What is the geomagnetic field

The Earth can be regarded as a magnetic dipole, with one pole near the geographical North Pole and the other near the

geographical South Pole. Geomagnetic field includes basic magnetic field and variable magnetic field. The basic magnetic

field is the main part of the earth's magnetic field, originated in the earth's interior, relatively stable, belongs to the static

magnetic field part. The variable magnetic field includes various short-term changes in the Earth's magnetic field, which

mainly originate in the Earth's interior and are relatively weak.

The reinforced concrete structure of modern buildings can cause geomagnetic disturbance on a local scale, and the

compass may also be affected. In principle, a non-uniform magnetic field environment will produce different magnetic

field observations depending on its path. This positioning technology, known as IndoorAtlas, makes use of such changes

in the geomagnetic field indoors for indoor navigation, and the navigation accuracy can reach 0.1m to 2m (the software

provided by the company can conduct real-time positioning, and the positioning accuracy can reach 2m to 3m after

testing, but when the motion state changes, the positioning accuracy can reach 2m to 3m. The positioning accuracy of

the software is reduced or even unable to locate).

However, the navigation process using this technology is still a little cumbersome. You need to upload an indoor floor

plan to the map cloud provided by IndoorAtlas, and then you need to use its mobile client to physically record the

geomagnetic field in different directions at the target location. The recorded geomagnetic data is uploaded to the cloud

by the client so that others can use the recorded geomagnetic data for accurate indoor navigation.

Before the acquisition of IndoorAtlas, Baidu hoped to implant a geomagnetic positioning scheme in the mobile phone,

but later, there was no later. The main reason is that the acquisition of the initial position is not easy, and it needs to be

effectively solved by other technologies.