Abstract: A moving target simulator system for pulse Doppler radar includes a processor for processing received radar signal and transforming the signal into patterned pulses before subjecting the patterned pulses to an 180 degree phase-shift by a phase-shifter. The system also includes a reference signal provided by a corner reflector located in proximity of the simulator. The reference signal and a phase-shifted signal from the simulator are processed by the radar equipped with a phase corrector circuitry to correct a phase drift problem associated with the use of a small antenna with the simulator.

Abstract: There is disclosed a method and apparatus for verifying the integrity of a smart antenna system. A signal simulator replicates the respective signals received at the multiple sensors of the antenna array, with signal parameters that include the correlated effects of Doppler, delay and angular spread. A combination of hardware and software capabilities simulate a primary line-of-sight signal, plus reflected signals and refracted signals, which requires manipulation by the smart antenna processor to extract the temporal and spatial information of the signals of interest. The simulated signals may be varied in numbers, amplitude, phase, delay and bearing components for representing a variety of terrain, environmental, equipment and capacity conditions encountered in alternative environments and conditions. The output of the smart antenna processor is checked against the input parameters to compare, verify and calibrate the smart antenna system.

Abstract: The computation system of the present invention comprises an improved method of moment estimation for devices which measure spectra as a function of range or time. The preferred embodiment of this system is illustrated as part of an automated meteorological monitoring system for the accurate real time detection of meteorological phenomena, such as winds, wind shear and turbulence. This automated meteorological monitoring system uses a standard weather radar transmitter to scan a predetermined volume of space with a stream of radar pulses to determine the characteristics of meteorological phenomena that are extant in the predetermined volume. The computation system of the present invention utilizes novel signal processing algorithms in the improved method of moment estimation to excise the valid data from the return echoes, which are corrupted by the presence of contaminating signals.

Abstract: The electromagnetic target generator of this invention is used to simulate radar target for the purpose of testing and experimenting on a variety of weapon systems radars. The weapon system radar being tested emits a radar signal which is received by the target generator. The target generator delays, doppler shifts, and reemits the signal for receipt by the weapon system antenna. The simulated target presented to the radar system under investigation has digitally controlled range, radial velocity, coordinated doppler and radar cross section. This provides a realistic radar target return without requiring real targets. The radar system is exercised in inflight and tactical operational configuration and no part of the weapons system radar is bypassed. Delayed radar target replicas are indistinguishable from real target waveforms. The electromagnetic target generator may be used in locations which preclude the use of real radar targets, such as anechoic chambers, and also may be used in the field.

Abstract: A system is tested for jamming resistance by supplying a simulated jamming ignal. The simulated jamming signal is produced by calculating a propagation path loss in the terrain between the system under test and a location where the jammer would be, predicting a jamming level in accordance with the propagation path loss, and generating a simulated jamming signal. The simulated jamming signal is supplied to the antenna port of the system under test. The testing does not require the use of either a real jammer or a pilot signal generator at the location where the jammer would be.

Abstract: A Doppler-based radar system used in monitoring the speed of moving vehicles includes a self test circuit and related method for independently and remotely testing the operability of the entire radar system including the critical microwave components. The self test circuit includes a low frequency modulation diode positioned adjacent the antenna horn. The modulating diode causes a change in the voltage standing wave ratio seen by the radar system(s), thereby modulating the energy of the reflected radar test signal. The modulated test signal is compared to the original test signal and a resultant control signal is generated. The radar system is combined with a retarder system controller and a control system computer to provide an industrial control application, such as for controlling railway cars in a hump yard. Any number of additional radar systems/retarder system controllers can be added to expand the application.

Abstract: A self-implementing, self-diagnostic system for an anticipatory collision sensor system includes a transducer device for transmitting a modulated carrier signal and receiving the reflected modulated carrier signal from an object; a detection device for detecting a plurality of Doppler shifted harmonic components from the reflected modulated carrier signal; a range determining device responsive to the amplitude of at least two of the harmonic components for determining the instantaneous range of the object; a velocity measurement device, responsive to the frequency of at least one of the harmonic components, for determining the relative, instantaneous velocity of the object; an indicating device, responsive to at least one of the modulated carrier signal, the reflected modulated carrier signal, the amplitude, and the frequency, to indicate the condition of the system.

Abstract: A photonic radar decoy (50) is provided which simulates an aircraft to a radar having an interrogating signal. A plurality of receiving antenna (52, 54, 56, 58, 60) are attached to the decoy (50) with each of the receiving antenna (52, 54, 56, 58, 60) independently capable of receiving the interrogating signal from the interrogating radar system. Each signal received by an antenna (52, 54, 56, 58, 60) is transmitted to a signal combiner and amplifier (82) by delay lines (72, 74, 76, 78, 80). The combiner and amplifier (82) coherently adds the transmitted signals, thereby producing a coherent signal which is amplified and subsequently emitted by a non-directional transmission antenna 106, simulating a dynamic and complex radar signature of an aircraft.

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: A radar target simulator for generating simulated targets used in testing a radar system. Simulated targets are generated out of the radar system noise. The radar system includes a radar receiver coupled to a receive antenna. The simulator has an input for sampling a transmitted output signal from the radar system. A first reference oscillator is provided for generating a first reference signal, and a first mixer is coupled to the first reference oscillator for mixing the first reference signal with the sampled signal from the radar system to provide a simulated target signal. A laser is coupled to the first mixer for generating a light output signal that corresponds to the simulated target signal. A plurality of selectable delay paths that each have a different predetermined delay length are coupled to the laser. A photodetector is coupled to the plurality of delay paths for convening the light output signal derived from a selected one of the delay paths into a radio frequency (RF) simulated target signal.

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: A portable test system is arranged to enable testing of an aircraft-mounted radar system. Simulated radar returns are transmitted via a test antenna positioned a short distance from an aircraft parked on an airport surface. The varying amplitude of received radar pulses is analyzed as the test antenna is illuminated by the main beam and side lobes of the radar antenna pattern as the radar beam is scanned. By controlling the amplitude of the simulated radar returns in inverse relation to the amplitude of received radar pulses, simulated radar returns inserted off beam center line are interpreted by the radar system as received on the beam center line. Test system transmissions, which may incorporate windshear effect test data, are thus enabled to create simulated effects usable for testing radar system response to a variety of airborne conditions, such as windshear. Test methods are also described.

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 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 programmable fiber optic delay system employs multiple programmable fiber optic delay lines, and switches among the delay lines for inclusion in an overall delay path. Switching among the delay lines is coordinated with the programming of those lines so that only a delay line with a settled delay program is included in the overall delay path. Each delay line consists of a plurality of fiber optic segments of varying length. The line's delay is programmed by switching in particular segments whose aggregate lengths correspond to a desired delay period. The multiple delay lines are used to simulate target speed and distance for use in testing a radar system. The programming of each individual delay line and the switching between lines is preferably controlled by a computer resident in the target simulator.

Abstract: A programmable radar target simulator provides microwave signals for testing a missile that is otherwise controlled by such signals when it is deployed. The simulator has the capability for initiating suitable microwave signals at the proper power levels in the fully automatic, semi-automatic, or fully manual modes. A control section and an IF section accept digital commands from an external computer or manual control from switches and thumbwheels on the front panel of the simulator to provide for the automatic and manual control signals respectively. A frequency synthesizer section provides three frequency modulated IF signals and one amplitude modulated coding signal which respectively are fed to the IF section and to the control section. Doppler frequency shifts are extracted and representative signals are provided in both AC and DC forms to a microwave section.

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: A synthesizer combines frequencies for multiple targets, accumulating the phase components separately and allowing the targets to change velocity separately. The amplitude of the simulated signal at the phase secified is generated using a method that combines coarse and fine angle components of the desired angle signal allowing small high speed memories to be used. A first ROM is addressed by high order bits of the phase component and a second ROM by the lower order bits. The outputs of the first and second ROM's are multiplied and then added to the output of the first ROM producing the amplitude of the desired phase. The system also allows the amplitude of the signal being synthesized to be modulated by multiplying the synthesized digital value by an amplitude modulator. The synthesized amplitudes for each frequency are combined. Digital zero order hold correction removes amplitude distortion from the output spectrum.

Abstract: A constant amplitude Doppler producing radar reflector for simulating a moving target. A plurality of dihedral reflectors having equal radar cross sections are rotated axially at equal rotational speeds. The dihedral reflectors are separated laterally and in the direction towards the illuminating radar by a distance which keeps the radar returns from the two reflectors in phase quadrature. With the radar cross sections of the reflectors being equal, the return signals to a linearly polarized radar maintains constant amplitude as the dihedral reflectors rotate.

Abstract: This system generates signals which vary randomly in frequency. The system includes a digital pulse generator generating multibit digital numbers varying randomly according to an encoded statistical distribution pattern. A first source of digital signals is connected to the pulse generator which perturbates the signals in frequency and applies them to an adder. Another source of digital signals connected to the adder combines with the perturbated first signal. A digital integrator connected to the pulse generator triggers release of the perturbated first signals and converts the combined perturbated signals to multibit outputs which may be applied to digital-to-analog converters, and in turn to frequency modulators to produce analog signals perturbated in accordance with the statistical distribution pattern.

Abstract: A monitor for an electronic TACAN (ELTA) includes a 16-way switch whereby samples of the r.f. signal fed to each TACAN antenna element are fed via a common lead 30 to (a) means for r.f. phase correlating the samples with the transmitter generated signals, and (b) means for determining the relative phse and amplitude of the low frequency modulations in the sampled signals.

Abstract: A calibration instrument for calibrating a continuous wave microwave doppler radar includes a piezoelectric sounder and means to energize the sounder to produce an acoustic signal to simulate motion of a body to the radar.

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.