Role Of Satellite Communication In Safeguarding Our Borders

By Dr. MK Dhaka

INTRODUCTION

Satellite communication can be extremely useful in border areas for the following reasons:

1. Connectivity: Satellite communication provides a reliable means of communication in remote and rugged terrains where traditional communication infrastructure like cell towers or landlines is not feasible.
2. Emergency Services: In case of emergencies such as natural disasters or medical emergencies, satellite communication can be crucial for coordinating rescue efforts and providing medical assistance.
3. Security: Satellite communication can enhance border security by enabling real-time monitoring and communication between border patrols and control centers, helping to prevent illegal border crossings and other security threats.
4. Remote Monitoring: Satellites can be used to monitor border areas for illegal activities such as smuggling or unauthorized border crossings, providing valuable intelligence to border security forces.
5. Infrastructure Development: Satellite communication can support the development of infrastructure in remote areas by providing connectivity for construction crews, engineers, and other personnel involved in infrastructure projects.

Satellite communication can also improve connectivity in mountainous border areas in various ways:

1. Internet Access: Satellite internet can provide high-speed internet access to remote communities, schools, and healthcare facilities in mountainous areas where terrestrial infrastructure is lacking. For example, the government or NGOs could set up satellite internet hubs to provide internet access to schools in remote mountain villages, enabling students to access online educational resources.
2. Telecommunications: Satellite communication can support reliable voice and data communications for residents, businesses, and government agencies in mountainous areas. For instance, satellite phones can be used by border security forces to maintain communication in remote border outposts where traditional communication networks are unavailable.
3. Disaster Response: In the event of natural disasters such as earthquakes or landslides, satellite communication can be critical for coordinating disaster response efforts. For example, satellite phones can be used by emergency responders to communicate with headquarters and coordinate rescue operations in remote mountainous areas.
4. Weather Monitoring: Satellites can provide real-time weather information for mountainous regions, helping to predict and monitor weather patterns that could affect the safety of residents and travellers in the area. This information can be used to issue early warnings for potential hazards such as avalanches or flash floods.
5. Navigation: Satellite-based navigation systems like GPS are essential for navigation in mountainous terrain, where traditional landmarks may be scarce. GPS can help hikers, climbers, and border patrols navigate safely through rugged mountain terrain, reducing the risk of getting lost or stranded.

COMMUNICATION SATELLITES BASED ON THEIR ORBITS:

1. Geostationary satellites are commonly used for Satellite Communication (SATCOM) due to their unique characteristics. Geostationary satellites are used for long-distance telecommunications, including voice calls, video conferencing and data transmission. They enable reliable communication between distant locations, such as between different countries or continents. Geostationary satellites are also used for military communication purposes, including secure voice and data transmission, reconnaissance, and surveillance. They provide a secure and reliable communication channel for military forces deployed in remote or hostile environments.
2. Low Earth Orbit (LEO) satellites are increasingly being used for SATCOM due to their lower latency and higher data speeds compared to geostationary satellites. Here are some examples of how LEO satellites are used for Satcom:
3. Global Internet Coverage: Companies like SpaceX, OneWeb, and Amazon are deploying constellations of LEO satellites to provide global broadband internet coverage. These satellites can deliver high-speed internet access to remote areas and underserved communities where traditional infrastructure is lacking. OneWeb and StarLink services may be available in India very soon.
4. Remote Sensing and Earth Observation: LEO satellites are used for remote sensing and Earth observation applications, such as monitoring environmental changes, tracking weather patterns, and managing natural resources. These satellites provide valuable data for scientific research, disaster management, and agricultural monitoring. ISRO has been launching a CartoSat series of satellites for high-resolution imagery.
5. Maritime and Aviation Connectivity: LEO satellites are used to provide connectivity for maritime and aviation applications, including internet access for ships and airplanes. This connectivity enables real-time communication, tracking, and monitoring of vessels and aircraft, improving safety and efficiency at a global scale.
6. IoT and M2M Communication: LEO satellites are used for Internet of Things (IoT) and Machine-to-Machine (M2M) communication, enabling connected devices to transmit data over long distances. This is particularly useful in remote areas where terrestrial connectivity is limited. DEAL, DRDO has initiated a project on Space-based Military IoT to address various defence use cases by exploiting LEO satellites.
7. Emergency and Disaster Response: LEO satellites play a crucial role in emergency and disaster response efforts by providing reliable communication links in areas affected by natural disasters or humanitarian crises. These satellites enable first responders to coordinate rescue operations and provide assistance to those in need.

Satellite-based Navigation Systems: Satellite constellations are used for navigation services through a technology known as satellite-based navigation systems. These systems utilize multiple satellites in orbit to provide accurate positioning, navigation, and timing (PNT) information to users on the ground, at sea, or in the air. Here are some examples of satellite constellations used for navigation services:

• Global Positioning System (GPS): The GPS is a constellation of satellites operated by the United States government. It provides PNT information to users worldwide, allowing them to determine their precise location, speed, and time. GPS is widely used in aviation, maritime, transportation, surveying, and outdoor recreation, among other applications. GPS is controlled and operated by the United States government (U.S. Space Force).
• Galileo: Galileo is the European Union’s global navigation satellite system (GNSS). It is designed to provide an independent and highly accurate positioning service under civilian control. Galileo enhances the availability and reliability of PNT information, particularly in high-precision applications such as agriculture, construction, and scientific research. Galileo is controlled and operated by the European Union (European GNSS Agency).
• GLONASS: GLONASS is Russia’s GNSS, similar to GPS and Galileo. It provides global coverage and is used for navigation, mapping, and timing applications. GLONASS is particularly useful in high-latitude regions where other GNSS systems may have limited coverage. GLONASS is controlled and operated by the Russian government (Russian Space Forces).
• BeiDou: BeiDou is China’s GNSS, which provides global coverage with an emphasis on the Asia-Pacific region. It offers positioning, navigation, and timing services for various applications, including transportation, agriculture, and disaster management. BeiDou is controlled and operated by the Chinese government (China National Space Administration).
• Regional Satellite Navigation Systems: In addition to global systems like GPS, Galileo, GLONASS, and BeiDou, there are also regional satellite navigation systems. For example, India’s NavIC (Navigation with Indian Constellation) provides PNT services in the Indian region, supporting applications such as transportation, agriculture, and disaster management. NavIC is controlled and operated by the Indian government (Indian Space Research Organisation).

All systems are used for various applications, including transportation, agriculture, surveying, disaster management, and military applications. While all these systems provide similar positioning, navigation, and timing services, having multiple systems increases availability and redundancy, particularly in challenging environments such as urban canyons or high latitudes. Users can benefit from using multiple systems simultaneously to improve accuracy and reliability.

Current Trends in SATCOM technology:

Several trends that are shaping the field of satellite communication are as follows:

• High-Throughput Satellites (HTS): HTS use multiple spot beams to provide higher data throughput and capacity compared to traditional satellites. They are increasingly being used for broadband internet access, especially in remote or underserved areas. ISRO has also launched several High throughput satellites like GSAT-29, GSAT-11 and GSAT-19. GSAT-9 was launched in Nov 2018. This communication satellite has Ka/Ku band high throughput transponders and a Q/V band payload. GSAT-11 was launched in Dec 2018 and is ISRO’s heaviest and most advanced HTS communication satellite.

HTS satellites have a higher data processing and transfer capacity than conventional satellites while using the same amount of orbital spectrum. They use powerful beams instead of wide beams, which gives them a throughput that is 10 to 100 times higher than conventional satellites.

• Non-Geostationary Satellite Constellations: Constellations of low Earth orbit (LEO) and medium Earth orbit (MEO) satellites are being deployed to provide global coverage and low-latency communication for a variety of applications, including broadband internet, IoT, and remote sensing.
• Software-Defined Satellites: Software-defined satellites use reconfigurable onboard processors and software-defined radios to adapt to changing communication requirements and improve flexibility and efficiency. This technology is prevalent in military communication satellites of advanced nations.
• Inter-Satellite Links (ISL): Inter-Satellite Links is a radio communication service that allows satellites in a constellation to communicate with each other and relay data in space. ISLs are essential for LEO satellites to create a robust global network because they can only see small portions of the ground at a time. ISLs enable direct communication between satellites in space, bypassing the need for ground stations. Both microwave and optical ISLs are being used.
• Satellite Internet of Things (IoT): Satellites are being used to provide connectivity for IoT devices, especially in remote or isolated areas where traditional communication infrastructure is lacking.
• Advancements in Ground Segment Technology: Ground stations are adopting technologies such as phased array antennas, optical communication and advanced signal processing techniques to improve satellite communication performance and efficiency.
• Increased Demand for Satellite Services: The growing demand for broadband internet access, remote sensing, disaster management, and other satellite services is driving innovation and investment in satellite communication technologies.
• Non-Terrestrial Networks: Non-Terrestrial Networks include satellite and other space-based communication systems and are gaining increasing attention in the telecommunications industry, especially for extending coverage to remote or underserved areas and enabling new use cases. Even the 5G standard addresses NTN connectivity.
• Broadband SATCOM: Broadband satellite communication can provide high-speed internet access to users in rural, remote, or underserved areas where terrestrial broadband services are not available. Satellite technology enables broadband services to be delivered to almost any location on Earth, making it ideal for providing connectivity in remote or isolated regions. Broadband satellite systems typically support two-way communication, allowing users to both receive and transmit data. This enables a wide range of interactive services, such as video conferencing, online gaming, and VoIP.

Broadband satellite systems can use different access technologies, such as DVB-RCS (Digital Video Broadcasting – Return Channel Satellite) or MF-TDMA (Multi-Frequency Time Division Multiple Access), to efficiently manage communication with multiple users. While broadband satellite communication offers many benefits, it also faces challenges such as latency (delay in data transmission due to the distance to the satellite), signal interference, and limited bandwidth compared to terrestrial broadband technologies.

These trends indicate a shift towards more advanced, efficient, and flexible satellite communication systems that can meet the increasing demand for connectivity and data services across the globe.

Indian Scenario:

In India, the Indian Space Research Organisation (ISRO) is the main agency for design, development and launch of space segments for various missions. ISRO has launched several geostationary satellites for communication like INSAT-3A, INSAT-3C, INSAT-4B, and INSAT-4CR, GSAT-6, GSAT-7, GSAT-10, GSAT-15, GSAT-17, GSAT-19, and GSAT-29.

For defence forces, Defence Electronics Applications Laboratory (DEAL) of Defence Research and Development Organisation (DRDO) is responsible for design and development of SATCOM ground segment. Here are some key aspects of DEAL satellite systems:

Purpose: DEAL aims to provide secure, reliable, and jam-resistant communication for the Indian defence forces using satellite-based systems.

Technology: Ground segment is equipped with advanced communication systems and encryption technologies to ensure secure communication channels for military operations.

Integration: These systems are integrated with other communication and surveillance systems used by the Indian defence forces to enhance situational awareness and command and control capabilities.

Development: The development of defence SATCOM ground system is part of DRDO’s efforts to enhance India’s defence capabilities and ensure the security of its borders and territories.

SATCOM Products:

Manpack Satcom Terminal (MST): MST is a battery-operated S-band Manpack terminal operating over a GSAT-6 satellite and forms a Mobile Satellite Service (MSS) network. It operates at the maximum information rate of 32 kbps. This terminal can be used for data transfer of images, captured videos, file transfer, etc. in addition to voice capability. The MAC of the network is based on TDM/TDMA technology. These terminals communicate in two hops via Hub where the Umbrella Network Control and Management System (UNCMS) resides and allocates resources dynamically on a call-by-call basis.

Satellite Phone: Satellite Phone is a battery-operated S-band handheld terminal operating over a GSAT-6 satellite and forms a Mobile Satellite Service (MSS) network. It is the first Indian Satellite Phone made for a Powerful Indian MSS Satellite with the primary service being voice. This terminal interacts with the satellite in TDM/SCPC mode. Satellite Phone is capable of communicating with MST and captive telephone exchanges via the Terrestrial Interface Gateway at Hub.

Satcom Messaging Terminal (SMT): SMT is a battery-operated S-band handheld terminal operating over a GSAT-6 satellite and forms a Mobile Satellite Service (MSS) network. It is primarily a Messaging and Reporting terminal. This terminal supports Periodic Location Reporting using GPS and SMS service. The SMS from SMT can be sent to Hub and SMT to SMT. The SOS message transmission facility is provided to the user. It also enables the Navigation aid to the Users.

Ku band MF-TDMA terminal: A Man Portable Ku band MF-TDMA terminal with 0.76M antenna has been realized. The antenna is a Parabolic Reflector Antenna with a positioning system made of lightweight Carbon Fibre-reinforced plastic (CFRP) material having 6 panels which are detachable. The Antenna pointing is done manually using IMU sensors, GNSS and a compass. The antenna has a Tripod mechanical assembly to position the Antenna and RF Front end. The RF front end consisting of BUC and LNBC of the terminal is compact and lightweight. The terminal baseband hardware is based on software-defined radio architecture. The baseband modem technology is based on Multi-Frequency- Time Division Multiple Access (MF-TDMA) in TX (Return link) and DVB S2 in Rx (Forward link). MPST derives power from the external power supply of 48V DC. The external power supply is powered by an AC/DC adaptor and battery.  It is a robust terminal for Military Applications. It is capable of providing all-terrain secure high data rate IP services like VOIP, Video Streaming, Video Conferencing, File Transfer etc.

Avalanche Warning Terminal: In the Himalayan border region, Avalanches pose a serious threat to life, establishments and other critical assets of our armed forces. The legacy avalanche alert system requires a man in the loop to disseminate avalanche and weather forecasts. By leveraging satellite communication, a solution has been realized wherein met data is collected and avalanche forecast is disseminated through a satcom link leading to near real-time dissemination of alerts.

These are some of the satellite products developed by DEAL, DRDO for Indian defence forces and paramilitary forces to facilitate their functioning in difficult terrain.

Dr. MK Dhaka, Outstanding Scientist & Scientist-H, joined DEAL, DRDO in Oct 1990.  Thereafter, he has worked on several important DRDO projects