Comprehensive Study Guide for Satellite Architecture, GSM Networks, and Electronic Warfare

SATELLITE ARCHITECTURE AND ORBITS

• Satellite Categories and Classifications

  • Communication Satellites: Designed for transmitting and receiving data and signals over long distances.

  • Remote Sensing Satellites: Used for monitoring the Earth's environment and resources.

  • Weather Satellites: Specifically utilized for meteorological observations and climate monitoring.

  • Navigation Satellites: Provide autonomous geo-spatial positioning (e.g., GPS).

  • Scientific Satellites: Used for space research and scientific experimentation.

  • Military Satellites: Specialized for defense and national security operations.

• Military Satellite Applications

  • Communications: Secure data and voice transmission for armed forces.

  • Intelligence gathering: Reconnaissance and surveillance operations.

  • Navigation: Critical for troop and asset positioning.

  • Early warning: Detecting missile launches or hostile movements.

  • Weather forecasting: Assessing environmental conditions for tactical planning.

  • Timing data: providing precise synchronization for military hardware and networks.

• Core Orbital Definitions

  • Orbit: A trajectory or path that is periodically repeated. This specific definition was highlighted by the professor.

  • Trajectory: The path traced by a moving body.

  • Perigee: The point on a satellite orbit that is closest to Earth.

  • Apogee: The point on a satellite orbit that is farthest from Earth.

  • Footprint of a Satellite: The surface area on Earth covered by a satellite. Alternate terms include "Earth coverage" and "Ground track coverage."

• Satellite Linkage Concepts

  • Uplink: Information beamed UP to a satellite from an Earth station.

  • Downlink: Information beamed DOWN from a satellite to an Earth station.

  • Two-way Satellite Links: Communication links that utilize BOTH uplink and downlink transmissions.

• Orbital Types and Characteristics

  • GEO — Geostationary Orbit:

    • Definition: An orbit where the satellite moves at the same speed Earth rotates, causing it to appear stationary relative to a fixed point on the ground.

    • Altitude: $35,786\,km$.

    • Characteristics: Huge coverage area; high latency due to distance.

    • Primary Uses: Communications and weather satellites.

  • HEO — Highly Elliptical Orbit:

    • Definition: An orbit used primarily to provide coverage to high latitude regions (polar regions) that are not effectively covered by GEO satellites.

    • Example — Molniya Orbit:

      • Purpose: Coverage of high latitude regions ignored by GEO.

      • Details: High-angle highly elliptical orbit.

      • Inclination: $\approx 65^\circ$.

      • Eccentricity: $\approx 0.75$.

      • Apogee: $\approx 40,000\,km$.

      • Perigee: $\approx 400\,km$.

      • Period: $12$-hour orbit.

      • Requirements: $3$ satellites are needed for uninterrupted service.

      • Professor Emphasis: "Molniya is high angle."

• Orbit Classification by Distance

  • GEO — Geostationary Orbit: $35,786\,km$.

  • MEO — Medium Earth Orbit: $10,000\,km$ to $20,000\,km$.

  • LEO — Low Earth Orbit: $160\,km$ to $500\,km$.

• Orbital Classification Factors

  1. Inclination

  2. Eccentricity

  3. Distance from Earth

• Beam Antennas Used by Satellites

  • Global Beam: Covers the entire Earth coverage area visible to the satellite.

  • Hemispheric Beam: Covers half of the globe.

  • Zone Beam: Covers a specific, selected region.

  • Spot Beam: Provides narrow, concentrated coverage for high-density areas.

  • Steerable Beam: An antenna beam that can be redirected remotely to different locations.

SATELLITE SYSTEMS AND PROVIDERS

• The Iridium Constellation

  • Orbit Type: Low Earth Orbit (LEO).

  • Company: American.

  • Satellite Count: $66$ operational satellites.

  • Capabilities: Voice, low-speed data, and messaging services.

• Mobile Satellite Service (MSS) Providers by Country

  • Iridium: USA.

  • Thuraya: United Arab Emirates (UAE).

  • Inmarsat: British (UK).

• Global Satellite Navigation Systems

  • GPS: USA.

  • GLONASS: Russia.

  • Galileo: European Union.

  • BeiDou: China.

GSM AND CELLULAR NETWORKS

• GSM — Global System for Mobile Communications

  • Definition: A digital cellular technology used for transmitting mobile voice and data services.

  • Standardization: The most widely accepted telecommunications standard globally, used extensively in Europe, Asia, Africa, and Australia.

  • Generation: $2G$ technology.

  • Services Introduced: SMS (Short Message Service) and MMS (Multimedia Messaging Service).

• GSM Technical Implementation (FDMA and TDMA)

  • GSM utilizes both FDMA and TDMA for network access:

    1. FDMA: Frequency Division Multiple Access divides the total bandwidth into separate carrier frequencies.

    2. TDMA: Time Division Multiple Access divides each frequency carrier into specific time slots.

  • Technical Breakdown:

    • Total Bandwidth: $25\,MHz$.

    • Carrier Frequencies: $124$.

    • Channel Width: $200\,kHz$.

    • Time Slots per carrier: $8$.

• GSM Frequency Bands

  • Most of the world: $900\,MHz$ and $1800\,MHz$.

  • USA / Americas: $850\,MHz$ and $1900\,MHz$.

• Access Methods in Cellular Technology

  • FDMA: Frequency Division Multiple Access.

  • TDMA: Time Division Multiple Access.

  • CDMA — Code Division Multiple Access:

    • Definition: Multiple users share the same frequency at the same time through the use of unique codes.

    • Applications: $2G$ and $3G$ mobile networks, GPS, and military communications.

    • Common Bands: $800\,MHz$ and $1.9\,GHz$.

• LTE — Long Term Evolution

  • Developer: 3GPP (3rd Generation Partnership Project).

  • Purpose: The standard path toward $4G$ technology.

  • Bandwidth Range: $1.4\,MHz$ to $20\,MHz$.

  • Advantages over GSM:

    • Higher data rates.

    • Lower latency.

    • Improved roaming capabilities.

    • Improved handovers between cells.

GSM COMPONENTS AND DEFINITIONS

• NSS — Network Switching System

  • Purpose: Performs call switching and mobile management functions.

  • Key Components:

    • MSC: Mobile Switching Center.

    • VLR: Visitor Location Register.

    • HLR: Home Location Register.

    • AuC: Authentication Center.

    • EIR: Equipment Identity Register.

• G-MSC — Gateway Mobile Switching Center

  • Purpose: Determines the current location of the MSC for a subscriber being called.

  • Functions: Interfaces the mobile network with external telecommunications systems.

  • Interfaces:

    • PSTN: Public Switched Telephone Network.

    • ISDN: Integrated Services Digital Network.

    • PSPDN: Packet Switched Public Data Network.

    • PLMN: Public Land Mobile Network.

• Subscriber and Identity Registers

  • HLR (Home Location Register): A permanent subscriber database that stores service profiles, location information, and activity status.

  • TMSI (Temporary Mobile Subscriber Identity): A temporary identity assigned by the VLR to protect subscriber identity; it has local significance only.

  • IMSI (International Mobile Subscriber Identity): A unique identity assigned to a registered mobile subscriber, stored physically on the SIM card.

  • IMEI (International Mobile Equipment Identity): A unique identifier for the physical mobile device, similar to a serial number. It is stored in the EIR (Equipment Identity Register).

  • Critical Usage of IMEI/EIR: The IMEI is used to recognize and block obsolete, stolen, or non-functioning equipment.

• BSS — Base Station Subsystem

  • Purpose: Handles the radio communication system.

  • Components:

    • BTS (Base Transceiver Station): Radio equipment that defines a specific cell and handles radio communications with mobile stations.

    • BSC (Base Station Controller): Controls multiple BTS stations; handles handovers, frequency hopping, channel setup, and radio resource management.

GSM CALL FLOW AND TELEPHONY

• GSM Phone to PSTN Call Sequence

  1. MSC/VLR receives the call request.

  2. MSC/VLR checks authorization.

  3. MSC/VLR initiates setup with the PSTN.

  4. MSC/VLR asks the BSC to allocate a traffic channel.

  5. BSC successfully allocates the traffic channel.

  6. The called party answers.

  7. A handover occurs if the user moves to a neighboring cell during the call.

• VoIP — Voice Over Internet Protocol

  • Definition: Voice communications conducted over IP or Internet networks instead of the traditional PSTN.

  • Applications: FaceTime, WhatsApp, Skype, and Google Talk.

  • Capabilities: Voice, SMS, fax, and multimedia communications.

• HPCP — High Power Cordless Phones

  • Technology: Analog UHF.

  • Transmissions: Voice, data, fax, and internet.

  • Range: $1\,km$ to $150\,km$ (under optimal conditions, up to $500\,km$ Line of Sight/LOS).

EW, SIGINT, AND CYBER OPERATIONS

• CNO — Computer Network Operations: Military operations involving communication or computer networks.

• EW — Electronic Warfare: The exploitation of the electromagnetic spectrum to assure electromagnetic spectrum superiority.

  • Electronic Attack (EA)

  • Electronic Protection (EP)

  • Electronic Support (ES)

• SIGINT / EW Support: The use of intercepted electromagnetic emissions to determine capabilities, intentions, formations, and locations of actors of interest.

• SIGINT Sub-disciplines:

  1. COMINT (Communications Intelligence): Collected from intercepted communications (voice, messaging, traffic analysis).

  2. ELINT (Electronic Intelligence): Collected from non-communication emitters (radar, weapons systems).

  3. FISINT (Foreign Instrumentation Signals Intelligence): Signals from weapons testing/development (telemetry, sensors, tracking systems).

• Discipline Comparisons

  • EW Examples: Jamming, radar exploitation, signal direction finding.

  • SIGINT Examples: Communications interception, traffic analysis.

  • Cyber Examples: Malware, backend attacks, hacking.