Abstract: An entropy based signal transmission, reception and analysis method and apparatus in which the entropy of time dependent signals is determined by utilizing a selected Green's function relationship. Information with respect to a medium with which the signals have interacted is derived by comparison of the entropies of the signals. In a preferred embodiment, the density distribution functions of selected digitized time segments of the signals to be analyzed are determined by utilizing the selected Green's function relationship and the entropies of the signals are then determined from the density distribution functions and compared with each other to derive the desired information.

Abstract: First and second passive sensors (14,16), which may be mounted on different earth orbiting satellites, provide relative azimuth and elevation coordinates to sensed objects (A,B,C) such as hostile missiles. Minimum and maximum possible ranges to the objects (A,B,C) along lines-of-sight (18a,18b,18c) from the first sensor (14) are predetermined, and used to calculate "range lines" (24,26,28) which are coincident with the lines-of-sight (18a,18b,18c) and extend from the respective minimum to maximum ranges respectively. The range lines (24,26,28) are transformed into the field of view of the second sensor (16), and matched to the azimuth and elevation coordinates of the respective objects (A,B,C) using a basic feasible solution (greedy) or global optimization algorithm.

Abstract: The present invention is a Multiple Target Doppler Tracker which tracks a plurality of components, including debris and submunitions of a munition burst apart above the ground. A plurality of transmitters transmits constant frequency (CW) signals towards the burst event of the munition and a plurality of receivers receive the signals reflected from the components. The signals received by the receivers are processed into frequency spectra. The spectra are analyzed to determine the path of a selected number of components. Using the path information the selected components are tracked with tracking devices.

Abstract: A system for the accumulation of detailed moment-to-moment information concerning the movements of players and of the ball in a sporting contest. One or more cameras (11, 12, 14) are situated so as to cover the entire playing area (10) of the event. The output of at least one of these cameras is provided to a digital image processor (22), which tracks the movements of the images, or silhouettes, of players in the camera images. By employing multiple camera views of the same playing area, the tracking processor can, in most cases, resolve ambiguities arising from overlaps in any one view. For the remaining, unresolved, cases, one or more human operators, provided with the same or similar camera views, are employed, through an interactive interface. The operators are provided with apparatus (30) for identifying players, through a query/response method, as requested by the tracking processor (22).

Abstract: A computer method is disclosed for extracting data on a target from a clutter degraded environment by using non-time-synchronized results from two sensors stations. The method, which is employed in satellite tracking systems, transforming multiple non-synchronous sensor returns comprised of angles from line of sight observations from passive sensors into target position coordinates. Observations from successive returns of each sensor are paired and a triangulation point is calculated. Successive triangulation points are used to determine points on the projected trajectory of the target. These calculated target position coordinates may then used to project the future path of the target.

Abstract: A method of passive ranging and geolocation of multiple emitters by a single detection platform. Two independent emission sequences support formulation of two independent algebraic equations involving a triangular arrangement of platform and emitters. One sequence constitutes an interrogation signal by one emitter and a transponded or reflected signal from another. A second emission sequence constitutes the reversed order of emitters from those of the first emission sequence. The method utilizes the steps of measuring the time difference of arrival at the platform of signals having travelled the direct path and the transponded or reflected paths, and measuring the angles of arrival of received signals for each independent emission sequence. A series of steps computing ranges and angles based on prior measurements provide a set of desired ranges and angles identifying the relative positions of the emitters relative to the platform.

Abstract: A bistatic radar system includes a transmitting radar site; a receiving radar site; and an optical fiber RF link system for transmitting RF signals from the receiving site to the transmitting site and for transmitting command and control signals from the transmitting site to the receiving site.

Abstract: An optical RF stereo systems includes multiple remote vehicles, a processing center, and optical RF link systems for transmitting RF signals from remote vehicles to the processing center and for transmitting command and control signals from the processing center to remote vehicles.

Abstract: The entropy-based signal receiver uses the entropy of a received signal or a quantity that is closely related to entropy as the means to measure changes in the signal as a function of time or origin. The changes that are of interest are those associated with either signal level or signal structure. Entropy is a measure that responds in some fashion to either type of change. The entropy-based signal receiver transforms time segments of a received signal into entropy-related quantities. By comparing entropy-related quantities of received signals, one can obtain information about the emitters of the received signals and the nature of the medium through which the signals were propagated. The sensitivity of the entropy-based receiver is significantly better than the more conventional energy-based receiver in detecting the changes in a signal that result from reflection or scattering by inhomogeneities in a wave-propagating medium.

Abstract: To passively measure the range to a target, GPS signals which are scattered by the target are used to determine the distance from the target to an observation station whose position P.sub.o is determined by a GPS technique. If the delay time from the reflected signal of the target can be measured, the position P.sub.t of the target can be calculated. Four simultaneous nonlinear equations from the four satellites can be written as(x.sub.t -x.sub.i).sup.2 +(y.sub.t -y.sub.i).sup.2 +(z.sub.t -z.sub.i).sup.2+(x.sub.t -x.sub.o).sup.2 +(y.sub.t -y.sub.o).sup.2 +(z.sub.t -z.sub.o).sup.2 =Ct.sub.itowhere i=1, 2, 3, 4 represent the four satellites having positions, P.sub.i, C is the speed of light, t.sub.ito is the time for the satellite signal travelling from the ith satellite to P.sub.t then to P.sub.o. The trace of P.sub.t forms ellipsoidal surfaces with respect to P.sub.i and P.sub.o. The point where the ellipsoidal surfaces intercept represents the position of the target.

Abstract: A system for continuously and precisely measuring the positions of a generally symmetrical object, e.g., a tennis ball, in motion in a predefined three-dimensional region, e.g., a tennis court, which transmits multiple radar signals from first, second, and third, spaced antenna devices, respectively, into the three-dimensional region. Multiple return signals are sensed and are compared with the transmitted signals to determine the phases of the return signals, to thereby obtain ambiguous ranges of the object. Ambiguities are removed by using the Chinese Remainder Theorem to obtain less-ambiguous ranges. Time-of-arrival range information is used in conjuction with the less-ambiguous ranges to provide unambiguous ranges over the range of interest. The unambiguous ranges are used to compute three-dimensional coordinates of the object that are accurate to within approximately 0.1 inches.

Abstract: Mine panel alignment is controlled by recording the electromagnetic phase modulation and/or signal attenuation between spaced distant transceivers in the panel and a transceiver on a cutting machine to measure the distance between the transceivers. Through trilateration, the position of the cutting machine with respect to the known fixed locations can be determined and adjustments made to the cutting machine functions to maintain desired panel alignment.

Abstract: A system is disclosed for determining the position of at least one target by triangulation, comprising two passive sighting devices which measure the intensity of radiation received along a sighting line which scans a vertical sighting plane. They are disposed at a distance from each other along the same vertical axis and are driven in rotation about this common axis so that their sighting planes merge. A circuit extracts the angular coordinates of the target, relative to each of the sighting devices, and computes the distance of the target by triangulation in the vertical sighting plane.

Abstract: A method and system for determining a spatial parameter of an object by generating at least two radiation beams which are rotatably displaced with respect to said object and so as to have, at any instant of time, a known predetermined position with respect to each other. By determining the time interval(s) between successive interceptions of the beams by the object, said parameter may be computed.

Abstract: The positions of a plurality of targets (26) are located using three or more sensors (20, 22, 24) such as radars which sense only the bearing angle of the targets. The intersecting bearing lines (30) form triangles (28) representing both true targets (26) and false targets (28). The false target triangles (28) are separated from the true target triangles by analyzing the size and position of each triangle. Bearing data defining the triangles is first ordered and then sequentially examined in a manner such that a first group of false targets (28) is eliminated from consideration. The bearing data defining the remaining triangles is processed through coarse and fine gates to eliminate second and third groups of false targets (28). A fourth group of false targets (28) is eliminated by using a global maximum likelihood procedure, in which a likelihood function is maximized through the use of discrete optimization techniques.

Abstract: A distance-measuring arrangement including transmission means for transmitting a wave in a measuring field, receiving means for receiving the wave reflected from a moving body moving in the measuring field and for producing a beat signal from the Doppler frequency. Delimiting means is provided for forming, in the measuring field, at least two datum lines (Ca and Cb) and processing means is provided for processing the distance information obtained from measuring the Doppler frequencies at the instants when the moving body crosses the datum lines. The delimiting means are formed from thermal detectors disposed in an optical assembly having at least two optical axes for defining the datum lines. A timing circuit is provided for defining the instants at which the moving body crosses the datum lines and for applying this information to the processing means.