At the end of last month, the third International Mobile Satellite-5 was successfully launched into the orbit by the Russian Proton-M rocket, thus building a new generation of "International Mobile Satellite" constellation. At the end of this year, the constellation will become the world's first system to provide a global coverage of high-speed mobile broadband network services, the "Global Alert" service, from a single provider. This can be achieved even in the most remote and difficult to access areas. It’s time to "the Internet is everywhere." US "Iron Star Next Generation" Satellite Four days ago, China successfully launched the communication technology test satellite No. 1, which was mainly used to carry out the test of broadband communication technology in the ka-band. Because satellite mobile communication has the advantage of being free from geographical obstacles and user motion limitation, it can achieve near-seamless coverage of oceans, mountains and highlands, and can meet the needs of various users for mobile communication coverage. It has become a satellite. One of the main trends in the development of communications. At present, mobile communication satellites have high orbit (geostationary orbit) and low orbit. They have their own strengths, coexist and develop, and are constantly being updated to improve performance and competitiveness. High-altitude mobile communication satellites have been developed for four generations The earliest mobile communication satellite was a geostationary orbit mobile communication satellite, which has been developed for four generations. Currently, the geostationary orbit mobile communication satellites that can be used in the global satellite mobile communication service are only "international mobile communication satellites", including the second generation mobile communication satellites - the international mobile satellites - 3, the third generation mobile communication satellites - the international mobile satellites. -4. International Mobile Satellite-5 is mainly used for broadband multimedia communication. Whether it belongs to the fourth-generation or fifth-generation geostationary orbit mobile communication satellite is still inconclusive. "International Mobile Satellite" is a global mobile communication satellite system operated by International Mobile Satellite Corporation. It provides nearly 150,000 communication terminals to the world through a limited bandwidth frequency resource. It provides traditional mobile voice services, low-rate data services, high-speed Internet access, and global maritime distress and security business services. The four international mobile satellites-4 launched between 2005 and 2008 are the main force of international satellite mobile communications. However, in the context of the emerging aviation and maritime broadband satellite communications market, International Mobile Satellite Corporation decided in 2010 to develop a high-capacity satellite using the ka-band, International Mobile Satellite-5, to provide “global newsletter†services to high-end customers. Government and commercial users provide the world's first high-speed mobile broadband service, providing global mobile broadband communication services for marine vessels and flight flights, and passengers' intra-flight communications connections during the flight, delivering high-resolution images, voice and data streams. Developed by Boeing, the International Mobile Satellite-5 has a design life of 15 years and a payload power of 11.2 kW. Three aircraft have been launched. The first was launched in December 2013, covering Europe, the Middle East, Africa and Asia; the second was launched in February 2015, covering the Americas and the Atlantic; the third covered the Pacific. The constellation will become the world's first system to provide a global coverage of high-speed mobile broadband network services, the "Global Alert" service, by a single vendor by the end of 2015. For technical reasons, general mobile communication satellites can only provide narrow-band mobile communication services, but the international mobile satellite-5 is uncharacteristically providing broadband mobile communication services. Compared with International Mobile Satellite-4, the bandwidth and speed of International Mobile Satellite-5 have increased, providing new and old customers with many new opportunities to strengthen their network interconnection functions, deploy high-traffic applications and set up efficient solutions. The solution, all of which can be achieved even in the most remote and hard-to-reach areas, has contributed to global mobile broadband, and truly “the Internet is everywhereâ€. However, the International Mobile Satellite-5 user terminal is portable and does not support handheld. Low-orbit mobile communication satellite group strong return The geostationary orbit mobile communication satellite also has some shortcomings, for example, the orbit is high, the path is long, and the link loss is large, and the transmission is prolonged, which is not suitable for personal mobile communication; the single-star cost is too high, and once the transmission fails, the loss is heavy; the stationary orbit resource Very nervous; this satellite cannot achieve true global coverage and has blind spots at both poles. To this end, since the mid-1990s, a number of mobile communications low-orbit satellites have been put into construction. The satellites in the low-orbit mobile communication satellite system are small satellites, generally operating in orbits of 500 to 1500 kilometers, which can overcome various shortcomings of geostationary orbit satellites, such as small size, light weight, low cost, short manufacturing cycle, It can be mass-produced; the satellites are mutually backup and have less loss; the ground terminal equipment is simple, the cost is low, and it is easy to carry; because of the low orbital height, it can eliminate the problems of telephone transmission delays when using geostationary satellites; Seamless gap personal mobile communication. The reason why the constellation mode works is because the low-orbit satellite has a small coverage area. In order to achieve global coverage and continuous communication, it is operated by a constellation method composed of a plurality of small satellites. It is a satellite placed on several orbital planes that use various communication links to connect satellites in each orbital plane. The entire constellation forms a large platform, forming a cellular service cell on the surface of the earth. The user in the service area is covered by at least one satellite, and the user can access the system at any time. According to different working frequency bands and service contents, low-orbit mobile communication satellite systems can be divided into small low-rail and large low-orbit. The former consists of inexpensive small satellites, operating at frequencies below 1 GHz, providing low-cost, low-data-rate Email and two-way paging and other narrow-band data communication services. The US "orbital communication" satellites fall into this category. The latter consists of more than 24 small satellites, operating at frequencies between 1 and 2 GHz, providing voice and medium-to-high-speed data transmission and global personal communication services. The US "铱" satellite and "global star" belong to this category. . They are all launched in a multi-star way. The low-orbit mobile communication satellite system has now “strongly returned†after the “decline†of the 20th century. The three major low-orbit mobile communication satellite constellations in the United States are currently being updated. Among them, the number of second-generation "orbit communication" satellite constellation users can be increased by up to 12 times compared with the first generation, the data transmission rate is faster, the transmission volume is larger, and the collision avoidance, navigation aid, search, rescue, etc. There are a wide range of applications; the second generation of "铱" satellites - "Iron Star Next Generation" can provide new enhancements in speed, bandwidth and flexibility, with a maximum data download rate of 30 megabits per second; The lifetime of the “Global Star†has been extended from 7.5 years in the first generation to 15 years, providing greater peak demand call capacity and higher data transfer rates for file transfer and video applications. Xingdi United is the future development direction The development trend of geostationary orbit mobile communication satellites is large antennas and high power, so it is necessary to develop large-scale communication satellite platforms. In addition, we must break through and master large-scale expandable antenna technology, multi-beam forming technology, etc., and drive market development through innovative technological advancement and market development models. The development trend of low-orbit mobile communication satellites is to establish a constellation consisting of hundreds to thousands of small satellites to better provide users with low-cost Internet access. In recent years, U.S. Space Exploration Technologies has proposed a plan to launch 4,000 small satellites. The British company has proposed a program to launch 900 small satellites. South Korea’s Samsung has proposed a plan to launch 4,600 small satellites. The goal is to provide high-speed Internet access to all parts of the world, including the most remote areas. The biggest difficulty in building such a satellite Internet is still the cost issue. Although the manufacturing and launching costs of low-orbit satellites are decreasing year by year, they are still more expensive than terrestrial networks. In addition, satellite networks are inherently vulnerable to interference and large terminals. Therefore, it is difficult to say whether it is possible to build a global satellite Internet in recent years. Star-land joint is the development direction of satellite mobile communications. The satellite mobile communication system is mainly used to cover "slits" between adjacent terrestrial cellular networks and areas that cannot be covered by terrestrial cellular networks. Therefore, satellite communication systems must be tightly integrated with terrestrial cellular communication systems. Through analysis and research, experts have proposed the idea of ​​“one satellite (or a group of satellites in the sky), a network on the ground, and the integration of heaven and earthâ€. The auxiliary ground component developed and put into use is a patented technology that can be solved by heaven and earth. The satellite signal is in the high-rise city and the problem of poor indoor coverage, which is a good way to achieve seamless coverage of large areas. The key to the commercial success of future satellite mobile communications is to achieve seamless indoor and outdoor coverage, and the terminal can automatically switch seamlessly between the auxiliary ground component base station and the satellite. In addition, the boundary between fixed and mobile communication satellite services is gradually blurred, and the maritime and aeronautical mobile services have become a hot spot for future development. With the popularity of Internet applications such as smartphones, tablets and other mobile electronic devices and social networks, satellite aviation and maritime broadband services that use satellites to provide broadband network access to passengers are quietly emerging. Furniture Lights,Furniture Lighting,Furniture Cabinet Lights,Furniture Bedroom Lighting Dongguan baiyou electronic co.,ltd , https://www.dgbaiyou.com
