Russians turn Raspberry Pi into fully-fledged autopilot Anyone with an interest in Raspberry Pis and autopilots – in common with the Low Orbit Helium Assisted Navigator (LOHAN) team – should nip down to Indiegogo to check out the Navio: an impressive-looking autopilot shield for the diminutive fruity computer. The Russian team behind the Navio is already well on the way to …
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> The restrictions only seem to apply to GPS units coming from the US.
Unless it's changed in the last decade and a half, one of the licensing conditions the Americans imposed for building GPS kit was that a) you should have a "manufacturing facility" (which for non-American companies has always been a nominal one) in the US, and b) that you should comply with the aforementioned speed+altitude restrictions.
Details are hazy though and things might have changed. In any case, U-blox incorporate this restriction.
What licensing conditions?
Anyone can build a GPS receiver and listen to the signals if they have the time and technical inclination. There are no enforceable licensing conditions.
There are various projects on the www using either FPGAs or sw to do the correlators so there really is no need to even use commercial chipsets.
> 2014
> Using GPS to put a force package on target
Instead of honest-to-God real-time terrain recognition in a matchbox the way the original Tomahawk Cruise Missile was doing it via a baseball-sized computer back when Reagan talked about the Evil Empire on TV.
Youngsters. These days they just want to have it easy.
Yes, anyone can build a GPS, and it might be the size of a pentium motherboard, or bigger.
The developers of the modern chips in the USA were told to incorporate 'envelope restrictions', which would stop aspects of operation of these conditions were exceeded.
Now with drones galore, what can they do?
Some aspects in this search to round out the topic.
http://bit.ly/1tKMH2v
You can get a device with built in GPS and a degree of Arduino compatibility (you can program it from the Arduino IDE at least) for less than $30 these days. It's called a NavSpark, and it has a 100MHz 32 bit core with FPU so it's quite fast enough for this kind of work. Add a 10DOF sensor and a PWM controller and you should have change out of $60, plus a much smaller and lighter system.
uBlox gps chips have a flight mode command switch which allows use above 12,000m as long as the speed of movement stays below a certain limit (300mph has been mentioned elsewhere)
different makers seem to have interpreted the gps restrictions in different ways,
ublox have taken the view that max height AND max speed = restriction
others have taken the view that max height OR max speed = restriction
I've always thought that having an autopilot running on a non real-time OS wouldn't really be ideal ?
ardupilot runs on arduinos of course, and recently on 32 bit arms for more speed/timers/etc but it is still running 'on the wire' so to speak - no OS.
Is there a pi compatible realtime linux OS ? And if not, other than getting a bit more oomph, this seems a bit of a dead end imho ? better to have your autopilot running on a protected realtime chip and just interfacing to the pi when you needed the CPU power ? i.e. just buy a 40 quid ardupilot (accelerometer, gyros, barometer, gps, arduino, etc) and just interface to the Pi via SPI or I2C for whatever wonders you need the pi to do (e.g. say recording video, image recognition, etc)
At the moment I have a Pi with GPS/magnetometer/Sonar so it knows where it is, and I'm getting a servo board which will feed into my dedicated flight controller (KK), but a single board that does all this will be cool.
If this board is going to be an all-in-one solution (flight control and location/direction) it will be great, but depends on how much work the Pi is going to do (and how much IO is still available), I hope the board is going to do all the flight control (specifically stabilisation, level, altitude hold etc.) and leave all the CPU to do the actual navigation, operate a camera etc. (and with Rx input it should be fantastically controllable for manual override).
Price is going to be the biggie, a KK flight controller is £20, servo board £20, GPS £25, magnetometer £2, sonar £2 so $145 for an integrated bit of kit is good, not bite your hand off good, but probably the best bit of "all-in-one" for the price.
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