Honeywell International Inc.

Honeywell G.m.b.h.

Chung-Jen Chen

Michael J Johnson

Charles H Lange

Rajesh Chandrasekhar

Lee Kevin Strandjord

Thomas Charles Greening

Gregory W Keith

Michael E Johnson

Systems and methods for performing vibration error suppression in a fiber optic gyro sensor. An example system includes a light source, a sensing loop assembly, a photo detector, and a processing component. The light source generates a light signal that is then modulated by the sensing loop assembly and applied to a fiber optic coil in the assembly. The photo detector receives a modulated light signal that is an output of the sensing loop assembly (coil) and generates an analog signal. The processing component converts the generated analog signal into a modulated digital signal, determines an average of the modulated digital signal, determines an intensity modulation amplitude based on the determined average of the modulated digital signal, and re-scales the modulated digital phase signal based on the determined intensity modulation amplitude.

Methods and systems for fiber optic gyroscopes vibration error suppression

A trans-impedance amplifier with gain control for a fiber optic rotation rate sensor. A variable gain amplifier having gain control based on keeping the amplifier output above a certain level. The gain control approach allows the amplifier bandwidth to remain constant. A gain control circuit includes a control device connected to ground and the amplifier feedback network. The input to the gain control circuit may be the amplifier output that has been filtered, or the input could be from an external circuit or microcontroller.

Variable gain constant bandwidth trans-impedance amplifier for fiber optic rate sensor

According to one aspect of the present invention, a method for calibrating a fiber optic gyroscope is provided. A method is provided for calibrating a fiber optic gyroscope. First and second portions of light from a first light source are propagated through a fiber optic line in respective first and second directions. A first voltage that causes a predetermined phase shift between the first and second portions of the light from the first light source is calculated. First and second portions of light from a second light source are propagated through the fiber optic line in the respective first and second directions. A second voltage that causes the predetermined phase shift between the first and second portions of the light from the second light is calculated. A difference between the first voltage and the second voltage is then calculated.

Method and system for calibrating a fiber optic gyroscope

A clock system for a fiber optic gyroscope is provided that includes a highly-tunable clock for the bias modulation and a separate asynchronous high-speed clock for the photodetector sampling. By separating the two clocks rather than using two derivatives of the same clock, the clock system and method can provide both the tunability objective of the bias modulation clock and the high-speed objective of the sampling clock, while using readily available, lower performance, radiation-hardened electronics parts.

Fiber optic gyroscope asynchronous demodulation

A phase jump amplitude and timing controller is used in a fiber optic gyroscope for suppressing color noise. The phase jump amplitude and timing controller inserts a phase/voltage jump into the feedback signal of the loop closure electronics of the fiber optic gyroscope. This phase/voltage jump breaks the repeated pattern of the drive signal. The IOC time-dependent characteristics are totally eliminated by the randomized feedback signal because no repeated signal is applied to the IOC. The randomized amplitude is preferably within the full &#xb1;&#x3c0; phase such that the optical errors average to zero. A fixed frequency higher than the interested spectral region can shift the color noise to higher frequency. A randomized frequency can spread the color noise over full spectrum, and totally eliminate the RDS. In other words, the color noise caused by the nonlinearity of the driving circuit and IOC spreads out over a wide range of spectrum such that no distinct frequency peaks are apparent in the spectral domain.

System and method for reducing fiber optic gyroscope color noise

A fiber optic ring interferometer, such as an interferometric fiber optic gyro (IFOG), with a sensing loop doubler. The IFOG device includes a light source, a circulator in optical communication with the light source and a photo diode, an integrated optical chip (IOC) capable of splitting light emitted from the circulator into two paths each of which is capable of being modulated, the IOC further being capable of combining light from each of the two paths when light travels in a direction towards the circulator, a fiber coil, and a polarization maintaining (PM) combiner/splitter disposed in between the IOC and the fiber coil. The PM combiner/splitter operates to send light through the fiber coil a first time in a first polarization state and to subsequently send the same light a second time through the fiber coil in a second orthogonal polarization state, whereby light travels twice the distance compared to a single loop IFOG device and, as such, effectively doubles the LD product.

Fiber optic gyroscope sensing loop doubler

Calibrating a seamless tiled display image having multiple overlapping discrete images produced by multiple displays includes generating a display-to-screen spatial transformation function to reduce one or more undesirable geometric projector characteristics for each of the projectors used in the tiled display. Then the method includes generating a screen-to-camera spatial transformation function to reduce one or more undesirable geometric camera characteristics for each of the cameras used in capturing the tiled display images used in the calibration. Then the method requires generating a spatial luminance transformation function for effective color calibration for each of the display images in the tiled display. Then the method requires inputting a high-resolution image into a tiled display processor to form the tiled images of the tiled display, segmenting the inputted high-resolution image to form tiled images based on an array of images used in the tiled display, and pre-warping each of the segmented tiled images using the display-to-screen spatial transformation function to reduce the one or more non desirable geometric projector characteristics. Then the method requires applying an inverse of the spatial-luminance transformation function to each of the pre-warped images to effectively blend colors in the tiled display images.

Electronic calibration for seamless tiled display using optical function generator

According to the preferred exemplary embodiments of the present invention, there is provided a phase jump amplitude and timing controller for suppressing the voltage-dependent errors responsible for the dead band. The phase jump amplitude and timing controller inserts a phase/voltage jump into the feedback signal of the loop closure electronics of the fiber optic gyroscope. The phase/voltage jump is provided at a frequency regular enough to ensure that the fiber optic gyroscope will not have enough time to settle into the dead band before the phase/voltage jump is supplied to the loop closure electronics. By providing a recurring phase/voltage jump with amplitude sufficient to move the signal out of the dead band, the loop closure electronics averages the voltage-dependent errors over the full feedback voltage range. This error averaging process effectively eliminates the voltage-dependent errors that cause the dead band phenomenon and allows the loop closure electronics to sense the actual rate of rotation for the fiber optic gyroscope.

Methods and apparatus for fiber optic gyroscope dead band error suppression modulation

Producing seamless tiled images from multiple displays includes measuring a luminance profile of each of the displays, computing a desired luminance profile for each of the displays, and determining a spatial gradient profile of each of the displays based on the measured luminance profile and the computed desired luminance profile. The determined spatial gradient profile is applied to a spatial filter to be inserted into each of the displays to produce the seamless tiled display image.

Method and apparatus for an optical function generator for seamless tiled displays

A display system that can be calibrated and re-calibrated with a minimal amount of manual intervention. To accomplish this, one or more cameras are provided to capture an image of the display screen. The resulting captured image is processed to identify any non-desirable characteristics, including visible artifacts such as seams, bands, rings, etc. Once the non-desirable characteristics are identified, an appropriate transformation function is determined. The transformation function is used to pre-warp the input video signal that is provided to the display such that the non-desirable characteristics are reduced or eliminated from the display. The transformation function preferably compensates for spatial non-uniformity, color non-uniformity, luminance non-uniformity, and other visible artifacts.

Method and apparatus for calibrating a tiled display

The present invention overcomes many of the disadvantages of the prior art by providing a display that can be calibrated and re-calibrated with a minimal amount of manual intervention. To accomplish this, the present invention provides one or more cameras to capture an image that is projected on a display screen. In one embodiment, the one or more cameras are placed on the same side of the screen as the projectors. In another embodiment, an array of cameras is provided on either or both sides of the screen for capturing a number of adjacent and/or overlapping capture images of the screen. In either of these embodiments, the resulting capture images are processed to identify any non-desirable characteristics including any visible artifacts such as seams, bands, rings, etc. Once the non-desirable characteristics are identified, an appropriate transformation function is determined. The transformation function is used to pre-warp the input video signal to the display such that the non-desirable characteristics are reduced or eliminated from the display. The transformation function preferably compensates for spatial non-uniformity, color non-uniformity, luminance non-uniformity, and/or other visible artifacts.

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Phoenix, AZ, United States of America

Chung-Jen Chen