Abstract: The invention is a method and apparatus for determining the rotation of a medium through which a light beam propagates by modulating the light beam with a pseudorandom sequence of bits. The method comprises the steps of (1) selecting a "0" or a "1" as the next bit of the modified pseudorandom bit sequence if one or more criteria are satisfied, the criteria being based on the measured properties of a plurality of prior bits of the modified pseudorandom bit sequence; otherwise: (2) selecting the next bit of an initial pseudorandom bit sequence as the next bit of the modified pseudorandom bit sequence, the next bit of the initial pseudorandom bit sequence being a function of one or more prior bits of the initial pseudorandom bit sequence.

Abstract: The oxygen breathing system with programmed oxygen delivery comprises a breathing circuit which a user exhales into and inhales from and a source of oxygen which delivers oxygen to the breathing circuit at a programmed rate. The oxygen is supplied at a high rate during the initial period of operation and at a low rate during the remaining period of operation. An overpressure relief valve in the breathing circuit opens during the initial time period because of the high oxygen delivery rate thereby flushing from the breathing circuit the nitrogen initially residing in the lungs of the user and in the breathing circuit. As a result of the flushing, the oxygen content in the breathing circuit approaches 100 percent at the end of the initial period and remains near this level during the subsequent time period.

Abstract: The invention is a method and apparatus for determining the rotation of a medium through which a light beam propagates by modulating the light beam with a primary pseudorandom bit sequence consisting of a plurality of contiguous P subsequences. Each P subsequence consists of a start sequence of predetermined length followed by a sequence of trailing bits. The method comprises three steps. The first step consists of deriving a feedback bit from each generating sequence in a P subsequence in accordance with a specified rule where a generating sequence is any sequence of contiguous bits in the P subsequence having the same length as the start sequence. The bit that follows a generating sequence is called the trailing bit for that generating sequence. The second step of the method consists of determining a sequence of one or more modifier bits to be used in modifying the P subsequence. The third step of the method consists of modifying the P subsequence utilizing the one or more modifier bits.

Abstract: The apparatus of the present invention uses radar altimeter measurements and stored terrain altitude profiles to provide pre-filtered observations to a Kalman filter for estimating barometric offset at the airport runway, and barometric scale factor for offsets above the runway. These offsets are used with the smoothed baro-inertial output from an inertial reference system to provide 3 dimensional constant rate of descent approach procedures to replace non-precision approach procedures based on constant barometric altitude step approaches. The horizontal positions used as reference for the stored terrain altitude profiles are obtained from a prior art navigation apparatus. The integrity of all measurements is assured by using long term averages of the Kalman filter residuals to detect failures. In addition, the estimated baro offset at the runway is compared for consistency with the baro offset obtained by the pilot from the airport by radio.

Abstract: The invention is a focusing polarization rotator for use in the resonant mirror system of a ring laser gyroscope. The focusing polarization rotator accomplishes the traditional task of rotating the plane of polarization of a light beam that passes through it and at the same time performs a focusing function on the light rays. In a resonant mirror system, the device acts to constrain the transverse dimensions of light beams that follow the closed light-beam path established by the resonant mirror system thereby obviating the need for one or more curved mirrors that usually perform this function. The focusing polarization rotator is a wedge-shaped lens made from either a magneto-optic transparent material with a magnetic field within the lens or a material having different indices of refraction for left- and right-circularly-polarized light. The wedge shape of the lens greatly improves the bias stability of the RLG in which it is used.

Abstract: The invention is a method for use in executing portable virtual machine computer programs under real-time constraints. The invention includes a method for implementing a single abstract virtual machine execution stack with multiple independent stacks in order to improve the efficiency of distinguishing memory pointers from non-pointers. Further, the invention includes a method for rewriting certain of the virtual machine instructions into a new instruction set that more efficiently manipulates the multiple stacks. Additionally, using the multiple-stack technique to identify pointers on the run-time stack, the invention includes a method for performing efficient defragmenting real-time garbage collection using a mostly stationary technique.

Abstract: The invention is a method and apparatus for generating a plurality of driving signals for a vibratory rotation sensor, the plurality of driving signals resulting in a plurality of readout signals from the vibratory rotation sensor. The method comprises the steps of determining a 2.times. tracking angle rate, transforming the 2.times. tracking angle rate into a trig function rate, transforming the trig function rate into a second trig function, and generating the plurality of driving signals utilizing the second trig function. The 2.times. tracking angle rate, determined from the plurality of readout signals, is the time rate of change of twice the tracking angle, the tracking angle being an angle which tracks the orientation angle of the standing-wave pattern of the vibratory rotation sensor. The trig function rate is the time rate of change of a first trig function, the first trig function being an approximation to a mathematically-exact (M-E) trig function.

Abstract: The invention is a method for determining gravity in an inertial navigation system which periodically produces and stores in memory position coordinates. The method comprises the steps of (a) retrieving the most recently determined position coordinates, (b) determining coordinates L.sub.u, L.sub.n, H.sub.u, and H.sub.n from the position coordinates, L.sub.u and L.sub.n being predetermined functions of geodetic latitude and H.sub.u and H.sub.n being predetermined functions of geodetic altitude, (c) determining the vertical component of gravity by substituting either or both L.sub.u and H.sub.u in a first polynomial expression, (d) determining the north-south component of gravity by substituting either or both L.sub.n and H.sub.n in a second polynomial expression, and (e) utilizing the components of gravity determined in steps (c) and (d) in the next determination of the position coordinates.

Abstract: The invention is an apparatus for sensing rotation comprising a housing, a resonator attached to the housing, a first set of electrodes consisting of one or more electrically-connected electrodes, and a second set of N electrodes. The resonator is a rotationally-symmetric, thin-walled object capable of vibrating in at least one of a plurality of standing-wave modes. The orientation of a standing wave with respect to a reference point on the resonator is specified by an orientation angle. The first set of electrodes are attached to either the resonator or the housing. The N electrodes of the second set are attached around the circumference of either (1) the housing if the first set of electrodes is attached to the resonator or (2) the resonator if the first set of electrodes is attached to the housing. The n'th electrode of the second set is attached at angular position .theta..sub.n with respect to the reference point on the resonator, opposing one or more of the second set of electrodes.

Abstract: The COPA accelerometer utilizes a sensing body having a non-zero product of inertia to sense acceleration when spun or oscillated about the y'-axis of an x'-y'-z' Cartesian coordinate system. The sensing body is pivotally attached to a platform and pivots about an axis parallel to the z-axis of an x-y-z coordinate system fixed in the sensing body, the z-axis being in the x'-z' plane. An orientation sensor provides a measure of the average angle between the y-axis and the y'-axis. The orientation sensor contains a laser diode which illuminates a plurality of regions of a photodetector thereby causing photodetector regional currents to flow out of the photodetector.

Abstract: The invention is a method for compensating for fringe visibility errors in a fiber-optic gyro. The light beam phase is modulated utilizing a phase-modulation generating function comprising a stepped waveform with steps of height 2.pi.k-.phi..sub.SE +j.phi..sub.M -.gamma..sub.ZS at time intervals .tau. where a phase step .phi. specified by the phase-modulation generating function is transformed into a change in light-beam phase of (.phi..sub.X /X).phi..sub.X where .phi..sub.X is the change in light phase produced by a phase step X. The integer k takes on the value -1, 0, or 1, j takes on the value -1 or 1, .phi..sub.SE is a phase determined by the fiber-optic gyro, .phi..sub.M is a predetermined phase value, and .gamma..sub.ZS is a phase designed to compensate for the fringe visibility errors. The phase .gamma..sub.

Abstract: The invention is an article of footwear comprising a heel, an outer sole, an innersole, and an upper wherein a storage facility is incorporated in an interior part of the article. One type of storage facility consists of a chamber in the heel having at least one opening and a closure for each opening. One type of closure has a push button which, when pushed, causes the closure to be partially or completely ejected from the opening to the chamber. The closure may include a receptacle adapted to receive and hold an object for storage in the chamber. Other types of storage facilities are pockets on the interior surface of the upper and in the innersole.

Abstract: The invention is a method for obtaining a measure of the light propagation time difference for two light-propagating-media paths. The first step consists of generating two substantially-identical frequency-modulated light waves whereby the frequency of the light waves is offset from a reference frequency by a different frequency increment for each basic time interval in each of a plurality of groups of three or more basic time intervals. Each frequency increment is the sum of a specified increment and a frequency-modulation-error increment. The frequency-modulation-error increments associated with the specified increments are independent of each other and unknown. The second step consists of feeding the two light waves into the entry points of two light-propagating-media paths having a light propagation time difference and obtaining a combination light wave by summing the light waves emerging from the exit points of the two light-propagating-media paths.

Abstract: The invention is a method for improving the performance of a fiber-optic gyro comprising counter-propagating light beams from a broadband source in an optical fiber configured as a coil. The fiber-optic gyro is of the type where the phases of the light beams are step-modulated at one or both ends of the optical fiber at time intervals equal to the light propagation time .tau. through the optical fiber, the step being in the range from 0 to 2.pi.-.delta. radians where .delta. is an infinitesimal. The step is the sum of an estimate of the Sagnac phase residual .phi..sub.SE with reversed sign and the quantity (2.pi.k+j.phi..sub.M) where the index k can take on the values -1, 0, and 1, and the index j can take on the values -1 and 1. The phase angle .phi..sub.M is a positive constant less than .pi. radians. The method comprises the steps of determining the interferometer output light intensity, determining the Sagnac fringe number n, calculating the error P.sub.

Abstract: The optical interconnection apparatus includes one or more terminator blocks which hold a plurality of jacketed optical fibers and a flexible matrix which encloses the jacketed optical fibers and partially surrounds the terminator blocks so as to anchor the terminator blocks within the matrix. Each terminator block comprises a jacket holder and a jacket clamp. The jacket holder has a surface with a plurality of grooves for receiving a plurality of jacketed optical fibers. The jacket clamp clamps a plurality of jacketed optical fibers in the plurality of grooves of a jacket holder. The terminator blocks are used with a mold having one or more guide structures for use in guiding each of the terminator blocks into the mold, a terminator block having one or more guide followers which engage and follow the guide structures of the mold when the terminator block is inserted into the mold.

Abstract: The invention is a bicycle seat attachable to a bicycle seat post. The bicycle seat comprises a right support section, a left support section, and an attachment device for fixedly attaching the right support section and the left support section to the bicycle seat post. For purposes of description an x-y-z coordinate system fixed with respect to the portion of the attachment device that attaches to the bicycle seat post is defined. The z-axis is aligned with the bicycle seat post, the y-axis is normal to the plane of the bicycle frame, and the x-axis is directed toward the front end of the bicycle when the bicycle seat is properly oriented with respect to the bicycle. The right support section has an angular range of adjustment about a z'-axis, and the left support section has an angular range of adjustment about a z"-axis where the z'-axis and the z"-axis are different axes fixed with respect to the x-y-z coordinate system and within 30 degrees of the z-axis.

Abstract: The invention is a method for reading out a vibratory rotation sensor comprising the steps of (1) driving the vibratory rotation sensor with a plurality of driving signals and (2) obtaining one or more readout signals resulting from the interaction of the driving signals and the vibratory rotation sensor. The functional dependence of all tracking-angle-dependent driving signals is expressible for a specified range of tracking-angle values as a single specific function of the tracking angle. A tracking-angle-dependent driving signal is the sum of two or more component signals where only one of the component signals is dependent on tracking angle. The single specific function specified for any one of a plurality of tracking-angle range of values can be the same as or different than the single specific function specified for any other tracking-angle range of values.

Abstract: The invention is a method and apparatus for compensating for sculling in a strapdown inertial navigation system. The method operates on a sequence of inputs .DELTA.V.sub.B (n) derived at times n.DELTA.t from the outputs of one or more accelerometers. Separately compensated quantities .DELTA.V.sub.Bc (m,p) calculated at times (pJ+1/2).DELTA.t for M values of m are obtained by summing A(m,k).DELTA.V.sub.B (pJ-j-k) over k from 0 to K-1 and over j from 0 to J-1 where the constants A(m,k) are chosen to minimize sculling error in the individual .DELTA.V.sub.Nc (m,p) quantities where .DELTA.V.sub.Nc (m,p) is the representation of .DELTA.V.sub.Bc (m,p) in the navigation frame of reference. The final compensated quantity .DELTA.V.sub.Bc (p) is obtained by summing B(m).DELTA.V.sub.Bc (m,p) over m where the constants B(m) are chosen to minimize sculling error in .DELTA.V.sub.Nc (p) where .DELTA.V.sub.Nc (p) is the representation of .DELTA.V.sub.Bc (p) in the navigation frame of reference.

Abstract: The invention utilizes a sensing body having a non-zero product of inertia to sense acceleration when oscillated about the y'-axis of an x'-y'-z' Cartesian coordinate system. The product of inertia is computed with respect to an x-y-z coordinate system fixed in the sensing body, the z-axis being in the x'-z' plane, the y and y' axes being aligned in the absence of acceleration. The sensing body is pivotally attached to a platform and pivots about an axis parallel to the z-axis. A torquing device applies a torque about the z-axis to the sensing body sufficient to cause the angle between the y-axis and the y'-axis to be zero in the absence of acceleration when the sensing body is being oscillated at a predetermined rate. The accelerometer also includes an orientation sensor which provides a measure of the average angle between the y-axis and the y'-axis. A drive assembly oscillates the platform about the y'-axis.

Abstract: The invention is a method and apparatus for quantitatively characterizing the pressure-induced nonreciprocity of a fiber-optic coil where the pressure-induced nonreciprocity is a property of a fiber-optic coil which pertains to the degree to which light beams, initially in phase, differ in phase as a result of traversing the fiber-optic coil in reverse directions while the fiber-optic coil is being subjected to a time-varying pressure. The method comprises the steps of applying time-varying pressure to the fiber-optic coil for a predetermined time period, measuring the phase difference of light beams traversing the fiber-optic coil in reverse directions during the predetermined time period, and obtaining a measure of the nonreciprocity of the fiber-optic coil utilizing the measured phase difference.