With the constant development of traffic, road networks become complex and positioning technology emerges. Except for the traditional compass and map, there is something very advanced, and GPS tracker and mobile phone location. However, the two things work differently. And they come with different positioning accuracy and reaction time.
Mobile phone service also know the location of the LBS – Location Based Services. You get the location information (latitude and longitude) of mobile terminal users through the network of mobile telecommunications operators as GPS Base Station.
Backed by the platform of electronic maps, the value added service provided to users. For example, China Mobile M-zone users’ location offers research services.
What is the first substantial work? The phone will win different TOA (Time of Arrival) by measuring the downlink pilot signal from different base stations. By using trigonometry formula, usually can calculate the location of phones based on the measurement result and base station coordinates.
As for the current estimation algorithm, the location information of more than three stations should be considered. Therefore, the algorithm is much more complicated. In general, the more the stations are measured, the greater the accuracy. And the location capability is greatly improved.
At present, the location of mobile service is limited to positioning. You can provide users with information about the market and a restaurant surrounded by electronic mapping service. It can not provide air navigation services.
GPS-Global Positioning System consists of three sections: square constellation of GPS satellites, ground control system and the GPS receiver. What is the basic principle of GPS position? The satellite ephemeris parameter sent and messages in constant time.
After receiving the signal, the GPS receiver will resolve the location of the receiver based on the formula of trigonometry. 2D positioning can be achieved with three satellites. The 3D position can be achieved with four satellites. The instructions on movement and speed can be calculated based on updated information from the receiver.
There are 24 GPS navigation satellites in six orbital diffusion. There are four satellites in satellite or at least eleven more on the horizon at any time at all. So GPS tracking is finely guaranteed. The GPS receiver is working to capture and deal with the satellite signal. The real-time 3D position and velocity can be calculated.
The mobile position is strongly influenced by the environmental factor is based on the existence of mobile communications base station. In the suburbs and rural areas, rang placement is 10 to 20 meters. Since there are many tall buildings in cities, the signal is difficult to convey. The range is 100 to 200 meters. The positioning response time is about 3-6.
The monitoring system is out of the question in the area where there can be no mobile signal received. However, as the GPS Base Station is covered by at least four satellites at any time, the signal is guaranteed. As the satellites are dominant, the long-range accuracy is a few meters to several meters.
| GPS Base Station |
