The Big Data Trip Card can only look up information about all the cities and towns I've been to in the previous 14 days, not the exact number of days I've been to a particular place.

The Big Data Trip Card obtains the user's location information through the location of the base station where the user's cell phone is located. It can be used nationwide, truly covering the whole country with one network, and can also check the international itinerary of the user's domestic cell phone number. Since the service uses base station data, in order to ensure the continuity of communication and realize the coverage without blind area, the base station signals of two places at the junction of administrative divisions may overlap, resulting in deviation of the results. Adjustments can be made in conjunction with other certifications when used.