Mobile device navigation

[AndyB]

The tablet phone world best works on Wi-Fi rather than USB. I use UDP but a lot use TCP. It depends on your specific use case.

You therefore need to convert from Wi-Fi to NMEA0183 ( bi-directional really) and also have an app that can produce a GPS signal in NMEA0183 format that is spewed out over Wi-Fi. There is a solution to this.

I have looked at using the phone as a GPS source and have found an app - Share GPS which claims to do this. also there is another app called Bricatta.

I also really like NMEA Instruments - Wirelessly which will give you a fish finder approach. I have written my own depth graph ( output to a kindle) so have not used this nor the ones above. It does rely on a Wi-Fi signal with the appropriate NMEA sentences.

To get from Wi-Fi to NMEA you would need to use a device like MiniPlex-3Wi. If I was starting all over again I would go for this rather than using a raspberry pi to convert the NMEA stream to Wi-Fi.  This miniplex device takes Wi-Fi signals and outputs them over a NMEA0183 output which you can connect to your TackTick. 

I am not sure what you mean by way point data. Is this a GPX format or NMEA waypoint and subsequent XTE sentences? I have tried to design and build a system for sending out a way point and then the appropriate XTE sentences until the next waypoint. It would take this from a GPX format from the chartplotter such as Navionics and also current position and COG. It is mathematically quite demanding and as I rarely use it I gave up. I am currently teaching myself to write android apps so when I have achieved that then I may return to the problem and start with a waypoint and then see if I need an XTE with the ST1000+. To be able to create a route on Navionics etal and then export it to a file which you then start following would mimic exactly what the current chartplotters do. It is the XTE sentence which is demanding.

Hope this helps and that I have understood your question correctly.

[Graham W]

Thanks Andy.

From what their developers say on the Android app store, it appears that the apps that you mention (Share GPS, Bricatta) have been developed mainly to use the GPS in a mobile phone to provide data to a tablet that for whatever reason doesn’t have its own GPS.  Or to let people know where you are.  Unless I’ve misunderstood (which is entirely possible), the apps can’t turn a tablet into a “talker” and send out NMEA sentences to a multiplexer for use on an NMEA network.

When I had my old Garmin GPS/fishfinder linked in to my Tacktick system via NMEA, I could tell the Garmin to navigate to a waypoint that I had previously saved.  Then the Tacktick system would use the Garmin-provided waypoint (WPL) to calculate clever stuff like velocity made good towards waypoint (VMC) and estimated arrival time.  Or maybe it wasn’t calculating it but also taking VMC etc from the Garmin.  Anyway, the Tacktick displays would show this data in big clear numerals, unlike on the Garmin’s difficult to read small screen.

Now that I have a tablet taking the place of the Garmin, it can pick up and display NMEA data from the Tacktick system (on UDP via a Digital Yacht WLN10).  However, the Tacktick system can’t pick up waypoints that I have saved in, say, Navionics on my tablet.  This isn’t much of a problem as the tablet can calculate and display waypoint-related information like VMC, XTE, ETA etc all by itself.  Just maybe not in NMEA format.

Most mobile phone and tablet processors are hugely more powerful than expensive but somewhat dumb and inflexible GPS/fishfinders.  I’m curious to know why mobile devices don’t yet seem to be bidirectional, by whatever means available.  That might be useful, for example, if you have big clear NMEA instrument displays but are relying on an app on your mobile phone for the GPS calculations and outputs.

I looked at the MiniPlex-3WI that you mentioned but got a bit lost trying to understand what it does.  Is it a bit like my Digital Yacht WLN10 but with many more ports, or does it have additional capabilities?

Reading your response and particularly your penultimate paragraph, it appears that you have already worked on some of this.  If there was a simple way of sending to an NMEA system WPL-related sentences derived from a waypoint chosen in an app like Navionics, then Garmin and the other oligopolists would be truly doomed.  Unfortunately Garmin now owns Navionics and I can already detect the dead hand of the parent as the hardware specialists try to protect their part of the business from erosion by their own software and app developers.

[AndyB]

The TackTick system has a NMEA gateway that acts like a multiplexor in that it transmits different NMEA sentences over its one NMEA output and receives different NMEA sentences over its one NMEA input. The sentences then get distributed over its internal Wi-Fi using a protocol I do not know to all its devices who also provide sentences as in a true network.

I assume you have connected the NMEA connections to the WLN10 which also has one NMEA input and one NMEA output. This will take the NMEA sentences and broadcast them over Wi-Fi either using UDP or TCP. UDP is generally used to broadcast and TCP for 2 way communication.

Navionics as an example will read the Wi-Fi port  and if it can display the sentences depending on what sensors you have connected to the TackTick network.

If you want to introduce a GPS sentence ( I use $GPRMC) you need to create it from somewhere  and inject it into either the tacktick network (T908 very expensive) and then it will appear via the gateway , through the WNL10 and into your tablet or you take the sentence from the tablet and inject it into the WLN10 and then into the tacktick network.

The phone and tablet ( if android) is exactly the same device so an app such as GPSShare will create an GPRMC type sentence on any android device that can run it. You can it  connect to the WLN10 via TCP. The GPS Share app is such an app that reads the internal GPS and broadcasts it on a port on the WiFi for any other device to pick up.

My ST1000+ can be set to operate in 3 modes Auto, Track (RMB/XTE) and Wind Trim (VWR). I have setup my Miniplex ( just a competitor to the WNL10 with more connections) to take the VWR sentence from the NASA wind instrument and send it to the ST1000+ via a NMEA connection. I find Wind trim very useful on a close reach/ close hauled but use Auto for other wind directions.

Track mode is where it takes a RMB/XTE sentence and sails the boat to the prescribed waypoint. I do not know of any tablet based chartplotter apps that produce an RMB ( which also contains the XTE). What you can do is create a GPX file which is a file describing the route. From this extrapolate the RMB information and then send that to the ST1000+. This is about as far as I got. I was going to use Navionics to export a file and then load it onto the raspberry pi ( via a webpage ) and then get the raspberry pi to send the appropriate RMB and XTE from the GPX file to the ST1000. ( you have to create the sentence from the GPX file - not easy) This was all going well until I got to the XTE part where the mathematics blew my mind. Then there is the usual issue of knowing when you pass the waypoint so you can send the new one etc.

It maybe that the tacktick network can display RMB information but the issue I have is how you produce it. This is where the professional setups have an edge. Most will import a GPX file from the planning device and then send NMEA sentences to the tillerpilot to steer the boat.

It maybe that you do not need XTE and this is something I need to experiment with. Winter is long and cold and maybe a project I can resurrect.

Apologies for the long response....

[Graham W]

Andy,

Your second and third paragraphs are exactly how I am set up.  And I agree that the Tacktick T908 GPS antenna is a crazy price, especially as it doesn’t even receive Galileo signals.  I have a more capable Digital Yacht T160 antenna at around 1/3 the price.

Are you talking about GPSShare or Share GPS?  I couldn’t find the former anywhere and wonder if it’s still around.  Google have chucked quite a few apps off its store recently.  Share GPS seems to do what I think are relevant things with NMEA sentences. 

As you mention, there are ways of controlling tiller pilots using various tablet and mobile apps like OpenCPN and iNavX and interesting new app navCenter (for iPad). This presumably involves sending NMEA sentences over wifi the opposite way to what I am currently doing.

As with electric outboards, I’ve been an early adopter of this sort of gadgetry only to see much better and cheaper solutions appear a couple of years down the road.  I’ll see how I get on next season with what I have (which is already more than adequate) and await developments.

Thank you for all your effort in answering my questions.

[Graham W]

I read someone’s 2021 post on another forum about why it was wrong to use a tablet for navigation:
1.  They overheat in the sun and shut down - true for the iPad but not the Sailproof, so far anyway.
2.  They’re not sunlight readable - as above.
3.  Operating systems can shut down an app unexpectedly when new power-saving measures are introduced.  I haven’t experienced this on Android apps but it’s early days.
4.  If you’re using your tablet to navigate, you can’t or shouldn’t use it for anything else - which is why you also have a mobile phone
5.  Even if your tablet is waterproof, it ceases to be so when you inevitably have to connect it to a power source - this depends on the size of your screen and battery and whether the latter, as with the Sailproof, is swappable
6.  Night mode when navigating can still be too bright - not a problem on the Sailproof.

Substantial progress in the past two years - long may it continue!

[AndyB]

Hi , I meant Share GPS. It seems ideal but has not been updated for a while and will not work on my android devices. I will spend sometime looking for others but maybe this is my first project.... A simple GPS sharing app for tablet chartplotters.

I use a USB GPS connected to my raspberry pi from which I export the RMC sentence to Wi-Fi so have no real need for the above.

Unfortunately ( for me) INavX only interfaces to Wi-Fi with the Apple version. If I was Apple based then yes it could provide sentences to control the tiller pilot. Just what I wanted. I have communicated with them and they have said - not in the next 12 months they are recovering from Google's massive change for Android. However I will move when it comes on board as it will make INavX much better than Navionics.

OpenCPN uses SignalK for this sort of thing. It does have a plug-in for the ST1000 and other tiller pilots but SignalK would be required ( if I am correct) and it runs on a raspberry pi or other good linux devices. Also being raster based not so good for the Solent area for the reasons I suggested earlier.

As you say Graham time will cure the issues above.

[Graham W]

A reply to a query that I sent to Digital Yacht: “Not many apps output data but if your app does then …. any data that your App outputs, will be received wirelessly and output to the T122.”

This relatively new app looks a possibility for Android: NMEA Over Network by KikiManjaro.  No waypoints, as far as I can tell, but current position data is available.

[AndyB]

Garmin strikes again... big company destroying the competition read this from INavX....

Hi Andy,

Since Garmin purchased Navionics and subsequently canceled our reseller agreement for Navionics charts, we are rather limited in our chart offerings for iNavX Android.  If you have iNavX Android installed on your tablet you can see everything we currently offer on the Store page in iNavX.  Tap the blue Charts button seen near the bottom in the center of the page when viewing any chart then tap the Store tab.  That page lists all charts with prices that we offer for use in iNavX.  At this time we do not offer anything for the UK and nothing in vector charts at all.

I wish I had better news for you.

iNavX Support
Jim

[Graham W]

Typical behaviour from an oligopolist. It wouldn’t matter so much if they invested in more capabilities for the Navionics app.  But their attitude seems to be that if you want more capabilities, you should spend £££ on one of their very expensive boxes.

The charts on the iOS version of iNavX are OK but nothing to write home about - see the attached and compare them with the various chart views of other apps that I posted on the first page of this thread.

[Matthew P]

Face the wind and smile!

I continue to be amazed at the technical expertise of many forum contributors and very much appreciate them sharing their knowledge with us.  My technical expertise is best described by HW Tilman as a “hard hitting mechanic”.

For cruising I still want a chart plotter to tell me where I am, where I should not go and how deep the water is. But backed up and by waterproof charts big enough for me to orientate myself and make sensible course setting decisions and identify coastal features a mile or more away.  Shamelessly cut-and-pasting from an earlier post my personal quest remains to find a chartplotter for use in open boats that is:

a) Truly waterproof - can operate after being dunked in water, not just splash-proof.

b) Easy to operate with wet cold fingers in gloves by a wet, cold, tired eejit .

c) Bright and clear enough to read in strong sunshine.

d) Displayed big and clear enough to read with misted-up glasses.

e) Robust (including cable terminations)

f) Equipped with an operating system to use with Android or Apple Apps

g) Self contained with 8 hour minimum battery life and re-chargeable.

iPads and smart phones in plastic cases meet some of these criteria but fail on b) - easy to use with wet fingers by an eejit and c) clear in bright sunlight.  These are more important than long internal battery life.

Aside from £800-ish for marine chart-plotters - that mostly fail g) - does anyone have recommendation that does not require a 100GByte techno-ninja to set up and use?

Incidentally, a well known Sailing Master who sometimes contributes punishing posts to this forum, helms, encased in balaclava, dark glasses, drysuit and thick gloves that would cut most mortals off from any sensory perception of their environment.  I’ve sailed with him and we didn’t even have tell tales on the shrouds, let alone “Tacktick”, or whatever, electronics. His race record speaks for itself.

Face the wind and smile! 

Matthew

[Llafurio]

What works for me, sailing in rough home waters strewn with islands, rocks, shallows, and wherever else I go,
is a rugged waterproof phone for € 210.00, held with a strip of velcro on the centreboard capping, running the Navionics Boating app.
That phone works so well, I use no other in daily life anymore. Dropped it in water, dropped it on concrete, many times, no damage.
C.

[Graham W]

To Matthew and all others who prefer ‘plain sailing’ to tinkering with gadgets - give it time.  The perfect cheap tablet system which ticks all your boxes will appear eventually.

Battery life is currently in inverse proportion to screen size but this (and exceptional readability) will be solved with coloured e-ink screens, using much less power.  Expensive lithium batteries for tablets will become cheaper and have more capacity, perhaps a lot more capacity.  Batteries may not even use lithium any more but something safer and more environmentally friendly.  The 24+ hour tablet will arrive and when the batteries on even that version are exhausted, wireless charging for tablets won’t be far away.  Someone will invent a wireless waterproof mouse-like gadget with button and arrow functions so that even neoprene enthusiasts will be able to control apps other than on a touch screen.  Something like this https://www.medicalexpo.com/prod/shezhen-aitmon-technology-co-ltd/product-300881-1004420.html.  And apps will have more features and become easier to use.

In the meantime I’m afraid that you’ll have to put up with us gadget enthusiasts, for whom every new technological breakthrough is another blow against greedy and badly-behaved black box manufacturers.  Quite a lot of the disrupting technological advances are being achieved by small companies in places like Cambridge science parks and remote towns in New Zealand.  We spend our money unwisely with them (but have fun doing so) so that eventually you won’t have to.

Didn’t the said Sailing Master purchase one of the latest Garmin GPS/fishfinders with a sophisticated depth transducer, so that he could find the tidal channels at Mylor and make full use of the currents?

Face the future and smile!

PS Other than price, this new tablet claims to already meet all of Matthew’s exacting requirements https://www.tripltek.com/tripltek9.

[Willie The Rut Lander]

Hi Matthew

As a non-technocrat, but not quite a technophobe, I struggle to understand much that Graham and Andy write on this subject. However, last spring I did take Graham's implicit(?) advice and bought a Sailproof SP10. While it was quite expensive it seems to meet all your requirements though I have struggled to get the battery to last all day, which means it must be charged on the go, which then means it's not totally waterproof. I don't know how much a second battery costs but I charge mine very successfully either from the 12V battery or a power-pack.

If you are interested in a Sailproof I strongly recommend you DM me - it's good news don't worry!

Willie

[Graham W]

I struggle to understand much that Graham and Andy write on this subject.

Me too!

I did take Graham's implicit(?) advice and bought a Sailproof SP10. While it was quite expensive it seems to meet all your requirements though I have struggled to get the battery to last all day, which means it must be charged on the go, which then means it's not totally waterproof. I don't know how much a second battery costs but I charge mine very successfully either from the 12V battery or a power-pack.

Well, I bought an SP10 myself.  I’m impressed with it - it excelled in the bright sunshine on a yachting trip in the Ionian, where the boat’s own plotter screen, unhelpfully, was down below.  I bought a spare battery  - it’s currently priced at £65 plus shipping.

The Tripltek 9 Pro reflects the march of progress since the Sailproof SP10 first came out in April 2022.  It has a smaller screen (8”) but with a significantly higher resolution and brightness. Of particular interest is its charge port, which is IP68 waterproof when in use. So with a waterproof (in use) USB charge socket (eg a Scanstrut ROKK) wired to a decent 12V battery, the days of tablet range anxiety are effectively over.

No doubt something even better will be along shortly.

[AndyB]

Hi All,
I bought the Sailproof SP08 sometime ago.  It runs Navionics and Imray although I generally use Navionics. It displays AIS and gets its COG and SOG from the sensors but I could use it with its internal sensors would just lose out on AIS. I have a self made mount in the cockpit see attached - reflection is from the camera

It has not run out of battery yet and normally lasts about a day and half on 75% screen illumination (tracking on) and a day on 100% screen illumination. 75% is fine for sunlight directly on the screen. I have used gloves and it works ok - better than a friends Garmin. I tend to charge it when it is not raining during a sail just to keep the battery topped up

So for me it answers all the questions from Matthew and I have no problems recommending it.