Written by Administrator Sunday, 03 October 2010 03:48

Basic GNC Product

FTS, Inc has developed a flexible guidance, navigation, and flight control system for use in its concept air vehicle systems activities. The FTS Guidance Electronics Unit (GEU) is comprised of a GPS aided inertial navigation system, mission computer with guidance/ flight control laws, data link channels, and air vehicle I/O interfaces. The unit is intended to be custom configured for each application and therefore has a variety of configuration options.

The GEU has three IMU options 10 deg/hr, 1.0 deg/hr, and 0.005 deg/hr gyro bias drift performance. With these options users can select the characteristics they need versus system cost for example, a user might care most about static heading accuracy which could vary from 0.05 milliradians up to 3 milliradians static heading error for highest to lowest cost IMU, or free inertial position drifts from100 ft in 1 minute to 3 ft in one minute after GPS loss of signal. The GEU also has several GPS operating modes including code phase L1 only to carrier phase differential L1/L2 also a function of sensor cost or expected environment.

Guidance comes in the form of an iterative flight path controller with separately tunable horizontal and vertical channels. It is capable of determining optimum range or speed profiles based on minimum energy loss calculations. The guidance acceleration commands can be converted to skid to turn or bank to turn controls configurations. Flight controls options currently include throttle, X-tail, conventional rudder & aileron & elevator, V-tail ruddervator & aileron, and thrust vectoring configurations.

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FTS Tier One Navigation Unit

FTS was selected by Scaled Composites to provide the Tier One Navigation Unit (TONU) for their successful X-Prize entry. The TONU consisted of a GEU adapted as a System Navigation Unit (SNU), a color LCD Flight Director Display (FDD), and telemetry / ground data reduction system. The TONU provided the White Knight and SpaceShipOne navigation reference system, flight instrumentation measurement, primary flight displays, and telemetry downlinks. The FDD contained a customer programmable display processor and a daylight readable color flat panel display, and digital data collection interfaces. The FDD provided both aircrews with feedback of position, velocity, attitude, acceleration, and spacecraft angular rates and various air vehicle parameters such as propulsion, environmental control, consumables, and reaction control status.

The SNU was a self aligning GPS-INS intended to quickly acquire GPS after SSO release, align, and provide boost phase guidance targets and re-entry targets even with the loss of GPS signals due to spacecraft attitude. The SNU included a gyrocompass alignment capability for static alignment during pre-takeoff operations. The SNU also included enough memory for several hours of on-board data recording at 100 Hz frame rates.