More and more mobile phone applications need location services, such as map applications, applications for finding toilets in nearby restaurants and friends nearby. Everyone knows that mobile phones can be located by GPS, but GPS has two fatal defects.
Indoor positioning cannot be realized: the radio wave is too weak to penetrate the building, even if it is outdoors, it needs relatively empty ground, and the effect is not good in the deep well surrounded by such high-rise buildings (please skip the picture below for fear of heights);
The power consumption rate is amazing: even if GPS can be used in some outdoor occasions, the battery of mobile devices will be exhausted quickly if GPS is turned on all day, so most of the time everyone needs to use positioning services to turn on GPS, so that positioning services are not available everywhere;
As for WiFi and mobile base station positioning, both have the problem of poor positioning accuracy-/kloc-the error above 0/00 meters is normal.
In 200 1 year, Nokia took the lead in developing Bluetooth Low Energy Consumption (BLE) and finally entered the Bluetooth 4.0 standard. One of the most attractive features of BLE is that its power consumption is significantly lower than that of the previous generation Bluetooth standard, and it supports various sensors to interact with mobile devices through Bluetooth. One of them is related to positioning, that is, due to technological progress, the existence of Bluetooth beacons is allowed.
Bluetooth beacon is actually a Bluetooth module with battery. It provides a beautiful positioning scheme for the above GPS short board:
Very energy-saving and very cheap: the beacon itself can work continuously for six months to one year through various energy-saving measures (deep sleep, no connection, simple protocol, etc.). ), and a Bluetooth beacon can rely on such a button cell with a diameter of 2 cm. It is also very power-saving for the mobile terminal to turn on Bluetooth 4.0. For example, many people turn on Bluetooth all day, and turning on Bluetooth 4.0 will have less impact on the power consumption of mobile phones. In addition, according to the device cost, each beacon based on CSR chip in the figure below is only about 15 yuan RMB (excluding the shell), and the cost can be further reduced if it is widely promoted in the future.
Suitable for indoor positioning: the work of Bluetooth beacon is as simple and boring as that of lighthouse-a Bluetooth data packet is broadcast by radio at regular intervals, which can be the geographical coordinates of the current location (such as latitude and longitude) or any other information (such as store name). ) except the beacon ID. The mobile phone supporting Bluetooth 4.0 can receive this information and use it to complete the positioning. After the contents of the data packet can be configured, beacons can be attached to areas that need indoor positioning (such as shopping malls, amusement parks, shopping centers, etc.). Stick double-sided adhesive at will, and the mobile terminal can find its position through these beacons as long as it turns on Bluetooth. The positioning accuracy is closely related to the laying density and transmission power of these Bluetooth beacons. Even if a simple signal strength algorithm is used. If one is laid every 10 meter and the transmission power is controlled at a very small level, I estimate that there is no problem in controlling the positioning accuracy below 5 meters.
Of course, these Bluetooth beacons can be used for more than one purpose, and they can also be used for many interesting applications.
For example, fix beacons on children's schoolbags, pets and even valuables to remind you when they leave you within a certain range-it should be noted that there have been such applications before, but in the end it became cumbersome because of too much power consumption.
For people who often lose things, you can also use your mobile phone to help you find keys or other valuables with labels (within a certain range). That's what this Kickstarter project does: Kickstarter > & gtiphone4s honey: never lose your keys again. Author: Geoffrey litwake (MM in the video is beautiful! ), as if using a mobile phone to detect the signal strength of a Bluetooth beacon to find the location of the item. In addition, this project has raised enough funds!
In principle, any mobile device that supports Bluetooth 4.0 can use Bluetooth beacon, but at present, only iOS has implemented BLE API, and iPhone4S will support it in the future. It's a pity to use Android platform. Even if your mobile phone supports Bluetooth 4.0, you have to wait for the system with API level 18 or above (Android 4.3) to use this function normally.