AIS and radar targets are out of sync

[lvnmdrm]

Hello,

I have AIS650 and RD418D connected to my c90 MFD via STng.

My AIS ship display icon is off by several degrees, more or less depending on COG.

It is quite disconcerting to watch my ship moving sideways to COG.

More disconcerting is the overlay of radar.

Distance from a target, whether AIS target or land mass, seems to be an issue.

The further away, the more the overlay display is off.

A land mass target may be off by an inch or two, many degrees from COG, compared to the underlying chart.

An AIS ship target, similarly, will be off.

Stated another way, I will see two targets of the same vessel, one radar, one AIS, separated by some distance on my MFD until we have approached each other.

Similarly, I see two targets of the same land mass, one radar, one charted, separated by some distance on my MFD until I am closer to the land mass.

What might be causing this to happen and what is the solution to fix it?

Unfortunately, after reviewing the screen shots taken with the radar overlaying a chart, it appears the radar targets were not captured.

Thank you,

Dan

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Dan,

The subject problem is indicative of a misalignment or problem with the source of heading data which has been interfaced to the system. Please click here to view a FAQ addressing this subject.

[lvnmdrm]

Hmmmm!
I think I understand.
My autopilot is a Raymarine EVO400.
I didn't give it a second thought when the AP indicated a course far different from COG displayed on my MFD (supplied, I assume from the AIS/GPS antenna).
I didn't care that the AP was off if I could see my COG.

Now I am beginning to understand how the heading data DOES make a difference.

The boat is in San Diego and I am in Seattle until January.
This will have to be put off until then, but I can see the configuration (and installation) issues I must address when I return.

Thank you,

Dan

[Chuck - Raymarine - Moderator]

You're welcome.