Reasons for identifying the current location with a PC without GPS: The story behind a personal computer revealed by the "middle person"

　Hello. I'm Tomoyuki Shiraki, and I'm in charge of product planning at HP Japan. Have you ever been surprised to see your current location when you open a map on your PC browser? It's a common function for smartphones equipped with GPS, but some people may wonder, "Can a PC know the current location?" This time I would like to cut into such a simple question.

What is the familiar "GPS: Global Positioning System"? It is said that GPS was originally developed for military use in the United States, but in fact, GPS has been incorporated into consumer devices and other devices since before the era of feature phones, not to mention smartphones, and has become a familiar presence for ordinary people.

　Just like in a spy movie, it's wonderful that you can pinpoint where you are basically anywhere on earth, whether it's deep in the jungle or on the Pacific Ocean, as long as you can see the sky.

Indispensable for ships

　GPS is sent from artificial satellites orbiting the earth "satellite position information" and "the time when radio waves including that position information were emitted" to locate yourself. By receiving radio waves from four or more satellites at once, the current position (latitude and longitude) can be determined.

This is a bit of a digression, but as explained in the general theory of relativity, gravity is different on Earth and in outer space, and the latter is slightly faster. Even if you use an accurate clock, there will always be an error, so it seems that the artificial satellite operates while automatically correcting the clock error. From this story, I feel a little romantic about GPS.

The only information that can be obtained with GPS is latitude and longitude. By applying this number to the map obtained from the Internet, we users will be able to use it conveniently and easily.

　By the way, GPS is called A-GPS, "a type that determines the position by combining satellite orbital data sent from mobile base stations and GPS time signals" and "satellite orbital data sent from satellites" and a standalone that uses the GPS time signal.

In the case of standalone, it takes time to complete the first positioning after turning on the power, but you can determine the position even if you are not connected to the internet. In the case of A-GPS, the satellite orbit data necessary for GPS positioning can be obtained from mobile base stations at high speed, so positioning can be performed quickly after turning on the power.

　Although GPS is indispensable for mountaineering and sailing, it also has its weaknesses.

The weak point of GPS is... the city?

Have you ever used a car navigation app on your smartphone and when you enter a tunnel or under an overpass, have you ever experienced that the icon of your car displayed on the map stopped moving forward? Radio waves emitted by satellites have difficulty reaching underground, under elevated tracks, inside buildings, and in the shadows of buildings. Simply put, GPS is “not good at cities”.

　In the case of a dedicated car navigation system, when position information cannot be obtained from GPS, the car It continues to identify the position based on information such as direction, tilt, and speed from the vehicle speed signal, gyro sensor, and acceleration sensor.

　In the case of PCs, there should be a relatively large number of indoor uses, so situations where GPS is actively used will be limited. Even if you look around the PC market, you will hardly see a PC with a built-in GPS. So how can a PC get its current location?

There are various ways in which a PC can obtain its current location

　Actually, in situations where GPS is unreliable (= not equipped with), PCs and tablets, like car navigation systems, can use Wi-Fi, mobile phones, etc. The current location is determined using the location information of the telephone base station and the IP address information of the network.

　The reason why location information can be obtained from Wi-Fi is that platformers such as Google and Apple have built a database that links the MAC address and location information unique to Wi-Fi devices, and it is because you can refer to it. This information is updated frequently and is very accurate.

　Wi-Fi and mobile base station radio waves have a limited reach, so it can be inferred that the user is within that range. Wi-Fi is also very useful in places where GPS is not available, such as inside buildings, buildings, and underground.

　Compared to mobile base stations, Wi-Fi radio waves do not reach very far, so it is possible to pinpoint a more accurate position.

　The IP address can be roughly determined from the provider's location information. It is used for purposes such as displaying web advertisements with content closely related to the region.

　These location information can be used by developers via apps and browsers as the "Geolocation API". Even if GPS location information cannot be obtained, it can be used conveniently, such as displaying content according to the current location.

Then, some of you may be wondering, "What is the reason for the existence of GPS?" It's all about accuracy. As long as the radio waves from the satellite are acquired, the current position can be determined most accurately.

　With work style reforms, there will be more and more opportunities to bring out mobile PCs. Under such circumstances, location information will also be used for purposes such as work efficiency and security. In such a case, I would be pleased if you could refer to what you should consider as a means of acquiring location information.

Author: Tomoyuki Shiraki

Japan HP PC & Tablet Evangelist. He belongs to the Personal Systems Business Headquarters and is in charge of product manager (product planning) and business plan (sales planning) for tablet products for corporations. The theme is to provide the essence for realizing better work styles in the modern age of globalization by widely communicating the fun and splendor of PCs and tablets.

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