全球定位系统毕业论文外文文献翻译.doc

外文资料及译文外文资料及译文1.外文资料全球定位系统第一节 The principle of GPS一、 GPSGPS(Navigation Satellite Timing and Ranging /Global Position System )，GPS clock and distance navigation system/global positioning systems, referred to as global positioning system (GPS), along with the rapid development of modern science and technology, and set up a new generation of satellite navigation and positioning system precision. Global positioning system (GPS) is in 1973 by U.S. defense forces began to organize, and common basic completion in 1993. This system consists of space constellation, ground control and user receiver is composed of three parts.图1-1 GPS Satellite distribution（一）Global positioning system1.1 Space constellation GPS space by 24 working part constellation spare satellite and three satellite. Work in 6 orbit satellite distribution within the surface. Each track surface distribution has 3 4 satellite, satellite orbits earth's equator Angle relative to the average height of 55, orbit for 20200 kilometers. Satellite operating cycle for 11 hours 45 minutes. Therefore, in the same station daily satellite layout is roughly same, just four minutes every day in advance. Each satellite about 5 hours every day in the horizon, located above the horizon of the satellite number with more time and place, at least 4 November, most. This layout can guarantee on earth at any time, any place can also observed above four satellites. Satellite signal transmission and reception and the influence, so the GPS is a global, all-weather real-time navigation and positioning for system. After the completion of the global positioning system, its work in the space distribution of satellite 1-1 as shown. GPS satellite zips are installed on the light, microprocessors, message signal emission equipment, storage, and provide power supply by solar cells have little fuel, satellite is used to regulate the satellite orbit and posture, and in the monitor of instruction, start spare satellite.1.2    The ground monitoring systemGPS ground monitoring system in the world by five sites. One master station, 3 injection station. Five monitor are equipped with automatic acquisition, data center, double-frequency GPS receiver, precision clock, environmental data sensors and computing devices, and to master station provides all kinds of observation data. Master station (in Colorado) for system management and data processing center, its main content is the use of this site and other monitor the observation data of the satellite's star calendar calculation and satellite clock and atmospheric delay correction parameter, provide global positioning system, and the time base station, these parameters to adjust sidetracked into orbit, the satellite to enable spare satellite instead of failure satellite, etc. Injection station master station will be calculated and satellite star calendar, clock, satellite navigation message and other control commands into corresponding satellite etc, and storage system into the correctness of monitoring information. Besides, the master station, GPS ground monitoring system, various unattended highly automated and standardized work.1.3 User equipment parts User equipment including GPS receiver host, antenna, power and data processing software component. The host for the microcomputer, quartz oscillators core, and the corresponding input and output interface, and equipment. In the special software under control, the host for homework, satellite data acquisition, processing and storage of the equipment, the system state inspection, alarm and maintenance, the receiving system of automatic management. Antenna, often used for collecting all from each azimuth, arbitrary nonnegative Angle of satellite signal. Due to the satellite antenna pedestal weak signal in a pre-amplifier, amplification, reoccupy coaxial cable input host. Power supply for host and aerial part, can use through rectifier voltage, the mains, also can use the accumulator.（二）Global positioning system (GPS) signals GPS satellite launch a coherent wave, the wavelength and frequency respectively： and as a carrier with two modulation signal, a kind of navigation signal, another kind is message signal. Navigation signal is divided again, frequency for code rate for the coarse yards (C/A code) and the rate for the essence, the frequency of code (P). Thick yards (C/A code) repeat each signal encoding, can quickly capture signal, according to the design for rough positioning, Pure code (P) yards signal encoding every seven, and repeat each satellite, structure is very complex, not capture, but can be used for accurate positioning. Message signal while the rate to the carrier and modulation in, including satellite, the correct star calendar and satellite working state. Through the message signal receiver can choose the best one group of graphics, positioning signals observation data processing.第二节 GPS Positioning method一、  GPS Positioning method classification（一）、 The static and dynamic positioning By means of static GPS positioning and can be divided into dynamic positioning.1、Static positioning If you stay in the surrounding relatively fixed protection can not perceive motion, or movement is so slowly that require months or years, namely that can be reflected in the earth for fixed-point relative coordinates is fixed, the determination method for the coordinates of static positioning is called. In the mathematics model of the static localization, the position is constant. Due to the rapid solutions of GPS "unknown" technology of the cycle time of operation, static already shortened to a few minutes, so, in addition to the original geodetic measurement and monitoring of the force applied, rapid static orientation has been widely applied to the common measurement and engineering measurement.2、 Dynamic positioning Cars, ships, aircraft and aircraft in motion, people often need to know their real-time position. In these sports carrier mounted on GPS receiver, real-time GPS signals measured antenna location, called the GPS kinematic positioning. If the only measure the real-time position, the carrier of sports also determine the speed, time and location, etc, thus guiding status parameters to reserve the object orientation, called the navigation movement. GPS navigation is virtually dynamic positioning.(二)、 Absolute positioning and relative location According to determine the GPS receiver in earth coordinate system in different position, can be divided into a single absolute positioning and the relative positioning, such as machine, 2-1.1、 Absolute positioning图2-1 Absolute and relative positioningTo determine the absolute positioning is independent coordinate system in the position of the dot. Because single absolute positioning error by satellite reception when the effect, low precision. Mainly used for low precision dynamic positioning, such as ships, aircraft navigation of mineral resources, geological investigation, Marine fishing and determine the relative position of the initial value.2、Relative positioning Relative location is determined simultaneous tracking same GPS signals of several sets of the relative position between the receiver is a kind of method. Since the synchronous observation, the synchronization of many error signal obtained station is identical or similar (such as satellite clock error, error, the signal of the star alex atmospheric transmission error, etc.), can avoid or weaken these errors, obtain high relative position. Relative positioning, signal processing and data than absolute orientation is complex, relative positioning is the synchronization between baseline vector (station), and 3d coordinate need at least a spot for known to the rest of the each point coordinates. The static and dynamic positioning can position by relative positioning, such as earth deformation measurement, ground control aerial photogrammetry, etc. In the dynamic positioning, often USES "difference", a GPS receiver will be placed on the base coordinate, known as the receiver in sports, all receivers carrier, according to the known synchronous control results, the positioning correct number starting position, in order to improve the real-time to positioning accuracy. This is based on a single point positioning and relative location of positioning mode.（三)、 Pseudorange method and the carrier phase method GPS satellite positioning, according to the different signal processing, can divide again pseudorange method and the carrier phase method. 1、Pseudorange method The positioning principle is simple. When positioning, receiver and the oscillation of A satellite signal the same group (P yards range yards or C/A code), through delay and receiver receive signals, when two groups compared each other completely coincide (related to signal measured signals, namely for the delay in quantity, satellite signal transmission time with A series of modified times the speed of light, satellites and draw the oblique distance antenna phase center. If the four (or above), i.e. the distance can satellite stations calculate intersection method of location and clock error four unknown. Due to the wavelength range yards. To one percent of the estimated $yards range resolution, length of to 0.3 meters (P) and 3 meters (C/A code) the ranging accuracy. Therefore, the pseudorange accuracy is relatively low. 2、The carrier phase method The carrier is a measure of carrier signal, measurements, determine the satellite signal and reference signal receiver, calculate the phase difference observation. Then the same principle and pseudorange method, the position of the station clock error, etc. The wavelength modulated symbol, than much shorter wavelength of one percent, to $yards range resolution, estimating length reached 1.9 cm (P) and 2.4 L centimeters (C/A code) the ranging accuracy. In the measurement and precision air triangle measuring, high precision, often USES relative positioning method, the carrier phase to eliminate system error.The carrier phase method for measuring the complete phase observation data from several parts: (2-1） Type: for the first phase, the observational S, for the position of the receiver observation R phase, for the actual phase observations, for the whole cycle count, also called the whole cycle unknown, for the actual observation time t the integer part, first observed for the duration of zero, every moment, observation by continuous accumulated through counter counts, called after the cycle count, for the actual observation in the integer part, with high precision measurement.二、 GPS positioning operation mode Mainly includes GPS real-time GPS navigation positioning, afterwards (with) the dynamic positioning and used to measure the static or dynamic) relative orientation accurate.1 . GPS kinematic positioning GPS real-time navigation) is required (and observation data in the positioning of the moment, its main purpose is to navigation. AS mentioned above, the absolute positioning (single point positioning) by the us government's "SA" (choose usability) and "AS" (the electronic technology, the influence of deception by civil service standard of GPS level position precision of 100 meters. So many users using differential GPS system (CDGPS and WADGPS) to improve the precision. CDGPS pseudorange method and the users of the station standing range within 100 miles, precision for 5 10 meters. The carrier phase method CDGPS (also called RTK) standing and users in the station within range, 30 kilometers, the accuracy of cm. And WADGPS big scope is to create multiple known coordinates, standing and vice standing vice standing by data from receiving chain of error sources, after three corrections to users, communication WADGPS pseudorange method for positioning accuracy of about 1 3 meters, CDGPS superior. And stood and vice standing distance can reach over 1000 kilometers.2. Dynamic positioning postprocessing This is a kind of carrier phase of dynamic positioning technologies. Usually a receiver is placed in the ground, and the other on the known a (or more) receiver in high-speed motion object, jr, afterwards synchronous according to the carrier phase difference between objects in motion relative to determine the location of known. Its characteristic is standing with users need to stand between the transmission of real-time data, the distance between the two is less restricted. But in high-speed motion of the object is how to determine the unknown and the whole week jump problem is the technical difficulties. In recent years, the GPS technology of dynamic initialization OTF (again) greatly improve something comes after the practicability of the dynamic positioning. It can reach the cm-level positioning accuracy. Mainly applicable and low orbit satellite cm-level precision GPS satellite, aerial photogrammetry, airborne gravimetry, magnetic moment of determine the cm-level 3d coordinate of the airborne GPS technology.3. Used to measure the static（and dynamic) relative positioning Static relative positioning using two sets of (or above), the GPS receiver respectively in each of the baseline endpoints, synchronous observation above four satellites 0.5 1 hour, baseline length in 20 kilometers. The baseline netted closed graph, constitute the whole event after adjustment, the precision can reach. Applicable to higher accuracy of measurement and control of national land earth deformation monitoring, etc. Rapid static relative position in the central area with a base station, GPS receiver continuous tracking all visible satellites, in order to each other a receiver to the above five starting synchronous satellites, each 1 2 minutes to benchmark station starting at baseline length within 15 kilometers, with the benchmark stood for radiation center. Afterwards the processing precision can reach, but poor reliability. Applicable to small range of control measure, engineering surveying and cadastration, etc. Accurate dynamic relative position in the zone, a GPS receiver with benchmark for tracking all visible satellites, another a receiver in starting sites for five first above synchronous satellites for 1-2 minutes and then keep track of all of the satellite, under the situation of continuous flow to the observation of the number of seconds, the observatory was starting to stand at the baseline length benchmark within 15 kilometers. Its characteristic is starting to keep each phase lock. In case of loss locks, must extend unlocked site observation time after 1 2 minutes to determine the unknown and the whole cycle count cycle. Accurate dynamic relative positioning error in baseline can reach 1 2 cm long, suitable for engineering measurement circuit measurements and