GPS SpaceThe space is part of GPS satellite by 24 work [1]， it is located above the surface of the 20 200km， evenly distributed in six track surface (4) each track surface， orbit for 55 ° A In addition， there are four star orbiting satellites active The distribution of satellite in global anywhere at any time can be observed in 4 above， and can keep good satellite positioning accuracy of geometrical image This provides a continuous on time in the global navigation GPS satellite produces two groups， one group called Morse code (C/A Coarse/Acquisition Code11023MHz)， A group called the P (Procise Code 10123MHz)， P Code for higher frequency， not suffer interference， high precision， so by the US military control， and the password， generally， mainly for folk cannot US military C/A code for measures to lower accuracy， and deliberately used mainly open to The ground controlThe ground control station by a master， five global stations and 3 ground control There are equipped with precision of the station clock and continuous measuring cesium visible satellites to accept The satellite observation stations will obtain data， including the ionosphere and meteorological data， after initial treatment， to master Master station from various stations， satellite tracking data calculated the orbit and clock parameters， then will result to 3 ground control The ground control station in each satellite run over to the navigation， master station instructions and data into a The injection of each star GPS satellite， and in every time inject stood range from satellite before finally If a ground fault， so in the satellite navigation of stored information can also be used for a period of time， but the navigation precision will gradually User equipment partsUser equipment parts namely GPS signal Its main function is to capture by certain Angle of satellite deadline to choose to follow these satellites and satellite， the When the receiver to capture the satellite tracking， after receiving antenna can be measured and satellite pseudo distance and the distance change， satellite orbits parameters， such as the demodulation Based on these data， the receiver can handle the computer by positioning solution method and computing the user's position in the longitude and altitude geographical position， speed， time， The hardware and software receivers in GPS data post-processing software package and form a complete GPS user GPS receiver unit and receiving antenna structure is divided into two parts of the Receiver generally USES machine and together two kinds of dc power Setting machine aims to replace the power supply without interruption continuous In use within the time machine power battery charging After shutdown， machine battery power for the RAM， memory， in order to prevent the loss of At present various types of accept machine， weight and small volume and light， facilitate the field The Ground control system (by now)， the Station so the control Station (Master)， so now the Antenna (Ground)， the Antenna control Station， colo springfield， Colorado (are) The ground control station is responsible for collecting information by satellite， and alex， relative to star satellite data from the atmosphere Secondly， the existing users receiver for two and two， double-frequency due to price factor， general user buys more for single-rate Aiming at the application of GPS road engineeringThe application of GPS in road construction， is mainly used to establish various road engineering control network and determination of the control points electricity， Along with the rapid development of the highway to survey technology， puts forward a higher request， due to long， known points less， therefore， with the conventional measure method not only， and the net difficulties are hard to meet the requirement of high At present， China has gradually establish lines using GPS technology， then head high precision control network layont wires with conventional Practice has proved， in a few tens of kilometers within the scope of the point error only 2 centimeters， reached the conventional method to realize the accuracy， but also greatly ahead of GPS technology also applied to the control measure of large Since it is unnecessary to tong， can form strong nets， improve accuracy of inspection， via conventional measure fulcrum is GPS technology in the measurement of the tunnel has broad prospect of application， GPS， reduced need through conventional method， the intermediate links， therefore， high speed， high accuracy， significant economic and social A GPS navigation and traffic management in automotive applicationsThree-dimensional navigation is the primary function， GPS， ships， aircraft and ground vehicles pacers can use GPS navigation device for Car navigation system is in the global positioning system (GPS developed on the basis of a new Car navigation system by GPS navigation， self-discipline， navigation and microprocessor， speed sensor， gyro sensor and cd-rom drives， LCD GPS navigation systems and electronic map， radio communication network， computer vehicle management information system， combining can achieve vehicle tracking and traffic management and many other A GPS in long-distance passenger vehicle management application (for example)，In the first set of professional long-haul GPS vehicle management system， and long-distance communication GPS intelligent management system， for example， it is combined with the satellite positioning technology， GPRS/CDMA communications business， GIS， image collection technology， computer network technology， and database in the company to build a passenger control (C/S structure and B/S structure combining)， and the other for points， the public security bureau and control YunGuan departments and departments of the control system， established by the control center system， wireless communication system platform (GPRS/CDMA)， global positioning system (GPS)， four parts and trackside equipment all-weather， a full range of driver and vehicle tracking management platform， System can be registered vehicle dynamic tracking and monitoring implementation， pictures， driving record， management， data analysis and so on the function， monitoring vehicles in electronic map， and display of vehicles running track data， Operating terminal optional internal network or the Internet server to visit and through the center to provide online IE browser integrated passenger management data analysis of the control system (B/S structure)， And the capacity of the system software available according to the center of the hardware configuration and operating terminal server， the most greatly expanded， net vehicles 500，000 can not only is long， can the passenger vehicles such social And the system still can use group management， different types of vehicles into different groups， facilitate the operation GPS technology application examples in the navigatorGPS navigators international leading brand: Ahada YiHang (of) -- from silicon valley， now login China!The core products function:1) map queryA penny saved is a penny gained in operation on a terminal search your destination A penny saved is a penny gained can record you always want to place， and retain information， also can be Shared with others and the location A penny saved is a penny gained fuzzy query your attachment or a location near the station， hotel， such as ATM2) route planningA penny saved is a penny gained GPS navigation system will be set according to the starting point and destination， automatic programming A penny saved is a penny gained planning routes whether can be set to pass some A penny saved is a penny gained planning routes whether can avoid high-speed F3) automatic navigationA penny saved is a penny gained speech navigation:To provide drivers advance in speech， navigation condition intersection traffic information， such as a way to understand the wizard tells you how to drive to the Navigation in one of the most important function， make you need， through watching operation terminal voice prompt can safe A penny saved is a penny gained picture navigation:In the end， will display operate maps and position of the car now， driving speed， the destination of the route， planning， crossing the road to A penny saved is a penny gained redesign line:When you have the line planning， or go wrong when crossing， GPS navigation system according to your present position， for you to plan a new route to the GPS principleGPS navigation system is the basic principle of measuring the satellite to known position of the distance between the user receiver， and then integrated satellite data can know the location of the To achieve this objective， the position of the satellite can according to record the clock time on satellite star found in a Visible GPS navigation system is part of the satellite launch navigation However， due to the use of the user to accept machine with satellite space-borne clock clock synchronization， may not always except user 3d coordinate x， y， z， will also introduce a Δ t is the difference between the satellite and the receiver as unknown， then use four equations will these four So if you want to know， the receiver's place at least four satellites can receive the GPS receiver can receive the GPS clock can be used to accurately on the two levels of second time information， Used to forecast the next few months in the general position of satellite prediction star alex， Can be used to calculate the location for the satellite radio star alex， the coordinates for a few meters to dozens of accuracy of each different， rice (change) satellite， And the GPS system information， such as GPS receiver to code measurement can get satellite receiver， because of the distance to the clock contains receiver satellite transmission error， error and the atmosphere is called 0A yards of measured pseudorange called UA yards pseudorange and accuracy for about 20 meters of P yards， measured pseudorange called P yards pseudorange and accuracy for about 2 GPS receiver of received signal， decoding technology， or other information on the carrier modulation in removed， can restore Strictly speaking， the carrier phase should be called the carrier frequency phase， it is patted the received by doppler frequency influence of satellite signal receiver carrier phase and machine generated signal phase difference General bell in the epoch receiver determined to keep time measurement， satellite signal， it can track record of phase change， but start when the value of the receiver and satellite observations of the oscillator is not know the initial phase of the epoch， also don't know phase integers， namely the fuzzy degrees， only in data processing as Phase observations of high precision and mm， but the premise is a whole week， so only in fuzzy relative positioning， and a continuous observation can use phase observations， and to achieve superior level meters positioning accuracy of also only using phase According to the localization way， GPS positioning and relative into single point positioning (difference) According to a single point positioning receiver is the observation data to determine the position of the receiver， it only USES pseudorange observation， can be used as a compendium of navigation and positioning Relative location (difference) is based on the observation data of two above receiver to determine the relative position between the observation methods， it can be adopted pseudorange observation may adopt phase observation and geodesy or engineering measurement shall be made phase observation value relative In the GPS observation satellite and the receiver is contained in the clock， atmospheric propagation delay， the multipath effect etc， in the positioning error when calculating by satellite radio star alex， the influence of error in relative positioning error when most public offset or weakened by positioning accuracy， so will greatly improve， double-frequency receiver can according to the observation of two frequency offset the atmosphere， the main part of the error of the ionosphere， high accuracy in the distance between the receiver when significant difference (air)， should choose double-frequency
