测绘英语论文（测绘专业）.doc

GPS positioning principle and overviewIn the 1980s, the GPS satellite measurements are nearly 30 years development of a major space measuring technique. It not only has no tong, all-weather, global, but also has the characteristics such as good, fast, etc, and is widely used in the world, have replaced the trend of geodesy.In the past 10 years, has become a GPS surveying IU GG (international federation of geodesy and geophysics), IA G (international) geodetic measurement and F IG (international federation) conference engineers are the main topics of academic discussion. Therefore, the domestic and overseas scholars think: the GPS satellite measurements technology is a milestone in the history of surveying and mapping.Facing this situation, in order to learn foreign advanced experience, with the international advanced level as soon as possible, it is necessary for us to understand the concept of GPS system composition, principle, characteristics, main USES, and prospect. Let us know by GPS.The global positioning system (GPS) is in the 1970s by the armed forces of the joint development of new generation space satellite navigation and positioning system. Its main purpose is for land, sea and air three areas to provide real-time, all-weather and global navigation services, and information collection, for nuclear monitoring and emergency communications and other military purposes, is the important component of the global strategy. After more than 20 years of research and experiment, to $30 billion dollars, March 1994, global coverage up 98% of 24 GPS satellite constellation has completed. Monitor.andThe global positioning system consists of three parts: (1) the ground control station by the master, be responsible for the management, coordinate the (ground control system), the antenna (master station in under the control of a satellite, to inject found message), data collection center (station), and automatic auxiliary system (data), (2) of the spatial distribution of 24 satellite components, in six ways plane, (3), mainly by the user device GPS receiver and satellite antenna.GPS principle, it is by 24 GPS satellite from the ground 1 thousand kilometers, with the high cycle of 12 hours orbiting the earth in any time, and in any point on the ground can be observed at 4 star above the satellite.Because the position precision, satellite observations, we in the GPS satellite receiver can get into the distance, using 3d coordinates of distance formula, using three moons, can be composed of 3 equation, the observation position (X, Y, Z). Considering the clocks and clock satellite receiver between error, actually has four unknown, X, Y, Z, thus needs and introduced the first four satellites, forming four equations are solved, and the latitude and longitude and elevation of observation.In fact, the receiver can often locked 4 star above, then, the satellite receiver by satellite constellation distribution can be divided into several groups of four, then through the algorithm of selected as a group of minimum error, so as to improve the precision positioning.Due to the satellite orbit, satellite clock error, atmospheric troposphere, ionosphere to signal, and the influence of human SA protection policy, make civil GPS positioning accuracy of only 100 meters. To improve the precision, commonly used differential GPS technology, establishing DGPS (differential) (the benchmark for GPS observation stations, using the known precise coordinates, compared with observations, thus a fixed number, and published. After receiving the fixed number of receivers, and their observations, compared to a comparison of error, the accurate location. Experiments show that, using differential GPS positioning accuracy can improve to 5 meters.The main features of global positioning system (1) all-weather, (2) global coverage, (3) 3d varied timing high-precision, (4) fast time efficiency: (5) widely used.The main purpose of the GPS in the following aspects:1, all-weather global positioning satelliteAccording to the monitoring center can understand all vehicles, and in real-time position in the center of electronic map display vehicles was precisely the state (such as speed, running direction, etc). This system by using the vector of electronic map, the designated area of any inquiry vehicles, Optionally, amplification, mobile electronic map, Can undertake with screen window display monitor, or more in a window will target, automatic tracking, etc. The main parameters for monitoring vehicles, vehicle (precise location to 15 meters), running speed (accurate to 1 km/h), the movement direction (1) and precise time information (accurate to 1 second),2, the emergencyThe monitoring center of car terminal received alarm signals (such as active emergency alarm, illegal damage alarm, b&e alarm, illegal move alarm), system, automatic classification by way of voice, alarm control hint of vehicles with marked on the map display alarming state and alarm site, and will alarm target surveillance level, and automatic track record. According to the monitoring personnel timely alarm for scheduling and acoustic processing.3, information queryCenter control system with abundant, comprehensive data information, can be required to confirm customer, provide the following services: after the password(a) vehicle information query: to provide the relevant information query, vehicles such as vehicle location and motion, plates,Car drivers names and their subordinate units, and communication style; etc.(b) geography information: information, provide map location information retrieval, calibration, road along the main building, for example, the station, hotel, railway stations, airports, public security bureau, residential; etc. 4, air-conditions (security), remote cut power control functionThis function is one of the outstanding characteristics of maximum protection of life and property security. Driver When the vehicle is grabbed by pilfer, the pilot can avoid conflict with robbers positive, if press the alarm switch quietly, or use the telephone to get out after 10 seconds left, center alarm center can receive warning signal (vehicle theft is moving 50 meters, dispatching management center can be received alarm signal), management system according to the vehicle archives, showing alarm vehicles of various data (e.g., Numbers, models, license plate, the color, the name, age, gender, etc), and at the same time, the center of electronic map showing alarm immediately, the position of vehicle speed and direction of running, vehicles and criminals DunXing everywhere.The monitoring center after authorized to real-time monitoring vehicles (sim card opening speech function) and control (control), remove lock, cooperate with the police vehicle out quickly, tracking capture criminal police, distress, return the driver of the stolen vehicles.4 and historical data record, analysis and playbackThe system automatically records each vehicle running trajectory, and the specific number of requests a service, emergency number and specific time, theft alarm, according to the number of specific time and preserved in the historical data, electronic map playback selected the actual process of vehicle driving, also can be in electronic maps quickly reproduce selected vehicles route, and the time for later processing passengers complain, road accidents, stolen, robbed provide evidence that such events.5 and real-time scheduling functionAfter installation of the system, the vehicle in the net all distribution and real-time operation condition, dispatching center can be clear at a glance, panoramic, readily available by the control center to take effective measures, to reasonably in vehicle scheduling. This system can also function of management department to strengthen management of vehicle management industry provides convenient and effective help.6 and cross-border alarm functionAccording to certain routes (area) operation of vehicles, vehicle dispatching management center of operation can be set limits, when the vehicle and trackside equipment, beyond boundaries will be sent to the vehicle dispatching management center, the center will automatically alarm cross-border open real-time tracking program into vehicle monitoring and control personnel can send messages (instruction) or to inform the driver to voice the monitoring sites related to register or driving back to the correct operation on the road.7 and speeding alarm functionScheduling management center of different kinds of vehicles, set the speed limit when the driver driving faster than the limiting value, vehicle-mounted system will automatically alarm, dispatching center control center through the scheduling system remind driver slow down.8 and the road alarmDrawing from the vehicle route, reach a certain value deviation alarm that center.9 and electric alarmVehicle meet mandatory cuts or voltage instability shows alarming information.10 and electronic fenceSet the maximum/smallest electronic fence, form a square of the latitude and longitude of electronic fence, so that the system monitoring alarm. Car entering or leaving electronic fence generating alarm status.11 and grading managementThis system can realize classification management functions, such as a monitor center in jinan, Qingdao, yantai, etc in many places, establish monitoring center points classification management.12 and remote maintenanceBut for the monitoring center remotely software maintenance, testing, installation; etc. Can change to the car terminal remote IP address, update the car machine program.13 and oil consumptionBut for the oil tank in vehicle inspection, the oil tank energy within the transmission of real-time monitoring center, make the administrator to the real-time detection, while petrol tank inside the amount of oil suddenly change monitoring center receive