1、 Background of the birth of Tiantong satellite phone

The 2008 Wenchuan earthquake

On May 12, 2008, a 8.0 magnitude earthquake struck Wenchuan, China, causing almost complete paralysis of the ground communication network in the entire earthquake stricken area. At this critical moment, people found that their mobile phones had lost signal, unable to make calls, send text messages, access the internet, and communicate with the outside world. Rescue personnel and command units outside were also unable to immediately understand the situation in the disaster area. This has caused great obstacles to the rescue work, delayed the rescue progress, and also caused further losses to the people in the disaster area.

At that time, China did not have its own communication satellite system and satellite communication equipment, and could only use American satellite phones to carry out earthquake relief work. At that time, there were global or regional mobile satellite communication systems such as Iridium and maritime, which were widely used in various fields such as personal communication, ocean transportation, offshore fishing, and transportation logistics. In the event of natural disasters such as earthquakes, floods, and typhoons, they could communicate without barriers and played an extremely important role in emergency rescue and disaster relief.

It is precisely the communication shortcomings exposed in the Wenchuan earthquake that have made China deeply aware of the urgency of independently building a mobile communication satellite system. Afterwards, China launched the project demonstration of an independent mobile communication satellite system, determined to fill the gap in the field of satellite mobile communication.

Development History

The development history of Tiantong-1 satellite has witnessed China's continuous progress in the field of satellite communication.In 2010, the Tiantong-1 satellite was officially approved, and the Fifth Academy of China Aerospace Science and Technology Corporation immediately launched the research and development of Tiantong-1 01 satellite, marking the beginning of China's journey to independently build a satellite mobile communication system.

The Tiantong satellite was developed by the China Academy of Space Technology, and after years of research and unremitting efforts,On August 6, 2016, China's first independently developed high orbit mobile communication satellite, Tiantong-1 01, was successfully launched into its designated orbit at the Xichang Satellite Launch Center. On August 20 of the same month, First Call was established, which was undoubtedly an exciting beginning. Afterwards, in June 2017, satellite in orbit application tests were completed from the east to the Diaoyu Islands, west to Hongqilafu, south to Zengmu Ansha, and north to Mohe, achieving long-term communication between 400 terminals in a single area and 1000 terminals in multiple areas, fully verifying its communication capability and stability. In July 2017, the Ministry of Industry and Information Technology approved the special section 1740, laying the foundation for subsequent business commercialization.

In March 2018, China Telecom launched its first satellite mobile communication service to the commercial market, marking China's entry into the "mobile phone era" of satellite mobile communication, filling the gap in China's independent mobile communication system, breaking the current situation of relying on foreign satellite mobile communication services, and having important milestone significance. At the same time, several domestic enterprises began to enter the Tiantong mobile communication terminal and chip business, such as Huali Chuangtong launching Tiantong handheld chips and Tiantong handheld devices in the same year. Tiantong satellite business products have been gradually launched in the market, allowing this advanced communication technology to enter the market and serve the public. In November 2018, the Ministry of Industry and Information Technology issued the first Tiantong terminal network access license, which means that the relevant terminal equipment has met the network access standards and can be put into use in a more standardized and secure manner. In February 2019, the Ministry of Emergency Management included Tiantong in the implementation guidelines for local emergency management informationization, highlighting its important position in the emergency field. In September 2019, the Tiantong Terminal Industry Branch of China Telecom Terminal Industry Alliance was established, further promoting the coordinated development of the industry chain. On December 18, 2019, the Ministry of Industry and Information Technology approved the official commercialization of China Telecom's Tiantong service, and Tiantong's satellite service officially began its journey of serving society.

On November 12, 2020, China successfully launched the Tiantong1-02 satellite into its designated orbit using the Long March 3B carrier rocket at the Xichang Satellite Launch Center.

On January 20, 2021, China successfully launched the Tiantong1-03 satellite into space using the Long March 3B carrier rocket from the Xichang Satellite Launch Center. The satellite has successfully entered its designated orbit.

In September 2021, the Ministry of Industry and Information Technology approved China Telecom's "Tiantong International Code Application"; In June 2023, China Telecom submitted an application report for the Tiantong International Code to the International Telecommunication Union, which officially accepted the application. The relevant review work is gradually being carried out, indicating that Tiantong's satellite business is steadily moving towards internationalization and is expected to play a more important role on the global communication stage.

The current coverage area of the Tiantong satellite system mainly includes China and its surrounding areas, the Middle East, Africa and other related regions, as well as most of the Pacific and Indian Ocean waters. There are no restrictions on terrain coverage, and communication coverage can be achieved in oceans, mountainous areas, plains, forests, Gobi, and deserts. Covering various mobile users such as vehicles, airplanes, ships, and individuals, Tiantong-1 provides 24/7, stable, and reliable mobile satellite communication services for personal communication, ocean transportation, offshore fishing, aviation rescue, tourism and scientific research, and supports voice, short message, and data services. In the event of natural disasters, Tiantong-1's emergency communication capabilities can play a significant role.

The Tiantong Satellite System is constructed, operated, and promoted by China Telecom for civilian systems, and will form a wide area, three-dimensional, and ubiquitous access spatial information network together with ground mobile communication networks.

2、 The working principle and composition of Tiantong satellite phone

Composition of Communication System

The Tiantong satellite phone mainly relies on the Tiantong-1 satellite communication system to achieve communication functions. The system mainly consists of communication satellites (systems), ground measurement and control stations, communication earth stations (gateway stations), satellite phones, and other parts.

Communication satellites are located in space and are responsible for forwarding, relaying, or regenerating communication signals, much like aThe 'air bridge' allows signals from different regions to be transmitted through it. For example, when a user on one end sends a signal, the communication satellite can receive and process it accordingly, and then forward the signal to the target direction.

The role of ground measurement and control stations is crucial, as they are responsible for satellite tracking, telemetry, remote control, status monitoring, and position maintenance. By using various professional equipment and technical means, we can constantly grasp the specific situation of the satellite in space, ensuring that the satellite can operate stably and accurately on the established orbit. Once any abnormalities or deviations from the orbit are detected, the ground measurement and control station can promptly issue instructions for adjustment.

The communication earth station (gateway station) establishes a channel for signal transmission and reception between users and satellites, which can be set up in different locations such as land, sea, or air. It can receive signals from user terminals and transmit them to satellites, as well as receive signals forwarded by satellites and transmit them to corresponding users, making it an important relay station for information exchange.

And Tiantong satellite phone is a terminal device directly used by users, establishing communication links between users and communication earth stations or users and satellites, facilitating users to make calls, send text messages, and perform data transmission operations anytime and anywhere, meeting people's communication needs in different scenarios. These parts work together to build the Tiantong-1 satellite communication system, enabling Tiantong-1 satellite phones to function in many complex environments and provide stable and reliable communication services for people.

Overview of Working Principle

The working principle of Tiantong satellite phone is to use Tiantong-1 satellite as a relay station to forward radio signals and achieve communication between different earth stations.

Specifically, when a user initiates a call using the Tiantong satellite phone, the terminal device will first send out wireless signals containing call information, which are transmitted in a specific frequency band to the Tiantong-1 satellite in the airAdvance. After receiving signals from user terminals, the Tiantong-1 satellite will process the signals accordingly, such as amplification, frequency conversion, etc., and then forward the processed signals to the direction of the target earth station or target user terminal.

Similarly, when there is a signal to be transmitted back to the calling user, the signal is first sent to the Tiantong-1 satellite, which then forwards the signal to the corresponding user terminal, ultimately achieving communication between the two parties. Regardless of whether the user is in areas that cannot be covered by ground cellular mobile communication networks such as deserts, plateaus, Gobi, polar regions, oceans, or in other extreme environments, as long as they are within the coverage range of the Tiantong-1 satellite, they can use this working principle to achieve all-round, all-weather satellite mobile communication services such as voice and data through Tiantong-1 satellite phones, ensuring that communication signals can be continuously stable and allowing users to always maintain contact with the outside world.

3、 Highlights of the functions of Tiantong satellite phone

（1） Extremely wide coverage

The Tiantong-1 satellite is a geostationary orbit satellite with an altitude of36500 kilometers. At present, there are three stars covered, which were launched into space in 2016, 2020, and 2021 respectively. The Tiantong-1 satellite uses point wave velocity coverage to achieve high-density signal two-way voice, SMS, and data communication. Its coverage area covers China's territorial waters and surrounding areas, as well as related regions such as the Middle East and Africa. Most of the Pacific and Indian Oceans are also within its coverage area.

Unlike the coverage range of radio and television signal area beams, it can provide all-weather, all day, stable and reliable mobile communication services such as voice, short message and data for users in China and surrounding areas, the Middle East, Africa and most of the Pacific and Indian Ocean waters. Whether it is terrains such as oceans, mountainous areas, grasslands, Gobi, deserts, or geological disasters such as floods and earthquakes, when the ground mobile communication network does not have communication conditions, as long as it is within the coverage range of Tiantong-1 satellite, seamless coverage can be achieved without geographical limitations, meeting the satellite communication needs of users in remote areas such as suburban outdoor areas, forests, deserts, oceans, and mountains that cannot be covered by ground mobile communication networks, truly ensuring comprehensive communication.

Multi scenario communication mode

Tiantong satellite phone has rich and practical communication functions, supporting voice, short message, data communication, and location services. And it also integrates with the ground4G/5G network, public intercom, and other communication modes have strong applicability. For example, the X5u 5G satellite integrated communication handheld device launched by Huilingxing Technology uses domestically produced CPUs from Ziguang Spreadtrum, which not only supports 4G/5G basic functions, but also integrates multiple functions such as Tiantong satellite phone, Beidou-3 short message, low orbit satellite communication, Mesh self-organizing network, public network intercom, RTK centimeter level high-precision positioning, greatly facilitating the selection and application of industry users.

For example, in daily use, when in an area covered by ground network signals, it can rely on the ground4G/5G network provides convenient and fast communication like regular mobile phones, allowing for high-speed and stable data transmission, smooth and clear voice calls, and other services; When entering areas that cannot be covered by ground-based cellular mobile communication networks, such as remote mountainous areas, vast deserts, and vast oceans, it will automatically switch to satellite communication mode, relying on the Tiantong-1 satellite system to ensure smooth communication and achieve voice, short message, data communication, and location information transmission. At the same time, the public network intercom function can also leverage the advantages of instant communication and group communication in scenarios such as multi person collaboration and team work, greatly meeting people's communication needs in different scenarios and truly becoming a multifunctional communication tool in people's hands.

Powerful emergency function

The emergency function of Tiantong satellite phone is outstanding and can play a crucial role in critical moments. It has one click functionalityThe SOS emergency call function allows users to immediately send a distress message to the pre-set rescue personnel and make a distress call by simply pressing the corresponding button when they encounter an emergency situation. The distress message will also include information about the user's current location, which can accurately locate the location of the rescuer and greatly shorten the rescue response time, providing valuable opportunities to ensure the safety of the user's life.

In addition, in some extreme situations, such as power outages and other accidents, it relies on its built-in large capacity battery to continue working, achieving 24/7 online connectivity without losing communication capabilities due to external power outages. At natural disaster sites such as earthquakes and floods, ground communication facilities are often prone to damage and power supply may be interrupted. However, the Tiantong satellite phone, with its powerful emergency function, can maintain smooth communication and provide stable and reliable communication support for emergency rescue command and disaster relief, as well as seeking help from affected people. It has become an indispensable and important communication tool in emergency rescue scenarios.

Diverse terminal types

In order to adapt to different application scenarios, Tiantong Satellite Phone has developed multiple terminal types, including handheld devices, portable boxes, broadband internet terminals, data acquisition terminals, Tiantong tablets, and fixed satellite phones.

Handheld terminals are compact, lightweight, and easy to carry, suitable for personal use in outdoor travel, outdoor sports, remote area exploration, and other scenarios. Users can take them out anytime and anywhere for communication and contact; Portable terminals not only ensure certain communication functions, but also further optimize the convenience of portability, making them suitable for use in situations that require frequent movement and high communication requirements, such as geological survey personnel transferring between different survey sites; Carrier terminals can be installed on vehicles, ships, airplanes, and other transportation vehicles to provide stable satellite communication services for industries such as transportation, offshore fishing, and air passenger transport, ensuring their communication needs during travel or flight; Data collection terminals focus on the collection and transmission of various types of data, and are often used in special work scenarios that require remote data collection and transmission, such as field data collection, environmental monitoring, and other fields; Fixed terminals are generally installed in specific indoor locations, such as emergency command centers, remote office spaces, etc. They can provide relatively stable and reliable communication services, becoming a communication hub in the region. Even in the face of adverse weather, geological disasters, etc., they can ensure uninterrupted communication and assist in smooth command and dispatch work.

4、 Application scenarios of Tiantong satellite phone

Emergency relief field

In the field of emergency rescue, Tiantong satellite phone shoulders an extremely important communication responsibility. When natural disasters such as earthquakes, floods, typhoons, etc. occur, ground communication facilities are often prone to serious damage, and communication equipment such as mobile phones that rely on ground base stations will lose signals, leading to difficulties in rescue command, coordination, and information transmission.

For example, in a certain earthquake disaster, the ground communication network in the earthquake area was almost completely paralyzed, and conventional communication methods were ineffective. However, the Tiantong satellite phone can still be used normally due to its characteristics of not relying on ground base stations and forwarding signals through the Tiantong-1 satellite as a relay station. Rescue personnel can use the Tiantong satellite phone to timely report key information such as the disaster situation and the location of trapped personnel to the command center. The command center can also rely on it to issue accurate rescue instructions to various rescue teams, ensuring the orderly progress of rescue work.

For example, in flood prevention and disaster relief, when faced with the situation of communication base stations being destroyed and some areas being submerged by floods, Tiantong satellite phones can be put into use in temporary emergency command places to ensure smooth emergency command and duty telephone communication between flood prevention units, allowing information to be transmitted in a timely manner and buying valuable time for rescue and disaster relief. When Sanming City was hit by continuous heavy rainfall, multiple communication facilities were damaged, and some villages and towns were at risk of communication interruption, China Telecom utilized the Tiantong satellite capability to ensure reliable and smooth communication. Emergency command personnel and rescue workers transmitted frontline disaster situations and deployed rescue decisions through Tiantong satellite in a timely manner, and people in disaster stricken areas could also report their safety to their families.

In addition, the Tiantong satellite phone indoor fixed mobile dual-use landline terminal also plays a unique role in emergency relief, as it can meet the needs of24-hour network standby, indoor fixed workstation standby "standing guard", through the intelligent management platform, it can also perform cloud management, real-time monitoring of equipment information, location, online status, etc., truly achieving cloud management and real-time "on duty". In the event of extreme disasters and the occurrence of "three disconnections" (circuit breakers, power outages, and network disconnections), it is still possible to ensure information exchange between the emergency site and the command center, achieve "finding people" and "communication", and assist in efficient command and dispatch.

Indoor Command Center

In indoor command centers of emergency, fire, public security, armed police, transportation, civil air defense, water conservancy, land use, energy and other departments, Tiantong satellite phone is an indispensable and important communication tool.

These departments need a stable and reliable communication method that can ensure smooth communication of command and dispatch information when carrying out tasks and responding to emergencies. Indoor command centers often undertake the key task of gathering information from all parties and issuing decision-making instructions. Once communication is poor, the entire emergency response and rescue operations may be seriously affected.

The Tiantong satellite phone indoor fixed mobile dual-use landline terminal has demonstrated its advantages here. Its working principle is to place the Tiantong satellite handheld terminal on the indoor landline, connect it to the outdoor antenna to receive signals, and be as convenient to use as a regular landline. It supports the Tiantong-1 satellite network and also supports customizationVarious communication modes such as 4G/5G full network, network, and intercom can be used to make and receive satellite calls, send and receive satellite text messages, perform satellite positioning, and report location SOS、 One click alarm and other functions, built-in large capacity battery, can continue to be used even in case of power outages or other emergencies, truly achieving 24/7 online connectivity.

For example, when the fire department responds to urban fires, the indoor command center relies on the Tiantong satellite phone to maintain close contact with on-site firefighters, real-time grasp the fire situation, personnel location and other information, and accurately command and dispatch firefighting operations; When handling major cases and carrying out security tasks, the public security department ensures timely and accurate communication of information between various command levels and different action groups through Tiantong satellite phone, ensuring the smooth progress of tasks.

Remote Area Guarantee

In remote rural areas and areas with weak ground signals such as power and energy extraction, Tiantong satellite phones have become a crucial communication hub.

Many remote rural areas are located in complex geographical environments such as mountainous areas and deserts. The construction of ground communication base stations is difficult and the coverage is limited, resulting in unstable or even no mobile phone signals. It is extremely inconvenient for villagers to communicate with others, which also brings many obstacles to the operation and management of rural areas and the response to emergencies. The Tiantong satellite phone can effectively solve this problem, providing stable communication services for rural areas, facilitating communication between villagers and the outside world, and also helping the village to seek help or report the situation to the outside world in a timely manner when encountering natural disasters or emergencies. For example, in some remote villages prone to natural disasters, the indoor landline of Tiantong satellite phone can serve as a communication hub within the village to ensure basic communication needs.

For remote power facilities or energy extraction areas, their operation and maintenance require continuous and stable communication support, so that staff can report work progress, encountered problems, and receive instructions from superiors in a timely manner. But these areas are often far away from cities and have poor ground signals. The emergence of Tiantong satellite phones has made up for this communication gap, allowing staff to contact the outside world anytime and anywhere, ensuring the normal operation of power and energy extraction work. In some deep mountain hydroelectric power stations and remote coal mining areas, Tiantong satellite phones ensure information exchange between staff and the outside world, helping smooth daily operations and emergency response work.

Maritime communication applications

In waters far from land, ground signals cannot be covered. The Tiantong satellite phone is installed in the ship's cabin, providing critical communication support for maritime activities and meeting the communication needs of many maritime activities such as maritime surveillance and offshore fishing.

For the maritime police supervision work, law enforcement personnel need to maintain contact with the onshore command center at all times when performing patrol, law enforcement and other tasks in the vast sea area, report the maritime situation, receive action instructions, etc. The stable signal transmission and reliable communication function of Tiantong satellite phone ensure the smooth progress of supervision work, and timely feedback and support in case of emergencies.

In terms of offshore fishing, fishermen go out to sea for operations, especially in remote areas where ordinary networks cannot cover. Therefore, satellite phones have become an important tool for them to communicate with land and their families. For example, Quanzhou in Fujian isDuring the "fishing season", Tiantong satellite phones were equipped for 1449 large and medium-sized fishing boats in the city, ensuring instant communication between fishing boats and shore stations, allowing fishermen to stay connected at sea and enhancing the risk warning capabilities of fishing boats; The Shouguang Marine Fisheries Development Center provides Tiantong satellite phones for fishing vessels with a capacity of over 110kW. With stable signals and high-definition communication technology, it can provide communication and positioning functions in extreme environments such as rainfall, humidity, and salt spray, effectively solving the problem of emergency communication for fishermen going out to sea and helping to build a "safe fishing industry".

In summary, the Tiantong satellite phone has broken the geographical limitations in maritime communication applications and built a reliable communication bridge for maritime activities.

5、 Future prospects

Looking ahead to the future, Tiantong satellite phone has broad development prospects. In terms of expanding the international market, with the approval of the Ministry of Industry and Information Technology for China Telecom to obtain international telecommunication code resources for satellite communication services, as well as the positive progress of submitting applications to the International Telecommunication Union and being accepted, Tiantong's satellite business has entered a new stage of international operation. This means that it will have the opportunity to provide mobile direct satellite communication services to international users in various fields such as ocean transportation, offshore fishing, aviation rescue, tourism and scientific research on a global scale, breaking geographical limitations, competing with similar foreign products, and further enhancing the influence and competitiveness of China's satellite communication industry in the international market. It is expected to occupy an important position in the global communication field like maritime and Iridium satellite communication systems.

Continuous investment in technology research and development will drive the continuous upgrading of Tiantong satellite phones in further optimizing performance. For example, in terms of signal transmission, it is expected to further enhance signal anti-interference ability and improve communication stability in harsh weather and complex electromagnetic environments by improving satellite communication technology and optimizing ground measurement and control stations; Terminal devices will also develop towards smaller and lighter sizes, lower power consumption, and more powerful functions, such as improving battery life, optimizing star search speed, and enhancing intelligent noise reduction effects, making the user experience more high-quality and convenient.

In terms of expanding application areas, its potential is limitless. In addition to existing scenarios such as emergency rescue, indoor command centers, remote area support, and maritime communication applications, with the integration and development of emerging technologies such as the Internet of Things, big data, and artificial intelligence, Tiantong satellite phones can be connected to various intelligent devices to achieve more diverse data collection and transmission functions, such as assisting in data transmission in fields such as field ecological environment monitoring and unmanned area resource exploration; It can also be applied to remote education, remote monitoring, etc