Through computers, mobile phones and other terminals, the Internet solves the information communication between people. The Internet of Things transforms the physical world into a digital world through sensing devices, and then realizes the connection between things and things, and people and things. From the world to the digital world, the Internet of Things has brought disruptive changes.
From the perspective of the overall architecture of the Internet of Things, location awareness is an indispensable part of the perception layer, providing basic location information for the entire Internet of Things system; from the perspective of applications, location services will penetrate many Internet of Things application scenarios Provide differentiated services.
Location services are the infrastructure services of the Internet of Things.
In fact, location services are not used all the time. Most Internet of Things devices require positioning devices. The intelligent terminal positioning device collects information, uploads it to the cloud, the cloud receives the information, sends feedback information to the terminal device, and the device completes the corresponding instruction.
In this series of information transmission process, location information is provided as important data to the cloud control center. On the one hand, the device location as the basic attribute of the "thing" is recorded by the cloud as reference information; on the other hand, the cloud platform uses multiple The location information of the equipment and the drawing of the visual interface help the comprehensive analysis of the Internet of Things system and make intelligent decisions.
Location services have covered many Internet of Things application scenarios.
Shared bicycles In
cities, shared bicycles are parked anytime and anywhere. How to determine which bicycles are parked at what time and place requires a bicycle terminal to send location information to the management background. Only through location services can it be convenient for users to find vehicles. Operators analyze and formulate delivery strategies based on location information and riding trajectories, and conduct unified scheduling.
In large-scale
animal husbandry, modern breeding methods mostly adopt stocking models. Several people or even one person need to manage tens of thousands of pigs, cows, and chickens. Positioning monitoring is required. On the one hand, it can be determined to facilitate management and prevent asset loss; On the one hand, food traceability can be realized, allowing consumers to buy safe and assured products.
Autopilot
In the Internet of Vehicles, the importance of location information is understandable. In the future, vehicle-road collaboration and intelligent driving will require high-precision positioning services. In this way, functions such as accurate parking of vehicles, active obstacle avoidance and way out for pedestrians can be realized.
Intelligent car search
in parking lots In large public parking lots, the environment and signs are not clear, which makes it difficult to distinguish the direction. Vehicle owners often spend a lot of time looking for empty parking spaces and vehicles. The underground parking lot intelligent car-finding guidance system based on indoor positioning technology can solve the above-mentioned problems.
The car owner enters the underground parking car search guidance system through the mobile phone app or WeChat public account, checks the current empty parking space status, number, location, and plans the nearest route to guide the car owner to quickly find the parking space and reduce the search time. You can quickly check the location of the vehicle by shaking it through WeChat or entering the license plate number on the mobile phone, and plan the nearest route navigation from the owner's current location to the parking space. Realize fast payment through WeChat or Alipay, without queuing or waiting, and get rid of the cumbersome process of traditional cash payment or machine terminal payment.
In smart industry, smart agriculture, smart city, smart transportation, smart healthcare, smart security, smart retail, smart home and other IoT solutions, an important service that we cannot do without is location services, and location As the most basic infrastructure service of the Internet of Things, services are often easily overlooked by enterprises and users.
This kind of habitual "ignorance" has actually begun to take shape in the Internet age. For example, there is a "frequently-visited place" in Apple mobile phones that uses location services. In the early days, consumers ignored this feature, which led to privacy leaks. Another example is the location information hidden behind the photos taken by mobile phones, and few people pay attention. In fact, there are location services in the takeaway software, chat software, weather software, and even game software we use every day. It can be said that without location services, there would be no convenient life now. In the era of the Internet of Things, location services are particularly important in the face of various “objects” without identity.
Generally speaking, positioning can be divided into two categories: indoor positioning and outdoor positioning according to different usage scenarios. Because different scenarios have different requirements, the positioning technologies used are also different.
Outdoor positioning technology
Satellite positioning
Satellite positioning is positioning by receiving the longitude and latitude coordinate signals provided by satellites. The main satellite positioning systems include: the United States Global Positioning System (GPS), Russia's GLONASS (GLONASS), Europe's Galileo (GALILEO) system, and China's Beidou satellite navigation The GPS system is the most widely used and most mature satellite positioning technology at this stage.
GPS global satellite positioning system is composed of three parts: space part, ground control part, user equipment part. The space part is composed of 24 working satellites, which are evenly distributed on 6 orbital planes (4 for each orbital plane). The distribution of satellites makes it possible to observe more than 4 satellites anywhere in the world and at any time. It can maintain a geometric image with good positioning accuracy. Although satellite positioning has high accuracy and wide coverage, its cost and power consumption are high, and it is not suitable for all users.
Base station positioning
Base station positioning is generally applied to mobile phone users. Mobile base station positioning service is also called Mobile Location Service (LBS, LocationBasedService), which obtains the location information of mobile terminal users through the telecommunication mobile operator's network (such as GSM network).
The principle of base station positioning is also very simple: we know that the farther away from the base station, the worse the signal. According to the signal strength received by the mobile phone, the distance from the base station can be roughly estimated. When the mobile phone searches for the signals of at least three base stations at the same time (current Network coverage is a very easy thing), you can roughly estimate the distance to the base station; the base station is uniquely determined in the mobile network, and its geographic location is also unique, so you can get three base stations (three points) The distance from the mobile phone, according to the three-point positioning principle, only needs to draw a circle multiple times with the base station as the center and the distance as the radius. The intersection of these circles is the location of the mobile phone.
Indoor positioning technology
WiFi positioning
At present, WiFi is a relatively mature and widely used technology. Because WiFi has become popular, there is no need to lay special equipment for positioning. This technology has the advantages of easy expansion, automatic data update, and low cost, so it is the first to achieve scale.
WiFi positioning generally uses the "nearest neighbor method" to determine which hot spot or base station is closest to, that is, where it is considered to be. If there are multiple sources nearby, cross positioning (triangulation) can be used to improve positioning accuracy.
However, WiFi hotspots are greatly affected by the surrounding environment and have lower accuracy. WiFi positioning can achieve complex and large-scale positioning, but the accuracy can only reach about 2 meters, and precise positioning cannot be achieved. Therefore, it is suitable for positioning and navigation of people or vehicles, and can be used in various occasions that require positioning and navigation such as medical institutions, theme parks, factories, and shopping malls.
RFID positioning
The basic principle of RFID positioning is to read the characteristic information (such as identity ID, received signal strength, etc.) of the target RFID tag through a set of fixed readers, and the nearest neighbor method, multilateral positioning method, and received signal strength can also be used. Determine where the label is located.
This technology has a short range of action, generally up to several tens of meters. However, it can obtain centimeter-level positioning accuracy information within a few milliseconds, and has a large transmission range and low cost. At the same time, due to its non-contact and non-line-of-sight advantages, it is expected to become the preferred indoor positioning technology. However, it has a short range of action, does not have communication capabilities, and is not easy to integrate into other systems, and cannot achieve precise positioning. It is difficult to deploy a card reader and antenna with a lot of engineering practice experience.
Visual positioning
Visual positioning systems can be divided into two categories. One is to determine the location of the sensor by collecting images with a moving sensor (such as a camera), and the other is to determine the location of the target in the image by a fixed-position sensor. According to different reference points, it can be divided into reference 3D building model, image, pre-deployment target, projection target, reference to other sensors and no reference.
The reference 3D building model and image are compared with the existing building structure database and pre-calibrated image respectively. In order to improve the robustness, the reference pre-deployment target uses the arranged specific image mark (such as a two-dimensional code) as the reference point; the projection target is to project the reference point in the indoor environment on the basis of the reference pre-deployment target. Refer to other sensors to fuse data from other sensors to improve accuracy, coverage, or robustness.
The Internet of Things, the largest "web" in history, is quietly changing our way of life, and the hidden hero behind it-location services, which play an important role as a provider of basic data capabilities, is about to come to the front and serve more industries. Provide more precise services. Miracle IoT (Beijing) Technology Co., Ltd. is a professional eSIM solution provider dedicated to promoting the popularization of eSIM technology in IoT applications. It also has NB-IoT+GPS module AM21E, 2G+GPS module AM900E, etc. A self-developed communication module that can be used for positioning can provide you with high-quality outdoor positioning services for the Internet of Things.
