Heading Allignment

[striperstan]

I have a question regarding heading alignment...

System consists of eS128, eS97, EV-200 autopilot, CP-470, RD424 HD radar and SR-150 XM weather receiver, all connected through STng network and Raynet via a HS5 network switch..

All devices have been updated to latest software release as of 8/19.

After installing all equipment and devices, my radar overlay lined up perfectly with Navionics chart data and heading line on chart lined up with visual observation, but heading reading was off by approx. 10 degrees when compared to magnetic compass (adjusted for variation and deviation), and to COG generated by GPS on all headings. I performed an "align to GPS" using the P70R control head, which was successful in that my COG and heading are now in alignment.

After performing the alignment, the radar overlay no longer matched the chart data, so I then used the radar heading offset until the chart data and radar overlay lined back up. My question through all of this is did I perform the proper procedures? Part of me believes that if the alignment (radar to chart) was correct in the first place, then maybe I should not have done the COG/Heading alignment procedure.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Stan,

The system's radar bearing is in need of alignment. Please click here to view a FAQ addressing this subject.

[striperstan]

Thank you, Chuck...Sorry if I wasn't clear, but as I posted above, I have already performed that task and everything is lined back up.. My question is whether it is normal for the radar to go from in alignment to going of alignment by performing the "align to GPS".

[Chuck - Raymarine - Moderator]

Q1. Is it normal for the radar to go from in alignment to going out of alignment by performing the "align to GPS".
A1. This is actually an invalid question. The reason is that the radar appears to have not been correctly aligned prior to the having performed the "align to GPS" command. Per the previously referenced FAQ, radar bearing alignment is performed within the Radar application, not the Chart application, prior to performing the heading alignment. When a) the Radar application is configured for Head-Up orientation and b) should the vessel be pointed directly (000 relative) at a distant target, and c) should the radar return from that object fall under the ships heading marker, then the radar bearing is properly aligned. I am suggesting that should you have examined the Radar application, not the Chart application, prior to the actions previously taken, then I believe that you would have actually determined that at the radar beaing was misaligned. Adjustments to heading alignment (typically very small) may then be performed within the Chart application to permit the radar image to properly overlay within the Chart application.

Symptoms such as you have reported would typically have occurred when the installer or operator had attempted to align the radar bearing from within the Chart application by observing the radar overlay.

[striperstan]

The radar was correctly aligned prior to performing the align to GPS.

[Chuck - Raymarine - Moderator]

Stan,

The system is designed to function in the manner which I have stated. Should you have a problem with the alignment in the future, please respond accordingly.