I am successfully using a 4G LTE network connection to send bidirectional telemetry AND HD (1280X1024 / 25fps) Video from my drones.  The video is perfect, the telemetry is perfect - regardless of range (assumes 4G is available).  I use my cell phone as a hotspot and connect using MISSION PLANNER on my laptop. The video is "snow free" and is viewed  on CHROME or FireFox browsers. 

The cost of all the equipment is under $100, but I do have to pay for a data plan ($15-$50/month) - and a small monthly amount for server time. The server setup is special to allow for the 4G<->4G connection.  The telemetry data is encrypted, the video data is not (at this time, anyway).  The system camera is non-standard but tiny.I can control the drone with a joystick connected through Mission Planner.  The latency is 0.8 seconds - max. The total weight of the system is 100 grams.  No equipment other than a computer running Mission Planner is needed on the "ground side" (except for a cell phone or other hot-spot).

I was thinking that others could use my setup as well. In that case I would have to set up multiple accounts on the server and manage them.  Before I take this any further -

Would anyone else be interested in the setup I have?

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I was surprised as well.  But the cell companies build their antennas to "shove" the signal toward the ground in order to maximize coverage area. In my area (near San Jose, CA), there are totally dead spots in coverage at 300'. I did an exercise - I turned my cell phone ON as I was flying into San Jose airport.  I got a signal at 5,000 ft when flying over Morgan Hill CA (10 miles from San Jose airport), but the signal then quickly disappeared and I could get NOTHING until I was 100' above the ground, ready to land at SJC.

But there are other areas (like Carmel Valley, CA) where the signal is great in the air. I think the difference (at least there) is due to the fact that some people live on the mountainsides, so they have to put more signal above the horizontal plane in order to get to those people.

Ivan R said:

btw i just use a RPi3 with Huawei 4G USB dongle and mavlink telemetry/control via MP and also have RFD900x radios for backup and RC control...I connect MP to the RPi IP and another MP instance connected simultaneously via RFD900x and it also does standard RC control....no video yet thou 

Ivan R said:

Charles, am surprised to hear the cell tower reception is worse at altitude...i get pretty good signal  (4 bars) on mine at 300ft or so, and the tower nearest is like 1 mile away.....i always thought with signal it would be better at altitude due to clear LOS  and no obstructions, up to a certain altitude of course....but even while on commercial flights i have gotten 3 bars inside a metal jetliner even as high as about 1,000ft

pretty nice, you should definitely do it....am kinda of doing the same thing, except manually, i run 2 simultaneous copies of MissionPlanner GCS, one connected via IP to the 4G modem and the other one serial to the RFD900x, either can fail and rarely are both down, but i am pretty impressed with the range of the RFD900x....Ive gone way out like 8 miles and still solid RSSI and since I fly beyond LOS way out in the middle of nowhere the 4G isnt as strong there, but the RFD has been impressive. I didnt mention but I run a Navio2+ board running linux, not a pixhawk, so there are a ton more possibilities I havent gotten to yet

Charles Linquist said:

I'll tell you a little more - I am strongly considering selling a package with everything set up.  My package works with both APM and PixHawk controllers.

The controller always "talks" at 115Kbaud, but that is buffered and converted to 57.6Kbaud, but only when using 915Mhz.  4G/LTE always runs at 115Kbaud. I use a TEENSY processor for the failover stuff, since it has 3 hardware serial ports.

The data coming FROM the Flight Controller is sent out using 4G and 915Mhz simultaneously, while the TEENSY picks the best option for INCOMING data (either 915Mhz or 4G) and passes only good data to the flight controller.  An algorithm prevents rapid back-and-forth.switching between the two and looks at timing, MAVLINK CRC , and packet sequence numbers in order to make its decision. The ground station does exactly the same thing.

The whole setup is amazingly reliable, and I generally don't have to worry whether or not 4G is available.  It just works. Of course the 915Mhz channel does have a limited range.  But I have had many instances where the 915Mhz backup came in awfully handy.



Charles Linquist said:

I'm a little reluctant to give too much away, since I worked very hard to get things working the way they are now - especially with the live HD video feed I get over 4G.

I will tell you that getting a hand-held remote (with real joysticks and a MODE control) connected to Mission Planner is harder than it should be.  The Logitech game controller that MP supports natively is a joke. 

And I should warn you as well that - while Verizon et. al. gives you a "coverage map", that map is at ground level.  There are locations around here where you get 2-3 bars at ground level and nothing at all at 350', so an automatic failover to 433/915Mhz (depending on local laws) is a must. I am a "ham" radio operator, so I can legally run 1W on those frequencies.



Ray Anderson said:

I have been looking for a way to connect via 4g to fly highway inspections and provide transportation security feeds via 4G.  Is there any chance that you could provide a schematic of what you are currently flying?  Once I can prove capability, I will be filing for an FAA BLOS waiver to enable the business model.

I use an RFD900+,  but I have put together a package (mostly from Texas Instruments) that gives me even more power than the RFD900.  It consists of two boards and I will probably combine them into one someday.

It is a real headache that the FCC says I can use hundreds of watts on 915MHz (I'm a "ham") UNLESS I'm controlling a model - in which case I'm limited to 1 Watt.  I'm thinking of using 433 MHz (which is legal for hams in the US) and should give even more range and less absorption from surrounding vegetation.  The antennas have to be long, but on bigger aircraft that will be OK.

Ivan R said:

pretty nice, you should definitely do it....am kinda of doing the same thing, except manually, i run 2 simultaneous copies of MissionPlanner GCS, one connected via IP to the 4G modem and the other one serial to the RFD900x, either can fail and rarely are both down, but i am pretty impressed with the range of the RFD900x....Ive gone way out like 8 miles and still solid RSSI and since I fly beyond LOS way out in the middle of nowhere the 4G isnt as strong there, but the RFD has been impressive. I didnt mention but I run a Navio2+ board running linux, not a pixhawk, so there are a ton more possibilities I havent gotten to yet

Charles Linquist said:

I'll tell you a little more - I am strongly considering selling a package with everything set up.  My package works with both APM and PixHawk controllers.

The controller always "talks" at 115Kbaud, but that is buffered and converted to 57.6Kbaud, but only when using 915Mhz.  4G/LTE always runs at 115Kbaud. I use a TEENSY processor for the failover stuff, since it has 3 hardware serial ports.

The data coming FROM the Flight Controller is sent out using 4G and 915Mhz simultaneously, while the TEENSY picks the best option for INCOMING data (either 915Mhz or 4G) and passes only good data to the flight controller.  An algorithm prevents rapid back-and-forth.switching between the two and looks at timing, MAVLINK CRC , and packet sequence numbers in order to make its decision. The ground station does exactly the same thing.

The whole setup is amazingly reliable, and I generally don't have to worry whether or not 4G is available.  It just works. Of course the 915Mhz channel does have a limited range.  But I have had many instances where the 915Mhz backup came in awfully handy.



Charles Linquist said:

I'm a little reluctant to give too much away, since I worked very hard to get things working the way they are now - especially with the live HD video feed I get over 4G.

I will tell you that getting a hand-held remote (with real joysticks and a MODE control) connected to Mission Planner is harder than it should be.  The Logitech game controller that MP supports natively is a joke. 

And I should warn you as well that - while Verizon et. al. gives you a "coverage map", that map is at ground level.  There are locations around here where you get 2-3 bars at ground level and nothing at all at 350', so an automatic failover to 433/915Mhz (depending on local laws) is a must. I am a "ham" radio operator, so I can legally run 1W on those frequencies.



Ray Anderson said:

I have been looking for a way to connect via 4g to fly highway inspections and provide transportation security feeds via 4G.  Is there any chance that you could provide a schematic of what you are currently flying?  Once I can prove capability, I will be filing for an FAA BLOS waiver to enable the business model.

Hey,
The system seems to be a very useful backup to RFDs. You mentioned about a special server setup, can you please explain how you're pushing a mavlink stream to an online server?

not speaking for OP, but with the Navio2 board I do this today with MavProxy via TCP, with Mavproxy you can multicast to different tagets

Sushanth J said:

Hey,
The system seems to be a very useful backup to RFDs. You mentioned about a special server setup, can you please explain how you're pushing a mavlink stream to an online server?

I use a Raspberry pi running SER2NET, AUTOSSH, WVDIAL, and a few other programs.

The switchover between 4G and RFD900 is done in a separate T

EENSY processor.  The TEENSY handles a lot of object avoidance stuff too, since it understands Mavlink, and all the Mavlink traffic is going through it

Sushanth J said:

Hey,
The system seems to be a very useful backup to RFDs. You mentioned about a special server setup, can you please explain how you're pushing a mavlink stream to an online server?

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