Abstract: A passive microwave velocity sensor uses the natural radiation from the terrain to determine ground velocity independent of altitude. The sensor employs two radiometric interferometers, which analyze inputs from two pairs of receiving antennas aligned along the direction in which velocity is to be sensed. Each pair of receiving antennas has a combined radiation pattern that generates a series of interference fringes along the terrain. Circuitry in each interferometer detects the variation in amplitude of terrain radiation as the antennas pass over the terrain. The frequency of the detected signal is directly proportional to ground velocity divided by altitude. The phase delay in the signals is inversely proportional to altitude. Dividing the frequency by the phase delay yields a signal directly proportional to ground velocity and independent of altitude.

Abstract: An improved method of spectral analysis suitable for use in microwave landing systems comprising sampling an unknown signal whereby nulls associated with a Sin x/x distribution are identified to facilitate the identification of a wanted signal.

Abstract: A lateral photodetector having a segmented annular ring formed on the out surface. The segments are electrically interconnected to provide four interleaved output electrodes.

Abstract: In one implementation of the inventive method an aircraft with an antenna mounted thereon is compelled to follow a sinuous path. The antenna normally provide 120.degree. coverage on either side of the aircraft. Full 360.degree. coverage is provided by the same antenna as the aircraft traverses the predetermined sinuous path.

Abstract: A radar transponder receiving regularly recurring pulses and providing selectively different delays for such pulses through the use of a single variable delay path, whereby the pulses, upon being received by the originating radar, appear as closely spaced identifying pulses for identifying the transponder.

Abstract: In a digital weather radar display, of the type which displays information on a cathode ray tube in the form of parallel intensity modulated sweep lines and which displays range marks in the form of a plurality of arcs of concentric circles, the positions of the range marks along each of the sweep lines are determined by utilizing a read only memory which stores, for each sweep line, an indication of the distance between range marks and the distance from the beginning of scan of the line to the first range mark.

Abstract: A distance measuring system is provided including a ground station transponder continuously transmitting a repeating pseudorandom coded bit pattern, and at least one aircraft interrogator receiving and locking onto the ground station signal. The aircraft interrogator transmits a coded interrogation signal in precise synchronism with an arbitrarily selected any one of the repetitive code words (bit patterns) that comprise the repeating pseudorandom coded bit pattern which are coded identically with the interrogation signal and waits for a reply. If the ground station receives the coded interrogation signal in synchronism with an identically coded word in its continuous transmission, it transmits a reply signal to the aircraft interrogator optionally encoded with synchronism error or interrogation steering information.

Abstract: Disclosed is a cathode ray tube of the postfocusing type for displaying color pictures having an apertured color selection means with an electrostatic postfocusing lens formed in each of the apertures. The electrodes of the color selection means at the higher potential are connected to a high voltage connection of the tube and the electrodes at the lower potential are charged by the electron beams with their voltage being stabilized by a series arrangement of zener diodes connected to the high voltage connection of the tube.

Abstract: A protected aircraft having a discrete address beacon transponder includes a ground base air traffic control radar beacon system (ATCRBS) interrogator, a collocated discrete address beacon system (DABS) transponder and a directional antenna on the protected aircraft. The protected aircraft synchronizes a local clock with the pulse repetition frequency (PRF) and scan rate of the ATCRBS interrogating his field of interest from which information the protected aircraft can calculate the azimuth angle of responding intruder aircraft with respect to the ground station. By means of his directional antenna the protected aircraft also determines the azimuth of the intruder with respect to itself. Interrogation by the protected aircraft of a collocated ground DABS transponder or a DME or other suitable means of measuring range provides a data base which together with the aforementioned azimuth angles permits the protected aircraft to calculate instantaneous position of the intruder relative to his own.

Abstract: A method and apparatus for telemetering information from the bottom of a borehole to the surface while drilling wherein a wireline is used to transmit the information from the bottom of the borehole to an intermediate position in the drill string, and a special drilling string, having an insulated electrical conductor, is used to transmit the information from the intermediate position to the surface. In an alternate arrangement, an electro-magnetic method may be used to transmit information from the intermediate position to the surface. There is also disclosed special equipment that permits removal of the jumper wire from the surface without removing the drill string from the borehold.

Abstract: A method and apparatus are described for directly converting heat to electricity within an array of thermoelements and heat pipes. The thermoelectric generator contains two conduits for two fluid streams, and a plurality of thermal bridges connecting points in both fluid streams, placing them in an overall counterflow heat exchange relationship. Each thermal bridge comprises at least one heat exchange surface with the first fluid stream, at least one heat exchange surface with the second fluid stream and at least one heat pipe, delivering heat to and/or from the thermoelectric element. The rapid heat delivery capability of the heat pipes, in combination with the counterflow heat exchange relationship between the two fluid streams within the generator, are responsible for the simultaneous considerable improvement of efficiency and power density of the generator.

Abstract: An antenna system in which the antennas are not mechanically rotated generates an amplitude-modulated signal of equal intensity in all horizontal directions with the phase of the amplitude modulation varying directly with bearing or azimuth to the antenna system. The antenna system uses a central antenna which radiates a carrier signal and a plurality of sideband antennas, 4 in number, which radiate upper and lower sideband signals. The phase of the upper sideband signal is advanced in increments of .pi./2 radians processing around the sideband antennas in a chosen direction, while the phase of the lower sideband signal is delayed in increments of .pi./2 radians proceeding around the sideband antennas in the chosen direction.

Abstract: A convergence apparatus in a convergence circuit of a CRT, comprises,Means for dividing a horizontal parabolic waveform voltage in suitable voltage levels corresponding to a vertical parabolic waveform voltage; means for shaping the waveforms of the divided voltage signals; means for composing the shaped voltage signals to give the shaped covergence correction voltage signal; andMeans for feeding the current corresponding to the shaped convergence correction voltage signal waveform to a convergence coil to correct the scanning positions of the electron beams.

Abstract: Interference between radar systems is eliminated by using shaped pulses. In one embodiment, the pulse has a cosine shape, in another a cos.sup.2 shape and in a third embodiment a cos.sup.n shape. In yet another embodiment, a single sideband shaped pulse is employed.

Abstract: An automatic phase and gain balance controller is incorporated in a typical baseband processor of a MTI radar system employing doppler processing techniques to effect balancing adjustments in the in-phase (I) and quadrature (Q) signal generation channels for substantially eliminating spurious image frequency component formations which may result from any unbalance therein. More specifically, the automatic controller provides two substantially non-interactive servo control loops to maintain balance between the I and Q signal generation channels by performing balancing adjustments on two adjustment parameters, namely phase and amplitude. Phase and amplitude imbalance errors between the I and Q channel are obtained in response to a pilot signal which is injected into the baseband processor of the MTI radar receiver, perferably during the dead times of the interpulse periods of pulsed reception.

Abstract: A moving-target indicator system uses adaptive loop cancellers for cancelg clutter. Each adaptive-loop canceller uses multiple memories and a switching circuit. The switching circuit switches each memory into the circuit to allow each of the memories to develop a weight W for a different selected range interval on a pulse-to-pulse basis.

Abstract: A microwave system is disclosed for simultaneous amplification and radiation of CW and pulsed signals wherein signals from a CW amplifier tube and a pulsed power amplifier tube are transmitted to an antenna where they are radiated as signals with circular polarizations of opposite direction. In one embodiment interstage circuitry between the amplifiers and the antenna includes a magic "T" hybrid and a 90.degree. phase shifter.

Abstract: Pulse radar apparatus particularly for marine use has a dispersive antenna so that transmitted pulses sequentially of two or more different frequencies are radiated in different azimuthal directions. The antenna is continuously rotated and the receiver has separate channels for the different frequencies and display means correlating information received on different frequencies from the same azimuth thereby to reduce sea-clutter on the display.

Abstract: A system for controlling the tilt of the vehicle and vibrator when the vibrator is being operated on irregular surfaces. Tilt switches detect excessive vehicle tilt. A bleeder network activated by the tilt switches reduces the pressure in the air bag on the side of the vibrator opposite from the direction of the vehicle tilt. A supply network repressurizes the air bag on the side of the vibrator opposite from the direction of the tilt.

Abstract: A rigid, fluid resistant enclosure adapted to encase a geophone electrically connected to a cable including a housing having an open end in and inner walls defining a cavity adapted to receive a geophone encapsulated in a fluid tight membrane or boot, which membrane has a sealing ring located around the top edge of the geophone, the open end of the housing having a counterbore axially aligned with and formed into the cavity terminating in a countersink having inwardly sloping walls defining a sealing surface which communicates with the inner walls of the cavity, a flexible header positioned within the counterbore and countersink of the open end of the housing and two resilient opposed elongated cable entry means having sealing nipples adapted to have a cable extended therethrough into a hollowed out central area which is to be electrically connected to the geophone and wherein the resilient sealing nipples have a plurality of axially aligned sealing ridges extending around the interior thereof to engage with