The drone was temporarily banned from flying. From 02:00 on March 1st to 24:00 on the 16th of March 2017, all units, organizations and individuals are prohibited from performing recreational sports activities of various sports advertisements within a radius of 200 kilometers centered on Tiananmen Square in Beijing. Before the Beijing Municipal Public Security Bureau issued this news, Dajiang Innovation Technology Co., Ltd. (hereinafter referred to as Dajiang) had set up a geofence system in the drones it produced, marking areas where drones could not flow in, such as Airport and surroundings. Once "out of bounds", no one will automatically return home immediately. The drone market is growing in a frenzy, and endless troubles have come one after another. The drone has repeatedly entered a place that is not allowed to enter. It is called "black flying." On January 15, a hobbyist took control of his own drone to fly into the clear space of Zhejiang Xiaoshan Airport in order to capture the sunset. In February, drones appeared at airports in Mianyang, Shenzhen, and Shantou, Guangdong. Kunming Changshui Airport was even invaded by drones six times in three days. The sky above and on both sides of the take-off and landing runway is the airspace necessary for the aircraft to take off, climb, descent, and hover. This is the airport clearance area. When there are low altitude flight conditions such as takeoff and landing, there are no ground obstacles in the airspace to prevent navigation and flight. When drones break in from time to time, it is extremely off guard. Therefore, the significance of anti-drone equipment began to be revealed. The principle of anti-"black" technology is very simple A cross-shaped body frame, four paddles, a controller like a game console handle, this is a drone that children can control. Just gently twist the button on the joystick to remotely control its takeoff and landing. In addition to such quadrotor, six-rotor and other multi-rotor aircraft, the large family of drones has fixed-wing and helicopter categories. The convenience of drones and the low cost of casualties have rewritten the military’s operational thinking and methods in this century. As technology matures, the non-military use of drones has also seen dramatic expansion in recent years. Google, Amazon, and many innovative companies have joined it, making it the next focus of consumer electronics. But not all places welcome drones to fly over. Because drones still do not have the ability to sense and avoid objects, in the airspace supervision, how to incorporate drones into the airspace of general aircraft flights, all countries have encountered regulatory difficulties. According to the “Provisional Regulations on the Management of Drivers for Civil Unmanned Aircraft Systemsâ€, drones under 7 kg, heights up to 120 meters, and visual flying within 500 meters are not required to obtain evidence, and there is no relevant regulation on driving behavior. At present, the mainstream drones in the market are mostly under 3 kg, and are not in the scope of supervision. However, in terms of restricting the technology of the "black fly" drone, some international military and industrial companies and technology companies have invested in scientific research. The anti-drone control equipment developed by the military enterprises is mainly based on laser interception and traditional firepower interception, which means that the intercepted drones will be destroyed. The technology company’s products mainly use web-based interception and radio interference. After the drone is discovered and interfered, it is often forced to drop or return along the original route and it will not be destroyed. Web interceptors operate like a shotgun bird. The operator uses the equipment to aim at the drone, launches a net to fly, opens in the air, and covers the drone to force it to land. This requires the operator to accurately predict the flight of the drone while aiming. The trouble is that if the operator is too far from the drone, the difficulty of aiming will be greatly increased, and it is very likely that no drone will be caught. Radio interference is more efficient. The drone mainly relies on two signal sources to control, one is the flight control signal sent by the control terminal, and the other is the positioning signal. The specific to the Chinese drone is the GPS signal or the Beidou signal. The source of these two signals is the key to countering. “The flight frequency band and remote control frequency band of UAVs are allocated exclusively by the Radio Management Committee. GPS and Beidou have also allocated dedicated frequency bands. As long as they are drones produced by legitimate manufacturers, the frequency bands that are shielded or interfered are the corresponding frequency bands.†Jia Hang (a pseudonym), a manager of the anti-drone technology company, told Caijing. If a flying drone is cut off from the flight control signal and positioning signal, it will be “emptyâ€, do not know where to fly, how to act, and then slowly fall vertically. If there is wind, it will drift with the wind until landing. This approach is straightforward. Although drones may be damaged during the fall due to wind speed and other effects, they are far more moderate than the destruction caused by military countermeasure equipment. In addition, it is also possible to cut off only the flight control signal through radio interference, so that no one is likely to fly back along the original flight route, and the flightman cannot adjust its route. The latest idea of ​​countering the system is: "arrest" the uninvited guest, shield the connection between the drone and the flying man, and control the drone to fly to the counterman. Some special sites, such as airports, military bases, barracks, or places where there is a high alert, such as a detention center, can securely deploy anti-UAV equipment: after installing radar detectors, infrared detectors, laser detectors, etc., at sites around an area, It will guard like a sentinel and will find drones approaching, facilitating the use of radio interference to drive away or capture drones. Some arming equipment even take into account the problem of network security, through the establishment of self-checking mechanisms and alarm functions to prevent the potential threats such as hacking. The "Sentinel" is very expensive. A square area is only installed in the four corners. It costs three to four million yuan. Lightweight and portable, it is the current technological research direction of the anti-drug industry. Knapsack-type anti-UAVs are seen on both domestic and foreign markets – a large shoulder bag containing power and signal transmitters, and the signal transmitters are often made into the shape of a gun. The operator simply takes the “gun†aim Drone. The key technical point after the operator aims at the drone is interference efficiency. If a UAV is flying in the air, the distance between it and the operators of the flying and the anti-UAV equipment is 300 meters, and it is precisely at this distance that the UAV equipment can only interfere with the flight. Signal, then the interference efficiency is 1 to 1. The efficiency of such interference is meaningless, which is equivalent to the fact that both parties have the same constraint power on drones. If you want to take countermeasures against drones earlier, you must have higher interference efficiency. "We have also seen some foreign countermeasures, which is a one-to-two interference rate," said Jia Hang. The higher interference efficiency can not only promptly drive away or capture UAVs, but in some extreme cases, it may also provide response time for follow-up action. This is a technical problem that is currently being resolved in the anti-drone industry at home and abroad. "Mastering the stick, but aiming for the yard" When the UAV's operating frequency band is not within the specified limits, there is no way for the anti-UAV device. In other words, drone manufacturers must abide by regulations during the production process, which is the premise of anti-drug equipment to play a role. “For manufacturers, extreme situations are not considered by us and there are few drones with illegal frequency bands.†Jia Hang said that some model aficionados may set illegal bands for self-made drones. Some are very small. Manufacturers of toys or models may also use illegal bands. Regulating UAV production is the source of regulation. Recently, the director of the Civil Aviation Administration, Feng Zhenglin, told the media that the CAAC will study the implementation of a real-name system for drones to reduce “scrambling.†For light aircraft such as entertainment and sports, electronic fences will be established in the aviation control zone. Airport data were entered immediately to ensure that drones could not enter various flight exclusion zones. The voice of regulating civil drones has been rising one after another. Since 2009, the Civil Aviation Administration of China has issued a number of related management documents, which are directed at the airworthiness management of UAVs, airspace management, and driver qualification management. An unmanned drone wants to fly, in addition to complying with the no-fly and fly-by rules, it has to complete a series of examination and approval procedures, such as airspace flight control, aircraft airworthiness certification, aircraft driver review, and aviation operations permit. When the regulations are relatively complete, "the key is to do a good job of communication and collaboration among various departments." Lin Jian, vice president of the Huaning Hanergy (Beijing) Institute of Aeronautical Technology, told the "Finance" reporter. Some drone manufacturers took the initiative to put their products on a "fighting rope." For example, DJI used geofence technology to upgrade the product and mark the no-fly zone. When the UAV is positioned in the no-fly zone For example, within Beijing’s Six Rings, it will not be able to start, or when it flies to the edge of the no-fly zone, it will automatically follow the out-of-control mode to return or land. “The height of the road is as high as one's feet.†In some forums, it has been a heated discussion about how to crack the geofence system in Dajiang. According to the “Beijing News†report, there are merchants claiming that Qianyuan can “crack†the no-fly zone of Dajiang’s drones. It is reported that police in Chaoyang District, Beijing have been involved in the investigation. One person in the drone industry also questioned: “The no-fly zone, in addition to the airport, there are some military facilities or areas, these are sensitive information, how do manufacturers have the right to understand the information of these no-fly zones?†In the anti-drug industry, there are no industry standards, and few manufacturers have their own development directions. China's civil drone manufacturers have already broken 1,000, mainly in Shenzhen and Guangzhou, and the scales vary from large to small. For many people, drones are still new things. Countering drones is even less of a thing. However, the airport and public safety fields have gradually generated demand for anti-UAV equipment. "Countermeasured drones are definitely special needs and will not be as large as civilian drones." Jia Hang believes that there may be five companies in the country that are engaged in the development of anti-unmanned aerial vehicles. "Financial" reporters searched the industry companies through the Internet, the results did not exceed 10. In 2016, the purchase volume of anti-drug equipment in the country was broken by one hundred. In 2015, this figure was less than 10 sets. The price of a counter-drone device is about 300,000 yuan. The future of anti-drone equipment will not be as common as civil drones. It is still difficult to speculate that when the cost and selling price drop to a few thousand dollars, ordinary people will not want to buy one, or provide security for villas and communities. With one? "In the next year or two, anti-drug equipment should develop rapidly," Jia Hang said. Markets and Markets, a global market research and consulting firm, predicts that by 2022, the global anti-UAV market will exceed US$1.1 billion.
Hex bolts made of zinc plated steel or stainless steel,are available in diameter from 6mm to 24mm and ideal for construction and repair.
Tap bolts with hex heads and fully threaded shanks,are extensively used in boat building,exterior woodworking and water treatment areas,etc.
Countersunk bolts,made of grade 4.8 and 8.8 steel,are available with slot,cross and hex holes in their heads and used when a flat surface needed.
Hex Nuts matching with Hex bolts,are made of quality low carbon or stainless steel,are available in standard,heavy type,jam and panel types.we have many kind of Screw bolt nut:carbon steel hex nut,flange nut,stainless steel lock nuts,stainless steel hex nuts(m2-m48),DIN934,DIN439 marks,hex nuts,flange nuts,DIN6923/GB6177,stainless steel and carbon steel lock nuts,length of 20,flange nut m20,hex flange nut,factory stainless steel cage nut with HIGH-reputation in,wing nut DIN315.
1.Material ; caron steel ,Alloy steel ,
2.:Size : M3-M100
3.Color : Black ,Color -plated zinc ,Copper plated ,hot dip galvanized
4. Standard : DIN/ANSI B18.2.1 /JFI/JIS
5 Certificate : ISO9001 : 2008 ISO/TSI6949,2009
6.Specification : Dia M3-M100, length :20mm-300mm
Hex Bolts,Round Head Bolts,Socket Bolts,Flange Bolts,Countersunk Bolts BAODING JIMAOTONG IMPORT AND EXPORT CO., LTD , https://www.chinagroundscrew.com
: The drone market is growing wildly, and the troubles come one after another. The drone has repeatedly entered a place that has not been allowed to enter. It is called "black flying," and the technology that counters "black flying" is also rapidly maturing.