Abstract: In one embodiment, a passive expendable decoy for an aircraft is provided by ejecting passive radiators from the aircraft along a transmission line trailing from the aircraft and excited by a jammer on the aircraft, such that the radiators accelerate under aerodynamic drag forces to the end of the transmission line and couple energy from the transmission line to free space. This provides angular deception to a tracking radar or homing missile since the point of radiation along the transmission line is determined by the instantaneous position of the expendable radiating element.

Abstract: An expendable jammer is ejected as a decoy from a target in which the jammer includes a single port, keyed primed oscillator which is primed with the low level signal received at its antenna. The priming signal is injected directly into the tank circuit of the oscillator which is rapidly turned on and off (keyed) to produce a rapidly pulsed signal which tracks the frequency of the priming signal. The resultant signal from the oscillator is transmitted back to the receiving section of the radar initiating the signal in such a manner that the receiver cannot distinguish the individual pulses of returned energy due to the high PRF of the returned signal. Thus the signal from the jammer is detected as a CW signal. The expendable jammer also has a multiple threat capability in which simultaneously arriving signals from different sources result in a jammer output at each of the different frequencies of the incoming signals with sufficient jamming power at each frequency.

Abstract: A method and apparatus for jamming radar and other electromagnetic signals is disclosed in which the jammer includes a single port, keyed primed oscillator which is primed with the low level signal received at its antenna. In one embodiment the priming signal is gradually shifted in frequency to introduce a false doppler and is then injected into the tank circuit of the oscillator which is rapidly turned on and off (keyed) to produce a rapidly pulsed signal which tracks the frequency of the shifted priming signal. In this embodiment the oscillator keying unit is itself keyed to modulate the output signal of the oscillator to provide false bearing information. In another embodiment, the priming signal is injected directly into the tank circuit of the oscillator and the frequency of the output signal from the oscillator is varied to induce false doppler information. In both embodiments the pulsed signal from the oscillator is detected as a CW signal.

Abstract: A silent radar system which detects a target and its position without the countermeasure operator located at the target being able to detect the presence of the radar. The silent radar operates by transmitting signals with specific characteristics which allow optimum processing by the radar while taking advantage of the limitations inherent in typical signal receiving equipment. The silent radar transmits low energy per cycle signals which are wideband, purely random noise, e.g. spread spectrum signals.

Abstract: Suppression of jamming from multiple sources is achieved by detecting the AM difference frequency produced by the beating of a desired signal and the smaller of the multiple jamming signal with the stronger jamming signal and applying same to one input of a single-sideband modulator while simultaneously applying the received signal (containing both the desired signal and the jamming signals) to the other input to the single-sideband modulator whereby the larger jamming signal is suppressed. The sum and difference outputs of the single-sideband modulator containing the upper and lower sidebands, respectively, of the desired signal plus the smaller jamming signal are each processed by a jamming cancellation circuit to suppress the smaller jamming signal and their outputs combined to receive the desired signal.

Abstract: Improved radar system performance in a jamming environment is achieved by detecting the AM difference frequency produced by the beating of the desired radar signal with the jamming signal and applying same to one input of a balanced modulator while simultaneously applying the received signal (containing both the desired radar signal and the jamming signal) to the other input of the balanced modulator whereby the output from the balanced modulator contains the desired signal but not the jamming signal.

Abstract: A pneumatic time delay valve primarily adapted for use in the ejection system of electronic or optical countermeasure devices and the like wherein an explosive squib is employed to create a momentary charge of high pressure gas used to depress the firing pin on the device to activate the device and also to push the device out of an ejection tube. The invention comprises means for splitting the pressurized gas into a first conduit communicating with the firing pin and a second conduit communicating with the device to apply the ejection pressure thereon and a time delay valve disposed within the second conduit for delaying the application of the gas to the device. During the time delay period, a piston is forced down a cylindrical bore forcing metering fluid through an orifice.

Abstract: A pneumatic time delay valve primarily adapted for use in the ejection system of electronic or optical countermeasure devices and the like wherein an explosive squib is employed to create a momentary charge of high pressure gas used to depress the firing pin on the device to activate the device and also to push the device out of an ejection tube. The invention comprises means for splitting the pressurized gas into a first conduit communicating with the firing pin and a second conduit communicating with the device to apply the ejection pressure thereon and a time delay valve disposed within the second conduit for delaying the application of the gas to the device. During the time delay period, a piston is forced down a cylindrical bore forcing metering fluid through an orifice.

Abstract: Attenuation of a signal is achieved by biphase modulating the signal with an asymmetrical duty factor rectangular wave. In one embodiment of the invention an input signal is applied to a phase reversal switch having as its second input thereto an asymmetrical duty factor rectangular wave.

Abstract: A satellite relay communications system includes a ground relay station arranged so that each message from one subscriber to another is relayed by the satellite relay to the ground relay, processed by the ground relay and then transmitted to the second subscriber by way of the satellite relay. Processing at the ground relay station includes a switching function in which the carrier frequency of each message is changed from the frequency used for transmitting by the subscriber sending each message to the frequency used for reception by the subscriber to whom the message is addressed. This permits each subscriber to use a single transmitting frequency and a minimum number of receiving frequencies.

Abstract: Improved radar system performance in a jamming environment is achieved by applying the received signal containing both the desired radar signal and a higher level FM jamming signal to a radar receiver only during the time when the instantaneous frequency of the jamming signal is not at or within prescribed limits of the radar frequency.

Abstract: This invention relates to a proximity sensing apparatus for energizing a control circuit whenever the distance between two objects moving relative to one another at an angle other than 180.degree. becomes a minimum, and more particularly, relates to a proximity sensing apparatus operating on the zero doppler principle for energizing a detonation circuit in a missile whenever said missile passes closest to a target.