What do sid, nid and bid in the telecom base station positioning API stand for respectively?

SID is the system identification code, and there is only one for each prefecture-level city.

NID is a network identification code, which is managed by the local network, that is, distributed by local branches. There may be one or three in each prefecture-level city.

BID stands for a certain cell in the network, which can be understood as a base station.

First, the base station positioning

Base station location is generally applied to mobile phone users, and mobile phone base station location service is also called LBS-Location Based Service. It is a value-added service that obtains the location information (latitude and longitude coordinates) of mobile terminal users through the network of telecom mobile operators (such as GSM network), and provides corresponding services for users with the support of electronic map platform, such as the dynamic location query service provided by China Mobile M-Zone at present.

Second, the principle

The general principle is that mobile phones measure downlink pilot signals of different base stations to obtain TOA (Time of Arrival) or TDOA (Time Difference of Arrival) of downlink pilot signals of different base stations. According to the measurement results and the coordinates of the base station, the location of the mobile phone can be calculated by using the triangle formula estimation algorithm. The actual location estimation algorithm needs to consider the situation of multiple base stations (three or more), so the algorithm is much more complicated. Generally speaking, the more base stations a mobile station measures, the higher the measurement accuracy and the more obvious the improvement of positioning performance.