
4.2. URBAN MANAGEMENT
Adoption of Mobile mapping technology to provide the inspectors with measuring function patrol car for urban management department for the scene forensics and law enforcement of illegal construction, illegal street advertising plaque, Jeeves and other acts, and the field measured by real images and video CDMA / GPRS or 3G network quickly transferred to the command center.
Figure 7: Urban management MMS
The car to inspect in urban area is mainly used for monitoring irregularities in urban management, there are often many sabotage the urban landscape, in violation of city planning behavior continue to occur in city, therefore, the need for urban management department of road construction and the basic situation within the jurisdiction of statistics, and continue inspections, by comparing the historical real image data is to determine whether there are irregularities ,and by combining with measurable functions and decision-making deal is to quantify the evidence.
With 3G or digital radio communications equipment, disseminate living conditions, it realize sharing data between enabling law enforcement command center and on-site Law enforcement car.
4.3. EMERGENCY RESPONSE
Figure 8: Emergency response MMS
The data which are acquired by Leador2000 MMS is used for accurately assessing of conditions on the ground. A special database which is quickly built by MMS (relief facilities, temporary residence, hospitals, etc.) is used for disaster relief facilities management, command and decision-making.
4.4. ROAD PATROL AND FACILITY MANAGEMENT
MMS can be utilized to carry out efficient road condition surveys, and facilities management. Laser scanning technologies, applied in MMS, allow full 3D data collection of slope, banking, etc.
For inspections of facilities and road incidents, by way of wireless transmission of real-time video-board camera and stereo image is sent to the rear of the command center.
Figure 9: Road patrol MMS
On the basis of road inspections, MMS can scan the pavement and find out cracks.
Figure 10: Detection of pavement cracks MMS
4.5. RAILWAY PATROL
Railway MMS is enable to record the state of the rail on both sides of geography, such as clearance status, and other dynamic information, a live recording of the integrated system, through the sensors mounted on the train, is enable to dynamically, real-timely record geospatial data along the railway.
Figure 11 : Railway patrol MMS 4.6. INTERNET APPLICATIONS
Internet and mobile device users are increasingly utilizing geo-spatial information, either in the form of mapping, or geo-referenced imaging. MMS provide geo-spatial data for the biggest Map ISP (Baidu Map).
Figure 12: High resolution panoramic camera MMS
Figure 13: Interface of Baidu map
REFERENCES
• Li, D.R. & Guo, S. &HU Q.W. (2008). 3S (RS, GPS, GIS) Integration Technology Based LD2000 series Mobile Mapping System and Its Applications: Volume 37 of Acta Geodaetica et Cartographica Sinica, SinoMaps Press, pp. 445-449
• Graefe, G.; Caspary, W.; Heister, H.; Klemm, J. (2003). The road data acquisition system MoSES-determination and accuracy of trajectory data gained with the Applanix POS/LV: Applanix Website, visited on February 15, 2003. http://www.applanix.com/pdf/Paper_Cairo.pdf
Contact
Changsheng Teng
Leador Spatial Information Technology Corporation,Beijing,China,Product Manager, Master degree on photogrammetry and remote sensing , tel. +86 10 6261 7985, fax +86 10 6261 7985, email: tengchangsheng@leador.com. cn
© Changsheng Teng, Sheng Guo, 2015
