[TG] [TG11] No GPS Info on MFD GPS Status Page

[magic8]

Manage to go for a sail today and GPS position on E80 appeared normal again until entering home port.this time i did not reset the GPS until at the berth.
The first image shows the incorrect GPS position as I was tied up on berth.
The second image shows correct GPS after GPS reset.
The third image shows the error with the cursor on the incorrect GPS coordinates.The GPS had worked perfectly for about 3 hours.
We are convinced the new GPS antenna is at fault as after the reset it performs perfectly for a while.
Don't believe it is anything to do with the setup as it only has any problems occasionally.
Thanks

[Chuck - Raymarine - Moderator]

magic8,

Should the system correctly plot the vessel's position after
1) a GPS restart has been commanded, and
2) should the Raystar 150 GPS Sensor be installed in a location affording it unobstructed view of the skies overhead, and
3) should the GPS sensor have been interfaced per the FAQ found here, and
4) should the GPS sensor have been separated from other antennas per the FAQ found here,
then it would be recommended that the Raystar 150 GPS Sensor be sent to Raymarine’s Product Repair Center to be bench checked / serviced.

[magic8]

Have been away for 5 weeks and finally got back out sailing.After consulting with the local dealer at raymarine request I removed the new GPS antenna and converter and took it to dealer to test. He had it setup for a day and could not fault it although the antenna was stationary the whole time so not sure how conclusive that was.
I was then asked to try it again and try to relocate the GPS antenna to a different position on the boat so temporarily fitted it to the top of the bimini(as per first photo) with obviously no obstructions.
During the way out there was momentary no position fix warning and then the boat steered to starboard for approximatily 10 seconds then returned to the track.
I had been recording the track and the next 2 pics show what happened to the GPS position.The second one is a close up.
On the return leg there were two further occurrences as per the last two pics.
Unless you have any other ideas really need to try another GPS antenna or converter as this is quite dangerous and unacceptable.
Thanks

[Chuck - Raymarine - Moderator]

magic8,

Within my prior response, I specified the following five actions:
1) a GPS restart has been commanded, and ... no answer provided

2) should the Raystar 150 GPS Sensor be installed in a location affording it unobstructed view of the skies overhead, and ... your photo appears to indicate that the GPS Sensor (as duct taped to the overhead would be a satisfactory location ... except for times when the boom (which appears to have relatively low clearance over the hard top) is positioned directly over the top to the GPS sensor. At such times, GPS accuracy may drop off and produce degraded position updates (as appear within your track)

3) should the GPS sensor have been interfaced per the FAQ found here, and ... no answer provided. Failure to install the manner specified within the referenced FAQ may also prevent the MFD's GPS Status dialog from fully populating. As you have not responded, it is my suspicion that the MFD's SeaTalk (not SeaTalk2 / NMEA 2000) port has been interfaced to the SeaTalk to SeaTalkng Converter ... or that the MFD's SeaTalk port has been interfaced to a powered SeaTalk bus which in turn has been interfaced to the SeaTalk to SeaTalkng Converter.

4) should the GPS sensor have been separated from other antennas per the FAQ found here, ... your photo appears to indicate that the GPS Sensor (as duct taped to the overhead) is not located near other RF emitters (VHF antennas, radar transducer, etc.).

If not specified previously, please additionally ensure that the MFD has been updated with the final E-Series Classic MFD software update (v5.69).

[magic8]

Answers to 5 requests

1.Previously a GPS reset corrected the fault .
On this trip the GPS momentarily had a GPS no fix then returned in a offset position, the boat turning sharply to get on the original track.
This can be seen on the recorded track. There was no input from me on this occasion.

2.
While GPS was temporarily fitted to top of bimini boom was in same position as photo.
Sail was not raised and boom ensured in same position as photo.

3.
The RS150 GPS antenna is connected directly to the new seatalk converter.
12v power was removed from the seatalk 1 network and the converter was powered with 12v which then powered the seatalk 1 network.
This was proved by removing the power to the converter and then the whole seatalk network was dead.
The converter centre yellow connection is wired to the seatalk1.
All other operations and indications good.

4.
Yes.GPS antenna nowhere near any other antenna.
Most antennas on top of mast !!!!!

5.
MFD has latest software
Local dealer has ensured antenna and converter has been updated

Thanks

[Chuck - Raymarine - Moderator]

magic8,

Q. The RS150 GPS antenna is connected directly to the new seatalk converter.
12v power was removed from the seatalk 1 network and the converter was powered with 12v which then powered the seatalk 1 network.
This was proved by removing the power to the converter and then the whole seatalk network was dead.
The converter centre yellow connection is wired to the seatalk1.
All other operations and indications good.
A. This description appears to differ from that specified within the previously referenced FAQ. As indicated therein, the MFD will be disconnected from the SeaTalk bus ... this may easily be accomplished by simply unplugging the MFD's SeaTalk/Alarm Cable. The unpowered SeaTalk bus will then be connected to yellow socket of the SeaTalk to SeaTalkng Converter. The MFD will instead be interfaced to a spur socket within the SeaTalkng backbonevia an A06061 E-Series Classic MFD to SeaTalkng Adapter Cable. An additional spur socket will need to be added, as the SeaTalk to SeaTalkng Converter only features two spur sockets. The E-Series Classic MFD to SeaTalkng Adapter Cable will be mated to the MFD's SeaTalk2 socket.

[Tom - Raymarine - Moderator]

Hello Magic8,

I hope Chuck doesn't mind me chipping in here, but some local knowledge might help clear things up. I'm based in Sydney, and one of our dealers has brought this to my attention.

The RS150 is a hugely accurate and reliable GPS antenna - I place considerable trust and confidence in their accuracy and reliability. The ST1-STNG convertor doesn't have any influence on the GPS position, it just blindly passes through what it receives and if there were a fault with that then the result would be no data rather than incorrect data.

This said, there are two things that we know of and have seen many times that can cause temporary but significant position errors in a perfectly-working RS150 (or similar) that has a good view of the sky:

1. RF interference. We have often seen noisy electrics or electronics radiating sufficient noise to partly or completely drown out the very weak GPS signals. Common culprits are LED light drivers, TV antennas, USB devices and 5V charging outlets, invertors and charge controllers, but almost anything electrical that's more complex than an incandescent globe is a potential culprit.

2. In Australia, Differential GPS mode. Modern antennas are sensitive enough to pick up the fringes of the Differential (SBAS) services available in other parts of the world. On the East coast we get Japanese MSAS, in NZ they get American WAAS, and in WA they pick up Indian GAGAN. This sounds good, but in fact what can happen is that the system uses only satellites for which there are differential corrections available, which means in fact a much less accurate fix (larger position error - there is always some position error in GPS/GNSS.) We therefore advise everyone in AU/NZ to turn off Differential mode in satellite setup.

Please disable Differential mode first. If no improvement, the problem is probably RF interference that a Raymarine Service Dealer could help diagnose, but if in doubt you can give us a call on the contact details at http://www.raymarine.com.au/view/index-id=1154.html

Regards,
Tom

[magic8]

Thanks for the input, I need it !!!!
At the request of the local dealer Markwell marine, I have isolated the E80 and the GPS antenna to its own circuit via the converter.
I have powered up the remaining seatalk network to give me an autopilot but they are isolated.
Will go for a sail when I get chance to see if the defect reoccurs.
Regarding the interference it was daytime so no lights , no radio ,no TV no USB , no inverters.
In fact the temporary position of the GPS antenna as per picture had the cable running through the cabin door straight into the converter.
I realise it is still possible though.
As you can see by the track the error happens in an instant and sometimes you have to reset the GPS position on the E80 because the error stays there.
The occasion that i reset it tied up to my jetty we had stopped the engines and were using little power and still the error was there.
Thanks again will let you know how the sail goes.

[magic8]

Just been out for a quick sail and all appeared normal with no GPS errors with the data split as suggested
However when I was on dock and reviewed the track that I had recorded it showed that I had sailed over the land!!!!
How accurate is that recorded track?
All the time I was navigating the GPS position looked good.
I have just read Toms input fully and still have DGPS on and will try next time with it switched off. I may have to put wiring back to normal to enable me to use TRACK mode.
Do you think it could make a difference?
Thanks

[Tom - Raymarine - Moderator]

Hello magic8,

Quote:As you can see by the track the error happens in an instant and sometimes you have to reset the GPS position on the E80 because the error stays there.
The occasion that i reset it tied up to my jetty we had stopped the engines and were using little power and still the error was there.

Can you confirm exactly what you mean when you say that the error stayed? The jag in the track history stayed, or you had a consistent and on-going error in your GPS position? If the latter, what was the form of the error: a consistent (position, direction) offset, a varying offset, a static GPS position?

Quote:However when I was on dock and reviewed the track that I had recorded it showed that I had sailed over the land!!!!
How accurate is that recorded track?

In order to save memory space the systems don't record vessel position continuously, instead they drop a new track point every so often. The track point interval can be manually configured to set time or distance intervals (trading off track accuracy against the length of the track that can be recorded with the available memory) but the default setting is automatic: the system will drop a new track point when it thinks you've made a significant course change. You can see that happening if you watch the track line as you go, and in your photo you can see that it's drawn track points where you've turned corners and joined these with straight lines in-between.
If you want better precision and fidelity in your track history for confined waterways, go into Menu > Chart Setup > Record Vessel Track By. Time-based tracks give the best results for this sort of thing, but if you choose a very short interval then you may run out of available track points in memory, in which case the start of the track will start to disappear in order to make space for the end of the track. E-series Classic could store up to 3000 points per track so at the shortest interval (2 seconds) would give just over 90 minutes. An interval of 10 or 30 seconds should be suitable for most purposes.

Of course, the track also relies on accurate GPS data so if you had a problem there that would also affect the track.

Regards,
Tom