We have been developing a small, easy to install device to provide cellular telemetry to any Pixhawk based drone.
We will be launching the kickstarter campaign this week.
I personally think cellular telemetry is way better than having to plan frequencies, powers, antennas, etc. What do you think?
The idea is of course not new, we have been flying SIM900 modules for years.
However, combining with proxy service, and all in a end-user-friendly package, is new.
It all depends on the price/service fees, and whatever this will be an open solution that anyone can buy and use, or if you want to have monthly fees and lock-in to your proxy servers.
Andre thanks for your insightful response.
The problem is without a proxy server it becomes quite tedious to find IPs, connect the devices, etc.
Both of us in the team are telecom engineers and it hasn't been easy for us so I think for most users it is difficult to come up with a DIY solution that is also practical. Same with radios, where you have to choose the right frequencies, power, filters, etc. if you want decent range.
I actually didn't know about the SIM900 modules, would you care to share some infos about your setup?
We have given a lot of thought about making it open source or making it closed and charging a subscription. As lucrative is it may sound, we actually don't love the idea of having our own servers, since it is a difficult task. However, we think it is the best option since we don't want the user to have to install and maintain his own server.
In your case, would you prefer to run your own server? Maybe we could do both, have our own servers, and release the code for the server, and let the user can decide what's best for him. We could create an app that runs a server in the phone, but you would still need a way for the modem to find the phone's IP..
I have been using these SIM900 modules by SIMCom , - very cheap, works well, plenty of sources, like this for example:
An microcontroller between can make the connection when needed, sp no Ardupilot code neeed.
I do map a lots of areas with no cellular coverage, so it's not a replacement for radio telemetry, but an nice option in places with coverage.
there are two main solutions to the get-the-IP for direct connection problem (if we skip dynDNS):
1: make the UAV end display it on a small display, enter IP into GCS (no autopilot code needed) , but in extreme long offline cases, the IP could change
2: custom AP firmware configures GPRS over radio modem based on GCS IP (which is within coverage and won't change.)
Then you have the proxy solution: (also useful for those who's carriers do not allow externally initiated data)
both GCS and UAV contact one predefined server, (both init outbound traffic) - and the server forwards the traffic between them.
The proxy solution, - (would be important to me) to be able to host myself, as it's mission critical.
It's really nothing to it, you need a Raspberry Pi or smaller, on an ISP that offers static IP with a script.
You may see me ignore two things other will pinpoint: "IPv6 just works"
- yes, but many cellular complanies still does not offer it, also , the GPRS device need to support it..
and "why not 3G, 4G , LTS"
- because it's often poor at altitude and outside cities, causes jumping between nets, and is not needed, GPRS is fast enough for the telemetry we need.
I agree that GPRS is good enough for telemetry data.
We have decided to create a companion app for configuration, since we have bluetooth connectivity in the hardware, it is the easiest option for the user
We have had a lot of problems with the Cell network part of transmitting the data. We have to use "Hole-punching" to be able to transmit data to a phone. (We want to be able to view the data in the tower app)
Sending data from the air module has been no problem though