Usage Classification This receiver is mainly used for the navigation of mobile carriers, and can give the position and speed of the carriers in real time. This kind of receiver generally adopts C/A code pseudorange measurement, and the single point real-time positioning accuracy is low, generally 10 m, and 100 m when there is SA influence. This kind of receiver is cheap and widely used. According to different application fields, this kind of receiver can be further divided into:
Vehicle-mounted-used for vehicle navigation and positioning;
Nautical type-used for navigation and positioning of ships;
Aviation type-used for aircraft navigation and positioning. Because of the fast running speed of aircraft, it is required that aviation receivers adapt to high-speed movement.
Spaceborne-used for satellite navigation and positioning. Because the speed of the satellite is above 7km/s, the requirements for the receiver are higher. This kind of receiver mainly uses the high-precision time standard provided by GPS satellites to serve time, and is often used for time synchronization in observatory and radio communication.
According to the carrier frequency of the receiver, the dual-frequency receiver can receive both L 1 and L2 carrier signals. By using the difference of ionospheric delay between two frequencies, the influence of ionosphere on electromagnetic wave signal delay can be eliminated, so the dual-frequency receiver can be used for accurate positioning for thousands of kilometers.
Classification by number of receiver channels
A GPS receiver can receive signals from multiple GPS satellites simultaneously. In order to separate the received signals from different satellites and realize the tracking, processing and measurement of satellite signals, the equipment with this function is called antenna signal channel. According to the channel types owned by the receiver, it can be divided into:
Multichannel receiver
Sequential direct communication channel receiver
Multichannel receiver
4.2.4 Classification according to working principle of receiver
Code correlation receiver
The code correlation receiver uses code correlation technology to obtain pseudo-range observations.
Square receiver
The square wave receiver uses the square wave technology of the carrier signal to remove the modulation signal to recover the complete carrier signal. The phase difference between the carrier signal generated in the receiver and the received carrier signal is measured by a phase meter, and the pseudo-range observation value is determined.
Hybrid receiver
The instrument combines the advantages of the above two receivers, and can obtain both code phase pseudorange and carrier phase observation.
Interference receiver
This receiver uses GPS satellite as radio source and uses interferometry to measure the distance between two stations.
After more than 20 years of practice, it has been proved that GPS system is a high-precision, all-weather and global multifunctional radio navigation, positioning and timing system. GPS technology has developed into a multi-field, multi-mode, multi-purpose and multi-mode international high-tech industry. According to the purpose and accuracy, it can be divided into static (single frequency) receiver and dynamic (dual frequency) receiver, namely RTK.
In the development and practical application of GPS technology, internationally renowned manufacturers include Trimble Navigation Company of the United States, Leica Geosystems of Switzerland, TOPCON Company of Japan, Magellan Company of the United States (formerly Terez Navigation) and Huace Navigation Company of China.
Tianbao's GPS receiver products mainly include SPS75 1, SPS85 1, SPS78 1, SPS88 1, R8, R8GNSS, R7, R6, 5800, 5700 and so on. As the holding company of the US military, it is one of the earliest GPS research and production enterprises in the world. Among them, SPS88 1 R8GNSS is a 72-channel GPS/WAAS/EGNOS receiver, which integrates a tri-band GPS receiver, a GPS antenna, a UHF radio and a power supply into a pocket unit, and has a super-tracking technology of Trimble Maxwell 5 chip. Even in the harsh electromagnetic environment, it can still provide effective tracking of satellites with less than 2.5 watts of power. At the same time, in order to expand the operation coverage and reduce the error in an all-round way, the mode of multi-reference stations with the same frequency can be adopted. In addition, it is fully compatible with Trimble VRS network technology, and its built-in WAAS and EGNOS functions can provide real-time differential positioning without reference stations. SPS75 1, SPS85 1 and SPS55 1 also have the function of receiving differential correction information of satellite stations, and the single-machine positioning accuracy can reach up to 5cm.
Leica Geosystems is a world-famous professional surveying company, which not only has great influence on the industry in terms of total station and camera, but also has made great contributions to the development and application of surveying GPS. It is a pioneer of fast static and dynamic RTK technology. The receivers in its GPS 1200 system include GX1230gg/atx1230gg, GX 1230/ATX 1230, GX 1220 and GX/220.
The GPS receivers produced by Topcon Japan mainly include GR-3, GB- 1000, Hiper series, Net-G3, etc. The GR-3 earth receiver can be 100% compatible with all available signals of the three major satellite systems (GPS+GLONASS+ Galileo). It is not only the first manufacturer in the world to develop a dual-star technology that can receive both American GPS and Russian GLONASS signals, but also the only receiver technology in the world that can receive all GNSS satellites at the same time. There are 72 super-tracking channels, and each channel can independently track three kinds of satellite signals. It is designed to resist a 2-meter drop, support Bluetooth communication and has a built-in GSM/GPRS module (optional). Static, fast and static accuracy: 3mm+0.5ppm horizontally and 5 mm+0.5 ppm vertically; RTK accuracy: horizontal 10mm+ 1ppm, vertical15 mm+1ppm; DGPS accuracy: better than 25 cm.
The GNSS receiver of the mid-range navigation mainly includes i80 Beidou full-constellation miniaturized intelligent RTK, N72 network reference station receiver and X9 1 full-constellation RTK. High-precision domestic products licensed by the People's Republic of China for manufacturing measuring instruments. Among them, i80 is a 220-channel Samsung eight-band GNSS receiver, which is integrated with imported card, full-band GNSS antenna, UHF radio, imported multimode Bluetooth, intelligent dual battery, with a diameter of 12.4cm, a horizontal dynamic accuracy of 8mm+ 1ppm and a vertical dynamic accuracy of 65438. Static accuracy: horizontal 2.5mm+0.5ppm, vertical 5mm+0.5ppm, built-in transceiver, which can reach the range of 2-8 kilometers (due to the difference of actual geographical conditions), and can not only withstand falling from 3 meters to hard ground, but also immerse in the depth of 1 meter. X9 1 has many measuring modes, such as static, fast static, RTK, PPK and code difference. The accuracy ranges from millimeter level to sub-meter level, which can be combined with mainstream instruments such as Tianbao and Leica, breaking the technical barrier of joint measurement with imports. The receiver of N72 network reference station has been built in 15 province, which provides high-precision positioning and the calculation software is stable and reliable.
Similar to car GPS terminals, there are also positioning mobile phones and personal locators. Because GPS satellite positioning needs third-party positioning service, it needs to pay different monthly/annual service fees.
All GPS positioning terminals have no navigation function. Because hardware and software need to be added, the cost is increased.
The car GPS advertisement we saw on TV is completely different from the car GPS above. It is a GPS navigation product. When navigation is needed, locate first, which is the starting point of navigation. This is different from real GPS positioning. It can't transmit the positioning information to the third party and the holder, because the navigator lacks the function of the mobile phone. For example, if you put the navigator in the car, your friend borrowed the car, and the navigator can't send you a message, then you can't find the location of the car. So the navigator can't locate it.
You said I bought a navigation phone, right? Think about it. If you leave your navigation phone in the car, will that phone call you or send a text message to a third party? It needs people to operate it. Therefore, the navigation terminal has no positioning function.
The navigation terminal can navigate the route, so that you don't get lost in a strange place, draw the route to your destination, tell you the current location, surrounding facilities and so on.
China has gained a huge market in the application of global positioning system. Many of them are navigation companies, but some of them are engaged in positioning management of GPS industry.
Various GPS/GIS/GSM/GPRS vehicle monitoring system software, the secondary development of GSM and GPRS mobile intelligent vehicle terminals, and the overall construction scheme of vehicle monitoring system. The system is widely used in public security, medical treatment, fire protection, transportation, logistics and other fields. This solution is based on NXP's PNX 1090 Nexperia mobile multimedia processor hardware and software, and is jointly developed by NXP and partner ALK Technology. NXP claims that this solution provides designers with everything they need to build a low-cost portable media player with navigation function and rich multimedia functions, including MP3 playback, standard and high-definition video playback and recording, FM radio, image storage and games. NXP uses its swGPS personal software running on PNX0 190 to realize GPS calculation, thus replacing a GPS baseband processor, thus reducing BOM cost and supporting field upgrade.
After GPS, a series of related applications are designed to mathematics and algorithms, as well as GIS system, map projection and coordinate system transformation!
Due to the error of satellite orbit and satellite clock, the influence of atmospheric troposphere and ionosphere on signals, and artificial SA protection policy, the positioning accuracy of civil GPS is only 100 meters. In order to improve the positioning accuracy, differential GPS(DGPS) technology is widely used to establish a reference station (differential substation) for GPS observation. By comparing the precise coordinates of the known reference station with the observed values, a correction number is obtained and released to the public. After receiving the correction number, the receiver compares it with its own observation value to eliminate most errors and get a more accurate position. Experiments show that using differential GPS(DGPS) can improve the positioning accuracy to 5 meters. The GPS early warning device is completed by setting coordinates in the GPS early warning device through GPS satellites. For example, if you encounter an electronic eye, set a coordinate directly below the electronic eye through related equipment. In this way, when the early warning device loaded with coordinate point data reaches this point, it will start the early warning about 300 meters before reaching the coordinate point, telling the owner that there is an electronic eye in front to measure the speed, so as to play an early warning role. This accuracy is related to the number of data points, mainly using satellite positioning.
Test the machine to distinguish the true from the false.
With the help of a friend in a car beauty shop, the reporter selected four so-called "GPS early warning aircraft", and through investigation and trial comparison, it was confirmed that one of them was an "electronic dog" with fake GPS. And draw the following conclusions:
A.GPS early warning device: one early warning point gives an alarm once and gives one-way early warning; Fixed-point alarm without interference; The accuracy of early warning can reach over 98%. There are many kinds of music and voices to choose from, and the sound quality is good.
B. False GPS early warning device: the same early warning point gives an alarm twice (both when driving to and leaving the early warning point give an alarm); Will be disturbed by some public facilities such as electric towers and send out false alarms; There are many omissions and the accuracy rate is less than 70%; The music and voice of alarm clock are single and the sound quality is poor.
GPStar intelligent GPS system
It is mainly composed of local monitoring center software management platform and remote GPS intelligent vehicle terminal. The remote GPS intelligent vehicle terminal feeds back the position information, driving speed and driving track of the vehicle to the monitoring center. After receiving these data, the monitoring center will analyze and compare them immediately, and display the processing results to the administrator in the form of normal information or alarm information, and the administrator will decide whether to take necessary measures for the target vehicle.