"Where are you, send me a location." When it comes to location, the first thing that comes to your mind may be the location based on the global satellite navigation system. However, the location permission of the mobile phone is a switch, and the corresponding location information cannot be obtained by turning it off. What should we do if we want to get the location at this time?
First of all, we need to know that all mobile phones have four positioning channels, one is satellite positioning, the other is WIFI cell positioning, the third is network IP positioning, and the fourth is base station positioning. For ordinary users, apart from base station positioning that cannot be used autonomously, the other three can be used when conditions are met.
IP positioning is a very broad positioning method. Although GPS positioning, Wifi, and base station positioning technologies are mature now, IP positioning still needs to be relied on when the above information is not available. In addition to this IP positioning has its own unique advantages: short positioning time and low power consumption . The accuracy of IP positioning is generally relatively low, usually in the city area, but some methods can be used to make the accuracy of IP positioning within 1km, which we call precise IP positioning.
Global satellite navigation system
Referred to as GNSS, it refers to all satellite navigation systems. It uses artificial satellites (4 or more) as navigation stations, uses satellite-based radio navigation systems to achieve signal propagation, and completes data correction through the base station's high-precision positioning equipment. Continuous, real-time and accurate three-dimensional navigation positioning and speed measurement within the range.
GNSS includes three categories: global, regional and enhanced, and is a complex combined system with multiple systems, multiple levels, and multiple modes. There are currently 4 global satellite navigation systems: GPS in the United States, GLONASS in Russia, Galileo in the European Union, and BeiDou in China; 2 regional systems: QZSS in Japan and IRNSS in India; and 5 related augmented systems: WAAS (Wide Area Augmentation System) in the United States, EGNOS (European Geographic Navigation Overlapping System) in Europe and MSAS (Multi-Function Transport Satellite Augmentation System) in Japan, GAGAN in India and NIGCOMSAT-1 in Nigeria, etc.
What we usually call GPS is usually only the part of the user equipment. It determines the location of the handheld by receiving signals from more than three satellites in different positions in the sky. In simple terms, it uses the principle of three lines in mathematics to determine a point.
IP positioning
IP positioning technology is a technology used to determine the geographic location of IP devices. In recent years, network applications based on geographic location have emerged one after another, mainly including targeted advertisements, social networks, network security, performance optimization, etc.
In an IP positioning system or algorithm, it generally includes four elements: positioning server, measurement node, node to be located and infrastructure.
The basic principle of IP positioning is to use the name, registration information, or delay information of an IP device to estimate its geographic location.
The basic principle of IP positioning algorithm design is: under the premise of ensuring positioning accuracy, try to reduce the measurement overhead, while having good scalability and protecting user privacy. The original location algorithm inferred the geographic location of the IP device by querying the DNS server or mining the information implicit in the host name. After that, some positioning algorithms estimate the location of the host based on the linear relationship between delay and geographic distance, and use topology information to reduce positioning errors.