Here’s an interesting thought: it’s possible to build a cubesat for perhaps ten thousand dollars, and hitch a ride on a launch for free thanks to a NASA outreach program. Tracking that satellite along its entire orbit would require dozens of ground stations, all equipped with antennas, USB TV tuners, and a connection to the Internet. It’s actually more expensive to build and launch a cubesat than it costs to build a network of ground stations to get reasonably real-time telemetry from a cubesat. The future is awesome and weird, it seems.
This is the observation the guys behind SatNOGS have made. They’re developing a platform for a completely open source ground station network, with the idea being people an institutions along every longitude and latitude would build a simple satellite tracking antenna mount, connect it to the Internet, and become part of an open source Near Space Network, capable of receiving telemetry from any one of the small cubesats whizzing around in low earth orbit.
Despite being what is probably one of the most ambitious and far-reaching projects in open source hardware, the design of the system is relatively simple: the hardware is a 3D printed alt-az mount, capable of pointing a pair of antennas anywhere in the sky. The stepper motor driver board is based on the Arduino, and the computer running each antenna node is powered by a BeagleBone Black or a WR703N router. The antenna receiver is, of course, an RTL-SDR dongle, capable of listening to all the common cubesat bands. Even the software is derived from open source projects. Tracking a satellite across the sky can be calculated with GPredict, and the team is working on an observation scheduling and management system that combines multiple ground stations for coverage across the globe.
It’s a great idea, crowdsourcing satellite tracking from people around the globe, and something that could be used by hundreds of institutions lucky enough to launch a small cube of electronics into orbit.
The project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.
If you’re just pulling telemetry from LEO, a quadrifilar helix would be a more cost-effective antenna… even crossed horizontal dipoles phased at 90 degrees. it eliminates the problems associated with cross-polarization(I understand the simplicity of mounting a linear-polarized antenna on a satellite, but it makes life a bitch if it has any rotation)… gain isn’t much of an issue except when the satellite is near the horizon, and an LNA usually solves that.
Granted, if you are transmitting, you might want a tracking system for your paired Yagi’s, parabolic, or helical.
But I do like the idea of a 3d-printed AA mount with associated control hardware. Those things are pricey, retail. Orbitron is another good program with hardware/software communication capabilities(with Doppler correction if the elements are known) for multiaxis control. Works great with HRD on an RTL-SDR… I use it for ARPT and OSCAR/AMSAT reception.
Sorry for being ignorant, but it is a real question.
Is current 3D printing so good you can make the A-A gearbox with it and not having it break really quickly? If yes, that is really cool.
It’s possible to print these http://www.strandbeest.com/shop/beasts_3d.php although they’re very light.
I’m guessing you could make a mould out of the printed parts and make a strong resin cast from that.
Hello! We are trying to push the printed gearpox to its limits with very good results for now.
I would be more than willing to donate some power and net bandwidth every month to deploy one of these (if someone wants to work with me on it). Small bonus is that the area around my place was just cleared of some trees so its got a decent amount of unobstructed sky.
already being done as part of funcube project. Open Source (github) ground station network.
warehouse.funcube.org.uk
very nice project!
could someone tell me what stepper driver it use?
there is a picture in the site but i couldn’t find it in the docs
A4988 Pololu are the stepper drivers.
I am curious how they plan to cover “all the popular cubesat bands” with two antennas. If they use circular polarized yagis then they will need 4 antennas. Also, a stepper motor seems awful expensive for something that doesn’t need to be very accurate. I’m curious to see how their project plays out. There are thousands of people doing this already with much, much better hardware but everything is one off and there is little coordination. Focusing on the network aspect seems like a good plan.