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[Editor's note]
In "Mobile Phone Positioning 20.1-1-18", Wang Ning, deputy director of the Academic Committee of Data Recovery Sichuan Key Laboratory and senior engineer of Information Security Technology of a former research institute, introduced the way of mobile phone positioning (GPS positioning, LBS base station positioning, WiFi positioning technology, A-GPS positioning, GPS-one positioning) and how to identify the mobile station (mainly including IMEI code, MEID code, IMSI code and MAC address). In this issue, we will introduce the collection method of mobile phone geographic location data.
News Replay: "Connect New York Plan" to convert the phone booth into a WiFi hotspot
According to foreign media reports, New York intends to implement the "Connect New York" (LinkNYC) program, which has been brewing for many years, to transform the city's 7,500 telephone booths into WiFi hotspots to create the world's largest and fastest city WiFi network. It is reported that each hotspot covers an area of ​​about 150 feet, and the data transmission speed is 1GB per second, which is 20 times faster than the average home Internet speed, which can help users save mobile phone data usage. Some people have expressed their welcome to this plan. They believe that public WiFi allows users to access the Internet without any need to worry about the data limit of telecommunications service providers. However, many people also expressed concern that the connection to the public network will lead to the leakage of mobile data.
Professional interpretation: 5 common methods for collecting geographic location data
For the "Telephone Pavilion Modification WiFi Hotspot" program promoted by the New York City government, why do many people express concern that this plan will lead to the leakage of mobile phone data? In fact, such concerns are not "a worry." Because the mobile phone uses the WiFi to locate the location, both the mobile phone user actively searches for the geographical location information generated by the WiFi hotspot, and the mobile phone user automatically scans the geographical location generated by the Wi-Fi hotspot without the knowledge of the mobile phone user. The location information data is located, and the geographical location data generated by the passive positioning of these mobile phone users is likely to be leaked without the user's knowledge. Here's a detailed explanation of the five common methods for collecting geographic location data:
1, GPS positioning data
The pure GPS solution and the latitude and longitude coordinates it generates are recognized standards for geographic data and are the basic way most smartphones get their geographic location. As long as the user turns on the GPS positioning function, the mobile phone can obtain relevant positioning data.
2. Base station signal tower data
When the GPS chip of the mobile device cannot receive the GPS signal, the mobile device needs to communicate with the cell tower to which it is connected and estimate the distance between them, and continuously report its geographical location, despite the geography obtained by this method. Location data is not as accurate as pure GPS data. The geographical coordinates of the base station signal tower are known fixed reference data, and now it is not only mastered by mobile communication operators, but has become public data. The national base station database on the Internet can be downloaded free of charge (as shown below).
3, WiFi hotspot data
This is a method of accurately obtaining geographic location data that requires the use of an effective WiFi hotspot. As mentioned in the previous chapter on WiFi positioning, since the location service is built in various mobile operating systems, the smart phone automatically scans nearby hotspots and uploads its location information (Mac physical address) when it is turned on. A huge hotspot location database is built into the location server in the network. This database is the key to positioning users. If your smartphone is connected to a Wi-Fi hotspot, you can call the geographic location information of all the hotspots near the mobile phone, and the server will calculate the approximate geographic location of the device by referring to the signal strength of the mobile phone relative to each hotspot. .
Such location service providers used to have only Skyhook and Google. Now Baidu has joined the ranks (as shown below), and their way of collecting location data is similar:
1. Active acquisition - Google's Street View car also has an important function is to collect wireless signals along the way, and mark the coordinates of the GPS positioning back to the server.
2. User Submission - Android mobile phone users will be prompted to allow Google Location Services to collect anonymous location data when "Use Wireless Network Location" is turned on. Some mobile phones using Baidu location service will have similar tips for collecting anonymous location data.
The principle of WiFi hotspot data collection is like this: If your home has a wireless router set up by yourself, you can always turn it on. Your neighbor is playing Google Maps on your mobile phone on the balcony. It happens that his mobile phone wifi is on, but there is no hotspot connected to your home. . When your neighbors use GPS to accurately locate on the map, the Google server will record the surrounding wifi hotspot information. At this point, your router is open and the MAC address is logged to the database. After a few days, you have to find a place, so connect your router to open Google Maps and search for it. Then you will be surprised to find that although you don't have GPS, your location is precisely located in your home. This is because, after you open Google Maps, it will upload the surrounding wifi hotspot information, and the MAC address of your router will also be uploaded to the server. Based on this address, the server will feedback the latitude and longitude of your neighbors using GPS to give you accurate Match the location. When thousands of people repeat the above positioning method, Google can build a rich and powerful wifi hotspot location database. Now for most APP providers, there is no need to collect WIFi location data like Skyhook and Google, and you can buy it on the Internet (see screenshot below).
The advantages of WiFi positioning are: 1 high precision, WiFi-intensive, crowded places are quite accurate; 2 speed is fast; 3 surrounding wifi can be located even if it is not connected. The premise is: Turn on WiFi! This is why many mobile phone users often encounter pop-up prompts to open WiFi when using location.
4, IP address location data
Whether it is wired Internet or mobile Internet, various network devices such as base stations, gateways, switches, routers, desktops or portable computers are assigned their own IP addresses, and the location of IP devices is fixed in a small local area. The geographic location of the mobile phone can also be obtained from the IP addresses of these networks when data is connected to these devices. Now there is a service on the Internet that specifically queries the geographic location by IP address (as shown below).
Some service providers also provide an IP address entry to the library when there is no IP address you enter in their IP address pool. This is similar to the Goole map providing the same name tagging function to collect IP geographic data (as shown in the figure below). Show):
In addition to the fee-based services, there is also a free IP address inquiry service. Taobao has a powerful free IP address database, and the update is also very timely (as shown below).
5, the location data reported by the user
When users sign up for email or mobile apps and services, they typically enter their location and postal code. In particular, when the user opens the "Location Service" function of the mobile phone, the location service module embedded in the mobile phone operating system automatically uploads the identification and location data of the mobile phone itself and the surrounding signal device, and the data can be converted into the latitude and longitude coordinates. To establish a geographic location file for the user group.
summary
This issue of the article details the five major collection methods for mobile phone geographic location data: GPS positioning data, base station signal tower data, WiFi hotspot data, IP address location data, and user-reported location data. In the next article, we will explain the generation and extraction of mobile phone traces, so stay tuned!
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