Abstract: A double-sided printed circuit board includes a component side and a circuit side. The dielectric material is undesirably flexible. To render the board rigid, the conductor bonded to the component side is a rigid plate. At locations at which plated-through component signal leads are to be attached, lead clearance holes are drilled through all the way through the thin conductor, the dielectric, and the plate. The holes are plated with conductor. From the exposed side of the plate, larger holes are drilled coaxial with the clearance holes, part-way through the plate. The hold bottoms make an acute angle with the axes. The exposed surfaces are plated with etch resist. A second depth-controlled drilling coaxial with the first is performed with a drill which has a reverse-angle face, to a depth which extends almost through the plate, to thereby remove etch resist in an annular region surrounding the original clearance hole.

Abstract: A robot manipulator uses multiple robot arms to grasp and move an object. The object is moved by the coordinated motion of the arms. Because of inaccuracies in the coordinated motion of the arms due to mechanical inaccuracies or to imperfections in the model used by the controller to evaluate the interaction of the arms with the environment, the actual motion of the arms may be slightly uncoordinated. This may result in the application of unwanted forces to the object which may distort or break the object, the arms, or both. A multiarm accommodation arrangement evaluates the forces applied by the arms to the object to determine the net forces, and generates position accommodation signals which are summed with the several mutually coordinated arm control signals to tend to cause the forces applied to the object to be zero or a desired finite value. In a particular embodiment of the invention, an outer loop provides position accommodation to control forces applied by the object to an external load.

Abstract: The individual components of a shielded ceramic, RF mounting package are metallized on three of their outer surfaces. The package includes circuit supporting ceramic substrate metallized along its edges as well as on the horizontal surfaces to permit continuous metal contact between the substrate and a metallized ceramic seal ring and the metal lid and base of the package.

Abstract: A paralleled amplifier arrangement includes a plurality of amplifier modules, the output ports of which are coupled to a common combining node. Switches are coupled to the output ports for selectively decoupling one or more of the amplifier modules from the combining node during those intervals in which the amplifier modules are held in reserve or are nonfunctional. Each amplifier module is associated with an isolation resistor which is coupled to all the isolation resistors. In order to reduce losses attributable to the isolation resistors when the decoupling switches are operated, the isolation resistors are each coupled to a switched network which decouples the isolation resistors associated with the decoupled amplifier modules.

Abstract: A spacecraft structure for orbital assembly and servicing includes a payload module, a propulsion module and a bus module each of these modules includes attachement means for separately attching to the cargo bay of the Shuttle directly and via planar cradles. The bus module includes module docking and latching fittings at each end and matching locking and latching fittings at one end of each of said payload and propulsion modules. The bus module includes sectionalized assemblies forming a matrix of identical cavities adapted to receive orbital replacement submodules that allow easy replacement of equipment in orbit by an astronaut.

Abstract: A rectangular antenna array includes a plurality of systolic vertical line arrays. Each vertical line array includes a plurality of signal processors. Within each line array, the signals received at any one moment are held or delayed as required, and the processors progressively form partial sums in an upward direction during first clock intervals and in a downward direction during alternate clock intervals. During each clock intervals, complete sums for one sample interval appear at an end of the vertical line array. The sums appear alternately at the top and the bottom of the line arrays. Beamforming in the horizontal direction is accomplished with systolic horizontal adders coupled to the tops and bottoms of the vertical line arrays. The horizontal adders transfer information and add in one direction during first clock intervals, and then in the other direction during third clock intervals of a four-interval cycle.

Abstract: A compact electromagnetic antenna pattern range includes a planar reflector which is controllable between a reflective condition and a transmissive condition. The controllable reflector is placed parallel to a second planar reflector, and a pulse of electromagnetic energy is injected into the space between the reflectors, propagating toward one of the reflectors. After a number of re-reflections, the controllable reflector is rendered transmissive and a substantially planar wavefront is made available for application to the antenna under test.

Abstract: An analog-to-digital converter (ADC) arrangement mounts at least one ADC integrated circuit on a six-layer printed circuit board including an analog ground plane in a second layer occupying a region distinct from a digital ground plane in a fifth layer. Analog signals are carried over paths of a first layer overlying the second layer ground plane. The analog signal paths may be configured as microstrip transmission lines. Digital signals produced by the IC are coupled onto digital signal paths overlying the digital ground plane. Third and fourth layers of the six-layer printed circuit board carry power to signal conditioning circuits. Conditioned power is coupled to the ADC integrated circuit and any other IC's.

Abstract: An unbalanced quadrature phase-shift keyed UQPSK modulator modulates two information signals onto mutually quadrature components of a carrier. If the carrier components differ from an exact quadrature relationship by an error angle, crosstalk orr distortion is introduced. The effects of such an error are ameliorated by a limiter following the modulator.

Abstract: Signals arriving from N channels are processed by an array of two-input, two-output decorrelation processors to produce N output channels in which the signals from each of the input channels are decorrelated from all of the other channels. The array of processors includes N-2 rows, each row containing N processors in a regular array having a form equivalent to a cylinder. The array of processors also includes a further last row containing N/2 processors, the outputs of which are the desired signals. An arrangement using a single row of N processors with switched feedback allows equivalent batch processing.

Abstract: The height of an object is determined by projecting a beam of light there across to form a light stripe. A camera views the object obliquely, and forms an image of the light stripe. As a result of the oblique view, the light stripe is imaged as a series of bright vertical lines on a horizontally-scanned image. Each horizontal line scan crosses the light stripe at a particular horizontal position, representative of the height of the object at that point on the image. The projection and imaging optics cause the light stripe to be several pixels wide, so that the height is not exactly known. A logic circuit finds the pixel with the greatest intensity and stores its position and value, and the values of its neighboring pixels. At the end of each line scan, the sum of the stored intensities is formed, together with a weighted sum, so that a ratio may be formed which represents the center position.

Abstract: An array of Radon transform processors accepts signals representative of the x and y positions of each pixel of an image together with signals representative of the magnitude or brightness of the image. Each Radon transform processor of the array is associated with one value of .theta., an angle relative to the x-axis, and each processor is associated with a different .theta.. Each radon transform processor multiplies the current value of x by cos .theta. and the current value of y by sin .theta., and adds the products to produce the value of rho, the distance from the image center along a line at angle .theta., at which each pixel contributes to a line integral. A memory stores the current pixel's magnitude by updating the line integral associated with the current value of rho by adding the pixel magnitude. When all pixels of the image have been evaluated, the memory of each processor of the array is read in sequence, and the value of the line integral for each value of rho is read from each memory.

Abstract: A robotic connector or interface includes a roughly conical male member in which the conical side may be concave. The male member includes a radial indexing pin, and a central bore in which polarized electrical connectors are located. A mating female member includes a cavity with a fundus and movable peripheral lips adapted for grasping the base of the male member when engaged for drawing the male member into full mating relation with the cavity. A tapered slot in the side of the female member guides the index pin to impart rotational forces so that mating can take place even if the approach is skewed. The electrical connectors are mounted on a separately indexed, spring loaded connector plate at the fundus of the cavity. A motor-driven linkage operates the peripheral lip members.

Abstract: A waveguide termination includes a rectangular waveguide having a pair of spaced-apart broad walls and a pair of narrow walls equally spaced from a plane of symmetry. The termination has a block or wedige of absorber material. The width of the absorber material is approximately half the width of the waveguide as measured between the narrow walls. The absorber material is located asymmetrically in the waveguide so that substantially all of the absorber material is on one side of the plane of symmetry.

Abstract: A data processor includes a reconfigurable arithmetic logic unit (ALU), which includes three ALU portions. One ALU portion includes two 16-bit input ports and a 16-bit output port. The other two ALU portions each include two 8-bit input ports and an 8-bit output port. A reconfigurable 16-bit register file is coupled to the inputs of the ALU portions. Switches couple carry output terminals of the second and third ALU portions to carry input terminals of the first and second ALU portions, respectively. With both switches conductive, a 32-bit ALU is formed from the three portions. With a first switch open, two independent 16-bit ALUs are formed. With the second switch open and the first closed, 24-bit mantissa, 8 bit exponent floating-point processing can be done by independent ALUs.

Abstract: A thermal control system adapted for test in a 1G gravity environment and for operation as a microgravity environment includes a capillary pumped loop with a wicked evaporator which produces a coolant vapor head of about 1/2 PSI upon absorbing heat from a heat source. A heat pipe includes a cylindrical portion adapted for absorbing heat, and also includes a radiator panel which rejects absorbed heat. A heat exchanger coupled to receive coolant vapor from the wicked evaporator includes a manifold which directs the vapor to a plurality of parallel fluid channels helically wound about and thermally coupled with the heat absorbing portion of the heat pipe. A liquid manifold is coupled to the liquid side of the fluid channels for receiving cooled liquid, which is returned to the wicked evaporator.

Abstract: A light-activated PIN diode switch arrangement is coupled to a source of direct voltage and to a load for control of the flow of load current. The PIN diode switch arrangement is connected so as to be electrically reverse-biased, so that no current flows therethrough. A source of light is coupled to the active portion of the PIN diode switch arrangement for rendering it conductive when flooded with light. High power and low inductance is provided by a configuration in which two PIN diode sets are physically and electrically connected together in a physical and electrical stack by a conductive heat sink. Laser diode arrays above and below the diodes of the stack selectively illuminate the intrinsic region of each diode bath through the adjacent doped region and also directly through the side of the diode.

Abstract: An intermediate-distance method for approach or separation of a spacecraft relative to a target vehicle is used in a range of distances of a few meters to a few tens of kilometers when the vehicles are in coplanar low Earth orbits. The method establishes a local horizontal at one vehicle, and propulsion is applied to maintain a line between the target vehicle and spacecraft at a constant angle relative to the local horizontal. The method is particularly attractive for use when the only information conveniently available is bearing (angle) and possibly bearing rate. When the orbits are not coplanar, thrust is applied in the cross-orbital-plane direction with an amplitude which is a maximum at the moment that one spacecraft lies in the orbital plane of the other.

Abstract: A swept-frequency radar system transmits pulses consisting of swept-frequency subpulses of nonuniform duration separated by short nontransmitting periods during which an array antenna is resteered. The pulses reflected from a target are processed by a method including estimating the target ranges, producing a reference signal at the time at which the pulse reflected from the target is expected to return. The reflected pulse is phase detected by means of the reference pulse to produce phase detected signals which include information relating to the error between the actual range and the estimated range. The phase detected signals are Fourier transformed to produce range error information. The nonuniform subpulse durations reduce the magnitude of range sidelobes.

Abstract: A radar system mounted on a moving vehicle uses a displaced phase center antanna (DPCA) and associated processing for taking the difference between the two signals received by the displaced antennas to provide moving target indication (MTI) by cancellation of the returns from stationary targets. The presence of moving targets is identified by threshold processing within discrete frequency bands. DPCA processing ordinarily results in amplitude nulls or "blind speeds" for targets moving at particular radial velocities. According to the invention, the two signals received by the displaced antennas are summed, weighted and divided into frequency bands which extend through the expected null region in a form of Doppler processing. Threshold processing is performed on DPCA processed signals within certain frequency bands outside of the null regions and on Doppler processed signals within other frequency bands, thereby substantially eliminating the blind speeds.