In a radar system it is necessary to distinguish signals reflected from wanted targets such as aircraft from those reflected from fixed terrain features, known as clutter. The clutter signals can in some cases be significantly stronger than the wanted signals. One method for dealing with land clutter is the use of a high resolution clutter map. The area around the radar is considered to be divided into cells, and an array of background signal estimates is maintained for these cells. Whenever a s...

A radar apparatus is comprised of; transmitting means for outputting a transmission electromagnetic wave; receiving means for IQ-phase-detecting a reception electromagnetic wave received when a transmission electromagnetic wave is reflected from a target object and returned from the target object; signal converting means for FFT-processing an output signal of the receiving means; and signal processing means in which if there are one pair of spectrums having positive and negative peak values of a...

A radar apparatus is provided with signal converting means for FFT-transforming an output signal of reception means for detecting a reception electromagnetic wave; amplitude peak value detecting means for detecting a peak value of an amplitude level from a spectrum made by data converted by this signal converting means; beam scanning means for changing a beam direction of a transmission electromagnetic wave and also a beam direction of the reception electromagnetic wave; and measured-angle proce...

A radar device for detecting distances and relative speeds of obstructions such as preceding vehicles has a stationary object identifier for identifying stationary objects such as roadside guard rails and the like and a stationary object eliminator for eliminating data identified as pertaining to such stationary objects. The stationary object identifier detects peak densities in a beat spectrum detected as a difference between transmitted and received frequencies of a radar beam modulated to ris...

A radar detector is comprised of a voltage controlling oscillator (VCO) instead of DROs, thereby decreasing the cost of radar detector. The radar detector comprises a voltage controlled 1st local oscillator generates a signal of a frequency of 11.2796 GHz to 11.9832 Ghz, two (2) 2nd local oscillators generate signals with frequencies of 0.603 GHz and 1.3668 GHz, a memory section which stores pair combination data indicating the relation between the frequency of said voltage controlled oscillator...

A radar apparatus is comprised of: receiving means for IQ-phase-detecting a reception electromagnetic wave received when a transmission electromagnetic wave is reflected from a target object and returned from the target object; signal converting means for FFT-processing an output signal of the receiving means; and amplitude level correcting means in which if there are one pair of spectrums having positive and negative peak values of amplitude levels, while absolute values of frequencies thereof ...

The inventive laser radar uses a multiple frequency processing technique for the purpose of extracting relative range information from a received signal by transmitting and receiving two frequencies that are derived from a reference signal source modulated by two modulators that are driven by a different frequency, the reference frequency source also serving as a local oscillator.

A multi-functional radar transponder functions as SART in an emergency condition and as monitor, GPS receiver and VHF transceiver for non-emergency conditions. The radar transponder has an antenna including a SART antenna, a GPS antenna and a Marine VHF antenna. The radar transponder further includes a SART circuit with a monitor output device for monitoring a radar signal, and transfer switches for transferring a monitor process in a normal mode to a responding process in an emergency mode, and...

A radar system is designed to allow switched use of a pulse radar mode for detecting a target at a long distance away and a phase-difference radar mode for detecting a target at a short distance away, whereby target detection can be performed from a very close range to a long range with high accuracy. Also, the pulse radar mode enables detection of a plurality of targets in different ranges.

A radar system allows switched use of an FM-CW radar mode and a phase difference radar mode, the FM-CW radar mode being designed for use in sensing a target at a medium and long distance away and the phase difference radar mode being designed for use in sensing a target at a short distance away, whereby a target at an extremely short to long distance away can be sensed with high accuracy.