SSP Implementation: GEO vs. LEO. Reza Zekavat

Size: px

Start display at page:

Download "SSP Implementation: GEO vs. LEO. Reza Zekavat"

Gary Conley
5 years ago
Views:

1 SSP Implementation: GEO vs. LEO Reza Zekavat 1

2 GEO Orbit SBSP Cost? Maintenance? Environmental? Solar storm? 2

3 Installa1on and Launching Costs GEO: km (22300 Mile) Interna1onal Space Sta1on: 278 km (173 mi) and 460 km (286 mi) 3

4 GEO Orbit Conges1on à Limited Units 4

5 Coverage Closer to the Equator 5

6 LEO? 6

7 LEO Implementa1on: Direct Transmission Lower al3tudes à lower power loss Lower transmission power per unit Higher reliability Lower cost of launching Complex? Handoff Process Synchroniza3on Rou3ng if a cluster is not in ground sta3on field of view 7

8 LEO Implementation: Direct Transmission Multi-Satellite Synchronization? Different Doppler Different distance to ground 8

9 Follower Leader Op1on PCBS visibility zone / cone Follower Satellite Leader Satellite 9

10 Follower-Leader Option Synchronization may not required if each spacecraft orbit in formation is carefully designed But how about conversion loss? RF to DC DC to RF 10

11 MEO- LEO (Tethered Op1on) Solar Power Harves1ng Units (SOPHU) Ionosphere Atmosphere Orbital Control Situation Awareness Power Distribution High Gain Comm. Power Relaying Security Reliability Transmission Line Structures (TLS) LEO Satellite Ground PCBS The Earth 11

12 Ci1es in the Equator Transmission Line Needed 12

13 Captured Power Transmission frequency: 5GHz The power harvested by solar cells: 1400W/m 2 TX Antenna Area (Km Aperture 2 Captured ) P t (db) 5000Km 1000Km Power GEO MW 1 TW 3 TW 500m MW 200 GW 600 GW (88dBi) KW 2 GW 6 GW 250m (82dBi) KW 340 MW 1GW ( ) ( ) L = log d + 20log f + L + L + L Direct Km MHz Ion Atm Ecl Eclipse Loss Ionosphere Loss Atmospheric Loss 13

14 GEO LEO DISTRIBUTION Central Distributed ACCESSIBILITY EFFICIENCY (POWER) Near Equator Lower Everywhere (Orbit Design) Higher RELIABILITY Low High COST/KWATT High Low HAZARD Higher Lower! SIGNAL PROCESSING Simpler Complex 14

15 Cost LEO GEO Launch Ground Stations Ground Power distribution With Tether Satellite Launch cost is a significant portion; Several launches will be needed ; The launch to lower orbits is much lower than to the GEO; Lower Launch cost Higher Launch cost Several smaller units are needed All units are identical, One huge unit is needed Production cost per unit is lower Lower Ground Station Cost No distribution is needed Higher Ground Station Cost Distribution is needed Not applicable Significant Cost Several studies tethers have been conducted. Commercially available. Technology is available Not applicable Several small identical units; lower production cost per unit; One huge unit Similar harvesting area to GEO Lower cost Higher cost 15

16 Research Areas 1. Analysis and comparison of already proposed techniques: a. Expected Efficiency; b. Expected Cost; c. Expected Space Needed on The Ground; d. Expected Reliability; e. Expected Durability; 2. The best techniques for absorbing solar energy in the space? a. Forming the Structure of Satellites; b. Designing the best Orbit; c. Solar Sensors; 3. Energy Transfer from the atmosphere to the earth surface (Wireless; Laser; Cable) a. Wireless Transmission Scheme (Modulation, Beam-forming) b. RF Optical Systems? c. Antenna structures (Number of Antennas, Antenna Design) d. Selecting the transmission parameters 16

17 Research Areas 4. Ground Receivers a. The Ground Antenna Structure (Size, Distribution, etc); b. Passive or Active Receiver? c. High Aperture Antenna Beam-forming 5. Energy Conversion (How energy should be converted to the City Electricity?) Whether Rectantennas are the best options? 6. Channel Modeling The effect of Ionosphere on the RF Signal and Ionosphere baser on their power; 7. Environmental Effects The Effect of High Energy Laser or RF signal on Ionosphere; 8. Cyber Systems a. The Control Process of the Whole Structure; b. Directing power from one satellite to another; 17

18 References 1. S. G. Ting and S. A. Zekavat, Space-based Solar Power via LEO Satellite Networks: Synchronization Efficiency Analysis, proc. IEEE Aerospace Conference, Big Sky, MT, March 03-09, S. G. Ting, S. A. Zekavat, and O. Abdlekhalik, Space-Based Wireless Solar Power transfer via a network of LEO satellites: Doppler Effect Analysis proc. IEEE Aerospace Conference, Big Sky, MT, March 03-09, S. G. Ting, O. Abdelkahlik, and S. A. Zekavat, Constraint Estimation of Spacecraft Positions, AIAA Journal of Guidance, Control, and Dynamics, Journal of Guidance, Control, and Dynamics, vol. 35, no. 2, S. G. Ting, O. Abdelkhalik, and S. A. Zekavat, Implementation of Differential Geometric Filter for Spacecraft Formation Orbit Estimation, International Journal of Aerospace Engineering, vol. 2012, Article ID , 13 pages, doi: /2012/910496, S. G. Ting, O. Abdelkhalik, and S. A. Zekavat, High Performance Spacecraft Formation Orbit Estimation using WLPS-based Relative Position Measurements: Signal Transmission Time Delay Modeling, EURASIP Journal on Navigation and Observation, vol. 2011, Article ID , 12 pages, doi: /2011/654057, S. A. Zekavat, and O. Abdlekhalik, An Introduction to Space-Based Power Grids: Feasibility Study, proc., IEEE Aerospace Conference, Big Sky, MT, Mar , S. A. Zekavat, O. Abdelkhalik, S. G. Ting, and D. Fuhrmann, A Novel Space-Based Solar Power Collection via LEO Satellite Networks: Orbital via a Novel Wireless Local Positioning System, proc. IEEE Aerospace Conference, March 07 12, Big Sky, MT, S. G. Ting, O. Abdelkhalik, and S. A. Zekavat, Differential Geometric Estimation for Spacecraft Formations Orbits via a Novel Wireless Positioning, proc. IEEE Aerospace Conference, March 07 12, Big Sky, MT,

19 Thank you Question? 19

DRONACHARYA GROUP OF INSTITUTIONS, GREATER NOIDA. SATELLITE COMMUNICATIONS (EEC 021) QUESTION BANK

DRONACHARYA GROUP OF INSTITUTIONS, GREATER NOIDA. SATELLITE COMMUNICATIONS (EEC 021) QUESTION BANK 1. Write the advantages and disadvantages of Satellite Communication. 2. Distinguish between active and