A signal-jamming theory of predation , anti jammer mobile official

Yang Changfeng, chief architect, BeiDou Navigation Satellite System, speaks at an international event. (Photo: BDS) On July 31, 2020, BDS-3, the global version of the BeiDou Navigation Satellite System (BDS), was formally commissioned, marking the completion of its three-step development process. BDS enters a new era of global services. With the principle of “serving the world and benefiting mankind,” BDS provides seven types of services to users worldwide, including positioning, navigation and timing (PNT) services, a global short-message communication (GSMC) service, a regional short-message communication (RSMC) service, an international search-and-rescue (SAR) service, the BeiDou satellite-based augmentation system (BDSBAS), the BDS/GNSS ground-based augmentation system (BDGAS), and the precise point positioning (PPP) service. BDS has been continuously making contributions to improving GNSS capabilities and promoting the development of GNSS applications and technologies. In 2020, as BDS construction was successfully completed, BDS has made fruitful achievements in application development and internationalization. System Construction Space Constellation Deployment. From March to June 2020, two BDS-3 GEO satellites were launched, while the in-orbit tests of two IGSO satellites, two GEO satellites, and two MEO satellites were completed. As the result, the global system constellation was successfully deployed. By the end of October 2020, 45 in-orbit operational BDS satellites provide services to global users, including 15 BDS-2 satellites and 30 BDS-3 satellites. Ground System Development. More than 40 new ground stations have been built, tested and commissioned. The BDS ground system is operating stably, supporting daily BDS operations. Basic Service Enhancement Generally speaking, the accuracy of the BDS signal-in-space is better than 0.5 m, BDS global positioning accuracy is better than 10 m, BDS velocity measurement accuracy is better than 0.2 m/s, and BDS timing accuracy is better than 20 ns. In the Asia-Pacific region, BDS positioning accuracy is better than 5 m, the velocity measurement accuracy is better than 0.1m/s, and timing accuracy is better than 10 ns. In the key service area, there are 30 BDS-3 satellites and 15 BDS-2 satellites that jointly provide the services using B1I and B3I signals. The actual average measured positioning accuracies are about 1.48 m horizontally and 2.99 m vertically (95% confidence), which are improvements of about 30% and 5% respectively as opposed to solely relying on the BDS-2 system. Globally, with the B1I, B3I, B1C and B2a signals, BDS-3 offers service availability of 100% (PDOP ≤6,). The actual measured positioning accuracies are about 1.54 m horizontally and 2.65 m vertically (95% confidence). Featured Services Benefit Users Presently, the BDS PPP service covers China and its surrounding areas. By broadcasting the high-precision orbit and satellite clock error corrections through the B2b signal, the high-precision positioning service is provided, while initial testing measurements show that the positioning accuracies are about 0.18 m horizontally and 0.26 m vertically (95% confidence). BDSBAS was developed in accordance with International Civil Aviation Organization (ICAO) standards to provide SBAS services with superior accuracy and integrity, enabling aircraft approach with vertical guidance of class I (APV-I). The BDSBAS services cover China and its surrounding areas, and the SBAS data, following ICAO standards are broadcast by the three BDS GEO satellites. In particular, the single frequency SBAS service is being provided through the BDSBAS-B1C signal. At the moment, the civil aviation certification process of the BDSBAS SF service is being prepared. The BDSBAS-B2a signal will provide the Dual Frequency Multiple Constellation (DFMC) SBAS service. BDS has been actively participating in the development process of the DFMC standards and carrying out the verification of the draft DFMC SBAS Standard and Recommended Practices. BDGAS consists of 155 framework reference stations and nearly 2,200 regional stations in China. The system carries out high-precision applications in many fields, such as surveying and mapping, land resources, earthquake monitoring, transportation and meteorology. Its basic services include real-time positioning at the meter, decimeter and centimeter levels, as well as precise post-processing positioning at the millimeter level. Being developed in accordance with Cospas-Sarsat standards, the BDS MEO-SAR service provides the detection probability of the international search-and-rescue service of better than 99%, with the characteristic return link capability. In July, a joint test was carried out using the BDS MEO-SAR satellites with the Cospas-Sarsat ground station in Maryland, U.S., and the relevant technical documents and the equipment admittance testing reports were formally submitted to Cospas-Sarsat, which provides Chinese contributions to the international MEO-SAR family. RSMC provides service to China and its surrounding areas through three GEO satellites. Its communication capability is greatly improved compared to BDS-2. With service capacity of 12 million times per hour, the transmitting power of user terminals is reduced to 1-3 W and the single message capacity reaches 1,000 Chinese characters. The construction of the RSMC service platform has been completed to promote the organic integration of short message and mobile communication services, and to further exert the advantages of the BDS featured services. GSMC provides global services through 14 MEO satellites with single message capacity of 40 Chinese characters. Figure 1. The number of visible BDS satellites as of BDT 13:00, Oct. 29, 2020. The number of visible satellites at Asia-Pacific Region is greater than 20. (Source: www.csno-tarc.cn) Integrated Applications As the system construction accelerates, BDS is also making great efforts to strengthen the development of BDS fundamental products and promote large-scale applications in various fields. The integrated applications and innovative development adopt the “BDS+” and “+BDS” models to improve quality and efficiency as well as to stimulate a healthy and fast-growing GNSS industry. Fundamental Products. At present, the fundamental BDS products have been used in areas such as mass-market applications, where the performance has reached or is close to the world-class level. Progress has been made in the research and development of multi-system baseband-RF integrated high-precision chips. The 28 nm chips have been mass-produced, and the 22 nm chips are about to be mass-produced. As a result, the function and performance of the chips will reach a new level. The BDS navigation chips, modules, high-precision boards and antennas have been exported to more than 120 countries and regions, serving millions of users worldwide. Industrial Applications. BDS has been widely used in various fields, including communication and transportation, public security, agriculture, forestry, animal husbandry and fishery, hydrological monitoring, meteorological forecasting, time synchronization, power dispatching, and disaster prevention and mitigation. Significant economic and social benefits have been generated. In the field of transportation, in the first three quarters of 2020, more than 7 million road vehicles were using BDS. The number of postal and express delivery vehicles using BDS reached 314,000, and the number of ships is about 1,369. In general aviation, 300 planes are using BDS. In agriculture, BDS-based automatic steering systems are on more than 45,000 pieces of agricultural machinery and equipment, saving 50% of the labor cost. BDS-based agricultural machinery operation supervision platforms are serving 10 million units of agricultural machinery equipment, greatly improving management and operational efficiency. In forestry, the BDS positioning and short message communication services are widely used in forest fire prevention, natural forest protection, forest inspection, pest control and so on. In the fishery field, BDS provides fishery managers and fishing vessels with ship position monitoring, emergency rescue, information dissemination, vessel management and other services. BDS terminals have been installed on more than 70,000 fishing boats and law enforcement vessels in China. More than 10,000 people have been saved. For disaster prevention and mitigation, a three-level platform covering the national ministries and the provinces was built to offer six-tier application services, deploying more than 45,000 BDS terminals. BDS plays an important role in the emergency response to major disasters such as flooding in South China and forest fire in Southwest China this year. BDS is accelerating entry into new infrastructural construction, and is deeply integrated with new technologies such as next-generation communication, blockchain, the internet of things, artificial intelligence, and more. New modes, formats and markets for BDS applications are constantly emerging. Mass-Market Applications. BDS-based navigation and positioning services have been adopted by various enterprises in the fields of e-commerce, smart mobile terminals, location-based services, the sharing economy and people’s livelihood, profoundly changing people’s production and lifestyles. Just like water and electricity, BDS provides public services that are easily accessible and available on demand. In smartphone applications, domestic and international mainstream chip manufacturers have released communication-navigation integrated chips compatible with BDS. More than 90% of mobile-phone companies applying for access to China’s domestic network support BDS positioning. Smartphones from Huawei, MI, Apple, VIVO, OPPS and other big brands in China are BDS-enabled. BDS Standards. The updating and upgrading of the BDS standard system is progressing smoothly, with Version 2.0 to be released soon. The BDS application standard systems will be published in electric, railway and other industries. The revision of the national BDS standards is advancing steadily. Four national standards were issued in early 2019, and 28 national standards will be released by the end of 2020. Forty-two standards related to the BDS program have been issued in three batches, while 58 new standards are being formulated. The work related to BDS intellectual properties is being carried out, and various innovation entities continue to improve BDS’ intellectual property creation, utilization and protection capabilities. Statistics shows that Chinese GNSS-related patent applications reached 12,170 in 2019 and 9,411 by the end of October, with an average growth rate of 21.7% in the past three years. International Cooperation Bilateral Cooperation. BDS continues to carry out bilateral cooperation with other GNSS to promote compatibility, interoperability and joint applications. Under the China-U.S. civil GNSS cooperation platform, working groups have been set up to continuously engage in cooperation and exchanges in areas such as compatibility and interoperability, augmentation systems and aviation applications, civil service provisions, etc. China and the Russian Federation held their seventh bilateral meeting in October, and have been pushing forward landmark demonstration projects such as joint ground station set-up, cross-border transportation and precision agriculture. China and the European Union are carrying out coordination, exchanges and cooperation under the framework of the China-EU space cooperation dialogue. Multilateral Cooperation. The BDS team participates in meetings of the International Committee on Global Navigation Systems (ICG), and continuously promotes discussions on relevant topics. The experience fighting COVID-19 using BDS/GNSS, as well as BDS applications in pandemic prevention and control, are being shared with the international GNSS community. During the ninth ministerial meeting of the China-Arab States Cooperation Forum held in July, video conferences promoted the deepening of China-Arab satellite navigation cooperation. International BDS Applications. With the export of BDS high-precision products, BDS is widely used in different regions and fields, such as land registration, precision agriculture, warehouse logistics in ASEAN countries, construction in Western Asia, airport timing and plying the seas in South Asia, power plant inspections in Eastern Europe, and land surveys in African countries. BDS high-precision products are exported to more than 120 countries and regions. BDGAS technologies and products are systematically exported, serving more than 100 million users worldwide. International Standards. BDS has been adopted by many international organizations including the ICAO, the International Maritime Organization, Cospas-Sarsat and mobile communication. A number of international standards supporting BDS have been released. In March, the International Electrotechnical Commission (IEC) officially issued the first international standard for BDS vessel receiving equipment inspection (IEC 61108-5), which provides the basis for global classification societies to carry out type certification of BDS equipment on vessels. In July, the first batch of 3GPP standards supporting the BDS B1C signal was officially released. The series of standards will support BDS signals in Assisted GNSS (A-GNSS) of 5G communication. By year’s end, the Radio Technical Commission for Maritime Services (RTCM) 10403.X standard, which fully supports BDS, will be officially released, marking an important milestone in the creation of a general data format standard for BDS receivers. Adhering to the development concept of “the Chinese BDS, the World’s BDS and the First Class BDS,” BDS development vigorously carries forward the Beidou spirit in the new era — independent innovation, open integration, unity and pursuit of excellence. By 2035, a more ubiquitous, integrated and comprehensive national PNT system with a spatial-temporal information service infrastructure covering space, sky, Earth and sea, and offering unified high precision, high intelligence, high security and high efficiency, will be built. It will provide core support for future intelligent and unmanned development; continuously promote system upgrading; integrate new technologies such as new generation communication and low orbit augmentation; strive to develop high-quality capabilities such as quantum navigation, full-source navigation, and micro PNT; and build a spatial-time information service infrastructure covering space, sky, Earth and sea, with high precision, high intelligence, high security and high efficiency.

a signal-jamming theory of predation