Aircraft Sensors, Shared?

[ICT_SLB]

Originally Posted by Obi Offiah

Cheers everyone, I really appreciate all your answers.
I've been trying to solve a couple of troubling questions surrounding flight control systems, that have been bugging me for a few years . I've attempted to cover all bases which is why at the moment I'm focusing on the FCS sensors and their possible relationships to the INS/IRS/AHRS.
ICT_SLB:
Its absolutely critical that at the very least, longitudinal and lateral acceleration data are furnished to an INS for 2D navigation. I think most systems also provide vertical velocity via a normal accelerometer (stabilised platform)?
Regarding flight control systems, I believe the minimum of a lateral acceleration and normal acceleration sensor are essential, to grant the required level of fidelity demanded by a modern FCS.
Considering both the older stabilised platform sensors and the modern strapdown systems, how usual is it to find longitudinal acceleration data fed into the flight control computer to aid aircraft flight characteristics?
BTW Swedish Steve, the B777 gyros, are they ring laser gyros?
Thanks
Obi

Obi,
Reread my post. All modern Attitude/Heading sources contain both a form of gyro [(AHRS - either rotating "Bender" (Rockwell-Collins) or micromachined sensor (Honeywell, Thales and several others - all using a Systron Donner assembly) or (IRS & INS - Ring Laser Gyro or IFOG - same thing cheaper construction)] plus accelerometers. Sets of three of both of these units are mounted at mutual right angles. The combination gives all the directions, rates and accelerations required by all systems on the aircraft - effectively there are no individual units such as a "Normal Accelerometer" as the whole set is used to provide and internally verify the output data.