On Wed, 2005-09-14 at 20:35 -0400, Steve Knoblock wrote: > The Digitrak is described as employing "gyroscopic rate sensors are > installed so as to sense motion about each of the major axes (roll, > yaw and pitch)." > > I assume they mean there is a spinning gryo around which three sensors > are arranged, to sense motion in each axis, pitch, roll and yaw. The > sensors report how much the aircraft has moved around the gyro for > each axis.
Gyroscopic rate sensors measure rotation rate around a single axis with respect to whatever they're mounted on. To measure 3 axis motion requires a minimum of 3 sensors. There are no gimbals or spinning objects (vibrating parts yes). Tracking orientation with them requires integrating the signals in a rotating reference frame. You also need an absolute reference because the integrated signals will drift. Here's something google turned up: http://www.smalltimes.com/document_display.cfm?section_id=76&document_id=7451 > >From what I can see of the various default instruments in FlightGear, > the only source of roll angle from an instrument is the attitude > indicator or indirectly, the turn coordinator, which the Digitrak does > not use. > > I conclude that to model the Digitrak fully, I would need to create C > code to represent this three axis gyro using the gyro.*** code that > the attitude indicator depends on. I have a little experience with C, > but not much. I nearly understand how the attitude indicator works > with the gyro model, but I still have to many questions to comprehend > all it is doing. > > I also assume that using /orientation/roll-angle is the best > substitute currently available. > > I would appreciate any help with this and please correct me if I am > wrong in any of this. The only way to really know what the Digitrak is doing is to know what it's really doing ;-) > I think the Digitrak would make an interesting contribution to > FlightGear. It would, but you may be limited to just a visual representation and some other autopilot code. It would be really hard to know exactly what their software is doing without access to source code. -Paul _______________________________________________ Flightgear-devel mailing list [email protected] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
