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Old 09-01-2018, 05:31   #31
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Re: AIS Closest Point of Approach warning

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Originally Posted by Olddave View Post
In addition to other useful suggestions amongst the posts here, I would suggest that you drop any consideration of vessel size.
We all operate under the international seafarers laws known as the Colregs. To cut a long story short, I am obliged to avoid a collision with a smaller vessel exactly the same as I would avoid being run down by a larger vessel.
Dave
That's not what the COLREGS say but
the point is well made.
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Old 09-01-2018, 05:45   #32
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Re: AIS Closest Point of Approach warning

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That's not what the COLREGS say but
the point is well made.
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Old 09-01-2018, 05:56   #33
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Re: AIS Closest Point of Approach warning

Thank you for all your work but, at this time, do we really need another AIS programme?

So many, many variables, not the least being that a single hander would have an entirely different set of priorities from the Mom & Pop shop. (Sorry - couldn't resist - apologies to all double handers)

Perhaps consultation with OpenCPN, and/all others, would be more beneficial, and less confusing, to the crusing community.

Which programme should I use?
Which is the best?
And, perhaps most importantly, is the other ship's AIS programme compatible with mine?
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Old 09-01-2018, 07:54   #34
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Re: AIS Closest Point of Approach warning

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Originally Posted by blueazimuth View Post
Thank you for all your work but, at this time, do we really need another AIS programme?
Sure, why not? If this new program does something better than the others (and "better" depends on many factors), then we get a new useful tool.

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Originally Posted by blueazimuth View Post
So many, many variables, not the least being that a single hander would have an entirely different set of priorities from the Mom & Pop shop. (Sorry - couldn't resist - apologies to all double handers)

Perhaps consultation with OpenCPN, and/all others, would be more beneficial, and less confusing, to the crusing community.
OpenCPN does seem to be the defacto open-source development platform. I use it (as well as my own NavMonPc), and appreciate all the good work that has gone into it. But if somebody wants to start fresh with a new concept I think we should encourage them -- we might learn something new.

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Which programme should I use?
Which is the best?
And, perhaps most importantly, is the other ship's AIS programme compatible with mine?
"Compatible with mine"??? In what way? How does this matter?
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Old 09-01-2018, 12:20   #35
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Re: AIS Closest Point of Approach warning

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BTW, the VesperMate has additional "gimmicks" like an anchor watch that seemed like an afterthought. You can push the "set" button and give it a radius, nothing else. If your anchor drags temporarily you cannot change that original position, only extend the radius.
Heinz, have you checked with Vesper re updates to your software? I dunno which model you have, but for the Vision model there have been a succession of updates, and they have all been useful, including greatly expanding the control you have in the anchor alarm mode.

One of the reasons that I like the Vesper mob... they have been great about passing along improvements in their gear to customers with older models, and at no cost.

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Old 14-01-2018, 23:38   #36
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Re: AIS Closest Point of Approach warning

Many thanks to all contributors for your excellent feedback. On the point of whether another AIS program is needed we always need to keep working and developing to improve what is out there, it can only be a positive. Also since AIS is a communications protocol compatability is inherent. I will try to take all of your points on board and produce something that satisfies most of your use cases.
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Old 17-01-2018, 00:32   #37
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Re: AIS Closest Point of Approach warning

So I am making good progress but one of my issues is a lack of test data - my boat is thousands of miles away on the hard so I can't use it to acquire test data. I have some AIS test data in an NMEA 0183 log file but it doesn't include own ship navigation data e.g. Heading, SOG, COG, GPS position. Is there any kind soul who could send me a copy of an NMEA 0183 log that includes AIS targets that would raise an alarm and also includes own ship navigation data so I can test the system properly.

Many thanks in advance
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Old 17-01-2018, 03:41   #38
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Re: AIS Closest Point of Approach warning

Damian,

Check NavMonPC web site. There you will find a real life NMEA file with lots of AIS targets. It is the start of a sailing race so plenty of close encounters.
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Old 17-01-2018, 10:29   #39
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Re: AIS Closest Point of Approach warning

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Originally Posted by transmitterdan View Post
Damian,

Check NavMonPC web site. There you will find a real life NMEA file with lots of AIS targets. It is the start of a sailing race so plenty of close encounters.
Yes! Here is the NavMonPc download page: NavMonPc

Here's a link to probably the best example: http://www.navmonpc.com/Downloads/Pa...12%20Start.zip
This is a .zip file. I had a Class-B transponder running for this one.

Here's a .txt file from an earlier race: http://www.navmonpc.com/Downloads/PacCupStart.txt
We only had an AIS receiver for this.
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Old 18-01-2018, 00:34   #40
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Re: AIS Closest Point of Approach warning

As to CPA I would like it to have the following:
1. Default circle of alarm, for all targets, easily managed.
2. Option to change the circle for a specific target, or stop alarm altogether for a specific target (Raymarine has a 'Buddy" function that does something similar by voiding specific alarms but does not allow change of CPA alarm radius. It is either alarm on or off for a target).
3. Clear indication whether the target is going behind or in front of me. Indication to be shown as additional character attached to CPA data, e.g. +/- sign or F/B letter (this in addition to the head vector attached to the bow of the target as offered by Raymarine).
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Old 22-01-2018, 12:31   #41
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Re: AIS Closest Point of Approach warning

Just a different viewpoint here. I operate a pilot boat and we use the CPA function because we want to hit the vessel. Approaching a ship we want the CPA to be zero. This cancels out tide and wind so we get there most efficiently. Alarms are a bother for us and the ability to shut them down varies with different electronics.
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Old 01-02-2018, 06:20   #42
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Re: AIS Closest Point of Approach warning

Many thanks to everyone who took the time to respond, it is really appreciated and many thanks to transmitterdan for pointing me to a data log file for testing. I have completed an initial implementation and I think I have managed to incorporate many of your suggestions. I have attached some screenshots of the AIS feature so you can see it working and hopefully provide some feedback . In essence it has these features;
  • Target list map overlay with own heading, SOG, COG and map range
  • configurable (unlimited) profiles for different scenarios with these options
    • Enable/Disable all alarms
    • Enable/Disable repeat alarms
    • Map Auto Follow own vessel or static map
    • Hide nearby targets (<50 meters)
    • Hide stationary targets
    • Map North Up or Course Up
    • Show threat targets only
    • List visible targets only
    • Tracking range limit
    • Collision radius
    • target list sort order (range, CPA, TCPA, threat level)
  • 6 colour coded levels of threat based on the CPA and intersecting courses
    • Collision Risk (configurable radius per profile and AIS target)
    • Bow Crossing within 1000 meters
    • Stern Crossing within 300 meters
    • Warning - CPA < 300 meters
    • Kilometer - CPA < 1000 meters
    • Nautical Mile - CPA < 1nm (1852 meters)
  • Ignore specific targets
  • Show point of intersecting courses
  • Show 10 minute velocity vector
  • Start and Stop alarm events for each threat level

Most options in the configuration profile can be applied to individual targets. The attached images illustrate the situations where
  • a target is a collision risk
  • crossing the bow of a target within 1000 meters
  • info about the bow crossing target
  • crossing the stern of a target within 300 meters

Any good or bad points so far ?
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Old 01-02-2018, 06:40   #43
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Re: AIS Closest Point of Approach warning

I like the color coding that shows the bow vs. stern crossing or collision status.
Also find the MMSI# displayed with the vessel a helpful confirmation of the vessel of interest.
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Old 01-02-2018, 07:07   #44
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Re: AIS Closest Point of Approach warning

Nice!

Any way to show vessel name instead of MMSI?
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Old 01-02-2018, 08:00   #45
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Re: AIS Closest Point of Approach warning

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Nice!

Any way to show vessel name instead of MMSI?
It does display the vessel name if it is in the incoming data. I am using an NMEA 0183 source log file through a signalk server for the incoming data stream. One of the many things I have to do is check that every piece of data makes it to the AIS screen.
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