AIS Tracking

[Chris CJ]

I like to review my AIS track after a days sail , normally I follow this on Vessel Finder ( free service ) recently this has been giving an incomplete track. Thought this is an issue with my AIS kit , checked all the connections , all appears to be ok , with 2 green lights showing the kit is working correctly. To double check I’ve used Marine Traffic ( free service) this shows a complete track.
Is this a case of getting you to pay for a service or do I have a problem
I’d be pleased to hear your thoughts on this
Chris

 

[Martin_J]

They both rely on amateur land based 'receiving stations' whereby people living near the sea (or lakes/rivers/canals) can set up an AIS receiver and upload all the AIS info it hears to the service provider (e.g. MarineTraffic or Vesselfinder) who can then make that received information avaliable on either their website, app.

I know on MarineTraffic you can display the receiving stations on their map.. and you can see which receiving station your position is being relayed through. I would expect you to be able to see the location of receiving stations on Vesselfinder as well.

 

[Martin_J]

With that in mind... There is likely to be somebody (or a number of people) signed up to Marinetraffic who have set up receiving stations within range of your track.

Perhaps Vesselfinder just don't have anyone signed up as a receiving station within range of where you were sailing, or their receiving kit is offline or just not receiving as well as it did.

Take a look at both services and see if you can work out where their receiving stations are in that area.

 

[Martin_J]

In Marinetraffic, turn on the layer showing where the receiving stations are..


And you will see a map showing their locations..



Although I note that they are not all 'land' based.. but you get the general idea. Green - online, red - offline and orange - poor range.

https://help.marinetraffic.com/hc/en-us/articles/205268157-Station-Details-page

 

[Martin_J]

And if you are in range of where there might be boats transmitting and wish to set up a receiving station yourself...

https://help.marinetraffic.com/hc/en-us/articles/205267187-AIS-Receiving-Stations

 

[Sandy]

Do you have a chart plotter or GPS tracker app on your phone onboard that you can download your track to some mapping/charting software?.

 

[wonkywinch]

Do you have a chart plotter or GPS tracker app on your phone onboard that you can download your track to some mapping/charting software?.

Or a smart phone with the Navionics Boating app, or Strava or one of many other track apps.

Edited to add Memory Map to the options.

 

[Boathook]

I've used outdooractive app on my phone to record some of my dinghy trips. Maps very similar to os maps.

 

[Chris CJ]

Both vessel finder and marine traffic have shown our full track today from Ushant to Cameret ( to shelter from some strong s/w winds forecast over the next couple of days .) Interesting how basic these tracking systems are set up , not a professionally as I had previously thought.

 

[jbweston]

As previous replies have said, whether you'll appear on this kind of app depends on whether you (that is your boat) is in range of a shore station that's (a) working and (b) feeding into that particular app's/website's service. It's common for the tracking not to work when, for example, you're well offshore.

If you want to check your AIS just call a friend's boat that's AIS receiver-equipped in range of your AIS and ask if they've got you on their display. Or you can call National Coastwatch if there's a station nearby as they are very helpful.

 

[Chris CJ]

Thanks for all your comments , we had another interesting experience the other day where the track suddenly altered putting us on the beach and then correcting itself , as shown below

 

[wonkywinch]

Thanks for all your comments , we had another interesting experience the other day where the track suddenly altered putting us on the beach and then correcting itself , as shown belowView attachment 178431

I see this all the time, I think you just have to accept the limitations of the web based AIS trackers. The level of accuracy you see is directly proportional to how much you are paying for the service.

If you want accurate tracks of your own voyages, you're going to have to record them yourselves then overlay your gpx file on Google maps etc.

Relying on AIS pings interpreted by amateur receivers feeding a free service on the internet is a different type of data than your own HPS derived track with many more points of data saved.