Commerical OTS mesh antenna network for glider tracking

I was wondering if gotenna might be a practical way to handle glider tracking.

https://www.gotenna.com/pages/mesh

https://vimeo.com/184624592

looks interesting, i wonder how it would handle 1 message per minute or faster update rates.

Chris

Well, I wasn't planning on announcing it just yet, but since you brought it up, I have been working for over a year on a soaring app using the original Gotenna. I have now updated it for Gotenna Mesh, and will be testing it soon. I will eventually release the app for others to use for free. It's an Android app, since I think Android is more common in the cockpit because of XCSoar.

For those unfamiliar with Gotenna, it's a little device that pairs with your smartphone via Bluetooth. The Gotenna can send and receive data with other Gotennas in range, without the need for a cellular connection. That means that gliders can transmit their GPS positions to other gliders directly from Gotenna to Gotenna. It's very low bandwidth, so it doesn't work for voice or video, but it's enough for GPS positions.

The Gotenna Mesh is a new version of the device, but the basic concept is similar. It operates on a different radio frequency than the original. The new frequency is legal to use in the air, while the original was not. The new one has a mesh networking feature, but as I will explain later, it's not useful for us.

My app could be useful for team flying, glider tracking, weather data, and collision avoidance. The Gotenna Mesh can be had for as low as $72 a piece at retail (they also go on sale often), so it's something any pilot or club can afford. Note that I have no affiliation with Gotenna. I make apps for a living, but I am making this app as a hobby and as a service to the glider community.

The app shows a moving map with your GPS position and the positions of other gliders. It shows the other gliders' altitude, vertical speed, and callsign. This is all done without the need for a cellular connection, thanks to the Gotenna. There are many other features I plan to add, such as showing live weather for nearby airports that are equipped with a Gotenna on the ground. The ground based Gotenna app could also send the positions of any gliders it sees to a website where anyone on the Internet can see them, similar to the SSA Sailplane Tracker.

This app will never be as good as Flarm for collision avoidance, but it will be better than nothing and way, way cheaper. It can broadcast your GPS position up to 5 times per minute, so every 20 seconds. That's good enough to tell you if there's another glider in the area, but not good enough to provide a useful warning if you're on a collision course. The 5 times per minute limitation is imposed by the Gotenna, in order to not hog the bandwidth on frequency. Flarm broadcasts your position every 1 second, IIRC.

I haven't had a chance to test the maximum range of the Gotenna Mesh, but I am hopeful that it will reach 15-20nm air-to-air. Probably less, ground-to-air. It transmits at 1 watt. Flarm transmits at 10mW, I believe. Range increases with the square of power (IIRC), so 1W doesn't mean 100 times longer range than 10mW. Still, the range should be sufficient for the purposes of the app. In the testing I did with the original Gotenna, battery life is sufficient for many hours of flying.

Note that the mesh functionality of the Gotenna Mesh is probably not going to be useful in this application. The Gotenna mesh technology was designed for a few hikers to send each other messages every few minutes; not 5 times per minute. Transmitting messages through the mesh network requires each node to rebroadcast any mesh messages it receives (a slight simplification). This rebroadcast comes out of your own 5-messages-per-minute budget. If there were more than a couple of gliders in the mesh network, you would have to spend your entire message budget rebroadcasting other's positions instead of your own. At least, in order to maintain 20 second updates. If you go down to 60 second updates, you could handle a few more gliders in the mesh network, but any more and it breaks down again. Better to keep the 20 second updates. I have toyed with solutions to get around this, such as bundling several gliders' positions in a single message, but ultimately you can't get around the fact that there is very limited bandwidth on the spectrum and using mesh networking eats it up quickly. Therefore the app only broadcasts your position to other gliders within RF range and never rebroadcasts positions of other gliders.

Anyway, that's enough for now. I will post more when there is news to share..

On Thursday, 26 October 2017 15:51:09 UTC-6, wrote:
Well, I wasn't planning on announcing it just yet, but since you brought it up, I have been working for over a year on a soaring app using the original Gotenna. I have now updated it for Gotenna Mesh, and will be testing it soon. I will eventually release the app for others to use for free. It's an Android app, since I think Android is more common in the cockpit because of XCSoar.

For those unfamiliar with Gotenna, it's a little device that pairs with your smartphone via Bluetooth. The Gotenna can send and receive data with other Gotennas in range, without the need for a cellular connection. That means that gliders can transmit their GPS positions to other gliders directly from Gotenna to Gotenna. It's very low bandwidth, so it doesn't work for voice or video, but it's enough for GPS positions.

The Gotenna Mesh is a new version of the device, but the basic concept is similar. It operates on a different radio frequency than the original. The new frequency is legal to use in the air, while the original was not. The new one has a mesh networking feature, but as I will explain later, it's not useful for us.

My app could be useful for team flying, glider tracking, weather data, and collision avoidance. The Gotenna Mesh can be had for as low as $72 a piece at retail (they also go on sale often), so it's something any pilot or club can afford. Note that I have no affiliation with Gotenna. I make apps for a living, but I am making this app as a hobby and as a service to the glider community.

The app shows a moving map with your GPS position and the positions of other gliders. It shows the other gliders' altitude, vertical speed, and callsign. This is all done without the need for a cellular connection, thanks to the Gotenna. There are many other features I plan to add, such as showing live weather for nearby airports that are equipped with a Gotenna on the ground. The ground based Gotenna app could also send the positions of any gliders it sees to a website where anyone on the Internet can see them, similar to the SSA Sailplane Tracker.

This app will never be as good as Flarm for collision avoidance, but it will be better than nothing and way, way cheaper. It can broadcast your GPS position up to 5 times per minute, so every 20 seconds. That's good enough to tell you if there's another glider in the area, but not good enough to provide a useful warning if you're on a collision course. The 5 times per minute limitation is imposed by the Gotenna, in order to not hog the bandwidth on frequency. Flarm broadcasts your position every 1 second, IIRC.

I haven't had a chance to test the maximum range of the Gotenna Mesh, but I am hopeful that it will reach 15-20nm air-to-air. Probably less, ground-to-air. It transmits at 1 watt. Flarm transmits at 10mW, I believe. Range increases with the square of power (IIRC), so 1W doesn't mean 100 times longer range than 10mW. Still, the range should be sufficient for the purposes of the app. In the testing I did with the original Gotenna, battery life is sufficient for many hours of flying.

Note that the mesh functionality of the Gotenna Mesh is probably not going to be useful in this application. The Gotenna mesh technology was designed for a few hikers to send each other messages every few minutes; not 5 times per minute. Transmitting messages through the mesh network requires each node to rebroadcast any mesh messages it receives (a slight simplification). This rebroadcast comes out of your own 5-messages-per-minute budget. If there were more than a couple of gliders in the mesh network, you would have to spend your entire message budget rebroadcasting other's positions instead of your own. At least, in order to maintain 20 second updates. If you go down to 60 second updates, you could handle a few more gliders in the mesh network, but any more and it breaks down again. Better to keep the 20 second updates. I have toyed with solutions to get around this, such as bundling several gliders' positions in a single message, but ultimately you can't get around the fact that there is very limited bandwidth on the spectrum and using mesh networking eats it up quickly. Therefore the app only broadcasts your position to other gliders within RF range and never rebroadcasts positions of other gliders.

Anyway, that's enough for now. I will post more when there is news to share.

I believe this has great potential. Please add iOS to your work list if possible

On Thursday, October 26, 2017 at 5:09:09 PM UTC-7, Ron Gleason wrote:
I believe this has great potential. Please add iOS to your work list if possible

It's possible I could do an iOS app in the future. However, in the meantime a used Android phone can be purchased for a song these days. Besides, it's better to keep your main cell phone in your pocket, in case you have to bail out and need it later.

On Thursday, October 26, 2017 at 5:51:09 PM UTC-4, wrote:
snip
So if the system you describe never uses the mesh then how does the data make it to the internet?
Chris

On Friday, October 27, 2017 at 9:54:41 AM UTC-7, wrote:
On Thursday, October 26, 2017 at 5:51:09 PM UTC-4, wrote:
So if the system you describe never uses the mesh then how does the data make it to the internet?
Chris

My app uses the Gotenna to send messages to anyone in range. The mesh feature of the Gotenna, which I don't use, lets you send messages to people *out* of range, by passing messages from person to person. That's what mesh networking is; passing messages from node to node, like a game of "telephone". The Internet is not involved in either case.

Where the app may use the Internet is in the special case where the app is being used on the ground. When on the ground, the smartphone will likely have a cellular Internet connection, in which case it can send data about any gliders it sees to a website (or app) for display. This is only for the benefit of people on the ground who want to track gliders.