Abstract: A radar stability measurement system uses a microwave delay line that may be coupled between a standby transmitter and a standby receiver to test the stability of the standby channel in a radar system having at least two channels. A pulse output by the standby receiver is sampled in portions. Several samples of each portion are taken, samples are analyzed to produce a sum of residue power (P.sub.rm) and a sum of zero Doppler power (P.sub.om) for the m-th portion. After all samples of all portions have been taken, a single indicator of stability is calculated as ten times the log of the ratio ##EQU1## The measurement system can also be applied to single channel systems, although a short interruption of system operation may be necessary.

Abstract: A two-parameter clutter map for storing two variables for every spatial location in order to define both the intensity of the interference and the fluctuation characteristics of the interference from scan-to-scan. The two variables are obtained by processing input data from an integrator in two n-pole integrators having different orders. The ratio of the two variables or their difference in logarithmic form is employed as a measure of the scan-to-scan fluctuation characteristics. An option to control alarms and the leading edge of moving rain storms is also provided.

Abstract: An electronic article surveillance system employs a resonant tag attached to an article being protected. An interrogation transmitter whose transmission frequency is periodically swept through the resonant frequency of the tag is positioned near an exit of the protected area. The resonant tag is periodically energized by the transmitter as the transmitter frequency passes through the resonant frequency of the tag to cause the tag to emit a periodic tag signal at the sweep rate of the transmitter. The tag signal is received by a receiver that generates an alarm upon the detection of a tag signal. The receiver employs synchronous integration in the form of a dual channel synchronous video integrator to independently process positive and negative pulses of the tag signal in order to differentiate the tag signal from extraneous signals and noise.

Abstract: A color coordination cone which permits a hair colorist to examine color mixtures before actual application. It is comprised of an internally illuminated cone-shaped base apparatus over which one or more transparent color cones comprised of twenty-four longitudinal color bands in eleven shades is placed. The color cones are rotated one over the other to examine the effect of mixing one color with another. In another embodiment of the invention, a colorless, transparent conical sheath with external tracks in radial planes corresponding to the edges of color cone shade levels is slid over the color cone. Elongated strips in various hues are slid between certain sets of adjacent tracks so that a particular hue on a strip will be positioned over a particular hue on the color cone and the results determined.

Abstract: Method for determining and using clutter estimates in a radar clutter map. The method does not require synchronization of the transmitted radar pulses with the azimuth coordinates of the map cells. Data inputs close to each map azimuth location are used to estimate the echo amplitude in the map cell which would result if the antenna beam was pointing directly at the clutter when one data sample occurred. A burst of pulses are transmitted and return echoes are processed to produce clutter signals at least twice within the time it takes for the antenna to scan one beamwidth. Clutter echoes received adjacent in azimuth to the map cell for which the value is being calculated are converted by a formula into a value for adjusting the present map cell value. The formula takes into consideration the magnitude of the values, the difference between the values, the antenna beam width, and the azimuth spacing of the samples.

Abstract: An adaptive detection threshold system for moving target detector and moving target indicator radar systems. The threshold system uses data from the echo input signal to reconstruct a threshold level closely resembling the output clutter residue in doppler filters due to point clutter sources. At least three azimuth data values are used, with the values being from adjacent coherent processing intervals and separated in azimuth a distance approximately equal to the beamwidth of the antenna system. The data at the same range from the three azimuths is combined to form an estimate of the residue at the output of a doppler filter, assuming that the echo is caused by point clutter. Compensation for radar instability and changes in scan rate or interpulse period is included. Data from conventional constant false alarm rate processing designed to control alarms from distributed interference, such as weather echoes, is also used to compensate the residue estimate.

Abstract: An arrangement for selecting between different doppler filter pairs having response characteristics optimized for ground clutter or moving rain clutter rejection. The selecting process detects the amplitude and mean doppler of the received radar echoes. The filter which is optimized for rain clutter rejection is normally used until clutter amplitude is detected above a predetermined value and the mean doppler is detected as being equal to or near zero. When such a detection is made, the filter optimized for ground clutter rejection is selected. Portions of the selecting device allow for the selection to be determined over several samples rather than switching the filters in each sample or coherent processing interval. Another portion of the circuitry changes the predetermined values which must be exceeded for a selection of the ground clutter filter, thereby preventing another filter change with only a small change in detected amplitude or mean doppler.

Abstract: A quickly demountable security-conscious door having a four-pin engagement with the adjacent door frame and having a plurality of rack and pinion mechanisms for movement of the hinge pin and lock bolt members into engagement positions with respective receptacles located in the door frame member. The door includes weather stripping provisions, operating knob rotational limits, and operating shaft spring assistance and uses Teflon.RTM. or other low-friction materials in appropriate frictional engagement positions.

Abstract: A radar having a multiplicity of receive beams stacked in elevation and a target height extractor especially for use therein are disclosed. In operation, a set of range sweeps corresponding to an azimuth scan of the stacked receive beams across a detected target is established. A range cell interval corresponding to the detected target is estimated for each range sweep of the set. A target range measurement is computed from a set of estimated range intervals. Only the radar receive beam echo information corresponding to the estimated range cell interval for each range sweep of the established set is used by the height extractor to compute a corresponding set of elevation angles. A target elevation angle is formed as the weighted average of this computed set. Only one height computation is performed for each established set of range sweeps based on a function of factors including the computed target elevation angle and computed range measurement of the corresponding established set of range sweeps.

Abstract: A system and method of compensating a digital doppler processor for unbalance in in-phase I and quadrature Q signal inputs thereof is disclosed. The method includes the steps of measuring the unbalance in the I and Q signal inputs to the digital doppler processor, determining a desired set of weighting coefficients based on the measured unbalance, and performing doppler filter calculations in the digital doppler processor with the desired set of weighting coefficients. The system comprises a sensor for measuring the unbalance in the I and Q signal inputs to the digital doppler processor, and apparatus for determining a desired set of weighting coefficients for the doppler filter calculations of the doppler processor based on the measured unbalance of the sensor.

Abstract: In a radar which transmits a phase-coded train of sub-pulses and which derives the in-phase (I) and quadrature (Q) components of the received echo signals with respect to a local reference oscillator is embodied a phase discrimination constant false alarm rate (CFAR) system partially comprising a phase angle sensor for measuring the phase angle of the echo signal as one of at least eight predetermined phase angle representations, which are characterized preferably by binary numbers in Gray format, based on the relative magnitudes and polarities of the I and Q components of the echo signal. The phase angle representations may correspond exclusively to phase angle increments in the phase angle interval of 0.degree. to 360.degree. with respect to the local reference oscillator. Preferably, the phase angle increments are evenly partitioned within the 360.degree. interval.

Abstract: A container opener which takes the form of an integral member which has a main straight body section. At one end of the main body section is attached the first extension which depends from the main body section at almost a right angle. The outermost end of the first extension is acutely arcuate so that it substantially bends over on itself with the outermost tip of the extension defining an angle of sixty degrees with respect to the plane of the main body section. A second extension is attached to the main body section and is to be generally curved and ending in a depending flange which is to be connectable with the locking tab type of pail lid.

Abstract: This invention discloses pulse radar apparatus for the transmission of radar pulses having a pair of frequencies in each rf pulse. One of the frequencies transmitted in each pulse is repeated in the succeeding pulse while the other frequency is changed to a new frequency. Moreover, the repeated frequency appears in the same relative position in the pulse pair as in its original occurrence.

Abstract: An MTI radar system having a four pulse canceller where the interpulse periods vary preferably according to a double or triple sawtooth pattern is disclosed. The four pulse canceller is comprised of a two pulse canceller cascaded with a three pulse canceller. The three pulse canceller is arranged to accomplish summations of three weighted pulses in two operations, one involving fixed binomial weights (1, -2, 1) and the other variable components (a', b', c'). The interpulse period choices and sequence of use permit the variable weights to be defined by polarity and binary fractions implemented by the use of controllable scalers and polarity reversers.

Abstract: A low PRF pulse doppler radar system utilizing a VIP digital filter bank signal processor to suppress echoes from terrain, rain, and chaff, and pass echoes from aircraft moving at higher speeds is disclosed.Each of a plurality of VIP filters individually provides high attenuation to undesired signals over designated frequency bands, the width of which are a large fraction of 1/T.sub.av where T.sub.av is the average interpulse period. Little or no attenuation of desired signals having doppler frequencies greater than 1/T.sub.av occurs. The outputs of the plurality of filters are desensitized to prevent false alarm from clutter, and the presence of a desired radar pulse echo is determined by a comparison with a threshold level.

Abstract: A pulse radar system transmits a pulse containing an upper and a lower sideband frequency signal. The upper and lower sideband signals are formed by a stable local oscillator signal and a coherent oscillator signal which are mixed in a mixer. The frequency separation between the upper and lower sidebands is sufficient to cause fluctuations in the desired target radar cross section to be statistically independent with respect to the upper and lower sideband frequency components in the transmitted pulse. Target reflected pulses are separately processed for each transmitted frequency component. The probability of detection is improved by mathematically combining the separately-processed output signals of each frequency component.

Abstract: A method and apparatus for determining the altitude of a transmitted signal by adding the altitude of the transmitting antenna to accumulated changes in altitude, determined in relation to the sine function of the elevation angle of the propagation path. The elevation angle of the propagation path is determined in relation to the elevation angle of the transmitting antenna and the local elevation angle change in the propagation path accumulated over the propagation range. The local elevation angle change in the propagation path is determined in relation to a dynamic, vertically dependent refractive index gradient model and in relation to a vertically dependent curvature model.