Abstract: A waveform generator (12') is responsive to a reference clock signal input for producing an output waveform which is a linear FM waveform. A reference clock signal is supplied to the generator which performs a double integration to obtain the phase of the output signal. The phase resulting from the double integration is used to obtain the sine of the phase using a lookup table. The sine of the phase is input to digital-to-analogue (D/A) converter, and the output from the D/A converter is filtered using a bandwidth matched to the bandwidth of the transmitted signal. The generator is useful in radar systems for area mapping and target identification.

Abstract: A method of providing motion compensation (i.e. phase, doppler frequency, and range closure correction) for wide band synthetic aperture radar (SAR) or classification/identification radar modes is disclosed. An improved radar system employing the method is also disclosed. The method involves dividing the motion compensation into both a focusing function and a range closure function. Either or both these functions is achieved by modifying the transmitted signal. For stretch waveform processing systems, the method involves generating both the transmitted and reference signals. The radar system includes a waveform generator capable of implementing the various motion compensation techinques when the transmitted waveform is a linear FM waveform.

Abstract: A method of signal processing for use in high duty factor radars for detecting targets at ranges both shorter and longer than a minimum range defined by a transmitted pulse having a defined pulse length. A coded pulse coherent array waveform is transmitted and a return signal which is a waveform reflected off a target is received. The reflected waveform is sampled and time shifted by adding data to its beginning and end. The vector is then processed (pulse compressed) to obtain target information. Target information can now be obtained which is normally in a "blind zone", because the distance of the target from the radar is such that it appears during an interval when sampling is not done because of waveform transmission.

Abstract: A system is provided for correcting the assumed orientation of the horizontal plane of an inertial navigation system on an aircraft, while it is flying over the ocean. The range from the aircraft to the ocean surface is measured along a boresight tilted at a small downward angle such as 6.degree. to 12.degree. from the horizontal, as by radar ranging, and the precise range and the precise tilt angle of the boresight with respect to the inertial or other horizontal is taken. The measured range is compared with an independently-derived range, and the difference is utilized to correct the assumed horizontal direction of the navigation system. The second range may be the range calculated on the basis of the downward tilt angle of the boresight from the assumed horizontal direction in the inertial navigation system, and the difference between the real and calculated ranges can be utilized to determine the error in the assumed horizontal direction of the inertial system.

Abstract: A device designed to float in a home pool and sound an alarm when the water is disturbed, which is peculiarly sensitive to disturbances in the water, including a transducer for sensing noise in the water, a high frequency filter connected to the transducer, a saturable amplifier connected to the filter, an integrator connected to the amplifier, and a trigger circuit connected to the integrator for initiating an alarm. The integrator has a rise time on the order of fifty milliseconds so that it rejects moderately loud disturbances unless they repeat many times within a short period of time, as is the case in noise reflected off the walls of an average size pool. The decay time of the integrator exceeds five hundred milliseconds so that the integrator output builds up over the period of at least two or three major noise pulses of a typical moderate splash in water.