Abstract: A fluid treatment plant has a filter module including at least a first filter and a second filter connected in series and connectable to a supply of fluid. A pump is fluidly connected to the filter module and a controller with a fluid quality sensor is connected to detect a quality of the fluid between the first filter and the second filter. A filter module detector is connected to the controller configured to uniquely detect a filter module connected to the pump, and the controller is controls the pump responsively to a signal from the fluid quality sensor and the module detector. The controller is configured to continue pumping based on output of the quality sensor and/or based on output from the filter module detector.

Abstract: Structures and methods are provided for deriving corrected star coordinates Ccrctd from measured star coordinates Cms that include star tracker charge transfer efficiency (CTE) errors. The structures and methods are based on a recognition that measured star coordinates Cms of star image centroids include CTE errors which are functions of the CCD path lengths over which the associated electrical charges traveled. In particular, the errors are substantially a product of a respective path length and a star-coordinate error factor &xgr; which, in turn, is a function of the star image magnitudes msi. Information contained in different measured star coordinates Cms is organized to facilitate the derivation of an estimate &xgr;* of the star-coordinate error factor &xgr; with conventional estimation processes. The measured star coordinates Cms are then corrected with the error factor estimate &xgr;* to realize the corrected star coordinates Ccrctd and, thereby, improve the accuracy of spacecraft attitude control.

Abstract: Structures and methods are provided for deriving corrected star coordinates Ccrctd from measured star coordinates Cms that include star tracker charge transfer efficiency (CTE) errors. The structures and methods are based on a recognition that measured star coordinates Cms of star image centroids include CTE errors which are functions of the CCD path lengths over which the associated electrical charges traveled. In particular, the errors are substantially a product of a respective path length and a star-coordinate error factor &xgr; which, in turn, is a function of the star image magnitudes msi. Information contained in different measured star coordinates Cms is organized to facilitate the derivation of an estimate &xgr;* of the star-coordinate error factor &xgr; with conventional estimation processes. The measured star coordinates Cms are then corrected with the error factor estimate &xgr;* to realize the corrected star coordinates Ccrctd and, thereby, improve the accuracy of spacecraft attitude control.

Abstract: A feedforward disturbance compensation system and method for use with a spacecraft that compensates for predictable disturbances exerted on the spacecraft. The invention comprises a model of the disturbance that is to be compensated, means for knowing when the disturbance will occur, and means for applying the feedforward compensation to the spacecraft in accordance with the model (a compensation profile). The present invention reduces pointing transients through the application of open-loop, feedforward compensation of actuators used to point the spacecraft. The shape of the feedforward profile is determined by an in-orbit test or is predicted by analytical means. For the in-orbit test case that compensates for an eclipse, for example, the spacecraft is flown through the eclipse once to determine the size and shape of the thermal shock disturbance and this information is stored in a spacecraft control processor.

Abstract: A method of spacecraft attitude determination is proposed which calculates the bias between the usual two-cell and four-cell earth sensor measurements. During period of sun or moon interference, when the two-cell mode is selected, this bias is added to or subtracted from the two-cell measurements. This removes the step change in the calculated spacecraft roll and pitch angles when the switch is made between two and four cell modes and allows a substantially more accurate measurement to be obtained from a given sensor for the period of time for which interference would otherwise reduce sensor performance.

Abstract: A method is provided for computing a stabilized vehicle speed value from a detected vehicle speed pulse signal and a detected engine speed signal, the vehicle speed value being for use by a vehicle speed control system. The method comprises several continuous cyclic steps commncing with generating a measured vehicle speed value from the detected vehicle speed pulse signal and generating a measured engine speed value from the detected engine speed signal. A current gear ratio is calculated from the measured vehicle speed value and the measured engine speed value. This current gear ratio is then passed through a single pole digital filter to filter changes in the gear ratio between consecutive cycles as a function of the current gear ratio and the gear ratio computed in the last preceding cycle of the computation. A current usable gear ratio is generated which is changed from the most recently generated usable gear ratio only if changes in the gear ratio exceed predetermined limit values.

Abstract: This invention provides a safety mechanism as an improvement to a bowstring release device and operative to prevent the accidental discharge of an arrow drawn in the bow. The safety mechanism disclosed comprises a slidable cam which is adapted to actuate a lock pin into a position to block the movement of a trigger member of the bowstring release device. When the safety mechanism is moved in the opposite direction, the lock pin is allowed to move away from the position blocking trigger movement under pressure of a biasing spring, thus freeing the trigger to operate.

Abstract: An electronic microcomputer based engine brake control device and a method for controlling an engine compression brake is disclosed. An algorithm for enabling engine brake operation includes monitoring a brake enable switch, engine RPM, engine fueling rate, cruise control or power takeoff system activation state, throttle position, manifold pressure and clutch pedal position. Engine brake operation is fully automatic and operates in a safe manner according to the disclosed algorithm.

Abstract: 1. In a communication system utilizing at least two independent binary coded pulse signal sequences, means for achieving and holding time synchronism between said two sequences which comprises the combination of pulse recurrence frequency searching means for controlling the pulse recurrence frequency of one of said signals relative to the other to bring said signal into synchronism with the other, and phase locking means including a periodic phase checking circuit and a phase variation correcting circuit responsive to the searching means bringing the signals into synchronism to operate on one of said signals for holding said signals in synchronism.

Abstract: 1.

Abstract: Method and apparatus for reducing torpedo drag in which polymer drag redug material is carried by the torpedo in concentrated form, ambient water is ingested and mixed with the concentrated polymer to produce a seawater-polymer solution of predetermined concentration, and the solution is ejected from the torpedo nose to be swept rearwardly in intimate contact with the exterior surface of the torpedo under torpedo forward motion.