For the “vulnerable” people such as the elderly, children, and pregnant women, the smartwatch’s functions such as positioning, calling, data monitoring, and movement trajectory are indispensable, and the positioning function is the most concerned by users. In view of offering any useful tips for your purchasing smart watch, in this Article, DTNO.I will break down the working principle of the positioning function of smart watches.
At present, the technologies mainly used in the positioning function of smart watches on the market are based on three types of positioning technologies: GPS positioning, Base station positioning, and WiFi positioning. If accuracy is not demanded, simple positioning can be achieved by using one of the positioning type alone. So first, we must ask the positioning type of the smart watch before purchasing. Next, we will comprehensively analyze the three positioning principles, advantages and disadvantages and application areas, and finally explain the meaning of the triple positioning, quadruple positioning, and five-level positioning of smart watches on these technologies.
GPS Global Positioning System
The basic principle of the GPS navigation system (United States) is to measure the distance between a satellite with a known location and the user’s receiver (GPS can ensure that 4 satellites can be observed at any point on the earth at any time) and then integrate multiple satellites data, to find out the specific location of the receiver. It is composed of a Space End + a Control End + a User End, and the accuracy is greater than 3m. This is a system can’t be built easily by ordinary countries. It depends on economic strength and technological level. At present, there are four mature satellite positioning systems in the world, they are: the United States’ global satellite positioning system (GPS), Russia’s Global Navigation Satellite System (Global Navigation Satellite System), referred to as GLONASS, European’s Galileo System and China’s Beidou Navigation Satellite System (BDS).
Advantages: GPS global positioning system has outstanding features such as all-weather, high precision, automation, and high efficiency.
Disadvantages: The indoor positioning weak, and it is greatly affected by the rainy and cloudy weather.
Location base station positioning (LBS)
Base station positioning principle: The mobile phone (SIM card function) measures the downlink pilot signals of different base stations to obtain the TOA (Time of Arrival) or TDOA (Time Difference of Arrival) of the downlink pilots of different base stations. With this measurement results are combined with the coordinates of the base station, and the trigonometric formula estimation algorithm is generally used to calculate the position of the mobile phone. The accuracy is not high, and it is greater than 100m.
LBS positioning is generally applied to mobile phone users. Mobile base station positioning service is also called Mobile Location Service (LBS-Location Based Service), which obtains the location information (latitude and longitude coordinates) of mobile terminal users through the telecommunication mobile operator’s network (such as GSM network) ), with the support of the Online Map Platform, a value-added service that provides users with corresponding services, such as the location query service provided by Mobile operator.
Advantages: Generally speaking, if there are more base stations can be measured by the mobile phone (SIM card function), then the measurement accuracy can be higher, and obtain more obvious improvement in positioning performance.
Disadvantages: A few remote areas may have weak or less signals.
WiFi can locate users. Because location services are built into mobile operating systems such as Android, iOS, and Windows Phone, each WiFi hotspot has a unique Mac address. When WiFi is turned on, the user’s smart watch will automatically scan for nearby hotspots and upload their location information. Less than 10m.
Advantages: WiFi positioning does not require the device to actually connect to WiFi, as long as the WiFi function can search for hotspots, positioning can be realized, so this is very convenient, especially significant for indoor environment.
Disadvantages: For outdoor environments, there are fewer WIFI facilities and positioning services are greatly affected.
Triple positioning, quadruple positioning, and five-fold positioning:
GPS positioning, base station positioning, and WIFI positioning are combined, and GPS is the dominant position in outdoor locations and positioning is implemented with the assistance of base station and WiFi. In indoor locations with weak GPS signals, WIFI is the dominant factor and positioning is implemented with the assistance of base station and GPS. Triple positioning technology intends to make up for the shortcomings of the lack of GPS indoors.
Adds the dimension of Bluetooth on the basis of three types of positioning, which can guarantee the near field communication with the user’s mobile phones. In public places such as parks and shopping malls, turn on the Bluetooth mode. For example, once the child wearing a smart watch has exceeded the safe distance to the parent, the parent’s mobile phone will immediately sound an alarm to ensure that the child is in a safe position.
Only a few smart watches on the market have proposed five-positioning technology to ensure accurate positioning. By using BDS+GPS+AGPS, the outdoor positioning accuracy can reach up to 2.5 meters. The base station + WIFI technology is used indoors, and by optimizing the background algorithm, multiple technologies can cooperate with each other to finalize the position. Compared with the method of solely relying on the base station positioning, the accuracy is greatly improved