You can quickly install a mobile tracking application on your smartphone, and use your mobile phone number to locate and find the specific location of the other party. It can track your child's location on the map at any time, protecting your family and children from cyber violence. You can check your family's information on your computer or mobile phone at any time, even if you are not around them, you can feel at ease.
- Mobile phone positioning
Track the real-time location and historical trajectory of the target mobile phone, support base station positioning, WIFI positioning, GPS satellite positioning and cell phone number positioning. - Location andmap
View the current location of all family members instantly. The history of all past locations will also be saved. - SMS monitoring
Identifiesmobile phone text messages and chat records, intercepts and alarms harmful messages and blocks the communication of harmful number segments. - Call record
Monitor the call history and content of the mobile phone, and intelligent voice recognition of the call content. - Application monitoring
Monitor theinstallation of application programs on controlled devices, report and limit usage time and frequency. - Chat behavior monitoring
Monitor mobile phone chat conversations, mobile phone screenshots, and social media application messages. - Website browsing monitoring
Record the websites visited by the mobile phone, including the URL and time.
Mobile Phone Spy App
What is mobile location technology?
Mobile phone positioning technology refers to a technology or service that uses a specific positioning technology to obtain the location information (longitude and latitude coordinates) of the phone, and to mark the location of the positioned object on an electronic map, or a technology that uses GPS and base stations to locate the phone . The GPS-based positioning method uses the GPS positioning module of the mobile phone to send its position signal to the server to realize the mobile phone positioning. Base station positioning uses the base station to measure the distance and finally determine the location of the mobile phone. The latter does not require the mobile phone to have GPS positioning capabilities, but the accuracy largely depends on the density of the base station, and the error sometimes exceeds one kilometer. The former has higher positioning accuracy. In addition, there is a way to use Wifi to locate in a small area.
Analysis of GSM mobile phone positioning technology
GSM mobile phone positioning methods can generally be divided into two types: network-based and terminal-based. Technically, it can be divided into three methods: Time of Arrival (TOA), Enhanced Measurement Time Difference (E-OTD) and GPS Assist (A-GPS).
TOA positioning technology
The TOA positioning method can be implemented on any existing mobile phone without any changes to the mobile phone. Specific implementation steps:
- The mobile phone to be located sends out a known signal, and three or more LMUs receive the signal at the same time. The known signal is an access burst signal sent out when the mobile phone performs asynchronous handover;
- After each LMU obtains the absolute GPS time when the signal arrives, the relative time difference (RTD) can be obtained;
- Based on the information in the first two steps, SMLC performs pairwise comparisons, calculates the time difference of arrival of the burst signal (TDOA), obtains the precise position, and returns to the application. To calculate the precise position of the mobile phone through triangulation, two other parameters must be known: the geographic location of the LMU and the time offset between each LMU. For example, the absolute GPS time that each LMU must provide, or the actual time difference (RTD) parameter can be obtained by placing a reference LMU at a known location. The LMU uses the access burst signal to determine the TOA. When a positioning request is issued, the LMU is selected and configured with the correct frequency to receive the access burst signal. At this time, the mobile phone transmits up to 70 access pulses (with a duration of 320 ms) at a specific power on the service channel (which may be in a frequency hopping mode). Each LMU implements and improves TOA measurement results in a variety of ways. Using the received burst signal can improve the probability of measurement success and measurement accuracy. Using diversity technology (such as antenna diversity and frequency hopping) can reduce the impact of multipath effects and improve measurement accuracy. When an application needs to know the location of the mobile phone, the application sends a request to SMLC, and at the same time informs the mobile phone number and positioning accuracy requirements. The measured TOA parameters and their error values are collected and sent to the SMLC. Based on the data, the SMLC can calculate the location of the mobile phone required by the application, and then send the location information and error range back to the application.
The TOA positioning method requires additional hardware (LMU) to accurately calculate the arrival time of the burst signal. There are many ways to realize it: LMU can be integrated in the BTS or as a separate device. When the LMU is used as a separate device, it can have a separate antenna or share an antenna with the BTS to realize inter-network communication through the air interface.
E-OTD positioning technology
Specific implementation steps: E-OTD positioning method is developed from the measurement of time difference (OTD), OTD refers to the amount of time obtained by measurement, and E-OTD refers to the method of measurement. The mobile phone does not need to attach any hardware to get the measurement results. For a synchronous network, the mobile phone measures the relative arrival time of several BTS signals; for a non-synchronous network, the signal also needs to be received by an LMU with a known location. Once the signal transmission time from the BTS to the mobile phone is determined, the geometric distance between the BTS and the mobile phone can be determined, and then the calculation is performed based on this distance to finally determine the location of the mobile phone. Specific implementation steps:
- The mobile phone receives the signal from each base station and gets the TOA parameter; the LMU gets the RTD parameter;
- The mobile phone transmits TOA and RTD parameters to the GSM network.
- OTD measurement requires synchronous, standard and analog pulses. When the frames sent by the BTS are not synchronized, the network needs to measure the RTD between the BTSs. In order to perform accurate triangulation, both OTD measurement and RTD measurement (when non-synchronized BTS) require 3 BTSs. After obtaining the OTD parameters, the location of the mobile phone can be calculated either in the network or in the terminal (the mobile phone is required to have various necessary information). The former is called mobile phone assisted mode, and the latter is called mobile phone autonomous mode. The position calculation is realized through the position calculation function module in the mobile phone or the network.
A-GPS principle
The implementation steps of GPS-assisted positioning are as follows: GSM network receives GPS auxiliary information; GSM network sends auxiliary information to mobile phone; mobile phone obtains GPS information, calculates and obtains its precise position; mobile phone sends position information to GSM network. There are two methods for this method: mobile phone assistance and mobile phone autonomous:
Mobile phone assisted GPS positioning
This solution is to transfer most of the functions of the traditional GPS receiver to the network processor. This method requires equipment such as antennas, RF units, and data processors. The GSM network sends a string of very short auxiliary information to the mobile phone, including time, visible satellite list, satellite signal Doppler parameters and code phase search window. These parameters help the built-in GPS module to reduce GPS signal acquisition time. The auxiliary data comes from the pseudo-distance data generated by the GPS module of the mobile phone and can last for several minutes. After receiving these pseudo-distance data, the corresponding network processor or positioning server can roughly estimate the location of the mobile phone. After necessary corrections are added to the GSM network, the positioning accuracy can be improved.
Mobile phone autonomous GPS positioning method
This kind of mobile phone contains a full-featured GPS receiver with all the functions of a mobile phone, plus satellite position and mobile phone position calculation functions. At the beginning of the calculation, more data is required than the mobile phone assistance method. These data can last for more than 4 hours or be updated as needed, usually including time, reference position, satellite ephemeris and time calibration parameters. If some applications require higher accuracy, you must continuously (interval about 30s) send differential GPS (DGPS) signals to the mobile phone. The DGPS signal is effective in a very wide area, and a reference receiver can serve a wide area. The final location information is calculated by the phone itself, and this location information can be sent to any other application.
Common problems of mobile phone positioning
Why does GPS mobile phone positioning need to connect to the network?
In order to speed up the positioning time, most mobile phones will connect to the network and download the auxiliary data of AGPS to know the current satellite status and which satellites can be received, so that the module can quickly capture the signal for positioning.
Another situation is that a lot of software will request its own location when starting positioning, such as calling the interface to use integrated positioning methods, such as base station information, WiFi information, etc., to quickly give you an estimated location, and then go to GPS positioning. At this time, a network connection will also be generated. In fact, it can be located without opening the network connection, but it is slower. The mobile phone is normal within 1-2 minutes, of course, provided that there is not too much blockage. With the current development, the positioning method has been integrated. The system interface will quickly provide location information through WiFi, base station, GPS, etc., and gradually provide a higher accuracy location in the background.
How does the mobile phone's LBS application locate the mobile phone through WIFI and base station?
In the current situation, there are two types of characteristics that have this kind of spatial location invariance and are easily acquired by mobile devices:
1. Base station information of mobile communication network
2. Access point information of wireless LAN
Therefore, when the base station information and WLAN AP information captured by the mobile device are consistent with the information previously captured, it can be considered that the user should be basically in the same location. If the base station information and WLAN AP information that can be detected in a place are collectively referred to as the electromagnetic spectrum characteristics of the place, and the relationship between the electromagnetic spectrum characteristics and the coordinates is recorded in the database, then the so-called positioning is actually based on the electromagnetic spectrum The process of feature finding spatial coordinates.
The above is a theoretical analysis of the basic principles of base station and WIFI positioning. From a practical point of view (program developer's perspective), what we need is to use the positioning interface provided by the service provider to send relevant electromagnetic signals to it. Spectrum features are used to obtain the spatial position of the corresponding features recorded in the database without having to care about the details of the algorithm behind it.
A functional mobile phone is always able to receive various wireless signals. The "local uniqueness" of these wireless signals is a key prerequisite for the positioning of the device. What is local uniqueness? Let us explain these specific signals and you will know.
A mobile phone can make calls and send and receive text messages, indicating that the mobile phone can initiate interaction with nearby base stations and send and receive signals. In particular, for smart phones, the base station ID can also be obtained through the system interface. Under normal circumstances, each base station ID is unique in the world, so if we scan a certain base station ID and we know the location of the base station, we can roughly estimate the location of the device. The premise for making this guess is that the signal transmission range of a base station is limited, and a normal mobile phone cannot receive the signal from this base station when it is far away. In textbooks related to wireless communication, when it comes to base station positioning, triangulation is always talked about. A mobile phone can scan the signals of three base stations, so it must be in the common coverage area of the three base stations, so the estimated range is much larger. Zoom out.
