From GPS to RFID, the growing number of positioning technologies
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[Abstract] Finding what you need among many similar things is a problem that many people often encounter in life. For example, the trouble I often encounter when I go to school is: finding my own bicycle among dozens or even hundreds of bicycles. This trouble is particularly prominent after snowing because these bicycles look so similar. Finding what you need among many similar things is a problem that many people often encounter in life. For example, the trouble I often encounter when I go to school is: finding my own bicycle among dozens or even hundreds of bicycles. This trouble is particularly prominent after snowing because these bicycles look so similar. Nowadays, there is a technology that can help people solve the problem of "finding things", which is positioning technology - using information technology to tell users the location information of an object. The most professional positioning system is the Global Positioning System (GPS) , and many industries including military, law enforcement, bus dispatch, taxi dispatch, logistics, and planning are users of the global positioning system. The global positioning system is very accurate, but the system is relatively complex. For ordinary users, positioning technologies based on mobile phones and radio frequency tags can also be considered. GPS, the king of positioning GPS is a system developed by the United States since the 1970s. This system, which took 20 years and cost 20 billion US dollars, was completed in 1994. The system provides information from 24 satellites located in the sky. Each satellite is evenly distributed on 6 orbital planes at an angle of 55 degrees and orbits the earth in a period of 11 hours and 58 minutes. Each satellite carries position and time signals. The client's GPS device can receive signals from at least 5 satellites anywhere on the earth. GPS is a new generation of satellite navigation and positioning system with all-round real-time three-dimensional navigation and positioning capabilities in the sea, land and air. After more than ten years of use by many professional departments around the world, it has been shown that GPS has significant characteristics such as all-weather, high precision, automation and high efficiency. Nowadays, the size of GPS client receivers is constantly shrinking, and the accuracy of the client is getting higher and higher. It has even appeared in some high-end mobile phones, laptops and other electronic products. Popular tools - mobile phone positioning GPS is powerful, but it requires special client devices to use, which is not conducive to its popularization among a wide range of people. However, in areas such as emergency services, users often urgently need to know their geographic location. Therefore, some countries have begun to consider using mobile phones, a highly popular terminal device, to provide positioning information. The US Communications Commission passed the Enhanced 911 Act in 1996 (revised again in 1999), which requires mobile phone operators to know the geographic location of each mobile phone (within an error of 50 to 100 meters). Any mobile phone that dials the US emergency service number 911 will have its location known by the government, even if the user himself does not know where he is. This act forced telecom operators to develop mobile phone positioning systems. In the mobile communication network, the earliest positioning technology was based on base station codes. The network side obtained the information of the base station where the user was currently located to obtain the user's current location. Its accuracy depended on the distribution of mobile base stations and the size of the coverage area. It could reach several kilometers in urban areas, while the error in suburban areas could be more than ten kilometers. In order to improve the accuracy of positioning, operators began to consider trigonometric positioning, which is a kind of positioning technology of the cellular phone network itself. It uses the time difference between the time when the mobile phone receives the signals sent by different base stations to reach the mobile phone, and calculates the longitude and latitude of the user through algorithm software. Today, the most advanced mobile phone positioning technology is Qualcomm's GPSone technology , which is a hybrid positioning technology that uses the global positioning system and the mobile phone positioning system. When the global positioning system satellite line of sight is fully/partially blocked, CDMA triangulation positioning technology is used for auxiliary positioning, so that the advantages and disadvantages of the two positioning technologies in different positioning environments can be complemented. Positioning the rising star - RFID In addition to mobile phone positioning technology, radio frequency tag (RFID) positioning technology is also an area that ordinary people can pay attention to. It can be arranged by users themselves in specific areas for positioning, such as parking lots and ski resorts. After placing RFID tag readers at specific locations in these areas (such as key entrances and exits), the system can detect the location of objects with RFID devices in real time. The principle is similar to arranging many guards at key locations to register passing items. When you need to find a specific object, you only need to query the registration information of the guards. From the medical sector to the manufacturing industry, RFID positioning systems have appeared in places where real-time data is important and where positioning is required during transportation . For example, some hospitals in the UK use RFID positioning systems to locate and track medical devices and healthcare equipment to reduce the occurrence of incidents such as theft of medical devices and equipment; Toyota has established an RFID positioning system in the automotive logistics supply chain, which reduces labor costs, automates work processes, and tells employees where to pick up cars; a ski resort in Colorado, the United States, is the first ski resort in the world to equip tourists with positioning devices. After tourists wear a watch strap with built-in RFID at this ski resort, they will be detected by readers throughout the ski resort. Using this system, tourists can know the location of their partners at the ski resort. The RFID positioning system does not require the cooperation of satellites or mobile phone networks. Its accuracy lies in the distribution of RFID readers, which can be set by the user according to actual needs. It is very suitable for users who only need to locate in a specific area and has extremely high practical value. According to a survey, in 2005 alone, the number of companies using RFID positioning technology in the world increased by 3 times compared with the previous year. Source: Guomen Times E Weekly
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