1. ORBCOMM Satellite System Cairo University Faculty of Engineering Comm. & Elec. Department 4th Year - 2nd semester Satellite Communication Courses Project

2. Introduction Orbital Communications (ORBCOMM) is a company that offers global asset monitoring , messaging and position determination services. ORBCOMM system is a low Earth orbit (LEO) satellite system. 3. Introduction System Description. Ground Infrastructure. Space Segment. 4. System Description 5. System Description Dynamic Channel Activity Assignment System: DCAAS uses a scanning receiver to measure the interference power across the entire uplink band. Identifies clear channels and assigns them for uplink use by SCs. Scanning evaluated at intervals of 5 seconds or less. 6. System Description Position Determination Capabilities: The SC measures the satellite downlink frequency to determine the Doppler shift. The Doppler shift, time, satellite position, and satellite velocity represent one data point. After enough data points are gathered, the SC can calculate the Doppler position. Some SCs are equipped with internal GPS receivers and associated GPS antennas. 7. Ground Infrastructure Overview of ORBCOMM Gateway: An ORBCOMM licensee requires a Gateway to connect to ORBCOMM satellites in view of its service area. The principal role of the ORBCOMM Gateway is to provide message processing and subscriber management for a defined service area. 8. Ground Infrastructure Overview of ORBCOMM Gateway: 9. Ground Infrastructure Gateway Message Switching System: Contains the software that performs the actual message processing, routing, and conversion between the SC and the ORBCOMM Message Switch (OMS) to traditional Mail protocol. 10. Ground Infrastructure Monitoring & Control: Audio alarming for all critical system failures. Collection and storage of system fault and performance data. Graphical interfaces for most system administration tasks. Real-time displays of OMS and GES information. 11. Ground Infrastructure Gateway Earth Station: Provides an RF communications link between the OMS and the satellite constellation. It consists of medium gain tracking antennas, RF and modem equipment, and communications hardware and software for sending and receiving data packets. 12. Ground Infrastructure GES-to-GCC Channels: GES-to-GCC links will operate over 56-kbps or 64-kbps data lines. The GES process communicates with the GMSS process using TCP/IP UDP packets. 13. Ground Infrastructure GES-to-Satellite Channels: A single 57.6-kbps uplink and downlink channel using the TDMA protocol. This protocol permits simultaneous RF links between a single satellite and several GES installations within the satellite footprint. 14. Ground Infrastructure Subscriber Communicator: A wireless VHF modem that transmits messages from a user to the ORBCOMM System for delivery to an addressed recipient, and receives messages from the ORBCOMM System intended for a specific user. 15. Space Segment Constellation Coverage and Availability: Plane designation A, B, C, D F G E Number of orbital planes 4 1 1 1 Number of satellites in each orbital plane 8 4 4 7 Inclination angle 45 70 108 0 altitude (km) 815 740 785-875 975 16. Space Segment System Redundancy: The ORBCOMM System provides redundancy at the system level due to the number of satellites in the constellation. In the event of a lost satellite, ORBCOMM will optimize the remaining constellation to minimize the time gaps in satellite coverage. 17. Space Segment Orbcomm Link Budget: Gateway-satellite Satellite-subscriber Uplink Downlink Uplink Downlink Frequency, MHz 149.4 137.2 148.95 137.5 [EIRP], dBW 40 6.5 7.5 12.5 Misc. losses, dB 7.3 7.3 11.3 11.3 [G/T], dBK-1 -33.3 -12.8 -26 -28.6 Data rate, kbps 57.6 57.6 2.4 4.8 18. Space Segment Satellite Description: Each satellite utilizes the popular TDMA multiplexing scheme and QPSK modulation. Orbcomm is the only current satellite licensee operating in the 137-150 MHz VHF band. 19. Space Segment Satellite Description: 20. Abstract Orbital Communications (ORBCOMM) is a company that offers global asset monitoring , messaging and position determination services. The ORBCOMM System consists of the ground infrastructure, a space segment, and a subscriber segment. 21. Abstract An ORBCOMM Gateway consists of a Gateway Control Center and one or more Gateway Earth Station sites, as well as the network components. Subscriber Communicators. 45 ORBCOMM satellites have orbited Earth. 22. Questions / Comments 23. Thank You By: Akram Ahmed