With your cell phone turned off, you can't check your trip history.

The principle of cell phone positioning is to use the base station to measure the distance to the cell phone to determine the location of the cell phone, the accuracy of this positioning method is very dependent on the distribution of base stations and the size of the coverage area. The "Big Data Itinerary Card" is green, meaning it has not traveled to or through a high-risk area in 14 days.

It should be noted that the color card is only a reminder of the place of visit, not associated with the health status, the health status is still checking the eight Min health code, green code on behalf of the health status verification did not see any abnormality. It is reported that the "communication big data trip card" service by the China Communications Research Institute, China Telecom, China Mobile and China Unicom jointly provided.

The trip track is introduced as follows:

If there is a color display error, a problem with the trip query, or a question about the trip, the user can call the customer service hotline of the respective operator (Telecom 10000, Mobile 10086, Unicom 10010) for advice.

The user's number can be used to assess the close contact with the population, whether or not they have been present in high-risk areas, and also to assess the location of the user and the distance from the nearest neighborhood where the outbreak has occurred. In addition to telecom cell phone users, mobile and Unicom cell phone users can also query the personal activity track.