Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 20-02-2017, 09:18   #1
Registered User

Join Date: Nov 2008
Location: Ottawa,Canada
Boat: Prout Snowgoose 37' Catamaran
Posts: 401
AIS Target display time

I'm wondering how a chartplotter deals with an AIS target which stops transmitting - how much longer after the last transmission does it keep it shown on the screen?

Is this configurable ? (Raymarine, Garmin, OpenCPN)?
Different for class A and B?

thanks.
__________________

geoffr is offline   Reply With Quote
Old 20-02-2017, 09:32   #2
Registered User

Join Date: Dec 2016
Posts: 738
Re: AIS Target display time

You are going to have to read the manual on this. There should be a way to read the time that the last signal was received. For one thing, Class B transmits only once every six minutes, so you should not assume that anything you see on the screen is "real time."
__________________

toddster8 is offline   Reply With Quote
Old 20-02-2017, 09:58   #3
Registered User

Join Date: Nov 2015
Location: Ireland
Posts: 259
Re: AIS Target display time

It can be configured in OpenCpn all right, but not separately for class A and B. I don't know about the others.
AedanC is offline   Reply With Quote
Old 20-02-2017, 14:48   #4
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPB
Posts: 8,645
Re: AIS Target display time

Quote:
Originally Posted by toddster8 View Post
You are going to have to read the manual on this. There should be a way to read the time that the last signal was received. For one thing, Class B transmits only once every six minutes, so you should not assume that anything you see on the screen is "real time."
That's a huge over-simplification and misleading.

Class B transmissions may be received up to 6 minutes apart, but frequently are transmitted every 30 seconds (depending on type of data,SOG and number of receivers in receiving equipment).
StuM is offline   Reply With Quote
Old 20-02-2017, 23:48   #5
Registered User

Join Date: Jun 2013
Location: canada
Posts: 2,554
Re: AIS Target display time

often you get a triangle with a line through it after it stops transmitting. then it'll disapear
smac999 is offline   Reply With Quote
Old 21-02-2017, 04:43   #6
Long Range Cruiser
 
MarkJ's Avatar

Cruisers Forum Supporter

Join Date: Dec 2007
Location: Australian living on "Sea Life" currently in England.
Boat: Beneteau 393 "Sea Life"
Posts: 12,827
Images: 25
Re: AIS Target display time

Settable in the plotter.

OpenCpn has a default of 8 minutes. You then see the target with a black line through it.

At Sea I have it set to longer.


Mark
__________________
Notes on a Circumnavigation.
OurLifeAtSea.com

Somalia Pirates and our Convoy
MarkJ is offline   Reply With Quote
Old 21-02-2017, 06:40   #7
Registered User

Join Date: Nov 2008
Location: Ottawa,Canada
Boat: Prout Snowgoose 37' Catamaran
Posts: 401
Re: AIS Target display time

Mark,

Thanks - that is exactly what I'm looking for.. now just need the default for Garmin/Ray plotters
geoffr is offline   Reply With Quote
Old 21-02-2017, 09:40   #8
Registered User
 
wrwakefield's Avatar

Join Date: Feb 2011
Location: Still enamored of higher latitudes; exploring Southcentral and Southeast Alaska— and British Columbia— for now...
Boat: Nauticat 43
Posts: 1,165
Re: AIS Target display time

Geoff,

It is configurable, with alarms, on the 3 main primary systems we use: OpenCPN, B&G Zeus Touch Chartplotter, Vesper Watchmate 850 AIS transceiver.

I don't remember the configurations allowing for differentiating between class A and B AIS transmitters, but would have to double-check to confirm.

Cheers! Bill
__________________
SV Denali Rose

Short on opinions; focused on research, facts & experience [yours and ours...]
wrwakefield is offline   Reply With Quote
Old 21-02-2017, 14:41   #9
Registered User

Join Date: Feb 2015
Posts: 785
Images: 1
Re: AIS Target display time

It looks like for an IMO compliant display, the lost target icon displays when there has been no report for the shorter of 6 minutes or 5 intervals. Both Class A and B devices report position every 3 minutes when stationary which is the longest interval. The 6 minute report interval, BTW, is for static data like Ship's name, and is the same for Class A and Class B.

I don't know whether consumer devices follow the same rules, but I can't see why they wouldn't.

Again, on an IMO compliant device, lost targets only go away when explicitly dismissed. I find in practice that they just disappear from the screen and are out of sight, out of mind.
__________________

__________________
www.MVTanglewood.com
tanglewood is offline   Reply With Quote
Reply

Tags
ais

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Automatic display AIS target ship names? Vigen OpenCPN 2 23-05-2013 05:22
Virtual AIS target useris OpenCPN 0 06-04-2013 12:51
Maxsea 10.3.2.1 does not display AIS Class B target names svBeBe Marine Electronics 7 17-03-2013 08:59
OpenCPN v2.5.0 Unable to Display AIS Target Query Window jsavage Navigation 4 28-11-2011 00:35
AIS Target Mouseover Data idpnd OpenCPN 11 18-06-2010 03:34



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:12.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.