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Old 28-08-2012, 13:31   #1
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Raymarine ST60 Autopilot without GPS Signal

Hi together!
I have bought a used boat which has a Raymarine ST60 system aboard. I learned that there is no GPS signal fed into this ST60 system. (It didn't work the former owner told me)
What does that mean for the autopilot? Sure I can't work with waypoints or similar, but that is not my interest.
I like to know if a GPS signal can help improving the steering performance of the ST60 autopilot. I like to have an autopilot which is as reliable as possible even under difficult conditions and at high speed.
Can anybody give me a hint?
Ulf
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Old 28-08-2012, 21:48   #2
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Re: Raymarine ST60 Autopilot without GPS signal

You can add a gps to the Seatalk bus, however, it won't bring much of anything to the party with regards to the autopilot. Having recently upgraded everything to Seatalkng, and swapping ST for x70 series instruments, I find that the gps will display nicely on the i70, but the autopilot work is still handled by the compass. (and the gyro in the Xcomputer)Where gps really comes into play is the mfd position indication on the new big displays. ( big also meaning price)
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Old 29-08-2012, 13:09   #3
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by Meriachee View Post
You can add a gps to the Seatalk bus, however, it won't bring much of anything to the party with regards to the autopilot. Having recently upgraded everything to Seatalkng, and swapping ST for x70 series instruments, I find that the gps will display nicely on the i70, but the autopilot work is still handled by the compass. (and the gyro in the Xcomputer)Where gps really comes into play is the mfd position indication on the new big displays. ( big also meaning price)
The newer X course controllers require SOG. I'm not sure if they will engage on compass or wind, but they certainly will not engage a track without SOG.
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Old 29-08-2012, 13:28   #4
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Re: Raymarine ST60 Autopilot without GPS signal

None of them will "engage a track" without a GPS signal.

All of them work by setting a heading that is derived from a fluxgate compass and (in some cases) a gyro.

This works fine, you set the heading and off you go, but leeway and current will set you off your course, just as it does when you're helming.

Connecting a GPS to the autopilot allows you to "go to" a waypoint on the GPS and then "Track" on the pilot uses the XTE (cross track error) information from the GPS to change the compass heading on the pilot and thus maintain the COG (course over ground).

The pilot doesn'tcare about SOG (Speed over Ground) unless its so close to zero that the pilot can't steer the boat.
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Old 29-08-2012, 13:48   #5
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by Albro359 View Post
None of them will "engage a track" without a GPS signal.

All of them work by setting a heading that is derived from a fluxgate compass and (in some cases) a gyro.

This works fine, you set the heading and off you go, but leeway and current will set you off your course, just as it does when you're helming.

Connecting a GPS to the autopilot allows you to "go to" a waypoint on the GPS and then "Track" on the pilot uses the XTE (cross track error) information from the GPS to change the compass heading on the pilot and thus maintain the COG (course over ground).
No, connecting the GPS to the chart plotter allows "go to" a waypoint. A chartplotter calculates BTW, DTW, and XTE, not the AP.

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Originally Posted by Albro359 View Post
The pilot doesn'tcare about SOG (Speed over Ground) unless its so close to zero that the pilot can't steer the boat.
IIRC, the 'pre X series' course computers would engage a track with no SOG from a GPS, they would work strictly from the APB, RMB sentences from the chart plotter (might need RMC if BTW is 'true'). The newer X series will not engage a track without pgn 129026 or 129029 on the STng network. These pgns come from a GPS. The chartplotter "go to" pgns are 129283 & 129284.
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Old 29-08-2012, 14:07   #6
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Re: Raymarine ST60 Autopilot without GPS signal

Sorry Dot Dun, you misread me....

The chartplotter gets its info from GPS...so whether its a chart plotter and /or GPS doesn't matter...the sentences that come out of the chart plotter are derived from the GPS sentences that the plotter receives. Whether the plotter has inbuilt GPS or not, its GPS information we are talking about.
The "Go To Waypoint" is done either on the GPS or the plotter, and the resulting information (like XTE) is sent to the pilot. XTE is what the pilot acts on. The other signals (SOG, DTW etc) are informational only. They may be displayed on the autopilot but they don't control it.

I didn't say the pilot calculated XTE, I said it uses that information from the GPS (plotter if you like) to recalculate the heading.

If the SOG is zero, the pilot will give an "off course" alarm as it can't maintain a heading. But its not the SOG signal that causes that, it's the XTE, 'cos no matter what the pilot does in steering the boat the XTE gets worse.

I don't know anything about pgns...that's getting off topic.
This thread was talking about the ST60 pilot...this is how it works, I know, I've got one...used it for nearly 10 years
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Old 29-08-2012, 14:22   #7
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by Albro359 View Post
Sorry Dot Dun, you misread me....

The chartplotter gets its info from GPS...so whether its a chart plotter and /or GPS doesn't matter...the sentences that come out of the chart plotter are derived from the GPS sentences that the plotter receives. Whether the plotter has inbuilt GPS or not, its GPS information we are talking about.
The "Go To Waypoint" is done either on the GPS or the plotter, and the resulting information (like XTE) is sent to the pilot. XTE is what the pilot acts on. The other signals (SOG, DTW etc) are informational only. They may be displayed on the autopilot but they don't control it.

I didn't say the pilot calculated XTE, I said it uses that information from the GPS (plotter if you like) to recalculate the heading.

If the SOG is zero, the pilot will give an "off course" alarm as it can't maintain a heading. But its not the SOG signal that causes that, it's the XTE, 'cos no matter what the pilot does in steering the boat the XTE gets worse.

I don't know anything about pgns...that's getting off topic.
This thread was talking about the ST60 pilot...this is how it works, I know, I've got one...used it for nearly 10 years
My original point, on the newer Raymarine "X" series course computers (which can be run from a ST60 controller), if there is no GPS on the STng network, it will not engage a track, regardless if there is a chartplotter sending it BTW, DTW, and XTE. The "X" series REQUIRES to see SOG from a GPS, which is more than the older computers required.

BTW, you most likely have a S1, S1G, S2, S2G, S3, S3G autopilot computer with a ST60 controller.
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Old 29-08-2012, 14:36   #8
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Re: Raymarine ST60 Autopilot without GPS signal

It won't take speed through the water from the knotmeter sender? I don't know anything about the Raymarine, but the Simrad (new) and B&G systems (older) I have used allow one to choose the speed input.

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Old 29-08-2012, 14:50   #9
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Re: Raymarine ST60 Autopilot without GPS signal

I know what I've got...

The title of this thread is : Raymarine ST60 Autopilot without GPS signal

The originator has an ST60 pilot, not Xyz or whatever, that's why he asked the question.
I tried my best to answer it.

In your case, where is this chartplotter getting the BTW, DTW, XTE information from ?..it must either have an inbuilt GPS or getting info from an external GPS.
In that case, unless someone has fiddled with the sentence settings, the SOG and COG info should be there as well. I don't see how you get XTE without GPS data.
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Old 29-08-2012, 15:05   #10
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by colemj View Post
It won't take speed through the water from the knotmeter sender? I don't know anything about the Raymarine, but the Simrad (new) and B&G systems (older) I have used allow one to choose the speed input.

Mark
I discovered the RM X10 refused to engage a track when I removed the GPS from the N2k (STng) network and connected one to the NN3D chartplotter on a different port (0183). There was still STW on the STng network from a RM xducer pod. So, if the X10 can use STW, it *should have* used it, but instead threw a 'no speed' error. So I have to assume the X10 wants SOG. When I told the NN3D CP to repeat SOG onto the N2k network (via the right PGNs), the X10 liked it and worked. There is no choosing data sources on the X10, or more specifically when using the X10/ST70 Pilot Controller combo.

Of course, that was all a test, I am now back to running a N2k GPS.
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Old 29-08-2012, 15:21   #11
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by Albro359 View Post
I know what I've got...

The title of this thread is : Raymarine ST60 Autopilot without GPS signal

The originator has an ST60 pilot, not Xyz or whatever, that's why he asked the question.
ST60 is not an autopilot, it's a control head that talks to a course computer hidden somewhere on your boat. The ST60 control head will work with a variety of Raymarine course computers. I was pointing out that when a ST60 is used with the newer "X" series course computers, the "X" series require a direct (or repeated) connection to a GPS in order to engage a 'track'. As you pointed out, it's not a requirement of whichever model course computer you have. Since we have no idea which course computer the OP has, I thought it was proper to inform him of this requirement on certain models.


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Originally Posted by Albro359 View Post
I tried my best to answer it.

In your case, where is this chartplotter getting the BTW, DTW, XTE information from ?..it must either have an inbuilt GPS or getting info from an external GPS.
In that case, unless someone has fiddled with the sentence settings, the SOG and COG info should be there as well. I don't see how you get XTE without GPS data.
A chartplotter calculates (as is the source of) BTW, DTW, and XTE, a GPS does not produce these parameters. All a GPS supplies is current position, speed over ground, course over ground (in true), time of day, and some supply magnetic variation (based on an antiquated database).
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Old 29-08-2012, 15:28   #12
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Re: Raymarine ST60 Autopilot without GPS signal

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I discovered the RM X10 refused to engage a track when I removed the GPS from the N2k (STng) network and connected one to the NN3D chartplotter on a different port (0183). There was still STW on the STng network from a RM xducer pod.
On the two non-RM systems we have had, the STW/SOG choice had to be set in the setup menu (or one of the other menu's). If set for SOG and the GPS was lost, the pilots do not automatically switch to STW and show an error.

Shouldn't STW be the preferred speed input? It would seem that using this would be the best input for the computer to use for calculating and updating steering parameters. It is the default setting on the Simrad and before Navico B&G systems.

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Old 29-08-2012, 16:41   #13
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Re: Raymarine ST60 Autopilot without GPS signal

The original post made no reference to any kind of chart plotter, which kinda precludes any benefit that a gps signal might bring to the party, with the exception of being able to display some nice numbers.
At least that's what I read.

I was looking for a whole lot more from adding the 130 to the new ng network, but the net effect is about the same with only the I and P instruments, even with the X computer. The compass, gyro, and wind inputs still do the majority of the data feed. Having said that, the auto tack rocks. Now the admiral doesn't have to budge if the crochet hooks are out!
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Old 29-08-2012, 19:34   #14
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Re: Raymarine ST60 Autopilot without GPS signal

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Originally Posted by colemj View Post
On the two non-RM systems we have had, the STW/SOG choice had to be set in the setup menu (or one of the other menu's). If set for SOG and the GPS was lost, the pilots do not automatically switch to STW and show an error.

Shouldn't STW be the preferred speed input? It would seem that using this would be the best input for the computer to use for calculating and updating steering parameters. It is the default setting on the Simrad and before Navico B&G systems.

Mark
I don't disagree and went searching the manual for dockside and seatrial setup procedures. Of course, no mention of STW vs SOG in the manual and it's been 4 years, 2 or 3 software revs, and lots of rum punch since I set it up. I don't remember any setup for speed. Will have to step thru the setup choices on the pilot controller next time I'm playing around and think about it.

I do remember finding it weird it wanted SOG.
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Old 29-08-2012, 20:02   #15
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Re: Raymarine ST60 Autopilot without GPS signal

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ST60 is not an autopilot, it's a control head that talks to a course computer hidden somewhere on your boat. The ST60 control head will work with a variety of Raymarine course computers. I was pointing out that when a ST60 is used with the newer "X" series course computers, the "X" series require a direct (or repeated) connection to a GPS in order to engage a 'track'. As you pointed out, it's not a requirement of whichever model course computer you have. Since we have no idea which course computer the OP has, I thought it was proper to inform him of this requirement on certain models.




A chartplotter calculates (as is the source of) BTW, DTW, and XTE, a GPS does not produce these parameters. All a GPS supplies is current position, speed over ground, course over ground (in true), time of day, and some supply magnetic variation (based on an antiquated database).
My Furuno GP-31 GPS has a function where one can set waypoints and has a GoTO function (even little handheld GPS devices have these functions) and the unit transmits XTE, amongst other things to the pilot . I set the waypoint, GoTo and then press Track on the control head of the pilot (yes you're right mine is an ST6000+, but its part of an ST60 SeaTalk network) and we go to the waypoint

No chart plotter in sight.

When you say "GPS" seems you are referring only to the GPS sensor that would be connected to your chart plotter.

So a mixup in terminology I think....and this discussion is getting rather pedantic... I'm as much to blame !
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