Radar/Plotter Bearing Mode

[Ian Kelly]

I have e127 and e125 networked MFDs with the e127 as master. The e127 is used as the chart plotter in North up mode and the e125 as the radar display in Head up mode. A data box is set up on the chart plotter to display cursor position with the bearing in degrees magnetic. I Have tried to set up a corresponding data box on the radar display which would read the cursor bearing in degrees relative to ship's head, as I do not have a heading indicator. This data box would show the same information as the VRM/EBL shows if the cursor is placed in the same position. However the only bearing setup choices I can find are degrees true or magnetic, both of which require a heading indicator. Without a relative bearing mode I am unable to get a cursor position on the radar display. Is there a setup option somewhere that will allow me to get a cursor position in degrees relative? Thanks.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Ian,

Relative bearings are only reported within the VRM/EBL and Tracked Targets List (MARPA & AIS) of the a/c/e/eS/gS-Series MFDs. As indicated within the FAQ found here, MARPA features require that the system be interfaced to a stabilized source of Heading data. The VRM/EBL feature does not require that the system be interfaced to a source of heading data and will always report relative bearings. All other bearing are reported within these MFDs in either True or Magnetic based upon the Bearing Mode configuration setting. As the VRM/EBL's primary feature is to report relative range and bearing to a target on the Radar application's screen and is enacted by touching the radar image of the object on Radar applications screen, the value of having the MFD additionally display relative range and bearing of the EBL within a Databox within the Radar application is unclear.

If I have missed the point of your thread, then please expand upon or clarify your initial thread relative to the points raised within this response.

Thanks

[Ian Kelly]

Thanks Chuck. We use the VRM/EBL to crosscheck bearing and range of radar targets against cursor position on the chart plotter. The plotter is set up with a data box to give us cursor range and bearing. When we had a heading indicator we were able to have a similar data box on the radar screen showing cursor range and bearing. In both cases bearing was degrees M making for a simple cross-check. We don't have a heading indicator now and are unable to get any cursor position information. I was curious as to why. Since we are operating the radar in head up mode I would think the system has all the information needed to display cursor range and relative bearing. Having cursor information as well as the single VRM/EBL is useful at times. I think you've answered my question - the software is simply not set up to do this.
Thanks again
Ian

[Chuck - Raymarine - Moderator]

Ian,

Radar features have their roots in radar systems which may not have included heading input (would have restricted them to Head Up orientation with the radar application), and correspondingly, all range and bearing data was relative to the radar transducer's ships heading marker. The ship's heading marker is typically aligned with the ship's head. All radar imagery is plotted is relative to the ships head. Without a heading reference, the MFD's chart application would be unable specify bearings of the cursor relative to the vessel's head. That said, the design of the a/c/e/eS/gS-Series MFD software does not presently support displaying cursor info relative to the ship's head ... only relative to true or magnetic north. A feature request will be logged according to consider also permitting cursor bearing data to be reported relative to the vessel's head. However, if/when implemented, this feature additions may require heading input.

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[Ian Kelly]

Thanks Chuck.

Ian

[Chuck - Raymarine - Moderator]

You're welcome.