1 / 16

Satellite Communications

Satellite Communications. Chris Webster NSF Users Workshop 2007 NCAR - EOL. Reasons / Motivation. Safety situational awareness Remote real-time instrument monitoring Remote real-time science Remote real-time instrument control Project coordination Troubleshooting. History.

teleri
Download Presentation

Satellite Communications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Satellite Communications Chris Webster NSF Users Workshop 2007 NCAR - EOL

  2. Reasons / Motivation • Safety situational awareness • Remote real-time instrument monitoring • Remote real-time science • Remote real-time instrument control • Project coordination • Troubleshooting

  3. History • 2002, Iridium first used on the P3 for IHOP • Small data feed including A/C track. • 2003, BAMEX – P3 • Chat introduced • 2005, RAINEX - P3 • Images sent to plane were requested. • We learned a lot. • 2005, HIAPER – INMARSAT • 2007, C-130 Upgraded to INMARSAT

  4. Existing EOL Uses • Driftsonde (Iridium) • Instrument Control & Data Retrieval • ISFF (GOES Motosat) • Summary Data Retrieval • ISS / GAUS (Motosat) • Instrument Control & Data Retrieval • Aircraft (INMARSAT & Iridium) • Chat, Two-way data, Trouble Shooting

  5. Driftsonde

  6. Options • GOES • Iridium • Capabilities / Limitations / Cost • GlobalStar • Motosat / Direcway - Consumer • INMARSAT 3 • Capabilities / Limitations / Cost • High Bandwidth Line of Site Options Exist • Commercial KU Band / TDRSS S Band • Commercial Remote Internet • Ground Dish (get photo from PASE).

  7. Iridium • Capabilities • True Global/Polar Coverage • 2800 baud per modem. • Pros • Compact • Multiple units can be ganged. • NASA DC-8 gangs 8 Iridiums. • Limitations • Low bandwidth • Thrashes and disconnects when too much traffic. • Cost • $1,500 per unit/modem (not including installation). • 7 cents per KB

  8. INMARSAT 3 • Capabilities • 64Kbps (per modem), there are two on each aircraft. • Upcoming INMARSAT 4 • 4 times the bandwidth • Fewer coverage holes • Pros • Good bandwidth • Limitations • Not Polar (~76 degrees Latitude). • Other “holes” exist in the globe. • Cost • $300K per unit • 5.7 cents per KB • GV, 1 second data is about $270 / hour using MPDS mode.

  9. Problems Encountered • Incomplete Global Coverage (some) • Dropped connections and cycling connections • Extraneous Traffic • Chat “away tracking” overhead • “Phone home” traffic • Microsoft automatic updates • Short time-out before redialing • Satellite Handoff • Security (Firewall necessary)

  10. Drop-outs are a fact of life • Aircraft Shadow • GV tail wing shadows antenna on 10 degree bank turn (away from satellite). • C130 conformal antenna shadow flying to/from a satellite. • Satellite Handoff • 1 minute for INMARSAT to redial. • Holes in Satellite Coverage (INMARSAT).

  11. Applications • Internet Relay Chat (IRC) • Data Feed from aircraft • Into SQL database available to anyone for real-time ground processing/display. • Generic file transfer • Google Earth tracks with satellite overlays • onboard and on ground.

  12. Your instrument can fly but you can’t.What do you need?

  13. What do you want? • Communication (chat) • Current weather products up to aircraft • Situational awareness (onboard and ground). • Aircraft Guidance / Coordination • Instrument monitoring • Are there unsatisfied needs? • Instrument Control • Short transmission lag

  14. Questions • How can we connect with the other SATCOM communities (e.g. Marine, Polar Research, Earth Sciences, Oil, Security, Transportation, HAM)?

  15. Priorities

More Related