Spread spectrum radar device using pseudorandom noise signal for detection of an object

A spread spectrum radar device which receives a reflected wave from a moving object based on a transmitted wave and detects said object, comprising:

• generating means for generating a pseudorandom noise signal;
• a transmitter for transmitting a wave whose band is spread by said pseudorandom noise signal;
• a receiver for receiving a reflected wave from the object based on said transmitted wave and putting out a received signal;
• despreading means for despreading said received signal by said pseudorandom noise signal and detecting a correlation of said received signal with said pseudorandom noise signal;
• a frequency converter for converting the frequency of said received signal to a signal with a low frequency;
• measuring means for measuring a period of said frequency-converted low frequency signal;
• and
• a detector for detecting the speed of said object according to said measured period;
• and
• wherein said detector detects the moving direction and relative speed of said object according to a Doppler-shift amount and a Doppler-shift direction of the frequency of said frequency-converted low frequency signal against a set center frequency.

A spread spectrum radar device which receives a reflected wave from a moving object based on a transmitted wave and detects a presence of said object and measures speed or distance to said object, comprising:

• generating means for setting and generating a code of a pseudorandom noise signal according to the relative speed of a supposed moving object so that a shift range due to the Doppler effect of the frequency of a received signal which is correlated, converted to a low frequency and has power concentrated does not overlap said shift range of the frequency of a signal which is not correlated but left spread, and so that the minimum value of the shift range of the frequency of said signal with power concentrated is larger than 0 Hz,
• a transmitter for transmitting a wave whose band is spread by said pseudorandom noise signal,
• a receiver for receiving a reflected wave from an object based on said transmitted wave and putting out a received signal,
• despreading means for despreading said received signal by said pseudorandom noise signal and detecting a correlation of said received signal with said pseudorandom noise signal, and
• a band passing device for passing the frequency of bands of a maximum value and a minimum value of the shift range of the frequency of said signal with power concentrated of said despread signal.

A spread spectrum radar device which receives a reflected wave from a moving object based on a transmitted wave and detects the presence of said object and measures speed or distance to said object, comprising:

• generating means for generating a pseudorandom noise signal;
• a transmitter for transmitting a wave whose band is spread by said pseudorandom noise signal,
• a receiver for receiving a reflected wave from the object based on said transmitted wave and putting out a received signal,
• despreading means for despreading said received signal by said pseudorandom noise signal and correlating said received signal with the pseudorandom noise signal, and
• a frequency converter for converting the frequency of said received signal to a signal with a low frequency, and
• a phase locked loop circuit for passing said frequency-converted low frequency signal in a narrow band,
• wherein said phase locked loop circuit has a lock-in range or lock range set in a frequency shift range where such a signal is supposed that is correlated at said despreading means, has power concentrated and frequency-converted by said frequency converter.

A spread radar device which receives a reflected wave from an object based on a transmitted wave and detects said object, comprising:

• generating means for generating a pseudorandom noise signal;
• a transmitter for transmitting a wave whose band is spread by said pseudorandom noise signal;
• a receiver for receiving a reflected wave from the object based on said transmitted wave and outputting a received signal;
• despreading means for despreading said received signal by said pseudorandom noise signal and detecting a correlation of said received signal with said pseudorandom noise signal;
• a delay device for delaying said pseudorandom noise signal for a prescribed delay time when detecting said correlation;
• and
• a distance measuring device for measuring the distance to said object according to said delay time when said correlation is detected.