Guidance Systems

Hi, Guys
Here we have a place to discuss rocket guidance systems.

Be good to see some chat here as this is going to be a key enabling technology for anybodies program.

Seems to me the only way to achieve the goals of the N-prize is with a very basic attitude pointing system, as the use of more advanced methods such as strap down inertial navigation will be too expensive. Our academic program in 2007 focused on the use of low cost MEMS sensors (Gyro's & Accelerometers) fused with 3 axis magnetometers and GPS, as a low drift inertial measurement unit. The project was built as a stack sitting on-top of PC104 form factor computer board, which also acts as the rockets main flight computer.



The IMU/FC stack is worth about $1500AUD, but could probably built for a quarter of that price using a different flight computer board. We choose an Intel XScale board running at over 400Mhz, to which we adapted a version of e-Cos which is free real time OS. The Board was the only one the sponsor had and cost over $500AUD, a board running a 200Mhz chip can be had for $80.00 these days. Should be more than powerful enough to crunch the guidance routines plus manage vehicle health, and flight events.

What I think is that a system using either a horizon or light tracking sensor, combined with a 3axis magnetometer should be able to generate a decent pointing package. And is going to be important because a small variation in your pointing angle could mean the difference between 9 orbits and no orbits. The implementation of say a small solar cell, might allow you to lock onto the sun as pointing source. Then if you pick the right time of the day when the sun is at your desired azimuth, you point and shoot.

I am also a little uncertain as to what the permit requirements will be with regard to teams assurance that payload is delivered to the correct orbital co-ordinates.

Has anybody investigated this yet?. FAA Office of Commercial Space Transportation should be a point of call to any prospective teams to see whats involved in getting a launch permit.