Satellite AIS detection at ITU

1
Satellite AIS detection at ITU

• Report on the development of the technology and
  use of the spectrum

2
Issues under consideration

• Performance limitations of the current service
• Slot reuse (multiple messages per slot)
• Slot overlap (insufficient slot time buffer)
• RF interference (terrestrial use of AIS1 AIS2)
• Limited dedicated maritime spectrum
• Channel 16 (75 kHz bandwidth allocation, 3
  channels)
• Channel 70 (25 kHz bandwidth allocation, 1
  channel)
• Necessity to revise the ITU (1371-3) AIS standard
• Privacy of data distribution

3
Technical approach

• Special short message (17ms) for satellite AIS
• Allows sufficient time buffer to prevent overlap
• Globally-dedicated marine frequencies (2)
• Uses channel 16 guard-bands (channels 75 76)
• Provides capacity, redundancy, non-interference
• Message timing (3 min) optimizes detection
• Provides 99.9 detection on one satellite pass
• Privacy for concerned Administrations
• AIS shore stations suppress the satellite message
  

4
Documents under review

• Report Improved satellite detection of AIS
• Draft New Report (May 2009, see backup slides)
• Updates previous Report ITU-R M.2084 (2006)
• Planned for final revision and approval Nov 2009
• Revision of Recommendation ITU-R M.1371-3
• Preliminary Draft Revision sent to IALA May 2009
• Revision to Annex 4 Long Range Applications
• Requires software update to shipborne AIS units
• May require modification to a footnote in RR Ap18

5
Required actions

• IALA Agree to draft rev. Rec. ITU-R M.1371-3
• A formality other revisions being consolidated
• ITU Produce/approve Rec. ITU-R M.1371-4
• 2-yr minimum revision cycle last revision 2007
• WRC Modify footnote n) in RR Appendix 18
• A formality does not effect current usage/users
• IMO Software update to shipborne AIS
• Updates to ships equipment are an MSC priority

6
Problems

• Lack of understanding of technical issues
• Misunderstanding service providers claims
• Desire for privacy generates negative bias
• Confusion over spectrum issues
• Political posturing at IMO
• Need for software update for ships AIS units
• Requires IMO action, however
• Updates are required for other important reasons