How did Hebei trip code appear before Beijing?

The mobile phone has no GPS positioning.

Communication Big Data Travel Card is a free inquiry service provided by China Xintong Institute, China Telecom, China Mobile and China Unicom for mobile phone users in China. Mobile phone users can query all the city information they have visited in the previous 14 days through this service.

As of March 25, 2020, the cumulative number of inquiries has exceeded 450 million.

From 20: 30 on 202118, the city name of the medium-high risk area is no longer marked in red on the travel card, but is marked in brackets after the city name. Precautions are only used as travel tips and have nothing to do with health status.

On March 30th, 20021year, the national government service platform "Epidemic Prevention Health Code" has integrated the relevant information of "Traffic Big Data Travel Card", which can show whether the user has been to medium and high-risk areas and other travel information in the health code, and help the health code "one code pass".

Technical principle:

"Communication Big Data Travel Card" analyzes "mobile phone signaling data", which is obtained through the location of the base station where the user's mobile phone is located. The collection, transmission and processing of signaling data are automatic, with strict security and privacy protection mechanisms, and the query results are available in real time, which is convenient and fast.

The data of "Communication Big Data Travel Card" can be used nationwide to achieve full coverage of a national network, and you can also check the international travel of my domestic mobile phone number. On the premise of ensuring user information security, these will provide scientific and accurate technical support for epidemic prevention and control, resumption of work and production, road traffic, entry and exit, etc.

The data source of the location query service provided by the travel card is "mobile phone signaling data", which is obtained through the location of the base station where the user's mobile phone is located. In order to ensure communication continuity, realize coverage without blind areas and provide better communication service quality, the signals of base stations in the two places at the junction of administrative divisions may cross-cover, resulting in deviation of results. This may happen if the user lives near the city boundary or travels long distances by car or train.