Abstract: A radar system achieves adjustment of a time-change characteristic of a frequency-modulating voltage signal to a voltage-controlled oscillator for determining a transmitting signal such that the time-change characteristic of the frequency-modulating voltage signal is changed by a minute amount and the frequency spectrum of a beat signal is determined. The adjustment is performed so that the shape of a bulge in signal intensity included in the frequency spectrum is the sharpest.

Abstract: A system for detecting and locating an underground object having stationary RF transmitter receivers that define a coordinate system for an area of interest, a sensor adapted to detect presence of an underground object and to provide a presence data, and a mobile RF transmitter receiver that is movable with the sensor, and is adapted to receive and/or transmit location data indicative of location of the mobile transmitter receiver in the coordinate system. A method is also provided for detecting and locating underground object including the steps of establishing a coordinate system for an area of interest, detecting presence of an underground object and providing a presence data upon detection of the underground object, and transmitting and/or receiving location data in a radio frequency, the location data being indicative of location of the underground object in the established coordinate system.

Abstract: An optical system is provided for laser encoder resolution extension with three-dimensional motion decoupling capability. The optical system includes a first prism mounted on a moving target, and a plurality of prisms, a retroreflector, a laser source, and a detector mounted on a fixed base. The moving target has three-dimensional linear motion freedom. The first prism on the moving target and the plurality of prisms and the retroreflector on the fixed base reflect a laser beam from the laser source to the detector define a three-dimensional optical path. The three-dimensional optical path provides multiple times optical resolution extension power for linear displacement measurement and encoding. This optic system is only sensible to the target motion on X direction and is substantially unaffected by movement in the Y and Z directions.

Abstract: A surveying instrument includes a surveying instrument body which is rotatable about vertical and horizontal axes and has a telescope optical system for collimating the surveying instrument relative to a survey point; a collimator optical system for projecting first light rays toward the survey point and for receiving the first light rays reflected at the survey point; an auto-collimating system which rotates the surveying instrument body to position the survey point on an optical axis of the telescope optical system; a distance measuring optical system for projecting second light rays toward the survey point and for receiving the second light rays reflected at the survey point; and a distance measuring device for calculating a distance from the surveying instrument to the survey point. The optical axes of the collimator optical system and the distance measuring optical system are offset from each other.

Abstract: A distance measuring apparatus includes components for transmitting electromagnetic waves such as laser light to scan a detection area, and receiving reflected waves. The detection area is partitioned into standard areas of a fixed width and signals corresponding to waves received from different standard areas are stored separately. Mutually adjacent standard areas are combined to form a single combined area, if the corresponding signals each fail to exceed a specified threshold value, and these signals are cumulatively added. Conditions of a target object, such as its presence and its position, may be judged on the basis of combined areas thus created such that the detection can be made with increased sensitivity although the resolving power is adversely affected. An upper limit may be introduced for the number of standard areas over which cumulative addition of signals may be made.

Abstract: An uncorrelated clutter noise cancellation method and apparatus employing a measured ambiguity function sample for each randomly-modulated transmission pulse in a randomly-modulated pulsed Doppler radar system. The ambiguity function samples are calculated from a stored copy of the randomly-modulated transmission signal. Estimates of the uncorrelated clutter backscatter are first developed by calculating the amplitude and phase of the radar returns detected in target range and velocity cells corresponding to stationary scatterers. The stationary scatterer contribution to each target cell, computed according to the sample ambiguity function, is then subtracted to eliminate the uncorrelated noise component in the return signal for the target cell. This clutter cancellation technique does not rely on correlations between the randomly-modulated transmission signal and the clutter return signal.

Abstract: A simultaneous dual polarization radar system is disclosed that utilizes a RF power divider to replace high speed dual polarization switches utilized in current dual polarized radar systems. The disclosed systems allow for transmission and reception in both horizontal and vertical signal modes simultaneously while repositioning critical receiver components above the elevation rotary coupler in a radar pedestal. A bypass switch is also utilized to allow for mode switching of a radar system and a dual polarization reception design is shown to allow for the economical capturing of linear depolarization ratios of selected atmospheric areas. These new designs eliminate the current problems experienced in current dual polarization radar system of long dwell times and velocity range reductions, and the elimination of the relatively expensive and unreliable polarization switch.

Abstract: The invention relates to an apparatus for optical distance measurement, having a transmitter unit (12) for emitting optical radiation (13), in particular laser radiation, in the direction of a target object (15); having a receiver unit (14) for receiving the radiation (16, 49) reflected by the target object (15); and having a control and evaluation unit (56) for ascertaining the distance between the apparatus and the target object (15), and also having at least one optical means (26, 28, 30, 50) for beam guidance. It is proposed that the relative position of the at least one optical means (26, 28, 30, 50) and the light source (17, 18) of the apparatus to one another be variable.

Abstract: An antenna base, a control circuit section, and a high-frequency circuit section are enclosed in an inner space defined by a housing and a radome. Inside this inner space, the control circuit section and the high-frequency circuit section are surrounded by the antenna base and the housing. A circuit GND common to the control circuit section and the high-frequency circuit section is electrically connected to the antenna base and the housing, and it is connected to a body GND through only capacitive impedance.

Abstract: A camera is disclosed which is provided with a sensor device that includes: a substrate having formed thereon which first and second line sensors that are arranged a fixed baseline length apart from each other and a third sensor for receiving light from a field which is arranged on a line in arrangement direction of the first and second line sensors, a first light receiving optical unit for condensing light from the field onto the first line sensor, a second light receiving optical unit for condensing light from the field onto the second line sensor, a third light receiving optical unit for condensing light from the field onto the third sensor, wherein, when focal lengths of the first, second, and third light receiving optical units are assumed to be f1, f2, and f3, respectively, the following condition is satisfied: f1=f2≧f3.

Abstract: A laser countermeasure system uses a fluence trigger along an optical path between an entrance and a detector at an output. The fluence trigger detects laser radiation and blocks the passage thereof beyond the trigger. A shutter at the front end can be operated in response to detection by the trigger. A threat analyzer also receives radiation and automatically breaks the radiation into spectral components for correlation to appropriate filters to remove the harmful coherent radiation. A tunable filter and/or a filter wheel is interposed along the optical path and is controlled by an adjustment system, illustratively servo controls. The adjustment system responds to the threat analyzer to select and interpose automatically the proper filter(s) to attenuate or block the coherent radiation. Thereafter, the fluence trigger and/or shutter operate to restore full operation along the optical path. The system and method provide look-through capability and mission continuity in the face of unknown laser threats.

Abstract: An apparatus (12) for determining the location of a vehicle occupant (20) in a vehicle interior includes a light source (40) for projecting at least one structured light beam (42) onto an area of interest (44) to form a light pattern on the area of interest. A beam divergence control device (50) alters the apparent location of the light source (40) with respect to the area of interest (44). An imager (60) detects the light reflected from the area of interest (44). A characteristic of the reflected light is measured, and the distance between the imager (60) and the area of interest (44) is measured, based on the measured characteristic of the reflected light.

Abstract: Movement of a GMTI radar during a coherent processing interval over which a set of radar pulses are processed may cause defocusing of a range-Doppler map in the video signal. This problem may be compensated by varying waveform or sampling parameters of each pulse to compensate for distortions caused by variations in viewing angles from the radar to the target.

Abstract: A method, apparatus, and system for automatic detection of targets from radar data are disclosed. Ground moving target indicator radar is used to collect radar data which is then filtered to suppress intensity of the clutter ridge. For each working point in a set of radar data, a working first-sense circular transmit/first-sense circular receive radar cross section, a working first-sense circular transmit/second-sense circular receive radar cross section, and a working asymmetry angle are calculated from a scattering matrix, then analyzed to classify the working point as a target point or a clutter point. This analysis suitably is performed by comparing data calculated for each working point to basis data collected in a look-up table in which combinations of a first-sense circular transmit/first-sense circular receive radar cross section, a first-sense circular transmit/second-sense circular receive radar cross section, and an asymmetry angle have been classified as target points or clutter points.

Abstract: In a shift clock signal generating apparatus, a delay line includes a plurality of unit delay elements connected in cascade. A reference clock signal propagates in the delay line while being successively delayed by the unit delay elements. Switches have first ends connected with output terminals of the unit delay elements respectively, and second ends connected with a shift clock signal output path. When specified one among the switches is in its on position, a delayed clock signal which results from delaying the reference clock signal by a prescribed time interval is transmitted via the specified switch to the shift clock signal output path as a shift clock signal. The specified one among the switches is determined on the basis of data representing a phase difference of the shift clock signal from the reference clock signal. The specified switch is set in its on position.

Abstract: A method of tracking a target (2) moving in an airspace and a target tracking system (10) for performing the method are described. A search sensor (12) searches a search space at a first clock rate (2&pgr;/&Dgr;T1) and establishes target information in regard to a track (4) flown through by the target (2). Calculation means (16) extrapolate an expected flight path (6) from the target information established and provide flight path data, which describes the expected flight path (8), to a tracking sensor (14), which covers a tracking space (15), and provides this data at a second clock rate (2&pgr;/&Dgr;T2), which is higher than the first clock rate (2&pgr;/&Dgr;T1). When the target (2) reaches the tracking space (15), the tracking sensor (14) is aimed at the expected flight path (6) on the basis of the flight path data provided, the target (2) is detected as soon as it is detectable by the tracking sensor (14), and the tracking sensor (14) is tracked on the target autonomously.

Abstract: A system and method of efficiently obtaining distance measurements of a target by scanning the target. An optical beam is provided by a light source and modulated by a frequency source. The modulated optical beam is transmitted to an acousto-optical deflector capable of changing the angle of the optical beam in a predetermined manner to produce an output for scanning the target. In operation, reflected or diffused light from the target may be received by a detector and transmitted to a controller configured to calculate the distance to the target as well as the measurement uncertainty in calculating the distance to the target.

Abstract: An electronic distance meter includes a sighting telescope optical system having an objective lens for sighting an object, and an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light toward the object via the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object. The light-transmitting optical system includes a light-shield mask having a translucent portion to define a beam profile of the measuring light. The translucent portion comprises a filter having an uneven density, light transmittance of a central portion of the filter being greater than light transmittance of a peripheral portion of the filter.

Abstract: An array antenna calibration apparatus simple in configuration and inexpensive while ensuring an accurate calibration of an array antenna is provided.

Abstract: The radar signature of a vessel is reduced by retrofitting it with an array (10) of elements (15) fastened to surfaces (14b) of the vessel. The elements (15) have planar faces (11-12) so oriented that incident radar signal (20) is reflected away from its angle of incidence.