Theory and application of high precision positioning Expected to finish reading in 12 minutes From mobile Internet to Internet of things, location is a basic and indispensable information, but from the refined industry application requirements, only higher precision location information can bring higher value, people can more accurately know the location of things, know the specific location of people, and better manage enterprises, personnel or materials. For example, to ensure the personal safety of tunnel construction personnel, to assist the prison to build a global and visual supervision platform; to improve the safety assurance efficiency of the petrochemical industry; to help upgrade the intelligent management of the construction site. However, the above industries have high requirements on ultra-high positioning accuracy, large capacity, low delay and high refresh rate. Location and navigation technology is responsible for providing real-time motion information of carrier (such as autonomous vehicle), including carrier position, speed, attitude, acceleration, angular speed, etc. Autopilot often adopts the way of multi-sensor fusion positioning. This paper mainly introduces the application of IMU in automatic driving positioning. Working principle of high precision positioning At the perception level of unmanned vehicle, the importance of positioning is self-evident. Unmanned vehicle needs to know its exact position relative to the environment, and there can be no more than 10cm error in positioning here. GPS can provide absolute positioning of meter level for vehicles, differential GPS or RTK GPS can provide absolute positioning of centimeter level for vehicles, but not all sections can get good GPS signals at all times. Therefore, in the field of automatic driving, the output of RTK GPS is generally integrated with the sensors of IMU and automobile (such as wheel speedometer, steering wheel angle sensor, etc.). The full name of IMU is inertial measurement unit, which is usually composed of gyroscope, accelerator and algorithm processing unit. Through the measurement of acceleration and rotation angle, we can get the self motion track. We call the traditional IMU and the system combined with the vehicle body, GPS and other information fusion algorithms as the generalized IMU for automatic driving. The emergence of this technology makes up for the lack of GPS positioning, and the two complement each other, enabling autopilot to get the most accurate location information. At present, the most widely used positioning method of unmanned vehicle is the integration of global positioning system (GPS) and inertial navigation system (INS). Integrated navigation involves complex coordinate system transformation, which requires initial calibration of the inertial navigation system. Generally, the reference navigation system (such as GNSS) is used to give the inertial navigation system an initial position value (the purpose is to establish the initia...

How much imagination can 5g network bring to industry? Expected to finish reading in 8 minutes 2020 is not only the year of outbreak, but also the first year of5gcommercial operation.5G, as the key of a new round of industrial revolution, according to the characteristics of ultra-high bandwidth, low latency and ultra large connection, will have a significant impact on human society. The first is to meet the needs of digital life, such as high-definition video, virtual reality VR and AR of augmented reality; the second is to meet the needs of digital society, such as smart city, environmental monitoring, intelligent agriculture, etc.; the third is the digital industrial demand, remote control and automatic driving of the factory. Ubiquitous demand and rigid demand As we all know, the industrial control network and management network of the traditional manufacturing plant belong to the internal network. We can understand it as a closed network, after all, the outside world is inaccessible. With the spread of the concept of industry 4.0, the development and application of domestic intelligent manufacturing, the factory needs internal network and external network for interconnection. From the actual situation, the manufacturers of textile, toys, food packaging and other industries tend to develop in the direction of flat internal communication network and functional architecture. Industry insiders said that the existing industrial wireless solutions can not meet the needs of intelligent factories, and the only hope is5G, while some traditional factories have to adopt the industrial scenario of wireless communication when they are transforming and upgrading. For example, it is very inconvenient to reconstruct the old factory wiring; the production sites in oil production, oil and gas pipelines and other fields are too far away, as well as the operation sites with poor environment such as corrosion and salt fog. How can5gmake production and manufacturing more optimized? Since it is industry 4.0, it is different from labor-intensive production and manufacturing. The use of robots and the collaboration between machines are the main scenes. The traditional industrial communication adopts the master-slave mode, and realizes the communication between the machine and the machine through the main control equipment such as PLC. The application of5gwill greatly improve the communication between machines and make them more efficient. In terms of factory logistics,5Gmakes it possible for logistics distribution vehicles in the park and plant area to realize automatic driving. In terms of remote operation and maintenance of large-scale manufacturing equipment,5gcan transmit more unstructured data, such as video, which can quickly understand the situation of the industrial site, and can quickly feedback the situation when operating the machine. In the future, no or few people factories need a lot of on-site data for decision-making support. The characteristics of ul...

Characteristic difference between PCB and FPC Expected to finish reading in 8 minutes Printed circuit board (PCB) On the insulating base material, a printed board for connecting and printing components between points is formed according to the predetermined design FPC (flexible printed circuit board) Printed board made of flexible base material. It is one of printed boards PCB is now an indispensable component in electronic equipment. PCB has different structures and uses, but there are many kinds. PCB can be divided into rigid board and flexible board according to the mechanical properties of whether the substrate can be bent, and rigid flex combined PCB (R-FPC) between them; moreover, PCB can be divided into single panel, double-sided board and multilayer board according to the number of conductive layers. Flexible printed boards (FPC) include conventional printed boards and IC packaging carrier boards (COB: chip on Flex). At the same time, FPC also has single panel, double-sided board and multi-layer board. At present, there are two kinds of multilayer boards: conventional through hole interconnection multilayer board and multilayer multilayer board (HDI board). FPC also has two kinds of multilayer boards with different structures and processes. FPC circuit board and PCB comparison, PCB is printed circuit board or printed circuit board, or printed circuit board. FPC is the abbreviation of FPC, also known as soft board, which is a hard board and a soft board. PCB consists of soft board and hard board, but most of them are hard. And FPC is mostly used for lines that are easy to fold, such as cell phone cable and LCD cable. FPC is used for soft light strip, and its folding resistance must be much stronger than PCB. Characteristics difference between soft board and hard board In fact, the soft board is not only flexible, but also an important design method of connecting three-dimensional circuit structure. This structure, together with other electronic product design, can widely support various applications. So from this point of view, soft board and hard board are very different. For the hard board, unless the circuit is made into a three-dimensional shape by means of mold filling, the general state of the circuit board is plane. Therefore, to make full use of the three-dimensional space, the soft board is one of the good plans. In terms of hard board, the common space extension scheme at present is to use slot plus interface card, but the soft board can complete similar structure with transfer design, and the direction adjustment is also relatively flexible. Using one connecting soft board, two hard boards can be connected into a group of parallel line system, or can be turned into any angle to adapt to different product shapes. The soft board can be connected by terminal connection, but the soft board can also be used to avoid these connection mechanisms. A single soft board, you can use the layout to configure many hard boards and connect them...

Understand the application scenarios of Nb IOT, Lora, EMTC, sigfox and ZigBee Expected to finish reading in 5 minutes Internet is connected to computers and mobile phones, so that people can send messages anytime, anywhere. The Internet of things may be connected to your lights, kettles, door locks, pipes, electricity meters and water meters, as well as the lamp posts on the side of the road when you walk your dog, the sprinklers on the way to work, small devices and large components, which are all inclusive, involving scenes that are also heaven and earth. People's consciousness is more complex than things, and the world of things is more complicated than people. The spectrum needed to connect people and things is completely different. People want to be online 24 hours a day and send messages and videos online at any time. Now try to take away a person's mobile phone and have a look, for fear that you will be called. But your lamp doesn't need to be connected with another lamp 24 hours at any time. If the Internet of things uses the early wireless network, it's not suitable for energy consumption, traffic and operation. No matter NB IOT, Lora, EMTC, etc., in the long run, there should be no monopoly of the king. Think of Pepsi, Sprite and fanda. In these Internet of things network connection technologies, users can choose appropriate network connection technologies according to their own needs. After all, there is no perfect technology, only suitable technology. What are the application scenarios of Nb IOT, Lora, EMTC, sigfox and ZigBee? NB-IoT&eMTC Let's start with Nb IOT and EMTC, which are the Heaven Sword and dragon sword in the hands of operators. Each has its own advantages. In terms of cost, Nb IOT is more cost-effective than EMTC; in terms of coverage, Nb IOT is 30% larger than EMTC, and EMTC coverage is about 9dB worse than NB IOT; in terms of capacity, EMTC can not meet the demand of large capacity, but in terms of speed and mobility, EMTC has more advantages than NB IOT, in addition, EMTC supports voice. That is to say, dynamic scenes involving frequent interaction with people have requirements for voice, bandwidth rate and mobility, such as Internet of vehicles, intelligent wear, logistics tracking, etc., EMTC is selected, while NB IOT is selected considering module cost, mass connection and other needs, such as intelligent electricity meter, air monitoring, intelligent water meter and other scenes. In the future, the hybrid networking of Nb IOT and EMTC, with complementary advantages of differentiation, is one of the main trends of Internet of things network connection. LoRa Next, let's talk about Lora. I mentioned the difference between Lora and Nb IOT before. Compared with Nb IOT, Lora has wider coverage and lower cost, and supports flexible networking. To some extent, Lora extends the boundary of Internet of things network connection. In some specific segmentation scenarios, such as remote or marginal areas, such as scenic sp...