JP2001074829A - Transmitter-receiver for fm pulse doppler radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter-receiver which detects positive beat frequency and a negative beat frequency and which can be made low-cost by a method wherein a modulation means is installed at a transmitting signal, a signal whose frequency is offset by an intermediate frequency portion by a local oscillation signal is transmitted and a video signal is obtained on the basis of the frequency difference between a received signal from a target and the local oscillation signal. SOLUTION: A power distribution means 10 uses a part of the high-frequency modulation component of an oscillator 6 as a local oscillation signal, and it outputs the remaining part as a transmission reference signal. A modulation means 13 receives a pulse modulation signal from a signal processing part 12, and it pulse-modulates the transmission reference signal so as to be output as a transmitting signal having a frequency component of FRF±ΔFIF. A first power amplifier 8a radiates the transmitting signal from a transmitting antenna 9a, and a receiving antenna 9b receives the signal. A fundamental wave mixer 11 receives the local oscillation signal and the receiving signal so as to be frequency-modulated, and it outputs a video signal having a frequency in which a modulation frequency FIF is offset to beat frequencies Fb1, Fb2. A second power amplifier 8b power-amplifies the video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting or installing on a moving object such as an automobile or a fixed object, and removing objects such as humans, vehicles and obstacles around the moving object and the fixed object.
The present invention relates to an FM pulse Doppler radar that detects radio waves.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a use situation when an FM pulse Doppler radar is mounted in front of a vehicle. In the figure, 1 is a road, 2a and 2b are vehicles passing on the road 1 in the direction of a, 3 is an FM pulse Doppler radar mounted on a following vehicle 2b of the vehicle 2a and monitors the front, and 4 is a roadside of the road 1. An obstacle 5 such as an installed telephone pole or an on-street parked vehicle parked on the road side is a person 5 passing or crossing the road 1.

[0003] Next, the use situation will be described. Road 1
The FM pulse Doppler radar 3 mounted on the vehicle 2b passing in the direction of b irradiates the frequency-modulated transmission radio wave to the front, and the vehicle 2a running in front, obstacles 4, humans 5, etc. Receives reflected waves from the vehicle, detects its strength, frequency shift due to Doppler, and the propagation time of radio waves, obtains the distance and relative speed to the vehicle 2a from the results, and generates safety warnings for collision prevention or safety measures such as brake control It is used for

[0004] Regarding the use situation of such a system, for example, see IEICE Technical Report MW94-48 (1994-09) "Development of millimeter wave application system in Japan" and Nihon Keizai Shimbun "ITS
All ”(P62-67).

FIG. 10 is a block diagram showing the configuration of a conventional FM pulse Doppler radar 3 mounted on a vehicle 2b in FIG. 9, wherein 6 is an oscillator, 7 is a switch, 8a, 8b, 8c and
8d is a first, second, third and fourth power amplifier, 9a and 9b are transmitting and receiving antennas, 10a and 10b are first and second power distribution means, 11a and 11b are first and second The fundamental wave mixer 12 is a signal processing unit, and 6, 7, 8a, 8b, except 9a, 9b and 12.
A transmitting / receiving device is configured by 8c, 8d, 10a, 10b, 11a, and 11b.

Next, the operation will be described. In FIG. 10, an oscillator 6 is a high-frequency modulation signal (of the frequencies FRF ± ΔF, FRF is a high-frequency component and ± ΔF is a modulation frequency component).
Is output. The switch 7 receives the pulse modulation signal from the signal processing unit 12, switches the high-frequency modulation signal in two directions as a transmission signal and a local oscillation signal, and pulse-modulates the transmission signal. The first power amplifier 8a power-amplifies this transmission signal. The transmission antenna 9a outputs the power-amplified transmission signal toward a target (omitted in the figure). The above is the operation of the transmission system of the FM pulse Doppler radar transceiver. Next, the operation of the local oscillation system will be described. The second power amplifier 8b power-amplifies the local oscillation signal. The first power distribution means 10a distributes the power of the amplified local oscillation signal in two directions with the respective phases reversed. Next, the receiving system will be described. The receiving antenna 9b receives a reflected signal from the target and outputs a received signal. Second power distribution means 1
0b distributes the power of the received signal in two directions. The first fundamental wave mixer 11a receives one output of the first power distribution means 10a and one output of the second power distribution means 10b.
A first video signal having a sum and a difference frequency of the two output frequencies is output. Similarly to the first fundamental wave mixer 11a, the second fundamental wave mixer 11b also includes the first and second power distribution units 1.
The second video signal is output in response to the other output of 0a and 10b. The third power amplifier 8c and the fourth power amplifier 8d power-amplify the first video signal and the second video signal, respectively. The signal processing unit 12 outputs a pulse-modulated signal to the switch 7, and digitally and Fourier-transforms the two power-amplified video signals to analyze on the frequency axis.
Obtain information such as the distance to the target and the relative speed.

Next, the operation principle will be described. FIG. 11 and FIG. 12 show operation principle diagrams of the conventional FM pulse Doppler radar. In FIG. 11, FIG. 11A shows the output of the oscillator 6, and FIG.
11B shows a transmission signal, FIG. 11C shows a local oscillation signal, FIG. 11D shows a reception signal, and FIG. 11E shows a time chart of a video signal. As described above, the delay time between the pulse of the transmission signal and the pulse of the reception signal is proportional to the target distance, and since the video signal is obtained at this timing, the distance to the target is obtained from this relationship. Also, a curve a in FIG. 12 (a) is a transmission signal, and the local oscillation signals (frequency F) of the first fundamental wave mixer 11a and the second fundamental wave mixer 11b.
Of RF ± ΔF, FRF is a high frequency component, ± ΔF is a modulation frequency component), and curve b is a received signal. A conventional FM pulse Doppler radar irradiates a target with a frequency-modulated and pulse-modulated transmission signal, the received signal has a delay time twice as long as the distance to the target, and a Doppler frequency shift due to the relative speed of the target occurs. appear. The received signal and the local oscillation signal are subjected to frequency conversion (homodyne detection) by the first fundamental wave mixer 11a and the second fundamental wave mixer 11b, so that the target distance and the target distance as shown by the curve c in FIG. The video signal has beat frequency components Fb1 and Fb2 corresponding to the speed. Next, in the signal processing unit 12, this frequency Fb1
And the distance to the target and the relative speed from Fb2.

FIG. 13 shows the input signal (received signal) of the first fundamental wave mixer 11a and the second fundamental wave mixer 11b and the spectrum of the local oscillator signal and video signal in the conventional FM pulse Doppler radar transmission / reception apparatus. The curve d in FIG.
The input signal (received signal) of the fundamental wave mixer 11a and the second fundamental wave mixer 11b, the curve e in FIG. 13 (b) represents the local oscillation signal of each fundamental wave mixer, and the curve f in FIG. 13 (c). Indicates the spectrum of the video signal output from each fundamental wave mixer. The first fundamental wave mixer 11a and the second fundamental wave mixer 11b receive the curves d and e and output video signals having frequencies Fb1 and Fb2. However, the video signals output from the first fundamental wave mixer 11a and the second fundamental wave mixer 11b have opposite phases (I / Q detection). Upon receiving the two video signals having the opposite phases, the signal processing unit 12 derives a target distance / speed. The signal processing unit 12 converts the inverted video signal into two
The reason for performing the signal processing is to determine whether the target is moving away (away) or approaching (approaching) from the FM pulse Doppler radar.
As described above, according to the conventional FM pulse Doppler radar, in order to obtain two video signals by performing IQ detection, most of the configuration of the receiving system is provided in two systems, which complicates the configuration of the apparatus. , The size of the apparatus has been increased. Also, with the complexity of the configuration, it has been difficult to reduce the price of the device. Therefore, the downsizing and cost reduction of the device are
This has been an issue in the development of a transceiver for pulse Doppler radar.

[0009]

The transmitting and receiving apparatus for the FM pulse Doppler radar as described above has two systems of most of the receiving system in order to obtain two video signals by IQ detection. As a result, there is a problem that the configuration of the apparatus becomes complicated and large, and it is difficult to reduce the price of the apparatus.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. A modulation means is provided for a transmission signal to transmit a signal whose frequency is offset by an intermediate frequency from a local oscillation signal, and a reception signal from a target is transmitted. The purpose is to obtain the video signal from the difference between the frequency of the signal and the local signal, detect the positive and negative beat frequencies, and eliminate the need for I / Q detection. And

[0011]

According to a first aspect of the present invention, there is provided an FM pulse Doppler radar transmission / reception apparatus comprising: an oscillator for outputting a high-frequency modulation signal; a part of the high-frequency modulation signal as a local oscillation signal; Power distributing means, a pulse modulating means for receiving the pulse modulated signal output from the signal processing unit and pulse modulating the transmission reference signal, and converting the received signal and the local oscillation signal obtained through the receiving antenna. Receiving a frequency conversion, and outputting a video signal in which a frequency is offset by a modulation frequency of the pulse modulation signal to a beat frequency component corresponding to the target distance and relative speed, and a modulation of the pulse modulation signal. A band-pass filter that passes only near the frequency, and offsets the frequency of the transmission signal to the local oscillation signal by the amount of the pulse modulation frequency. It has been set.

According to a second aspect of the present invention, there is provided an FM pulse Doppler radar transmitting / receiving apparatus, comprising: an oscillator for outputting a high-frequency modulated signal; And an N multiplier for multiplying the frequency of the transmission reference signal by N (N is an even number of 2 or more), and a modulation for receiving the pulse modulation signal output from the signal processing unit and pulse modulating the transmission reference signal Means, and incorporates an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel, and calculates the sum and difference of the frequency of the reception signal obtained through the reception antenna and the N-times frequency of the local oscillation signal. An even harmonic mixer that outputs a video signal in which a beat frequency component corresponding to the frequency is offset by the modulation frequency of the pulse modulation signal, and a modulation frequency of the pulse modulation signal A band-pass filter that passes only the vicinity of the wave number, wherein the frequency of the transmission signal is offset by N times the frequency of the local oscillation signal by the amount of the pulse modulation frequency.

Further, the transmitting and receiving apparatus for an FM pulse Doppler radar according to the third invention transmits a high-frequency modulated signal, converts a part of the transmitted signal into a local signal of a receiving system, and frequency-converts a received signal from a target object. A transmission / reception device, a transmission and reception antenna that radiates a transmission signal, receives a reflected signal from a target and outputs a reception signal, and a signal processing unit that obtains the target distance and velocity information from the frequency-converted signal. F
In an M-pulse Doppler radar, an oscillator that outputs a high-frequency modulated signal, power distribution means that uses a part of the high-frequency modulated signal as a local oscillation signal and the remainder as a transmission reference signal, and a pulse modulated signal output from the signal processing unit The first even harmonic mixer that pulse-modulates a signal of N times frequency (N is an even number of 2 or more) of this transmission reference signal and an anti-parallel with two diodes of opposite polarity connected in parallel Built-in diode pair, the modulation frequency of the pulse modulation signal into a beat frequency component according to the sum and difference frequency of the frequency of the reception signal obtained through the reception antenna and the N-times frequency of the local oscillation signal A second even harmonic mixer that outputs a video signal whose frequency is offset by an amount, and a band-pass filter that passes only near the modulation frequency of the pulse modulation signal. And Bei, in which the frequency of the transmitted signal, were offset by the pulse modulation frequency N times the frequency of the local oscillation signal.

Further, the transmitting / receiving apparatus for an FM pulse Doppler radar according to the fourth invention is a pulse-modulating apparatus using the clock signal of the calling name storage device which is required to be installed in the low power radio equipment in the first to third inventions. A signal is obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a block diagram of a transmitting and receiving apparatus for an FM pulse Doppler radar according to a first embodiment of the present invention. In FIG.
a and 8b are first and second power amplifiers, 10 is power distribution means, 11 is a fundamental wave mixer, 13 is modulation means for pulse-modulating a transmission signal, and 14 is a band-pass filter.

FIG. 2 is a diagram showing an embodiment F of the present invention.
It is a time chart of each signal of the transmitting and receiving device for M pulse Doppler radar, in which (a) shows the output of the oscillator 6,
(b) is a transmission signal, (c) is a local oscillation signal of the fundamental mixer 11, (d)
Shows a received signal, and (e) shows a video signal after frequency conversion of the received signal by the fundamental mixer 11.

FIG. 3 is a diagram showing an embodiment of the present invention.
FIG. 5 is a diagram illustrating the operation principle of the transmitting / receiving device for the M-pulse Doppler radar, where a curve g represents a local oscillation signal of the fundamental wave mixer 11,
A curve h is a received signal from the target, and a curve i is a video signal after frequency conversion of the received signal by the fundamental mixer 11.

FIG. 4 is a diagram showing an F-mode according to the first embodiment of the present invention.
4A is an example of each signal spectrum of the receiving system in the transmitting and receiving apparatus for the M pulse Doppler radar, wherein a curve j in FIG. 4A is a received signal, a curve k in FIG. 4B is a local oscillation signal of the fundamental wave mixer 11,
Curve l in FIG. 4 (c) is the spectrum of the video signal.

Next, the operation will be described. In FIG. 1, the oscillator 6a outputs a high-frequency modulation signal (the frequency is FRF ± ΔF, FRF is a high-frequency component, and ± ΔF is a modulation frequency component). The power distribution means 10 converts a part of the high-frequency modulated signal into a local oscillation signal (the curve g in FIGS. 2 (c) and 3 (a)).
Is equivalent to ), And outputs the rest as a transmission reference signal. The modulation unit 13 receives the pulse modulation signal from the signal processing unit 12, performs pulse modulation on the transmission reference signal, and modulates the frequency component FRF.
The signal is output as a transmission signal (corresponding to FIG. 2 (b)) having ± ΔF ± FIF (FIF is a pulse modulation frequency).
The first power amplifier 8a power-amplifies this transmission signal.
This transmission signal is radiated by a transmission antenna 9a, similarly to a conventional FM pulse Doppler radar, and is received by a target (omitted in the figure) and a reception signal (FIG. 2 (d) and FIG. 3 (a)) via a reception antenna 9b. And Fb1 and Fb2 are beat frequency components corresponding to the target distance / speed.) The fundamental wave mixer 11 receives the local oscillation signal and the received signal, converts the frequency, and converts the beat frequency components Fb1 and Fb2 into a video signal having a frequency offset from the pulse modulation frequency FIF (FIGS. 2 (e) and 3 (b)). ) Is output.) The band-pass filter 14 allows only signals near the pulse modulation frequency to pass, and suppresses unnecessary signals outside the band. The second power amplifier 8b performs power amplification of the video signal. The signal processing unit 12 receives the video signal, determines the separation and approach of the target from the FM pulse Doppler radar based on the polarity and frequency of the beat frequencies Fb1 and Fb2 with respect to the pulse modulation frequency, and determines the distance between the FM pulse Doppler radar and the target. And the relative speed.

Next, a time chart of each signal shown in FIGS. 2 and 3 will be described. The oscillator 6 outputs a high-frequency modulation signal as shown in FIG. The modulation unit 13 performs pulse modulation on the output of the oscillator 6 according to the pulse modulation signal from the signal processing unit 12 as shown in FIG. The local oscillation signal to the fundamental wave mixer 11 is
It is obtained as shown in (c). This transmission signal is irradiated and reflected on a target (omitted in the figure), and a reception signal as shown in FIG. 2D is obtained with a delay time twice as long as the distance to the target.
By frequency-converting the received signal and the local oscillation signal, a video signal as shown in FIG. 2 (e) is obtained. Thus, the target distance can be derived from the delay time between the transmission signal and the reception signal.

Next, the spectrum of each signal of the receiving system will be described. The fundamental wave mixer 11 includes a reception signal (corresponding to a curve h in FIG. 3A and a curve j in FIG. 4A) and a local signal (FIG.
This corresponds to the curve g in FIG. 4A and the curve k in FIG. 4B. ) And outputs a video signal (corresponding to the curve i in FIG. 3 (b) and the curve 1 in FIG. 4 (c)). As described above, the video signal has the spectrum of the beat signal from the target in terms of the frequency FIF + Fb1 and FIF-Fb2, and the Fb1, Fb2, and FIF
The separation and approach of the target can be detected from the polarity, and the distance and relative speed can be derived. Therefore, accurate target detection can be performed without increasing the size of the receiving system as in the related art, and the cost of the device can be reduced.

Embodiment 2 FIG. FIG. 5 is a block diagram of a transmitting and receiving apparatus for an FM pulse Doppler radar according to a second embodiment of the present invention. In the figure, reference numeral 6 denotes an oscillator, 8a and 8b.
Are first and second power amplifiers, 10 is power distribution means, 13 is modulation means, 14 is a bandpass filter, 15 is an N multiplier, 16 is an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel. Built-in even harmonic mixer.

Next, the operation will be described. In FIG. 5, an oscillator 6 outputs a high-frequency modulated signal (frequency is (FRF ± ΔF) /
N, FRF is high frequency component, ± ΔF is modulation frequency component, N
Is an even number greater than or equal to 2. ) Is output. Power distribution means 10
Outputs a part of the high-frequency modulated signal as a local oscillation signal and the rest as a transmission reference signal. The N multiplier 15 multiplies the frequency of the transmission reference signal by N. The modulating means 13 includes the signal processing unit 1
Receiving the pulse modulation signal from 2, the output of the N multiplier 15 is pulse-modulated, and a transmission signal having a frequency component FRF ± ΔF ± FIF (FIF is a pulse modulation frequency) is output. No.
The one power amplifier 8a power-amplifies this transmission signal. This transmission signal is radiated by a transmission antenna 9a similarly to a conventional FM pulse Doppler radar, and received by a target (omitted in the drawing) and a reception antenna 9b (frequency components are FRF ± ΔF ± FIF + Fb1, FRF ± ΔF ± FIF-Fb2,
Fb1 and Fb2 are beat frequency components corresponding to the target distance / speed. ). Even harmonic mixer 16
A video signal having a frequency obtained by offsetting the pulse modulation frequency FIF to the beat frequency components Fb1 and Fb2, that is, a frequency of the sum and difference of the N times frequency of the local oscillation signal and the frequency of the received signal is output. The band-pass filter 14 allows only signals near the pulse modulation frequency to pass, and suppresses unnecessary signals outside the band. The second power amplifier 8b performs power amplification of the video signal. The signal processing unit 12 receives this video signal,
Based on the polarity and frequency of the beat frequencies Fb1 and b2 with respect to the pulse modulation frequency, separation and approach to the target FM pulse Doppler radar are determined, and the target distance and relative speed are detected. As described above, according to the FM pulse Doppler radar transmission / reception apparatus, it is possible to detect the departure and approach of the target from one video signal, and to derive the distance and the relative speed. Thus, accurate and accurate target detection becomes possible, and the cost of the apparatus can be reduced.

Next, the characteristics of the even harmonic mixer 16 incorporating an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel will be supplemented. FIG. 6 shows a noise voltage included in a video signal output from an even harmonic mixer having a built-in anti-parallel diode pair in which a fundamental wave mixer and two diodes of opposite polarities are connected in parallel. In FIG. 6, a curve m is a fundamental wave mixer, and a curve n is a noise voltage included in a video signal output from the even harmonic mixer.
Thus, it can be seen that the noise voltage of the even harmonic mixer is much lower than the noise voltage of the fundamental mixer. Therefore, by using the even harmonic mixer, the noise figure of the receiving system can be improved, and the target detection distance performance can be improved.

Embodiment 3 FIG. 7 is a block diagram of a transmitting and receiving apparatus for an FM pulse Doppler radar according to a third embodiment of the present invention, in which 6 is an oscillator, 8a and 8b.
Are first and second power amplifiers, 10 is power distribution means, 14 is a band-pass filter, 16a and 16b are first and second even amplifiers incorporating anti-parallel diode pairs in which two diodes of opposite polarity are connected in parallel. It is a harmonic mixer.

Next, the operation will be described. In FIG. 7, an oscillator 6 outputs a high-frequency modulated signal (frequency is (FRF ± ΔF) /
N, FRF is high frequency component, ± ΔF is modulation frequency component, N
Is an even number greater than or equal to 2. ) Is output. Power distribution means 10
Outputs a part of the high-frequency modulated signal as a local oscillation signal and the rest as a transmission reference signal. 1st even harmonic mixer 16a
Is the frequency FRF of the sum and difference between the frequency of the pulse modulation signal output from the signal processing unit 12 and the N-times frequency of the high-frequency modulation signal.
A transmission signal having ± ΔF ± FIF (FIF is a pulse modulation frequency) is output. The first power amplifier 8a power-amplifies this transmission signal. This transmission signal is radiated by a transmission antenna 9a similarly to a conventional FM pulse Doppler radar, and received by a target (omitted in the drawing) and a reception antenna 9b (frequency components are FRF ± ΔF ± FIF + Fb1, FRF
± ΔF ± FIF−Fb2, and Fb1 and Fb2 are beat frequency components corresponding to the target distance / speed. ). The second even harmonic mixer 16b is a video having a frequency obtained by offsetting the pulse modulation frequency FIF to the beat frequency components Fb1 and Fb2, that is, the sum and difference frequencies of the N times frequency of the local oscillation signal and the frequency of the reception signal. Output a signal. The band-pass filter 14 allows only signals near the pulse modulation frequency to pass, and suppresses unnecessary signals outside the band. The second power amplifier 8b performs power amplification of the video signal. Signal processing unit 12
In response to this video signal, separation and approach to the target FM pulse Doppler radar are determined from the polarity and frequency of the beat frequencies Fb1 and Fb2 with respect to the pulse modulation frequency, and the target distance and relative speed are detected. As described above, according to the FM pulse Doppler radar transmission / reception apparatus, it is possible to detect the departure and approach of the target from one video signal, and to derive the distance and the relative speed. Thus, accurate and accurate target detection becomes possible, and the cost of the apparatus can be reduced. Also,
The use of the second even harmonic mixer 16b, which incorporates an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel to the receiving system, improves the noise figure of the receiving system and improves the target detection distance performance Can be done. Further, by using the first even harmonic mixer 16a for the transmission system, it becomes unnecessary to use the N multiplier 15 or the like.
It is possible to simplify the configuration of the transmission system.

Fourth Embodiment FIG. 8 is a block diagram of an FM pulse Doppler radar transmission / reception apparatus according to a fifth embodiment of the present invention. In the figure, reference numeral 6 denotes an oscillator, 8a and 8b.
Are first and second power amplifiers, 10 is power distribution means, 11 is a fundamental wave mixer, 13 is modulation means, 14 is a band pass filter, 17
Is a call name storage device.

Next, the operation will be described. 8, the oscillator 6 outputs a high-frequency modulation signal (the frequency is FRF ± ΔF, FRF is a high-frequency component, and ± ΔF is a modulation frequency component). The power distribution means 10 outputs a part of the high-frequency modulated signal as a local oscillation signal and outputs the rest as a transmission reference signal. The call name storage device 17 outputs a clock signal having a frequency component FIF. The modulating means 13 pulse-modulates the transmission reference signal with the clock signal, and outputs a transmission signal having a frequency component FRF ± ΔF ± FIF (FIF is a clock frequency). The first power amplifier 8a power-amplifies this transmission signal. This transmission signal is a conventional FM
Similarly to the pulse Doppler radar, the signal is radiated by the transmitting antenna 9a and received by the target (omitted in the drawing) and the receiving antenna 9b (the frequency components are FRF ± ΔF ± FIF + Fb1, FR
F ± ΔF ± FIF−Fb2, and Fb1 and Fb2 are beat frequency components corresponding to the target distance / speed. ). The fundamental wave mixer 11 receives the local oscillation signal and the received signal, converts the frequency, and outputs a video signal having a frequency obtained by offsetting the clock frequency FIF to the beat frequency components Fb1 and Fb2. The band pass filter 14 has a clock frequency FI
Passes only signals near F and suppresses unnecessary signals outside the band. The second power amplifier 8b performs power amplification of the video signal. The signal processing unit 12 receives the video signal, determines the separation and approach to the target FM pulse Doppler radar from the polarity and frequency of the beat frequency Fb1, Fb2 with respect to the clock frequency, and detects the target distance and relative speed. . Thus, according to this FM pulse Doppler radar transmission / reception apparatus, it is possible to detect the separation and approach of the target from one video signal, and to derive the distance and relative speed,
Accurate target detection can be performed without increasing the scale of the receiving system as in the related art, and the cost of the device can be reduced.

[0029]

According to the first aspect of the present invention, the separation and approach of a target can be detected from one video signal, and the distance and the relative speed can be derived. Accurate target detection becomes possible, and the cost of the apparatus can be reduced.

Further, according to the second invention, the separation and approach of the target can be detected from one video signal, and the distance and the relative speed can be derived. Accurate target detection becomes possible, and the cost of the apparatus can be reduced. Further, since an even harmonic mixer having a small noise component is used, the noise figure of the receiving system can be improved, and the target detection distance performance can be improved.

According to the third aspect, the separation and approach of the target can be detected from one video signal, and the distance and the relative speed can be derived. Therefore, accurate data can be obtained without increasing the scale of the receiving system unlike the related art. Target detection becomes possible, and the cost of the apparatus can be reduced. Further, since an even harmonic mixer having a small noise component is used, the noise figure of the receiving system can be improved, and the target detection distance performance can be improved. Furthermore, by using an even harmonic mixer for the transmission system, it is not necessary to use an N-multiplier or the like, so that the configuration of the transmission system can be simplified.

Further, according to the fourth aspect, since the separation and approach of the target can be detected and the distance and the relative speed can be derived from one video signal, the size of the apparatus of the receiving system is not increased as in the related art. Accurate target detection becomes possible, and the cost of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an FM pulse Doppler radar transmitting / receiving apparatus according to the present invention.

FIG. 2 is a diagram showing a time chart of the first embodiment of the FM pulse Doppler radar transmitting / receiving apparatus according to the present invention.

FIG. 3 is a diagram showing an operation principle of the first embodiment of the FM pulse Doppler radar transmitting / receiving apparatus according to the present invention.

FIG. 4 is a diagram showing a spectrum of each signal of a receiving system in the first embodiment of the transmitting and receiving apparatus for the FM pulse Doppler radar according to the present invention.

FIG. 5 is a diagram showing Embodiment 2 of a transmitting / receiving apparatus for an FM pulse Doppler radar according to the present invention.

FIG. 6 is a diagram illustrating an example of output noise levels of a fundamental wave mixer and an even harmonic mixer.

FIG. 7 is a diagram showing Embodiment 3 of an FM pulse Doppler radar transmitting / receiving apparatus according to the present invention.

FIG. 8 is a diagram showing a fourth embodiment of an FM pulse Doppler radar transmitting / receiving apparatus according to the present invention.

FIG. 9 is a diagram illustrating an example of an operation state of an FM pulse Doppler radar.

FIG. 10 is a diagram showing a conventional FM pulse Doppler radar.

FIG. 11 is a diagram showing a time chart of a conventional FM pulse Doppler radar transmitting / receiving apparatus.

FIG. 12 is a diagram illustrating the operation principle of a conventional FM pulse Doppler radar transmitting / receiving device.

FIG. 13 is a diagram showing a spectrum of each signal of a receiving system in a conventional FM pulse Doppler radar transmitting / receiving apparatus.

[Explanation of symbols]

1 road, 2a vehicle, 2b vehicle, 3 FM pulse Doppler radar, 4 obstacles, 5 humans, 6 oscillators, 7 switches,
8a first power amplifier, 8b second power amplifier, 8c third
Power amplifier, 8d fourth power amplifier, 9a transmitting antenna, 9b receiving antenna, 10 power distribution means, 10a first power distribution means, 10b second power distribution means, 11 fundamental wave mixer, 11a first basic Wave mixer, 11b second fundamental wave mixer, 12 signal processing unit, 13 modulation means, 14 band-pass filter, 15N multiplier, 16 even harmonic mixer, 16a first even harmonic mixer, 16b first even mixer Harmonic mixer, 17 call name storage.

Claims (4)

[Claims] 1. A transmitting / receiving apparatus for transmitting a high-frequency modulated signal, converting a part of the transmitted signal into a local oscillation signal of a receiving system, converting the frequency of a received signal from a target object, and radiating the transmitted signal and reflecting the signal from the target. An oscillator that outputs a high-frequency modulated signal in an FM pulse Doppler radar including a transmitting and receiving antenna that receives a signal and outputs a received signal, and a signal processing unit that obtains the target distance and speed information from the frequency-converted signal. Power distributing means for using a part of the high-frequency modulated signal as a local oscillation signal and the remainder as a transmission reference signal, and a modulation means for receiving a pulse-modulated signal output from the signal processing unit and pulse-modulating the transmission reference signal. Receiving the received signal obtained through the receiving antenna and the local oscillation signal, converts the frequency, and converts the pulse frequency component into a beat frequency component corresponding to the target distance and relative speed. A fundamental wave mixer that outputs a video signal whose frequency is offset by the modulation frequency of the pulse modulation signal, and a band-pass filter that passes only the vicinity of the modulation frequency of the pulse modulation signal. A transmitting / receiving apparatus for an FM pulse Doppler radar, wherein the local oscillation signal is offset by an amount corresponding to the pulse modulation frequency. 2. A transmitting and receiving apparatus for transmitting a high-frequency modulated signal, converting a part of the transmitted signal into a local oscillation signal of a receiving system, converting the frequency of a received signal from a target object, and radiating the transmitted signal and reflecting the reflected signal from the target. An oscillator that outputs a high-frequency modulated signal in an FM pulse Doppler radar including a transmitting and receiving antenna that receives a signal and outputs a received signal, and a signal processing unit that obtains the target distance and speed information from the frequency-converted signal. Power distributing means for using a part of the high-frequency modulated signal as a local oscillation signal and the remainder as a transmission reference signal, and an N multiplier for multiplying the frequency of the transmission reference signal by N (N is an even number of 2 or more); A modulation means for receiving the pulse modulation signal output from the signal processing section and pulse modulating the transmission reference signal, and an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel. The frequency is offset by the modulation frequency of the pulse modulation signal to a beat frequency component corresponding to the sum and difference frequency of the frequency of the reception signal obtained through the reception antenna and the N-times frequency of the local oscillation signal. An even harmonic mixer that outputs a video signal, and a band-pass filter that passes only the vicinity of the modulation frequency of the pulse modulation signal. The frequency of the transmission signal is set to N times the frequency of the local oscillation signal. An FM pulse Doppler radar transmission / reception device characterized by being offset by a modulation frequency. 3. A transmitting and receiving device for transmitting a high-frequency modulated signal, converting a part of the transmitted signal into a local oscillation signal of a receiving system, converting the frequency of a received signal from a target object, radiating the transmitted signal, and reflecting the signal from the target. An oscillator that outputs a high-frequency modulated signal in an FM pulse Doppler radar including a transmitting and receiving antenna that receives a signal and outputs a received signal, and a signal processing unit that obtains the target distance and speed information from the frequency-converted signal. A power distribution unit that uses a part of the high-frequency modulated signal as a local oscillation signal and the remainder as a transmission reference signal, and receives a pulse modulation signal output from the signal processing unit and receives an N-fold frequency (N: 1) Even harmonic mixer that pulse-modulates signals of 2 or more) and an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel. A video in which a frequency is offset by a modulation frequency of the pulse modulation signal to a beat frequency component corresponding to a sum and difference frequency of a frequency of the reception signal obtained through an antenna and an N-times frequency of the local oscillation signal. A second even-harmonic mixer that outputs a signal, and a band-pass filter that passes only near the modulation frequency of the pulse-modulated signal, wherein the frequency of the transmission signal is N times the frequency of the local oscillation signal. An FM pulse Doppler radar transmission / reception device characterized by being offset by an amount corresponding to a pulse modulation frequency. 4. The FM pulse Doppler radar according to claim 1, wherein a pulse modulation signal is obtained by a clock signal of a call name storage device required to be installed in the low power radio equipment. Transceiver.