초록 ▼

The present radar altimeter operates in accordance with the frequency modulated continuous wave principle in the C-band. The altimeter is constructed with microminiaturized integrated circuits and provides a completely digital signal evaluation and mode control which enables the transmitter to produ

The present radar altimeter operates in accordance with the frequency modulated continuous wave principle in the C-band. The altimeter is constructed with microminiaturized integrated circuits and provides a completely digital signal evaluation and mode control which enables the transmitter to produce a wave-form providing the altimeter with the following advantages. A silent mode during the signal evaluation greatly improves the resistance of the altimeter against electronic countermeasures. The transmitter frequency is stabilized and a compensation for Doppler frequency drift is provided. Further, the altimeter is able to discriminate between intended proper targets on the one hand and false or erroneous targets on the other hand. The altimeter is equipped with a self-testing unit which provides different functions in different modes.

대표청구항 ▼

A radar altimeter operating, preferably in the C-Band, in accordance with the frequency modulated continuous wave (FMCW) principle, comprising receiver means for receiving reflected radar signals and transmitter means for transmitting radar signals, said transmitter means including voltage controlle

A radar altimeter operating, preferably in the C-Band, in accordance with the frequency modulated continuous wave (FMCW) principle, comprising receiver means for receiving reflected radar signals and transmitter means for transmitting radar signals, said transmitter means including voltage controlled oscillator means (11) for generating a carrier frequency, micro-computer means (10) for controlling the operation of said altimeter, closed loop control circuit means (11f, 10a, 10b) interconnecting said voltage controlled oscillator means (11) and said microcomputer means (10), a variable signal attenuating circuit (13) connected to an output of said voltage controlled oscillator, a power amplifier (14) connected to an output of said damping circuit (13), a self-testing mode control circuit (30) including a transmitter MMIC-switch (15) and a transmitter antenna means (40) connectable through said transmitter MMIC-switch (15) to an output of said power amplifier (14), said self-testing mode control circuit further including a receiver antenna (41) and a receiver MMIC-switch (15a) for connecting said receiver antenna to said receiver means, and decoupling means (17) operatively connected to said receiver antenna for decoupling a portion of received radio frequency power, detector means (18) connected to said decoupling means (17) for providing a d.c.-voltage signal representative of said received radio frequency power, signal comparing means connected to receive said d.c.-voltage signal for comparing said d.c.-voltage signal with a reference threshold signal, said microcomputer comprising interrupt circuit means (20) connected to an output of said signal comparing means for causing a processing interruption and a “waiting loop”in response to a signal at said output of said signal comparing means signifying an excessive received radio frequency power, and wherein all circuits of said altimeter are constructed in accordance with MMIC-techniques for a complete digital signal evaluation and mode control.