Flight Computer with live Google Earth Tracking

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Jeffmhopkins

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Here's my flight computer I've been working on. Has GPS, accelerometer, gyroscope, magnetometer, barometric pressure, temperature, 70cm transceiver, two in-flight ignition channels, remote mains ignition, and full remote console.

From my base station I can login to the rocket, arm it with an arming code (at which case the buzzer starts up), remotely ignite main motor (which cannot be accomplished without arming and manual safety switch turned off) and then track in real time all the telemetry and view in Google Earth in real time. Powered by LiPo battery pack.

Still need to do some strengthening with hot glue before being finalized.

HPR thread here: https://www.rocketryforum.com/showthread.php?127775-The-EX-CATO
 
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The board is approximately 3"x2"x1". Fits well into my 3" body.

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I'm using a Teensy 3.1, it had the processing power, RAM, and serial ports necessary to handle constant polling and computation necessary to do all of this and then some.
 
Sorry for a double post, but here's a screen shot of me walking down the street and back, being tracked live in Google Earth.

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I've been busy sewing new parachutes, but next as far as electronics go next is to test the auto pilot. I'll accomplish this by attaching the electronics to an RC car and have it navigate to a set coordinate via GPS/magnometer in a field and establish a spiral around the coordinates. I'll continue to update when this progresses.
 
Only issue with live tracking is the need for a "live" internet access for the map updates. Kind of hard for remote launch sites but if you have the internet connection, looks slick.

Portable maps for off grid use can be helpful for many so they know the nearest road they need to use or that the rocket likely landed past that stream or creek.

Folks out west tell me a map is not necessary. The playa is so featureless all's that's needed is two points on a screen and a datum line to follow.

Higher frequency position updates make for a higher resolution track like you show above. They're really nice as opposed to the once every 5 second position reports from Ham radio based APRS trackers.

Although the only data point one needs to receive is the one that's sent just before touchdown. Get to that position and as long as the tracker is still working you'll get a new packet to home in on. Kurt
 
ok.. this might sound stupid... but here goes..

does the tracker/unit need its own internet connection ? I have an old cell phone I could activate with a pre paid card and use that.. or is it my phone that needs the internet connection ? Or both..

and finally.. are these for sale ? If so how much.

Thanks
Tom
 
ok.. this might sound stupid... but here goes..

does the tracker/unit need its own internet connection ? I have an old cell phone I could activate with a pre paid card and use that.. or is it my phone that needs the internet connection ? Or both..

and finally.. are these for sale ? If so how much.

Thanks
Tom

Tom,

Perfectly good question. Jeff the OP can answer but his tracker and the radio trackers out there like Beeline GPS, AP510 and the 900Mhz GPS trackers of which there are several, do not require an internet connection.

There are GSM, cell phone based trackers, that one simply dials up and it texts its position. They are a dime a dozen and require a service contract and possibly a monthly fee. If you have a self contained tracker, you can go anywhere and use it whenever you want. If the flying site has poor cell phone coverage you could still lose a rocket. Rf GPS tracking can give one a continuous datastream.

Many of the receiving programs for the Rf based GPS trackers require a datasource to display a map. That can be through a "live" internet connection or from a stored dataset. I believe Jeff might have been piping the GPS data into google earth. I don't know if he was doing it "live" or if he input the data after his tracking session. He'll be able to clarify that but he did mention in the first post he was doing it in "realtime". I suspect he has a receiver into an internet accessible
cell phone.

You can buy a few license free GPS trackers now, the cheapest being the EggFinder but you have to assemble it. The 900Mhz Beeline GPS tracker is assembled and ready to go out of the box. I don't know if one can pipe the data into a mapping program to give as good a picture as Jeff displays above. There are a few other 900Mhz ISM trackers available also. Once you track via GPS it's easy to get hooked on it. Walk to rocket, pick it up and go fly your next one. Kurt
 
GPS data for my project is received via the 70cm transceiver at the base station. Internet is not required except for pretty pictures in Google Earth. Even then, I can precache data and still be good. As of right now I'll have internet via my cell phone to download map data at my expected launch site, the GPS data though, is derived directly from the rocket's radio.

I'm using a 6 element yagi with LNA for the base station and still track the rocket during launch. Once landed the transceiver will act as a tracker in case GPS failure.

Even then, the project should be recovered only a couple hundred feet from a predesignated location because it will be using a steered parachute for recovery.

As of right now this is not for sale, but once refined I'll be looking to make it open, and might be creating a few to sell if people are interested enough.
 
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The steered parachute would really be a show stopper. Problem with precached map data is that can be unreliable depending on the mapping software being used. Depends upon the application. I thought I dutifully precached maps only to
have them disappear without an internet connection. Nonetheless, when push comes to shove, one can input the lat/long numbers into a handheld mapping GPS to get a "spot on a map". Kurt
 
Jeff-
Very interesting project. Good luck!

I have been flying Ardiunos in rockets (Uno, Due, Mega and Trinket sized) and have started flying a GPS unit connected to the Arduino and either logging the data or using RF to send the data to ground during the flight.
I have noticed that the altitude reported by the GPS seems fine during boost, but near apogee the altitude reported goes 150ft or more in error, but the lat/long seem to keep tracking fairly accurately. I know that GPS
is more accurate horizontally compared to vertically for many reasons - but seems to me that vertical drifts far more than does the horizontal during flight. I suppose this makes sense since vertical is changing rapidly during launch,
but the accuracy does not seem to improve during decent under chute.

What can you tell us about the GPS unit you are using and if you are seeing any issues with the GPS reported altitude?

I am using a GPS unit based on the MTK3339 chipet. 66 channel/10hz updates reported to be: -165dB

-Kerry
 
I'm using the Trimble Copernicus, which is sensitive down to about -152dBm and operates on 12 channels and outputs at 1Hz. It's left over from a High Altitude Balloon project. Noise is 3m horizontal and 10m vertical. I've yet to take it on a rocket trip, but when I do I'll cone back to you with results.

On a side note, the Copernicus was chosen as aGPS module due to its implementation of COCOM limits, which is 1200mph AND 59,000 feet. Many GPSes operate with an OR statement. These rules were put into place to insure no home made ICBMs.

Because Trimble went with the AND statement this GPS is good above 60k, as long as you are slower than 1200mph. But also good above 1200mph below 60k.
 
And I'm still playing around with names but the "Sparrowhawk Flight Computer" had a nice sound to it.
 
Jeff -

I agree - good name.

Also, I posted an example of the GPS altitude error I am seeing with my Arduino/GPS setup in the thread called "Measuring Engine Performance During Flight" for your reference.

Keep us posted on your progress. I think there is a ton of interest in your steerable recovery system. IIRC, there was a presentation made at a NARCON about 5 years ago in Massachusetts
(The Goddard NARCON) where someone showed their efforts at something similar. I know they also tested their homing software using an RC vehicle. I think they were successful in getting
an autonomous flight-back-to-pad, but I don't recall for sure. I don't think their electronics were anywhere near what you are showing here.
I am guessing someone on this forum will be able to correct me if my memory off. In any case, I haven't heard any other
similar work going on in this area since - but I think it is tremendously cool. Will be waiting to see your videos.

-Kerry
 
I've seen a couple of successful GPS recovered launches now, so I understand how feasible (not easy) the project is. The most recent was a memorial launch over here at the sodfarm with the MDRA this Summer.

I fear the deployment as the hardest part of this project. I hope to limit destruction of my test platform with my large backup parachute in case of issues. I'll be using a pilot chute and dbag to hopefully avoid mucking up the deployment process. All in all though the project is ambitious. I'm using research motors, scratch built rocket, homemade laundry and custom electronics! What could go wrong? :)
 
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