Outernet for sailors (weather forecast grib files)


#1

Hi from Barcelona,

I just find out this project and spent all the day reading about it and I think I can say that its really possible that in a few time it will be a Lantern in each boat in the world.

Sailors don’t have a really good way to get free digital weather forecast offshore. Before leaving we need to download grib files but you can’t trust in a forecast after 3 days so is critical to get updated forecasts.

http://www.globalmarinenet.com/grib_downloads.php

These forecasts are generated daily at 0015, 0615, 1215, 1815 GMT for every region of the world. GRIB forecasts are based on the National Weather Service, NOAA, Wave Watch III model yielding highly accurate forecasts every 6 hours for up to 7 days into the future. All GRIB forecasts are available via download or delivered by e-mail and optimized specifically for low bandwidth wireless connections.

These files are compressed and can be read by lots of marine software.

The question is, it would be possible daily access to these files through outernet? If so, it will be massively used by every sailor in the world.

What do you think?

Thanks!!!


#2

That sounds awesome!
I don’t know what the possibilities are for boat based reception (i assume they’re probably the same as land-based reception), or what the carousel will look like (in terms of daily update viability), but i can say that this is (in my opinion) definitely worth broadcasting.
The content suggestion is much appreciated.


#3

Its an interesting approach.
I think, the problem is how to keep the direction of the receiver parabola, at least for some minutes, in the geostat satellite position on a moving boat.
To track satellites, radio amateurs use two axes tracker system, but based on fix ground. The commercially available satellite tv receiver systems use only one axes, to track the geostationay belt, to receive more satellite. I think there are at least two approaches to try solve this problem:


#4

We intend to have 100% global coverage using shortwave at some point in future, and that would hopefully solve the tracking problem.


#5

The solution provided by @tjanos would be possible in big boats but permanent mount of a 60cm dish is not an option in small-medium boats. So we have short-wave in that case. Small-medium boats are already equipped with bidirectional HF radios and antennas (I suppose that the Lantern without a HF antenna is not worth in short-wave, isn’t it?) but we don’t have a free and unattended service to download grib files. Besides Lantern we could receive with cheap RTL-SDR dongles + upconverter + raspberry and obviously with normal HF radio receivers.

@branko, can you tell us some more information about outernet by short-wave? current state, implementation plans, bandwidths, transmitters, coverage…

and about grib files (and maybe weatherfax images) daily updated on outernet servers? is it possible? besides sailors, many scientific communities use these data.

Thanks again!!


#6

I’ll let @Syed answer that.

That’s definitely possible. Better weather app is on our ever-growing TODO list, so please be patient. We want to cover as many use cases as possible, so thanks for letting us know about yours. Another use case we want to cover is providing weather data to farmers.


#7

@Sailoog @branko Outernet over shortwave is still early. We won’t be releasing it until after Lantern and our mobile service is available. It’s really not meant to be a content delivery channel. Instead, we’ll use it as an ongoing update of all of the various higher speeds channels; kind of like an EPG. It will also be used as an emergency notification system.

Kim Elliot, who produces the VOA Radiogram program, has done a lot of work on shortwave data and we’ll largely be leveraging that. The bandwidth will be tiny; less than 10 kHz and the expected through put will be the smallest of any of our channels: 60 bps. Although we are likely to use other transmitters in the future, we’ll start with the international broadcaster that is based in Florida. This is a 100,000W station that can be received as far away as India.

How much daily bandwidth would a grib file update require? Are these data files or image files?


#8

Looks like there’s around 9MB of data and a GRIB Explorer viewer program. Sounds manageable.


#9

Thanks for your replies @Syed, @branko.
While you are in progress with that, I am going to do tests with tuners and dishes on board if I can. Let me know if you need details about grib files, on board communications or something.

Some extra info…

Grib are data files which can be read by viewer programs.
If you have satellite internet connection you will be able to either make requests from the program of an exact location and add all the data you are interested in (wind, rain, pressure, temperature, waves…) or download grib files (wind or waves) of predefined zones. Expensive.

If you have a HF transmitter and a pactor modem, you will be able to make requests of grib files by mail. That involves too much expensive devices and likely interferences. There are two services, one of then free but you need a Ham license.

Wind of all predefined zones is 3MB total weight. Waves are about the same. Files are from 5kb weight to 200kb . They are automatically generated 4 times at day but for general navigation it will be enough with just one update.

Having these files available to automatic unattended download from outernet it would be the best, cheapest and easiest option.


#10

Sailoog

I dont know, which type of data there are in the GRIB files, but I took a quick look at the GRIB Explorer demo. It display an animation of the wind streams on ground level. Mybe, it contains more, sophisticated meteo data visualizations too.
My notes here:
we are working in high altitude pico-ballooning, we need wind speed data in different altitude levels. Mainly, for prediction we use the nullschool website for this. On the about page, you can see, it based on the NOAA data, refresshing in every 3 hour. This page present animated vizualizations on google earth base, it is clickable for more data in a place, and has zoom features. On this web page tha data are presented in 7 altitude levels, it is usefull for us to predict the path of a balloon in known altitude, started from known coordinates.



I dont know, has any chance this google-earth based site to download periodically its actual data visualization, but it seems me, this is more or less usefull for sailors too.
t.janos


#11

Great link @tjanos I did not know.

The source of the data of that page and the grib files are the same.

I recommend this software to manage grib files. In altitude too.

http://www.zygrib.org/


#12

Ok, some additional info, to use the NOAA high altitude wind speed data:
NOAA has a publicly available prediction modell to predict pathes based on their satellite data. We use for prediction their special modell for ballooning.
You can start here to ask a modell run:
http://www.ready.noaa.gov/hypub-bin/trajtype.pl
And to make such prediction for a flying balloon, it is a feature on the display map, clickable from the actual balloon data on this page: (click HISPLIT, if it is available)
http://tracker.habhub.org/#!mt=roadmap&mz=6&qm=1_day&f=PS-36
(sry, it it is Off Topic)
t.janos


#13

Sailoog
thanks for the link to the open source grib viewer.
In the first try to compile it, it wasnot a success. I use an old debian linux, intalled on it the Qt4 graphic framework, need for compiling the zygrib. But at near the end of compiling, it need another, small lib, I havenot. Try to find, become clear, it exists for only the next Qt version. This is a trap on my system, it will be best to try to install it from precompiled version on ubuntu (in the near future).
t.janos


#14

Finally I found a description about the TracVision A7 flat antenna, produced KVH Industries, designed to car/van receiver of geostat. satellites.
It is a 3 parts text, with pictures on details.
http://www.embedded.com/print/4011121

It seems, the key element is the small antenna patterns, able to receive not only from the direction, and it able to receive the different circular polarizations on signals too, consequently not need to pointed exactly to the satellite direction, as the parabola need. It need to modify the LNB coupling too.
Maybe it is a good starting point for sailors. The big problem to try to make experiments is the prices.
I think, it would be good idea to start a sub-project in outernet too, studing this antenna types, because such antenna would be usefull at the lantern receiver too.
Another idea:
I have a 5.8 GHz wifi AP with flat antenna design. It has teflon PCB base, and special patterns, as you can see on this picture:

on this page:
https://sites.google.com/site/tlwa7510inside/
On the satellite we use more-or-less the double frequency, maybe the pattern design has half sizes for this frequency.


#15

The problem with using this kind of antenna for Ku or C band satellite links has to do with adjacent satellite interference. The planar antenna pattern for any specific frequency is a solved problem. The initial design costs some money, but the end product is very inexpensive. But when dealing with such a small aperture antenna, the field of view is essential hemispheric. This means that the receiver is seeing multiple sayellites, each of which is broadcasting at similar frequencies. It’s a solvable problem, which we are working on, but at a much slower pace than some other things.


#16

I see in the other thread your “mobile” antenna design. Have you any experiences with it? Can we see any more details about it construction, availability?


#17

As Cruising sailors once we have passed the relevant licensing test in out country we are eligible to run a Maritime ssb radio. These are often 150 Watts power. We are not limited by the restrictions imposed on Ham radio on boats and I believe are allowed to use the Maritime ssb for commercial purposes.

Maritime SSB combinesd with the opensource Winmore soundcard modem / protocol could be an excelent way to send the return low band width data path to Outernet / outernet maritime users.

George


#18

@Seasalt This is very intriguing information. Could you find out for certain if your license allows for commercial use? Who grants your maritime ssb license? What is the frequency range of the radios and how much do they cost? What is maximum power output and range?


#19

Every thing I am saying needs to be checked.

Most Maritme SSB HF radios are 150 watts plus and are chanelised. I believe bigger commercial ships have bigger radios.
Some cruising sailors have Ham radios but they are not allowed to send any messages of a commercial / encrypted nature on the HAM network…

i.e. They cannot send messages related to picking up charter guests etc.

The maritime radio is allowed to be used to discuss doing maritime business ie cargo transactions and picking up guests as well as the information in the message can possibly be encrypted.

There is a HAM radio HF email network called WINLINK using Pactor Modems and the new Winmor sound-card protocol to send asci and email messages. But all messages must be unencrypted and not be business related.

A worldwide Maritime radio commercial email service is available called Sailmail that I believe operates on the Maritime frequenciies. It has land based stations around the world that receive / send Pactor modem HF transmitted messages from ships and sailing vessels and forwards them onto the internet. It is a commercial service and I think it costs US$250 a year.

Seasalt.


#20

If boats could install an Adhoc microwave communication system to exchange updated files with each othe or use some implementation of the SatNOGS this would make it develop fater; https://satnogs.org/