SOT Geneva 2007 Iridium: low power satellite communications for autonomous instruments David Meldrum Scottish Association for Marine Science

SOT Geneva 2007 General considerations Iridium overview SAMS experience with Iridium Future plans

SOT Geneva 2007 General considerations Bandwidth Timeliness Availability Polar coverage Temperature spec Cost Energy Cash Physical size Reliability Future Technical support

SOT Geneva 2007 A common misbelief when things dont work as they should… The system operators know about it and are doing something to fix it WRONG on both counts! The system wasnt designed with your application in mind You are a very minor user You are a pain in the neck

SOT Geneva 2007 Satcom systems available globally to platform operators Inmarsat D+PagerGEO< 1 kbyte/day GOES, MeteosatMessagingGEO< 5 kbyte/day ArgosMessagingLEO< 5 kbyte/day Inmarsat CMessagingGEO< 10 kbyte/day OrbcommMessagingLEO< 50 kbyte/day IridiumVoiceBig LEO1 Mbyte/hr GlobalstarVoiceBig LEO (regional) 1 Mbyte/hr Inmarsat BGANInternetGEO50 Mbyte/hr

SOT Geneva 2007 Low Earth Orbit and Geostationary Earth Orbit Field of View for LEO (Iridium) and GEO (Inmarsat)

SOT Geneva 2007 Typical LEO polar orbit

SOT Geneva 2007 Satcom systems available globally to platform operators Inmarsat D+PagerGEO< 1 kbyte/day GOES, MeteosatMessagingGEO< 5 kbyte/day ArgosMessagingLEO< 5 kbyte/day Inmarsat CMessagingGEO< 10 kbyte/day OrbcommMessagingLEO< 50 kbyte/day IridiumVoiceBig LEO1 Mbyte/hr GlobalstarVoiceBig LEO (regional) 1 Mbyte/hr Inmarsat BGANInternetGEO50 Mbyte/hr

SOT Geneva 2007 Satcom systems available to POLAR platform operators ArgosMessagingLEO< 5 kbyte/day IridiumVoiceBig LEO1 Mbyte/hr Argos: 6 sats, 400 bits/s (will increase) Iridium: 66 sats, 2400 bits/s (will increase)

SOT Geneva 2007 Iridium overview Designed as a phone system: 2-way, real-time 24/7 availability, true global coverage 66 satellites Inter-satellite links pass traffic to ground station Basic data rate 2.4kbps Various modes of access Dial-up (better for larger file sizes) Short Burst Data, SBD (up to 2 kbyte per message) Future near broadband service, ~100kbps Platform location GPS Km-scale accuracy Iridium location in SBD

SOT Geneva 2007 Iridium constellation

SOT Geneva 2007 Iridium overview

SOT Geneva 2007 Dial-up: on-line session with mobile

SOT Geneva 2007 Transfer times for 37kbyte file Mode -> 3100 bps >4000 messages

SOT Geneva 2007 Short Burst Data Pathways Simple AT commands IRIDIUM NETWORK INTERNET SENSOR USER MODEM TX Buffer RX Buffer +SBDWB +SBDRB +SBDI

SOT Geneva 2007 Example received by user (MO message) From: Sent: Tue, 23 Sep :02:24 Subject: SBD Msg From Unit: MOMSN:152 MTMSN:0 Session Status: TRANSFER OK Message Size (bytes): 1960 Unit Location: Lat = Long = CEPradius = 2 Message is attached.

SOT Geneva 2007 seconds SBD Delivery Latency

SOT Geneva 2007 Iridium traffic

SOT Geneva 2007 Current constellation

SOT Geneva 2007 Replenishment plans Requirements and Supplier Selection Satellite R&D Satellite PDR Deploy & Launch Satellites st Launch 2 Satellites Satellite Qualification Calendar Year...

SOT Geneva 2007 Iridium ballpark costs Dial-up + SBD modem: $1000 SBD-only modem: $400 Monthly fee: $14 - $30 Call costs: ~$1 per minute $0.1 per kbyte for files > few kbyte Data costs: ~$1.50 per kbyte

SOT Geneva 2007

dalriada.nsm.ac.uk/ php

SOT Geneva 2007 Temperature record

SOT Geneva 2007 New suitcase buoys: GPS only

SOT Geneva (Taladega) SBD modem

SOT Geneva 2007

SAMS future plans: Solar powered Iridium drifters Transparent hulls from Technocean Solar panel equatorial plane SVPB sensor fit Li-ion batteries Iridium GPS Extensive diagnostics Participation in DBCP Iridium pilot programme….

SOT Geneva 2007 DBCP future plans Iridium Pilot Project (Iridium-PP) Practical evaluation in realistic conditions Small platforms Wide partnership Support (cash and in-kind) by Iridium, manufacturers and DBCP Open membership

SOT Geneva 2007 Iridium-PP mailing list

SOT Geneva 2007