Abstract: A near field planar wavefront generation method that uses a relatively small number (three to five) of transmitting antennas disposed a predetermined distance from an antenna array having a multi-wavelength aperture that is part of a system under test. The method creates a synthesized one-dimensional linear planar wavefront of radiation over at least ten wavelengths for testing the antenna array of the system under test. The planar wavefront is formed at a specific frequency and at predetermined distance from the transmitting antennas, typically in the range of from 100 to 200 feet. The transmitting antennas synthesize a plane wave with linear phase progression to simulate tilt variations. To achieve this, electromagnetic energy signals emitted by the respective transmitting antennas are amplitude and phase weighted to synthesize the one dimensional linear plane wave to produce a combined wavefront having a linear phase front across the aperture of the antenna array of the system under test.

Abstract: Apparatus and method for low cost monitoring the level of signal at a test point in a system for susceptibility to electromagnetic fields. A probe, including a detector diode, and a non-metallic, electrically overdamped conductor, which is transparent to the electromagnetic field, is used to monitor the signal level at a test point as an amplitude modulated radio frequency carrier. The carrier is transmitted to a monitor outside of the range of the electromagnetic field using a transmission link, such as an optical waveguide transmitter, that is transparent to the electromagnetic field when the system under test fails. The system under test can then be removed from the electromagnetic field and, for each frequency at which the system failed, a voltage can be injected, using a voltage injection probe, into the system at another point to recreate the detected level of signal at the test point that was coupled into the system from the electromagnetic field.

Abstract: A carrier frequency modulating system and method for producing a modulated carrier frequency is disclosed. The system comprises a carrier frequency signal generator for producing a carrier frequency signal at a carrier frequency at an output thereof. The system further comprises a sequencer for producing a modulation signal at an output thereof. This modulation signal comprises a plurality of modulation signal portions separated by at least one null modulation signal portion having a corresponding time length. The system is provided with a modulator for producing a modulated carrier frequency signal at an output thereof. The modulator has a first input connected to the output of the carrier frequency signal generator for receiving the carrier frequency signal, and has a second input for receiving the modulation signal. The system further comprises a power supply unit for supplying electrical power to the carrier frequency signal generator.

Abstract: An apparatus for generating one or more radar return signals representative of one or more remote objects useable in ground based, shipboard and airborne radar systems for testing the radar and its user. The apparatus may generate one or more return signal scenarios which may if required interact with the real or preprogrammed movement of the craft in which the radar is fitted. To ensure accurate and repeatable radar return signal generator apparatus operation, the radar's own built-in test signal output is used by the apparatus to calibrate the radio frequency portion of the apparatus, which adapts a remote object return signal scenario into the crafts radar device. To further improve the accuracy of the return signal, a digital first-in-first-out (FIFO) delay means is used to accurately allow the delayed reuse of the radar's own transmission signal.

Abstract: A radar system which detects the presence of objects in the proximity of a movable vehicle includes a signal source which generates object detection signals, a first antenna which transmits the object detection signals and receives the object detection signals as reflected signals reflected from an object in the proximity of the movable vehicle. The first antenna is further operable for receiving non-reflected test signals. A second antenna is provided for transmitting test signals which correspond to a delayed portion of the object detection signal generated by the signal source. A control unit is responsive to the reception of the reflected signals for providing an indication of the detection of the object, and is responsive to the reception of the test signals for providing an indication of the operability of the system.

Abstract: An in-flight radar warning receiver training system for use with a radar warning receiver (RWR) includes a real on/off switch for switching real threat track file data to a formatter. A generator produces threat/RWR simulated threat track file data. A merge operator combines formatted real threat data with the threat/RWR simulated threat track file data to form a combined threat track file. A prioritization method orders the combined threat track file data into prioritized threat track file data which is routed to a symbol generator, an audio/voice generator, and a memory for storing threat events having an input connected to the priority data output.

Abstract: An apparatus for producing an electromagnetic signal which simulates the radar signature of a vertical takeoff and landing vehicle is disclosed. The apparatus contains a means for receiving a radar signal, modulation means for modifying the radar signal, means for dividing the modulated signal into at least a first divided signal and a second divided signal, means for producing a Doppler composite signal, means for mixing the composite Doppler signal with the first divided signal, means for attenuating the second divided signal, and means for combining the attenuated second divided signal and the composite Doppler signal.

Abstract: A covert remote electronic warfare simulator is disclosed which includes eiving and signal processing apparatus for incorporating various electronic signal parameters and variables representing propagation effects from the environment borne by a low power control signal for redirection from a "victim" antenna into a "victim" receiving apparatus. The invention includes methods and apparatus for the subsequent replay of stored data representing the resulting signal(s) for data collection and detailed analysis in a laboratory setting. The simulator apparatus is interconnected between a "victim" receiving antenna and a "victim" transceiver to provide a simulated jamming signal.

Abstract: An apparatus is disclosed for testing the immunity of an electronic device to interfering electromagnetic radiation. The apparatus includes a room enclosing a bounded space for containing the electronic device to be tested and a plurality of radiating elements disposed on the interior surfaces of the room for generating an electromagnetic field in the room. Each of the radiating elements includes a controllable phase shifter, a controllable amplifier, and antenna. The circuits of the phase shifter and amplifier are connected by a common signal bus to a radio-frequency signal source and by a common control bus to a controller for individually adjusting the phase and amplitude of the radiated signal to create an electromagnetic field within the room having a predetermined strength and distribution.

Abstract: Systems and methods for simulating electromagnetic environments to be encountered by a moving object such as a missile are disclosed. The systems include compact ranges in "hardware in the loop" ("HIL") simulations as projection systems to provide cost- and space-efficient apparatus and processes for testing the performance of missiles and other objects. The systems disclosed may include mobile or stationary compact ranges and may use lenses or reflectors in connection with an array of one or more feed horns to convert spherical or "near field" wavefronts to plane waves within designated "quiet zones." If mobile ranges are employed, such ranges may be mounted on the flight tables used for repositioning the missile seekers during the simulations. Also disclosed are apparatus and processes for varying the amplitude and phase characteristics of the energy provided to an array of two or more feed horns in order to vary the apparent angle of received electromagnetic energy at electronic speeds.

Abstract: A moving target simulator is provided for testing a wide variety of radars ithout the need for a direct connection between the simulator and the radar under test. The simulator accurately replicates the pulse width and amplitude of transmitted radar signals and provides a delay feature that permits simulated target scenarios to be presented to a radar under test. The simulator incorporates control features that allow Doppler frequency changes to be accounted for and that permit signal level changes to be made as in accordance with inverse 4th law distance-dependent target-return power variation.

Abstract: A portable radar simulator which when connected to a transmitting means s as a waveguide horn antenna provides a radar signal to test a radar receiver. The portable radar simulator comprises a tunable oscillator which generates a continuous wave signal in the microwave frequency range with the desired frequency of the signal being selected by an operator. The signal generated by the tunable oscillator is supplied to a microwave switch. The microwave switch receives a control signal provided by a pulse repetition frequency generating circuit and in response to the control signal turns the switch on or off controlling the transmission of the oscillator generated signal to the wave guide horn antenna. The pulse repetition frequency generating circuit which comprises an integrated circuit timer and a monostable multivibrator provides a variable frequency and variable pulse width control signal. The frequency and pulse width of the control signal are, in turn, set by the operator.

Abstract: A portable radar simulator which when connected to a transmitting means s as a magnetron generated microwave threat transmitter simulates up to 2048 pre-programmed radar signatures. The portable radar simulator comprises a replaceable Erasable Programmable Read Only Memory (EPROM) which will hold up to 2048 pre-programmed radar signatures. Selection of a particular radar threat to be simulated is entered by an operator via thumbwheel switches located on the front panel of the simulator. The portable radar simulator simulates such radar parameters as jitter, stagger, frequency hop, simple and complex scans, pulse repetition intervals and frequency pulse widths.

Abstract: Faulty subarray module circuit boards are detected in a phased array antenna having many subarray module circuit boards while the antenna is fully assembled and operationally integrated with a radar system. A far field ratio frequency test source illuminates the antenna. Binary digital signals that control subarray steering bits are set to a reference setting. A particular subarray module circuit board that is under test has its 180.degree. main phase bit toggled between 0.degree. and 180.degree.. The radar selects the output of that particular subarray module by Doppler filter type of software filtering. The amplitude of the in-phase and quadrature phase signals from the radar is recorded. The binary digital signals that control subarray steering bits are set to a second setting. The 180.degree. main phase bit of the module under test is again toggled between 0.degree. and 180.degree.. The output of the module under test is again selected by Doppler filter type of software filtering.

Abstract: A system is disclosed in which a direction-finding system (12) employed on an aircraft (20) receives RF transmissions from a remote signal source (16). Amplitude and phase data concerning the transmission are used for direction finding but are perturbed by the various surfaces of the aircraft. To minimize the influence of such perturbations, a database (14) including model data subject to the same perturbations is employed by the system and incoming transmissions from signal source (16) are correlated to the database data to determine the proper azimuth and elevation associated with said transmissions. Several embodiments of a database production system (18) used in creating the database are also disclosed.

Abstract: A target simulates the coincident infrared and microwave signatures of a rce being tracked by a missile whose systems are undergoing test.

Abstract: A scan oscillator and a Pulse Repetition Frequency (PRF) oscillator with associated analog and digital circuits provide drive signals for two different RF PIN diode attenuators. When driven by a portable Gunn Diode Oscillator or other microwave source RF is generated that provides main lobe and adjustable side lobe radar signals to a directional microwave antenna. This output signal has adjustable scan rate, beam width, PRF, pulse width, and side lobe level and is self-contained in a package measuring 83/8.times.73/8.times.3 inches. The system allows "on the sail" testing for periscope mounted Direction Finding Systems.

Abstract: The device includes an array of antenna systems which send to a target seeking radar scene simulation signals synchronized with target seeking signals from the target seeking radar. Each of the antenna systems receives control signals which it uses to adjust the scene simulation signals. For FM/CW target seekers, the antenna systems mix the control signals with the target seeking signals. For pulse target seekers, the antenna systems mix the control signals with an illumination signal provided from an illumination radar.

Abstract: The microprocessor-controlled RF modulator apparatus will provide repeatable, controlled scintillation on a test bench generated low-power RF target waveforms for the purpose of providing a target returns with realistic radar cross section characteristics during testing of the F-16 (or any other) fire control radar. The microprocessor-controlled RF modulator apparatus is utilized in line between an RF target signal generator and the target horn to provide a variety of target situations for testing radar hardware and software.