Abstract: A solar-tracking power generating apparatus includes a plurality of sensing units having a directional light-extraction member each, a plurality of solar batteries associated with a light-gathering device each, and a solar trajectory simulation unit. Therefore, the solar-tracking power generating apparatus enables more accurate tracking of solar position and focusing of more sunlight on the solar batteries, so that the solar batteries could absorb more sunlight and convert the same into an increased amount of electric power.

Abstract: A targeting and tracking apparatus and method for optical transceivers is disclosed. The tracking function is performed internally by way of translating an internal optical fiber in the focal plane of the transceiver telescope using miniature motorized translation systems and/or micro-electro-mechanical systems (MEMS). The optical design of the transceiver provides a wide field of view and a pointing and tracking field of regard that is directly proportional to the translation of the optical fiber in the focal plane of the telescope. The apparatus and method can eliminate the need for external gimballing systems and scanning mirrors, and replace the gimballed optical beam steering function with motorized translation systems and/or MEMS that consumes very little power.

Abstract: A tracking system for tracking an object, the system having a first axis and a second axis perpendicular to the first axis. The first axis is at an angle to the vertical such that the object (or equivalently its path) does not intersect the first axis.

Abstract: A computer-readable medium having computer-executable instructions for performing a method. The method includes determining the transformation of an origin of an imaging device positioned in a vehicle and implementing exponentially stabilizing control laws based on the determined transformation and a distance to an imaged target. The method also includes generating a rotation output from the exponentially stabilizing control laws, generating a zoom output from the exponentially stabilizing control laws, determining a system latency in redirecting an optical axis and modifying a lens system along the optical axis, and determining the transformation of the origin of the imaging device with respect to global coordinates. A centroid of the target image is maintained within a selected distance from the origin of the imaging device. The apparent distance between the imaged target and the imaging device is also maintained.

Abstract: An apparatus for detecting radiation includes an entry window configured to receive radiation from a target, the entry window having an outer surface and an inner surface, such that the outer surface is not parallel to the inner surface. The apparatus further includes a radiation transmission assembly configured to receive at least a portion of the radiation received by the entry window. The apparatus further includes a radiation sensor configured to receive at least a portion of the radiation from the radiation transmission assembly.

Abstract: A target acquisition apparatus for use in association with a target, includes a weapon activation sensor, an image detector, a modulated light detector, a weapon processor, and a weapon transceiver for detecting activation of the weapon and producing a triggering signal. The weapon processor identifies a predetermined modulation characteristic from detected light radiation, identifies a predetermined spatial configuration within a predetermined portion of an acquired image, determines a local coordinate system, and produces a hit indication.

Abstract: The present invention is a solar tracking system which utilizes three supports arranged in a generally tripod configuration. In one embodiment, two of the supports are linear actuators, and the third support is a stationary universally pivoting joint such as a ball and socket joint. The tracking system may include cross-supports for increased stability, a linear rail for additional range of motion, and a mounting base to facilitate installation. This solar tracking system offers a stable, cost-effective design which is also capable of moving the solar module into an optional stowed position.

Abstract: Embodiments of the present disclosure include presenting data related to image information captured by a telescope on an electronic display, such as, for example, a high definition display. For example, a telescope control system may advantageously output video or other signals to one or more displays in a multi-media or image presentation. In certain preferred embodiments, such display comprises high definition displays, or the like. For example, such display may comprise entertainment, academic or other presentations.

Abstract: A mounting system comprising at least one mounting assembly is disclosed. A mounting assembly is used to mount at least one solar panel. The mounting assembly includes a support base, a rotating base, a first motor assembly, a solar panel base and a second motor assembly. The rotating base is mounted on the support base and rotates about its vertical axis by the help of the first motor assembly, which is disposed between the rotating base and the support base. The solar panel base is coupled to the rotating base through a set of links, which transfers the rotation of the rotating base to the solar panel base. The second motor assembly is disposed on the rotating base and it provides a tilting movement to the solar panel base, which enables solar panel base to tilt at a plurality of angle from the horizontal surface of the rotating base.

Abstract: A method and device produce an optical link with laser pulses between an emitter of the pulses and a receiver of the pulses. The optical link is used by a locating device for locating a body moving at constant speed away from the locating device. The locating device delays the start of emission of the laser pulses with respect to the departure of the moving body and varies the energy of the successive laser pulses in proportion to the square of the time elapsed since the start of emission of the pulses.

Abstract: A tracking concentrator with a positioning system for alternately aiming the tracking solar concentrator based on the sun or a database is disclosed. The preferred positioning system comprises a sensor adapted to detect an incident light level; a tracking database comprising solar angle information; an orientation processor; one or more actuators for aiming the one or more optical elements based on the orientation processor; wherein the orientation processor is configured to track the sun based on (a) the receiver if the sensed light level exceeds a determined threshold, and (b) the tracking database if the sensed light level does not exceed the determined threshold.

Abstract: A method to dynamically stabilize a target image formed on an image plane of an imaging device located in a moving vehicle. The method includes setting an origin in the image plane of the imaging device at an intersection of a first axis, a second axis and a third axis, imaging a target so that an image centroid of the target image is at the origin of the image plane, monitoring sensor data indicative of a motion of the vehicle, and generating pan and tilt output to stabilize the image centroid at the origin in the image plane to compensate for vehicle motion and target motion. The pan and tilt output are generated by implementing exponentially stabilizing control laws. The implementation of the exponentially stabilizing control laws is based at least in part on the sensor data.

Abstract: An optical system including a telescope and a principal pointing device for selecting a direction of observation is disclosed. The system furthermore includes at least one secondary pointing device arranged ahead of a part of the entrance of the telescope and oriented fixedly with respect to the principal pointing device. A set of photodetectors records a secondary image formed by the telescope from light rays directed by the secondary pointing device toward the entrance of the telescope The secondary image makes it possible to accurately determine the direction of observation.

Abstract: A system, method and medium tracks a motion of a subject using a laser by synchronizing an incident axis of the input image with an exit axis of the laser in order to radiate the laser based on an input image. The system includes a half mirror to reflect a predetermined amount of incident light and to transmit a remaining amount of the incident light, an image input unit to input an image reflected from the half mirror, a position identifying unit to identify a position of a first subject included in the input image, and a target tracking unit to track the first subject with reference to the identified position by radiating a laser transmitted through the half mirror onto the first subject along an axis from the half mirror and onto the first subject.

Abstract: An apparatus for detecting radiation includes an entry window configured to receive radiation from a target, the entry window having an outer surface and an inner surface, such that the outer surface is not parallel to the inner surface. The apparatus further includes a radiation transmission assembly configured to receive at least a portion of the radiation received by the entry window. The apparatus further includes a radiation sensor configured to receive at least a portion of the radiation from the radiation transmission assembly.

Abstract: Embodiments of the present invention include a system for detecting entry of an object from a first area into a second area. The system includes a light source for generating a light beam, the light beam defining a boundary between the first area and the second area. The system further includes a retroreflector positioned across from the light source, the retroreflector for reflecting the light beam back towards the light source and a photodetector positioned adjacent to the light source, the photodetector for detecting the reflected light beam wherein the photodetector generates a signal in response to detecting an interruption in the light beam signaling entry of an object from the first area to the second area.

Abstract: A method to dynamically stabilize a target image formed on an image plane of an imaging device located in a moving vehicle. The method includes setting an origin in the image plane of the imaging device at an intersection of a first axis, a second axis and a third axis, imaging a target so that an image centroid of the target image is at the origin of the image plane, monitoring sensor data indicative of a motion of the vehicle, and generating pan and tilt output to stabilize the image centroid at the origin in the image plane to compensate for vehicle motion and target motion. The pan and tilt output are generated by implementing exponentially stabilizing control laws. The implementation of the exponentially stabilizing control laws is based at least in part on the sensor data.

Abstract: A single, hard-mounted set of optics is utilized to replace a two field-of-view system for directed countermeasures. It includes within one continuous but distorted field of view the capability to detect, acquire and characterize targets at the edge of the field while precisely tracking with high target fidelity at the field center. With multiple targets, both tracking of a primary target and acquisition of a secondary target can occur simultaneously, greatly improving countermeasure effectiveness.

Abstract: A gimbal for a gimbaled mirror optical sensor system includes a mirror support rotatable about a first axis along which an optical sensor suite lies, the first axis being spaced apart from a desired pivot point of a variable line of sight, which may be for example a fixed-size window in the outer wall of an aircraft. The gimbal further includes two generally planar mirrors supported by and rotatable with the mirror support. A first mirror is spaced apart from the optical sensor suite along the first axis and is non-orthogonal to the first axis so as to reflect light from a second axis to the optical sensor suite, wherein the second axis sweeps an arcuate path about the first axis upon rotation of the mirror support. A second mirror lies along the second axis so as to follow the arcuate path upon rotation of the mirror support. The second mirror is pivotable so as to reflect light from the variable line of sight to the first mirror along the second axis.

Abstract: A method for generating positional information of an object is carried out by providing a reflector in the object and by providing a personal device containing a light generator and an imager. The personal device is mounted on a person holding the object at a mounting location that is identified to provide a first unobstructed line-of-sight between the light generator and the object and a second unobstructed line-of-sight between the imager and the object.

Abstract: It has been found that target optics produce non-specular, augmented optical returns when interrogated by a laser pulse. This non-specular radiation is detected by an active laser search system employing a direct-reading, thresholded focal plane detector that is able to detect non-cooperating targets with optics that employ a detector or optical element at the focal plane of their receiving optics. The pulses returned from such target optics have a width commensurate with the original transmitted pulse width, whereas passive background noise and the spread out active returns from the ground exhibit temporally long returns. By setting the sensor threshold sufficiently high, the system discriminates against noise and clutter while at the same time reducing the number of sweeps required to detect a target within the search area.

Abstract: The invention provides a method and apparatus for correcting for gain changes in detectors in a guided vehicle. In one version of the invention, an on board light source is used to generate a reference set of detector gains, which are stored in computer memory. The on board light source is then pulsed at subsequent times and the signals generated by the detectors are compared to the reference set of detector gains to determine whether any gains have changed.

Abstract: A method of determining the attitude of a spacecraft is provided. The method may include sensing the projections of a plurality of stars on a sensor, converting the projections into sensor-star directions, and determining the angular values of the spacecraft relative to the stars. The method uses equations to introduce focal length errors into the equations which convert the projections into star-sensor directions, thereby reducing the uncertainty introduced by incomplete knowledge of the errors on the results of the attitude angles of the spacecraft.

Abstract: A device providing an inertially stabilized laser beam as an optical reference. The device consists of a base and a small stabilized optical platform that emits the laser beam. The platform connects to the base through a mechanical flexure that allows relative motion in two axes. High-bandwidth angular rate sensors affixed to the platform measure platform motion in inertial space. Linear displacement sensors measure relative motion between base and platform. A closed-loop control system accepts these sensor measurements and command actuators that null the sensed platform motions, maintaining the optical platform fixed in inertial space. The digital controller implements a Sensor Blending Kalman Filter that blends high frequency signals from the platform with low frequency signals from a DC sensor (gyroscope) external to this device but affixed to the common base. The controller enables both stabilization of the laser beam and commanded pointing of the beam in inertial space.

Abstract: A system and method for navigation utilizing sources of pulsed celestial radiation are provided. A spacecraft, satellite, or other vehicle (12) has a pulse sensor (22) mounted thereto for detecting signal pulses (14) generated by a plurality of pulsars or other celestial objects (16). The detected signal pulses (14) are synchronously averaged at the known period of the pulsar or other celestial object (16) with respect to a timer (24). Timer (24) measures the pulse time of arrival at the pulse sensor (22) by comparing the pulse signal (14) with a pulse shape template (52), and a processing means (30) calculates the offset time between the measured pulse time of arrival at sensor (22) with a calculated pulse time of arrival at the solar system barycenter (SSBC).

Abstract: A system and method are provided for controlling an optical imaging system capable of providing an image of a target. The system includes a reflector, an optical amplifier and a tracking device. The reflector is capable of reflecting light representative of the image provided by the optical imaging system. In addition, the reflector is capable of being adjusted in at least one direction based upon movement of the image provided by the optical imaging system. The optical amplifier is capable of amplifying an intensity of the light reflected by the reflector with a variable gain based upon the intensity of the reflected light. And the tracking device is capable of receiving the light from the optical amplifier. As such, the reflector can be driven to a position in at least one direction based upon an image of the target represented by the light received by the tracking device.

Abstract: A device for detecting radiation direction is an integrated circuit that includes a first and second phototransistor positioned anti-parallel with respect to each other and a reference phototransistor. The device does not require impinging radiation to be mechanically aligned using pinholes, apertures or mechanical slits. The first phototransistor detects the direction of the radiation in an x-plane, and the second phototransistor detects the direction of the radiation in the y-plane. The first and second phototransistors have two differential pairs. The P type base regions are formed in the <111> plane of the silicon to form opposing sidewalls for receiving radiation signals from a radiation source. A current is induced in the PN junction of each phototransistor, thereby causing a current output on the emitters of the phototransistors. The differential currents represent rectangular coordinates describing the direction of the radiation detected on the <111> plane.

Abstract: Systems and methods for contiguously and accurately updating target object information during an entire target engagement period are provided. The target tracking system includes a database for storing starfield information, an optical beam source configured to illuminate one or more optical beam pulses, first and second camera systems, and a processor. The processor instructs the first camera system to track the object based on recordation of the tracked object, instructs the second camera system to stabilize the tracking image based on the instructions sent to the first camera system, and determines inertial reference information of the tracked object based on the stabilized image and starfield information associated with the stabilized image.

Abstract: A system for illuminating and reading information on a target (12) includes an illuminating device (14) for illuminating the target, separate from the illuminating device a user wearable reader device (11) for capturing an optical image of the target when illuminated by the illuminating device, detector means (30, 35) for detecting the location of the reader device and adjustment means (36, 22) for adjusting the illumination provided by the illumination device in response to a signal provided by the detector means so that a region (33) on the target illuminated by the illuminating means is readable by the reader device. A method of use of the system and an illumination unit for use in the system are also described.

Abstract: A system for using an image of the Sun for detecting objects traveling through Earth's atmosphere is disclosed. The system includes a receiver for collecting incident sunlight (solar energy) and a light sensitive device that produces a signal in response to exposure to light. A signal processor that is coupled to the light sensitive device, the signal processor sensing the collected incident sunlight and is programmed for providing an output signal corresponding to provide a detection signal in response to a shadow that moves across the light sensitive device.

Abstract: A method for detecting a non-fixed object in a system (12) is provided. The method includes applying a light emitting substance (13) to at least a portion (14) of an object (10). At least a section (20) of the portion (14) is illuminated with a non-fixed object illuminator (16). The object (10) is detected in the system (12) in response to illuminating the section (20). The object (10) is then determined to be a fixed or non-fixed object.

Abstract: A system for lighting an object has a radiation source, a first guidance device optically connected to the object, a second guidance device and a first subtracting amplifier in communication with the first guidance device. The first subtracting amplifier has inputs and at least one output. A second subtracting amplifier is in communication with the first and second guidance devices. A commutation unit is in communication with the first and second guidance devices and the first and second subtracting amplifiers. First, second, third and fourth actuators are in communication with the commutation unit. A first mirror is in communication with and controlled by the first and second actuators and a second mirror is in communication with and controlled by the third and fourth actuators. The first and said second mirrors are controlled by the actuators so that the system can light an object by reflecting the radiation source.

Abstract: A device for detecting the angle of incidence of radiation on a radiation incidence surface (14) comprises at last two first pairs (36) of photodiodes comprising first photodiodes (30) arranged along a first axis (12) and connected in series in a pair-wise manner. Each of the first photodiodes (30) comprises a space-charge zone (32) having a space-charge zone face (34) oriented towards the radiation incidence face (14). Further, the device is provided with a a shading mask (46) arranged at a distance (44) above the space-charge zone faces (34) of the first photodiodes (30) and comprising radiation-transmitting areas (48). Each radiation-transmitting area (48) is assigned to the space-charge zone faces (34) of the two first photodiodes (30) of a first pair (36) of photodiodes.

Abstract: A system and method for focusing electromagnetic energy on a moving target. Generally, the inventive system sends a pilot beam to a target and analyzes a return wavefront to ascertain data with respect to any distortions and other phase and/or amplitude information in the wavefront. This information is then used to pre-distort an output beam by so that it is focused on the target by the intervening distortions. In an illustrative embodiment, the pilot beam is provided by a beacon laser mounted off-axis with respect to the output beam. The reflected wavefront is received through a gimbaled telescope. Energy received by the telescope is detected and processed to ascertain wavefront aberrations therein. This data is used to predistort a deformable mirror to create an output beam which is the phase conjugate of the received wavefront. In a first alternative embodiment, a nonlinear optical phase-conjugate mirror is employed to generate the required wavefront-reversed replica of the received wavefront.

Abstract: An apparatus for controlling optical power in a microscope includes a measuring device for measuring the optical power, and a control unit for controlling a high-frequency source as a function of the measured optical power so as to achieve a selectable level of the optical power. The microscope includes a source providing light along an illumination beam path to a sample, a detector receiving detection light lead along a detection beam path from the sample, and an acousto-optical or electro-optical element located in the illumination beam path and driven by the high-frequency source.

Abstract: In a first embodiment, a single linear array of bi-cell optical detectors is arranged with each bi-cell optical detector having a rectangular aperture located a prescribed distance above the surface of the bi-cell optical detector. In the first embodiment, in calculating the position of a point source emitter, it is understood that each detector receives light from the point source emitter at a unique angle different from the angles at which the other detectors receive light from the point source emitter. A plot of detector ratios is made by taking the best fit line through the ratios from each detector and the location of the point where the detector ratio is zero yields the point of perpendicularity between the emitter and the linear detector array. Another embodiment contemplates a three dimensional detector having three linear arrays of bi-cell detectors arranged at the periphery of a measuring space mutually orthogonal to one another.

Abstract: In a first embodiment, a single linear array of bi-cell optical detectors is arranged with each bi-cell optical detector having a rectangular aperture located a prescribed distance above the surface of the bi-cell optical detector. In the first embodiment, in calculating the position of a point source emitter, it is understood that each detector receives light from the point source emitter at a unique angle different from the angles at which the other detectors receive light from the point source emitter. A plot of detector ratios is made by taking the best fit line through the ratios from each detector and the location of the point where the detector ratio is zero yields the point of perpendicularity between the emitter and the linear detector array. Another embodiment contemplates a three dimensional detector having three linear arrays of bi-cell detectors arranged at the periphery of a measuring space mutually orthogonal to one another.

Abstract: An imaging instrument includes plural spaced-apart photon collectors, whose sampled outputs are correlated in pairs to yield brightness line integrals across a remote object being imaged. These integrals can be subject to matrix decomposition to yield a 2D array of image data corresponding to the object. Another imaging instrument includes plural spaced-apart reflectors, each having an optical fiber end at its focal point. The precise positions of the optical fiber ends are controlled by a control system (e.g., including piezo-electric positioners) that can be operated to counter-act the effect of atmospheric turbulence. The other ends of the fibers terminate at an image plane and serve to provide an output image. The sensors may be arrayed in a non-uniform manner.

Abstract: A satellite location determination system for a constellation of satellites includes a plurality of optical transceivers. Each optical transceiver is associated with a respective satellite and includes an optical synthesizer, transmission conditioning optics, a telescope assembly, reception conditioning optics, and an optical to electronic signal converter. The optical synthesizer produces phase-coherent optical laser pulses. The transmission conditioning optics appropriately conditions the characteristics of the phase-coherent optical laser pulses. The telescope assembly receives an output of the transmission conditioning optics and transmits an optical transceiver output into space for reception by an optical transceiver associated with another of the satellites. The telescope assembly also receives an optical transceiver output from another of the satellites. Reception conditioning optics appropriately conditions the characteristics of the optical transceiver output received from another of the satellites.

Abstract: A method for providing a pilot with information associated with at least one region of a field of view visible to the pilot from within a cockpit without requiring a visual display. The method includes the steps of determining an eye gaze direction relative to a given frame of reference for at least one eye of the pilot, determining a reference direction relative to the given frame of reference, comparing the eye gaze direction with the reference direction, and if the eve gaze direction and the reference direction are equal to within a given degree of accuracy, generating audio output audible to the pilot and indicative of information associated with the reference direction.

Abstract: An apparatus and system for imaging radio frequency electromagnetic signals that is useful for imaging a target object in order to identify an unknown object or to determine the condition or configuration of a known object. One embodiment of an apparatus for imaging radio frequency electromagnetic signals comprises an optical source operable to output an unmodulated optical signal; an image sensor operable to receive the unmodulated optical signal and an incident radio frequency electromagnetic signal and to modulate the unmodulated optical signal with the received radio frequency electromagnetic signal so as to form a modulated optical signal; a lens operable to receive the modulated optical signal and to focus the modulated optical signal; and a photodetector operable to receive the focused modulated optical signal and output an electrical signal representing the focused modulated optical signal. The optical source may be a laser.

Abstract: A system for stabilizing an optical line of sight. An optical system including primary optics and relay optics includes a jitter rejection mirror located within the path of the relay optics. An auto alignment system is provided for maintaining alignment of the jitter rejection mirror in response to a control signal. An auto alignment sensor detects jitter in a reference beam passing through the jitter rejection mirror, and the generated control signal is used to reduce the jitter. The reference beam is supplied by a stabilized source of laser signals which are received by the primary optics, and relayed to the jitter rejection mirror.

Abstract: An imaging or viewing system, which automatically compensates for bright spots, which tend to overload or saturate imaging system. The system can be used with imaging type tracking systems, viewers and various types of optical devices which heretofore have been unable to provide satisfactory performance due to saturation or overloading of an imaging device due to bright spots, i.e., laser radiation flares or sunlight. The system in accordance with the invention is configured such that reflected radiation is imaged onto a first image plane without dividing the incoming radiation into two optical paths. A digital mirror device, i.e., is disposed at the first image plane. The radiation level of each pixel in the image plane is compared with a fixed threshold on a pixel by pixel basis and used to generate a mirror drive signal that automatically reduces the reflectivity of the corresponding mirror pixel to compensate for bright spots.

Abstract: A pyranometer for measuring solar irradiance at a selected site comprises a light detector adapted to produce an output signal in response to incident solar radiation, a reversible motor having a curved shadowband attached to its output shaft, means for mounting the light detector and motor so that the shadowband is at a fixed distance from the light detector; and a motor controller that is adapted to periodically cause the motor to rotate the shadowband from one to the other of two limit positions, with the shadowband acting to momentarily shadow the light detector during its movement between its two limit positions. A datalogger stores and processes the light detector's signal output to provide a measure of total horizontal, direct normal and horizontal diffuse solar irradiance.

Abstract: A prime focus unit that enables position and angle correction within a lens barrel while being located at the prime focus of a telescope. There is provided a first frame on which a barrel top inner tube of a telescope is to be mounted. A second frame is joined to the first frame by way of a Stewart platform comprising six jacks and three pressurized springs. An observation apparatus for collecting observation data and an optical correction system for effecting optical correction are provided on the second frame. If a change arises in the relative position and angle formed between the telescope and the observation apparatus in association with a change in the attitude of the telescope, the change can be eliminated by adjustment of a Stewart platform.

Abstract: A method and apparatus for post processing a star tracker measurement to remove a systematic error characterizable at least in part by a pixel phase is disclosed. The method comprises the steps of computing the pixel phase along a first axis from a measured star position and a star tracker characteristic, computing a first axis error correction according to the computed pixel phase, and computing a compensated first axis star tracker measurement according to the measured star position and the first axis error correction.

Abstract: A spacecraft power/sun acquisition method includes a pitch search phase in which the spacecraft is rotated about a pitch axis, stopped, quaternions reset to remember position, and yaw search phase is entered when a first TOA occurs from a first slit sun sensor, and a keyhole slew is performed when the first TOA does not occur. The method also includes yaw search phase in which a keyhole slew is performed by rotating the spacecraft about a yaw axis, stopping the spacecraft, and entering pitch search phase when the first TOA does not occur, and in which the spacecraft is rotated about a yaw axis, stopped, quaternions reset, and sun hold phase is entered when a second TOA occurs from a second slit sun sensor. Lastly, the method includes a sun hold phase in which the spacecraft is oriented to the sun and placed in spin at power safe attitude.

Abstract: A detector includes a filter for substantially blocking photons having wavelengths greater than about 250 nm. A photodiode has a low dark current less than about 0.4 pA/cm2. A current from the photodiode is proportional to a quantity of photons having wavelengths less than or equal to about 250 nm which pass through the filter and impinge the photodiode. A processor determines the quantity of photons impinging the photodiode as a function of the current. In a preferred embodiment, the photodiode is a SiC photodiode.

Abstract: A two-dimensional field of regard is scanned with a single plane mirror in the object space of a telescope, maintaining a fixed relationship between the rotational direction of scan and the projection of the telescope's focal plane. The two dimensional field of regard is covered by a series of conical arcs, each arc being scanned by rotation at constant angular velocity about the inner axis of the two-axis system. This scanning system accommodates applications such as TDI that require an opto-mechanical scan with a constant linear velocity (magnitude and direction) in the focal plane. Shading of IR images is mitigated by calibration at the ends of each scan line and by a scan geometry that minimizes changes in reflection angle.

Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.