Where is the grandeur?

[vaka08]

Does anyone know where the grandeur is now? It's headed to Bermuda. A few of the different tracking websites all have her indifferent spots. Were they delayed? Trying to avoid the storm?

 

 

Sent from my iPhone using Forums

[Firefighterhoop]

Hmm?? Bermuda Triangle?

 

Sometimes when they are between the US and Bermuda there is a delay in some of the tracking sites.

[Clarea]

The ship can be out of range of the land based AIS stations.

[chengkp75]

Does anyone know where the grandeur is now? It's headed to Bermuda. A few of the different tracking websites all have her indifferent spots. Were they delayed? Trying to avoid the storm?

 

 

Sent from my iPhone using Forums

 

The ship can be out of range of the land based AIS stations.

 

Different consumer tracking sites "enroll" (read pay for the data feed) different land based AIS stations. AIS is UHF "line of sight", so if a ship is more than about 40 miles from a station (not just the shore), it is considered "out of range", and various sites represent this in various ways. Some just give the last reported position (check the date/time stamp), some give an estimated position based on itinerary, course and speed at last reported position. Consumer vessel tracking is a corollary of the main purpose of AIS (identifying ships to each other on radar displays, much like the air traffic control transponders), so it does not have universal reach (except to governmental agencies) on a full time, real time basis.

[grneyes]

About 2 hrs from Bermuda

[Capt_BJ]

Different consumer tracking sites "enroll" (read pay for the data feed) different land based AIS stations. AIS is UHF "line of sight", so if a ship is more than about 40 miles from a station (not just the shore), it is considered "out of range", and various sites represent this in various ways. Some just give the last reported position (check the date/time stamp), some give an estimated position based on itinerary, course and speed at last reported position. Consumer vessel tracking is a corollary of the main purpose of AIS (identifying ships to each other on radar displays, much like the air traffic control transponders), so it does not have universal reach (except to governmental agencies) on a full time, real time basis.

 

A few technical details altho the 'general tone' of the above is correct. Technical geeky stuff follows

 

- AIS works on VHF not UHF. VHF-FM is used for bridge to bridge communication at sea. AIS "rides" on a VHF channel - actually two, but does NOT use the FM modulation used for voice, so the voice channels are still available too. {for radio geeks, this "new application" stayed within the existing maritime VHF bandwidth allocation}

 

- sites like "marinetraffic.com" employ mostly volunteer land base stations to collect AIS messages and forward to their collection and processing site (via web). On MarineTraffic you can find and read how to become a volunteer participant. When you see a position report you can even open it and see what station received/forwarded the report. If reporting from an area goes away .. drilling down usually shows the station is off line.

 

- as mentioned AIS was intended for bridge to bridge use only, and the wide area reporting is an unplanned use; AND VHF is "line of sight" communications, intended for fairly short range, 10 miles or so. Height of the antennas can extend this and base stations may see vessels as far as 20+ miles ... height matters. {OTOH boosting signal strength is a no-no.}

 

- BUT radio waves are not constrained to horizontal travel. Despite the ship to ship intent the AIS data does also go UP. There are efforts underway to use satellites to collect this data and send it back to earth. MOST of these efforts have been by commercial companies (with some government money) .. ORBCOMM is a significant player and a recent launch put several low altitude birds in orbit to participate in their system. Worldwide 24/7 coverage is not yet there. If you look at MarineTraffic ... there are the free accounts ... and if you want access to the satellite data there are paid accounts. It takes time to put a new satellite based technology up there ..... and lots of $$.

 

- VHF signals that make it to satellites are very weak so 'closer' satellites are better (aka low orbits, not geosynchronous ones 23,000 miles up) ... and the equipment to receive and send this data back to earth stations was not put in older birds ....

 

- in my previous life I was pretty involved with satellite communications, maritime communications, AIS and GPS . . .

 

- The WIKI discussion is pretty good, altho may get too technical for most folks .... https://en.wikipedia.org/wiki/Automatic_identification_system

 

 

 

*********

 

BUT to OP's original question

 

I see G' at the pier in Bermuda on the webcam right now!

Edited August 29, 2016 by Capt_BJ

[chengkp75]

A few technical details altho the 'general tone' of the above is correct. Technical geeky stuff follows

 

- AIS works on VHF not UHF. VHF-FM is used for bridge to bridge communication at sea. AIS "rides" on a VHF channel - actually two, but does NOT use the FM modulation used for voice, so the voice channels are still available too. {for radio geeks, this "new application" stayed within the existing maritime VHF bandwidth allocation}

 

- sites like "marinetraffic.com" employ mostly volunteer land base stations to collect AIS messages and forward to their collection and processing site (via web). On MarineTraffic you can find and read how to become a volunteer participant. When you see a position report you can even open it and see what station received/forwarded the report. If reporting from an area goes away .. drilling down usually shows the station is off line.

 

- as mentioned AIS was intended for bridge to bridge use only, and the wide area reporting is an unplanned use; AND VHF is "line of sight" communications, intended for fairly short range, 10 miles or so. Height of the antennas can extend this and base stations may see vessels as far as 20+ miles ... height matters. {OTOH boosting signal strength is a no-no.}

 

- BUT radio waves are not constrained to horizontal travel. Despite the ship to ship intent the AIS data does also go UP. There are efforts underway to use satellites to collect this data and send it back to earth. MOST of these efforts have been by commercial companies (with some government money) .. ORBCOMM is a significant player and a recent launch put several low altitude birds in orbit to participate in their system. Worldwide 24/7 coverage is not yet there. If you look at MarineTraffic ... there are the free accounts ... and if you want access to the satellite data there are paid accounts. It takes time to put a new satellite based technology up there ..... and lots of $$.

 

- VHF signals that make it to satellites are very weak so 'closer' satellites are better (aka low orbits, not geosynchronous ones 23,000 miles up) ... and the equipment to receive and send this data back to earth stations was not put in older birds ....

 

- in my previous life I was pretty involved with satellite communications, maritime communications, AIS and GPS . . .

 

- The WIKI discussion is pretty good, altho may get too technical for most folks .... https://en.wikipedia.org/wiki/Automatic_identification_system

 

 

 

*********

 

BUT to OP's original question

 

I see G' at the pier in Bermuda on the webcam right now!

 

I wasn't going to mention the satellite AIS, because the pay for services will only update once every 24 hours to keep traffic down. Government agencies have access to full time satellite AIS. I would doubt that worldwide real time AIS will ever be available, though you may know more, simply because of the volume of signals from the thousands of ships.

[Race Watcher]

Just returned home from Grandeur. Absolutely great trip. Best weather we have had in Bermuda. On the way home raced tropical depression 8. Captain went around the storm.