JP2003130944A - On-vehicle radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an on-vehicle radar device capable of suppressing the creeping effect of a transmission electromagnetic wave on a receiving means. SOLUTION: The electromagnetic waves generated by an oscillator 1 are subjected to PSK modulation by a modulator 2 to be emitted to space by a transmission antenna 4 and reflected by target matter 6 or other matter to be received by a receiving antenna 7. The received electromagnetic waves are subjected to IQ detection by an IQ detecting mixer 8. Both beat signals outputted from an I channel and a Q channel are multiplied by a multiplier 9 to output the voltage value corresponding to the phase difference between transmitting and receiving waves. An LO oscillator 10 outputs electromagnetic waves for LO to the mixer 8 while changes the frequency of electromagnetic waves corresponding to the voltage value to cancel the beat signal from matter other than the target matter 6. By this constitution, a signal processor 14 calculates the distance and relative speed of the target matter 6 on the basis of the beat signal outputted from the Q channel of the mixer 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted radar device, and more particularly to a vehicle-mounted radar device mounted on a vehicle for measuring a distance and a relative speed between the vehicle and a target object.

[0002]

2. Description of the Related Art As a radar device of this type, a device as shown in FIG. 6 is conventionally known. In FIG. 6, 101 is an oscillator that outputs an electromagnetic wave to be radiated to a target object, 102 is the power of the electromagnetic wave,
A power divider that operates as a dividing unit that supplies both a transmission ON / OFF switch 103 and a reception mixer 109 to be described later, and 103 is a transmission ON for pulse-modulating the electromagnetic wave distributed by the power divider 102 for transmission.
An ON / OFF switch, 104 is a transmitting antenna that radiates the pulse-modulated electromagnetic wave into space, 105 is a radome, 106 is a target object, 107 is a receiving antenna for receiving the electromagnetic wave reflected by the target object, and 108 is power. A receiving mixer that mixes the electromagnetic wave distributed for LO by the divider 102 and the reflected electromagnetic wave from the target object 106, 109 is a filter whose cutoff frequency is the reciprocal of the pulse time width, and 110 is according to the received power of the reflected electromagnetic wave. Amplifier with adjustable gain, 111 is AD converter, 1
Reference numeral 12 is a signal processing circuit that calculates the distance to the target object 106 and the relative speed of the target object 106 based on the data input by the AD converter 111.

Next, the operation of the conventional device constructed as described above will be described. First, an electromagnetic wave transmission operation will be described. First, the oscillator 101 outputs an electromagnetic wave having a transmission frequency ftx = 24.125 GHz, for example. The electromagnetic wave passes through the power divider 102 and is pulse-modulated by the transmission ON / OFF switch 103. The pulse-modulated electromagnetic wave passes through the radome 105 from the transmitting antenna 104 and is radiated into space.
In the pulse modulation, the switch 103 is closed and the transmission is turned on only for a pulse time width Tp, for example, 100 ns (equivalent to a distance of 15 m), and the transmission is turned off otherwise. The pulse repetition period is, for example, 1 μs (equivalent to a distance of 150 m).

Next, the electromagnetic wave receiving operation will be described. As described above, the electromagnetic wave output from the antenna 104 to the space through the radome 5 is the target object 1 existing at the distance R.
It is reflected at 06, passes through the radome 105 again with a delay time Δt depending on the distance R as shown in FIG. 7, and is input to the receiving antenna 107. When the target object 106 has a relative velocity, the reception electromagnetic wave frequency is Doppler-shifted by fb with respect to the transmission electromagnetic wave frequency ftx. The electromagnetic waves input by the receiving antenna 107 are received by the receiving mixer 108.
The mixed signal is mixed with the LO electromagnetic wave from the power divider 102, and a beat signal corresponding to the Doppler shift fb shown in FIG. 9 is output. The obtained beat signal is filtered by the filter 10.
After passing through 9, the signal is amplified by the amplifier 110 and input to the AD converter 111.

Next, a method in which the signal processing circuit 112 calculates the distance and the relative speed of the target object 106 from the data input to the AD converter 111 will be described.

For example, the distance gate width (tg in FIG. 7) is set to 6.6 ns in order to obtain the distance resolution of 1 m. Therefore, the sampling at the range gate is 150 MHz.

For example, to obtain a velocity resolution of 1 km / h, the Doppler frequency resolution Δf is calculated from the transmission frequency ftx = 24.125 GHz.

[0008]

[Equation 1]

Therefore, the measurement time of 22.4 ms is required. Here, for example, when the maximum measurement distance is 150 m, the pulse repetition period is 1 μs. Therefore, in order to obtain the velocity resolution of 1 km / h, the beat signal in the above device is 22400 pulses for each distance gate as shown in FIG. When all the data are acquired and FFT is performed for each distance gate, the Doppler shift f is obtained at a certain distance gate as shown in FIG.
b is output. In the case of FIG. 8, the Doppler shift fb is observed at the range gates 5 and 6.

Here, the distance and the relative speed are expressed by the following equation (2),
It can be calculated in (3).

[0011]

[Equation 2]

Here, Tg is the range gate time width, n is the range gate number, C is the speed of light, fb is the beat frequency, and f0 is the transmission frequency (24.125 GHz).

[0013]

The conventional vehicle-mounted radar device is configured to operate as described above to detect the target object and the relative velocity. However, in practice, as shown in FIG. In addition, a phenomenon occurs in which the transmitted wave is directly received during transmission (hereinafter, referred to as wraparound). This phenomenon of wraparound is mainly due to the fact that one antenna is used for both transmission and reception, so that the transmission wave leaks in the circuit and the transmission wave is very close to the radome 105 or the bumper of the vehicle. It is caused by reflection.

In the conventional apparatus of FIG. 6, in order to suppress the occurrence of the wraparound phenomenon to a low level, a transmitting / receiving antenna provided with a transmitting antenna 104 and a receiving antenna 107 is adopted.
However, in reality, the reflected wave at the radome 105 cannot be completely removed, and the sneak wave is much larger than the target object 106 such as a vehicle. Therefore, the detected voltage is too large and the amplifier 110 is saturated. There was a problem that it would end up. Further, if the gain of the amplifier 110 is lowered so as not to saturate the amplifier 110, there is a problem that a distant target object cannot be detected.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an on-vehicle radar device capable of suppressing the influence of the transmission electromagnetic wave on the receiving means.

[0016]

SUMMARY OF THE INVENTION The present invention is a vehicle-mounted radar device for measuring a distance and a relative velocity of a target object based on a transmission electromagnetic wave and a reception electromagnetic wave, the oscillation means generating the electromagnetic wave, and PSK modulating means for PSK modulating the electromagnetic wave generated by the oscillating means, transmitting means for radiating the PSK modulated electromagnetic wave into space, and radiated by the transmitting means and reflected by the target object or another object. A receiving unit that receives the electromagnetic wave, a receiving oscillating unit that outputs the receiving electromagnetic wave, an electromagnetic wave that is received by the receiving unit and a receiving electromagnetic wave that is output from the receiving oscillating unit are mixed, and a beat signal is generated. The detecting means for outputting, the position of the electromagnetic wave received by the receiving means and the electromagnetic wave output from the receiving oscillating means based on the beat signal. By controlling the frequency of the reception electromagnetic wave of the transmission / reception wave phase difference detection means that outputs a difference and the value of the phase difference output from the phase difference detection means to be 0, the target An in-vehicle radar device comprising: canceling means for canceling a beat signal from other than the object; and signal processing means for calculating the distance and relative speed of the target object based on the beat signal output from the detecting means. .

Further, the present invention relates to an on-vehicle radar device for measuring a distance and a relative velocity of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave, the oscillating means generating the electromagnetic wave and the oscillating means generating the electromagnetic wave. The electromagnetic wave generated is PS
PSK modulation means for K modulation, transmission means for radiating the PSK-modulated electromagnetic wave in space, receiving means for receiving the electromagnetic wave radiated by the transmission means and reflected by the target object or another object, IQ detection is performed on the electromagnetic waves received by the receiving means, and IQ detection means for outputting beat signals from the I channel and Q channel is multiplied by both beat signals output from the I channel and Q channel of the IQ detection means. And a voltage for outputting the LO electromagnetic wave to the IQ detecting means while changing the frequency of the electromagnetic wave according to the voltage value output from the multiplying means and the multiplying means outputting the voltage value according to the phase difference between the transmitted and received waves. The distance and the relative speed of the target object are obtained based on the beat signal output from the control oscillating means and the Q channel of the IQ detecting means. A vehicle radar apparatus having a signal processing means.

An on-vehicle radar device for measuring a distance and a relative velocity of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave, the oscillating means generating the electromagnetic wave,
PSK modulating means for PSK modulating the electromagnetic wave generated by the oscillating means, transmitting means for radiating the PSK modulated electromagnetic wave into space, and radiating by the transmitting means,
Receiving means for receiving the electromagnetic wave reflected by the target object or another object, and I for outputting an electromagnetic wave of a predetermined frequency
F signal oscillating means, first-stage mixing means for mixing the electromagnetic wave received by the receiving means and the electromagnetic wave output from the IF signal oscillating means to output an IF signal, and the first-stage mixing means. The phase difference between the transmitted and received waves is obtained by multiplying the IQ detection means for IQ detection of the IF signal and outputting the beat signal from the I channel and the Q channel by both the beat signals output from the I channel and Q channel of the IQ detection means. A voltage control oscillating means for outputting a LO electromagnetic wave to the IQ detecting means while changing the frequency of the electromagnetic wave in accordance with the voltage value output from the multiplying means;
A vehicle-mounted radar device comprising: a signal processing means for obtaining a distance and a relative speed of the target object based on a beat signal output from the Q channel of the detection means.

Further, there is further provided a delay means provided between the voltage controlled oscillation means and the IQ detection means for delaying the phase of the frequency of the LO electromagnetic wave by π / 2.

Further, there is further provided a delay means provided between the receiving means and the IQ detecting means for delaying the phase of the frequency of the electromagnetic wave received by the receiving means by π / 2.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described below with reference to FIG. 1 is a block diagram showing the configuration of an in-vehicle radar device according to Embodiment 1 of the present invention. First, the transmission system will be described. In FIG. 1, 1 is, for example, a transmission frequency ftx = 24.125G
It is an oscillator that generates an electromagnetic wave of Hz. Reference numeral 2 is a modulator that outputs a signal for PSK modulating the electromagnetic wave of the oscillator 1. Reference numeral 3 is a mixer for PSK modulating the electromagnetic wave of the oscillator 1 according to the output of the modulator 2. 4 is the mixer 3 and P
It is a transmission antenna that radiates SK-modulated electromagnetic waves into space.

The operation of the transmission system will be described. Oscillator 1
The electromagnetic wave output by is subjected to PSK modulation by the mixer 3 based on the signal from the modulator 2. At the output of the mixer 3, the phase of the electromagnetic wave of the oscillator 1 changes by 180 ° according to the pulse output of the modulator 2. The transmitting antenna 4 radiates the electromagnetic wave PSK-modulated by the mixer 3 into space. The emitted electromagnetic wave passes through the radome 5 and is reflected by the target object 6 having a distance R and a relative velocity V.

Next, the receiving system will be described. Reference numeral 7 is a receiving antenna for receiving the electromagnetic waves radiated by the transmitting antenna 4 and reflected by the target object or another object. Reference numeral 8 denotes detection means for mixing an electromagnetic wave received by the receiving antenna 7 and an electromagnetic wave output from a LO oscillator (reception oscillating means) described later, and outputting a beat signal. It is composed of a mixer which is IQ detection means for IQ-detecting an electromagnetic wave received by the antenna 7 and outputting a beat signal from the I-channel and the Q-channel. In the mixer 8, as shown, a mixer 81 for I channel, a mixer 82 for Q channel, and a π / 2 delay circuit 83 for delaying the phase by π / 2 phase.
Is provided. Reference numeral 9 is a transmission / reception wave phase difference detecting means for outputting a phase difference between the electromagnetic wave received by the receiving antenna 7 and the electromagnetic wave output from the LO oscillator 10, based on both beat signals output from the mixer 8. In the embodiment, it is composed of a multiplier that multiplies both beat signals output from the I channel and Q channel of the mixer 8 and outputs a voltage value corresponding to the phase difference between the transmitted and received waves. Reference numeral 10 denotes a receiving oscillating unit that oscillates a receiving electromagnetic wave, and controls the frequency of the output electromagnetic wave so that the value of the phase difference obtained by the multiplier 9 becomes 0. This is a canceling means for canceling the beat signal, and in the present embodiment, L that outputs the LO electromagnetic wave to the mixer 8 while changing the frequency of the electromagnetic wave according to the voltage value output from the multiplier 9.
It consists of an O oscillator. Reference numeral 11 is a filter for filtering the output of the Q channel mixer 82 of the IQ detection mixer 8, 12 is an amplifier for amplifying the signal filtered by the filter 11, 13 is A / D for amplifying the amplified signal.
The D converter 14 is a signal processor that processes the A / D data and calculates the distance R and the relative speed V of the target object 6.

The operation of the receiving system will be described. The reflected electromagnetic wave passes through the radome 5 and is input to the receiving antenna 7. At the same time, the transmitted wave is reflected by the radome 5 and input to the receiving antenna 7 (wraparound). The electromagnetic wave received by the receiving antenna 7 is IQ-detected by the mixer 8. The IQ-detected both beat signals are multiplied by the multiplier 9 and input to the LO oscillator 10. LO oscillator 10
Power is distributed in two directions, and one of them is supplied to the LO input of the I-channel mixer 81 of the IQ detection mixer 8. The other is π /, which delays the phase by π / 2.
It is supplied to the LO input of the Q channel mixer 82 of the IQ detection mixer 8 via the 2 delay circuit 83. IQ
The output from the Q-channel mixer 82 of the detection mixer 8 is filtered by the filter 11 and input to the amplifier 12 for amplification. The amplified signal is A / D converted by the A / D converter 13, and the signal processor 14 calculates the distance R and the relative velocity V of the target object 6 based on the A / D converted data. To be done.

Next, the operation of the radar of the first embodiment will be shown analytically. The transmitted wave is BPSK modulated with 0 and π, and is given by equation (4)
Can be shown as ω is the angular frequency of the transmitted wave. φ
(T) is a phase modulation component and is 0 or π.

[0026]

[Equation 3]

The received wave can be expressed by the equation (5) by summing the components reflected by the radome 5 and the target object 6. The first term of the received wave is the wraparound wave, and the second term is the reflected wave at the target object 6. Where Δω is the Doppler shift component corresponding to the relative velocity of the target object 6, the phase difference between the transmitted wave and the wraparound wave is θp1, and the phase difference between the transmitted wave and the reflected wave is θp2.
And

[0028]

[Equation 4]

Equation (6), which is a component not BPSK-modulated at the same frequency as the transmitted wave, is input to the LO of the I-channel mixer 81 in the mixer 8. However, since the line length is different from the transmission wave, the phase difference between the transmission wave and the LO wave is θp3. Here, the I channel is In-Phase, and the Q channel is Quadrature-Phase.

[0030]

[Equation 5]

The LO of the Q-channel mixer 82 in the mixer 8 receives the equation (7) which is a component not BPSK modulated at the same frequency as the transmitted wave. However, since the line length is different from the transmission wave, the phase difference between the transmission wave and the LO wave is θp3.

[0032]

[Equation 6]

Next, the output of the mixer 81 for the I channel is represented by the multiplication of the equations (5) and (6) and becomes the equation (8).

[0034]

[Equation 7]

The up-converted portion is cut by the filter.

[0036]

[Equation 8]

Next, the output of the mixer 82 for the Q channel is represented by the multiplication of the equations (5) and (7) and becomes the equation (9).

[0038]

[Equation 9]

The up-converted portion is cut by the filter.

[0040]

[Equation 10]

Next, regarding the output of the multiplier 9, since the amplitude B of the reflected wave of the target 6 is much smaller than the amplitude A of the reflected wave of the radome 5, there is a relation of A >> B.

[0042]

[Equation 11]

Since φ (t) is 0 or π,

[0044]

[Equation 12]

Therefore, after IQ multiplication, the wraparound wave and L
Since the phase difference voltage of the O wave is output and the VCO is controlled by the voltage, it operates so that the phases of the sneak wave and the LO wave match. Therefore

[0046]

[Equation 13]

It becomes Substituting this into the Quadrature-Phase wave equation (9)

[0048]

[Equation 14]

Therefore, the wraparound wave component is eliminated.
Substituting into the In-Phase wave equation (8)

[0050]

[Equation 15]

Therefore, the component of the wraparound wave is the maximum value.
It becomes A / 2.

The above is shown in FIG. A diagram is shown in which the phase φ (t) of the transmitted wave is changed from π to 0 from a certain moment, and the phase φ (t) of the transmitted wave is again set to π after continuing for a predetermined pulse time width Tp, for example, 100 ns (equivalent to a distance of 15 m). ing. The upper row shows the output of the I-channel mixer 82, and the lower row shows the output of the Q-channel mixer 81. In the upper stage, the component reflected by the radome is input to the receiving system at the same time when the phase φ (t) is changed from π to 0 (the wraparound wave), and the LO oscillator is set so that the phases of the wraparound wave and the LO wave match. Since it is controlled, the amplitude of the sneak wave becomes maximum according to the equation (13). Next, the reflected wave of the target 6 is input for the pulse time width Tp with a time delay Δt that depends on the distance to the target 6. Therefore, as shown in the upper part of FIG. 2, the reflected wave of the target is superimposed on the sneak wave. However, the output of the Q channel 81 in the lower stage is not affected by the amplitude of the wraparound wave according to the equation (12) even at the moment when the phase φ (t) of the transmitted wave is changed from π to 0. Then target 6
The reflected wave of the target 6 is input by the pulse time width Tp with a time delay Δt that depends on the distance to. Therefore, as shown in the lower part of FIG. 2, it becomes the same form as when only the reflected wave of the target is received. Therefore, the distance Δt and the relative velocity of the target can be obtained by obtaining the time Δt from the start of transmission to the reception of the reflected wave of the target and the Doppler frequency by signal processing as in the conventional example.

In the first embodiment, with the above configuration, the influence of the wraparound of the radome or the like can be minimized, so that the gain of the receiving amplifier 12 can be maximized and saturated by the wraparound wave at a short distance. Without this, the maximum detection distance is increased, and the performance as a radar is significantly improved. Further, the target can be accurately detected even at a short distance where the received pulse overlaps the transmitted pulse. Further, since the transmission system and the reception system can be completely separated, it is possible to almost eliminate the transmission / reception wraparound in the RF circuit. Also,
The degree of freedom in design can be improved by increasing the distance between the transmitting and receiving antennas.

In the first embodiment, as shown in FIG.
Although the / 2 delay circuit 83 is installed on the LO side of the Q channel mixer 82, the present invention is not limited to this case, and as shown in FIG. 3, it is provided between the receiving antenna 7 and the Q channel mixer 82 and on the RF side. Even if it is installed, the same effect can be obtained.

Embodiment 2. Hereinafter, a second embodiment of the present invention will be shown in FIG. FIG. 4 shows a heterodyne configuration of the reception system of FIG. 1 according to the first embodiment shown in FIG. That is, as shown in FIG. 4, an IF signal oscillator 15 for outputting an electromagnetic wave having a preset predetermined frequency, an electromagnetic wave received by the receiving antenna 7 and an electromagnetic wave output from the IF signal oscillator 15 are provided. A first stage mixer 16 for mixing and outputting an IF signal is added. Therefore, in the present embodiment, the IF signal output from the first-stage mixer 16 is input to the IQ detection mixer 8 and I
The Q detection mixer 8 IQ-detects the IF signal. Other configurations and operations are the same as those in the above-described first embodiment, and therefore the description thereof is omitted here.

In addition to the effect of the first embodiment, the effect obtained from the present embodiment is a heterodyne structure,
The cost can be reduced by reducing the number of high-frequency mixers in the first stage from two to one. Moreover, since the NF (noise figure) of the receiver antenna 7 can be reduced, the detection performance of the target object 6 is improved.

In the second embodiment, as shown in FIG.
Although the / 2 delay circuit 83 is installed on the LO side of the Q-channel mixer 82, the invention is not limited to this case, and as shown in FIG. 5, it is provided between the first-stage mixer 16 and the Q-channel mixer 82 and on the RF side. Even if it is installed, the same effect can be obtained.

[0058]

INDUSTRIAL APPLICABILITY The present invention relates to an on-vehicle radar device for measuring a distance and a relative velocity of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave. PSK modulating means for PSK-modulating the electromagnetic wave generated, transmitting means for radiating the PSK-modulated electromagnetic wave into space, and receiving the electromagnetic wave emitted by the transmitting means and reflected by the target object or another object Receiving means, a receiving oscillating means for outputting a receiving electromagnetic wave, a detecting means for mixing the electromagnetic wave received by the receiving means with the receiving electromagnetic wave output from the receiving oscillating means, and outputting a beat signal. And outputting a phase difference between the electromagnetic wave received by the receiving means and the electromagnetic wave output from the receiving oscillating means based on the beat signal. By controlling the frequency of the receiving electromagnetic wave of the receiving wave phase difference detecting means and the receiving electromagnetic wave of the receiving oscillating means so that the value of the phase difference output from the phase difference detecting means becomes 0, a signal from other than the target object is detected. Since it is a vehicle-mounted radar device that includes a canceling unit that cancels a beat signal and a signal processing unit that calculates the distance and the relative speed of the target object based on the beat signal output from the detecting unit, the transmission electromagnetic wave Since it is possible to suppress the influence of the sneak into the receiving means, the receiving system does not become saturated with the sneak wave at a short distance, the maximum detection distance becomes large, and an in-vehicle radar device with improved performance can be obtained.

Further, the present invention relates to an on-vehicle radar device for measuring a distance and a relative velocity of a target object on the basis of a transmission electromagnetic wave and a reception electromagnetic wave, the oscillation means generating the electromagnetic wave and the oscillation means generating the electromagnetic wave. The electromagnetic wave generated is PS
PSK modulation means for K modulation, transmission means for radiating the PSK-modulated electromagnetic wave in space, receiving means for receiving the electromagnetic wave radiated by the transmission means and reflected by the target object or another object, IQ detection is performed on the electromagnetic waves received by the receiving means, and IQ detection means for outputting beat signals from the I channel and Q channel is multiplied by both beat signals output from the I channel and Q channel of the IQ detection means. And a voltage for outputting the LO electromagnetic wave to the IQ detecting means while changing the frequency of the electromagnetic wave according to the voltage value output from the multiplying means and the multiplying means outputting the voltage value according to the phase difference between the transmitted and received waves. The distance and the relative speed of the target object are obtained based on the beat signal output from the control oscillating means and the Q channel of the IQ detecting means. Since it is a vehicle-mounted radar device equipped with a signal processing means, it is possible to suppress the influence of sneak waves of transmitted electromagnetic waves on the receiving means, so that the receiving system does not saturate with wraparound waves at short distances and maximum detection is possible. An on-vehicle radar device having a large distance and improved performance can be obtained.

An on-vehicle radar device for measuring a distance and a relative velocity of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave, the oscillating means generating the electromagnetic wave,
PSK modulating means for PSK modulating the electromagnetic wave generated by the oscillating means, transmitting means for radiating the PSK modulated electromagnetic wave into space, and radiating by the transmitting means,
Receiving means for receiving the electromagnetic wave reflected by the target object or another object, and I for outputting an electromagnetic wave of a predetermined frequency
F signal oscillating means, first-stage mixing means for mixing the electromagnetic wave received by the receiving means and the electromagnetic wave output from the IF signal oscillating means to output an IF signal, and the first-stage mixing means. The phase difference between the transmitted and received waves is obtained by multiplying the IQ detection means for IQ detection of the IF signal and outputting the beat signal from the I channel and the Q channel by both the beat signals output from the I channel and Q channel of the IQ detection means. A voltage control oscillating means for outputting a LO electromagnetic wave to the IQ detecting means while changing the frequency of the electromagnetic wave in accordance with the voltage value output from the multiplying means;
Since it is a vehicle-mounted radar device equipped with a signal processing means for obtaining the distance and relative velocity of the target object based on the beat signal output from the Q channel of the detection means, the influence of the sneak of transmitted electromagnetic waves to the receiving means. As a result, the receiving system does not saturate with a wraparound wave at a short distance, the maximum detection distance becomes large, and a vehicle-mounted radar device with improved performance can be obtained. Further, since the heterodyne structure is used, the number of high-frequency mixers in the first stage is reduced, and the cost can be reduced. Further, since the NF (noise figure) of the receiver can be lowered, the target detection performance is improved.

Further, there is further provided a delay means provided between the voltage controlled oscillation means and the IQ detection means for delaying the phase of the frequency of the LO electromagnetic wave by π / 2, and RF of the IQ detection means. Since the π / 2 delay circuit is arranged on the side, it is possible to minimize the influence of wraparound.

Further, there is further provided a delay means provided between the receiving means and the IQ detecting means for delaying the phase of the frequency of the electromagnetic wave received by the receiving means by π / 2, and IQ detecting means. Since the π / 2 delay circuit is arranged on the LO side of the means, the influence due to the sneak can be minimized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle-mounted radar device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing reception of pulse signals by the vehicle-mounted radar device according to Embodiment 1 of the present invention.

FIG. 3 is a block diagram showing a configuration of a modified example of the on-vehicle radar device according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a vehicle-mounted radar device according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a modified example of the on-vehicle radar device according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a conventional vehicle-mounted radar device.

FIG. 7 is an explanatory diagram showing an operation of a conventional vehicle-mounted radar device.

FIG. 8 is an explanatory diagram showing a method of detecting a target object of a conventional vehicle-mounted radar device.

FIG. 9 is an explanatory diagram showing an FFT result which is an example of a method of detecting a target object of a conventional vehicle-mounted radar device.

FIG. 10 is an explanatory diagram showing the operation of the conventional vehicle-mounted radar device, particularly the short-range detection.

[Explanation of symbols]

1 oscillator, 2 PSK modulator, 3 transmission mixer, 4
Transmit antenna, 5 radome, 6 target object, 7 receive antenna, 8 IQ detection mixer, 9 multiplier, 10
LO oscillator, 11 filter, 12 amplifier, 13 A
/ D converter, 14 signal processor, 15 IF signal oscillator, 16 first stage mixer, 81 I channel mixer,
82 Q-channel mixer, 83 π / 2 delay circuit,
101 oscillator, 102 power divider, 103 transmission ON / OFF switch, 104 transmission antenna, 10
5 radome, 106 target object, 107 receiving antenna, 108 receiving mixer, 109 filter, 110
Amplifier, 111 AD converter, 112 Signal processing circuit.

Claims (5)

[Claims] 1. An on-vehicle radar device for measuring a distance and a relative velocity of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave, the oscillating means generating the electromagnetic wave, and the electromagnetic wave generated by the oscillating means. PSK modulating means for PSK modulating, PSK modulating transmitting means for radiating the PSK modulated electromagnetic wave into space, and receiving means for receiving the electromagnetic wave emitted by the transmitting means and reflected by the target object or another object. A receiving oscillating unit that outputs a receiving electromagnetic wave; a detecting unit that mixes the electromagnetic wave received by the receiving unit with the receiving electromagnetic wave output from the receiving oscillating unit and outputs a beat signal; A transmission / reception wave that outputs a phase difference between the electromagnetic wave received by the receiving means and the electromagnetic wave output from the receiving oscillating means based on a signal. By controlling the frequency of the receiving electromagnetic wave of the receiving oscillating means so that the value of the phase difference output from the phase difference detecting means and the phase difference detecting means becomes 0, beat signals from other than the target object are detected. An on-vehicle radar device comprising: a canceling unit that cancels and a signal processing unit that calculates a distance and a relative speed of the target object based on a beat signal output from the detecting unit. 2. An on-vehicle radar device for measuring a distance and a relative speed of a target object based on a transmitted electromagnetic wave and a received electromagnetic wave, the oscillating means generating the electromagnetic wave, and the electromagnetic wave generated by the oscillating means. PSK modulating means for PSK modulating, PSK modulating transmitting means for radiating the PSK modulated electromagnetic wave into space, and receiving means for receiving the electromagnetic wave emitted by the transmitting means and reflected by the target object or another object. IQ detection means for IQ detecting the electromagnetic wave received by the receiving means and outputting a beat signal from the I channel and Q channel, and both beat signals output from the I channel and Q channel of the IQ detection means Multiplying means for multiplying and outputting a voltage value according to the phase difference between the transmitted and received waves; The distance and the relative speed of the target object are obtained based on the voltage control oscillation means for outputting the LO electromagnetic wave to the IQ detection means while changing the frequency of the magnetic wave, and the beat signal output from the Q channel of the IQ detection means. An in-vehicle radar device comprising: a signal processing unit. 3. Based on the transmitted electromagnetic wave and the received electromagnetic wave,
An on-vehicle radar device for measuring a distance and a relative velocity of a target object, comprising: an oscillating means for generating an electromagnetic wave; a PSK modulating means for PSK modulating the electromagnetic wave generated by the oscillating means; Transmitting means for radiating the electromagnetic wave into space, receiving means for receiving the electromagnetic wave emitted by the transmitting means and reflected by the target object or another object, and an IF signal oscillating means for outputting an electromagnetic wave of a predetermined frequency A first-stage mixing means for mixing the electromagnetic wave received by the receiving means and the electromagnetic wave output from the IF signal oscillating means to output an IF signal; and an IF signal of the first-stage mixing means for IQ detection. And then I
IQ detection means for outputting a beat signal from the channel and the Q channel and multiplication for multiplying both beat signals output from the I channel and the Q channel of the IQ detection means, and outputting a voltage value according to the phase difference between the transmitted and received waves. Means, voltage controlled oscillator means for outputting the LO electromagnetic wave to the IQ detecting means while changing the frequency of the electromagnetic wave according to the voltage value outputted from the multiplying means, and beat output from the Q channel of the IQ detecting means. An in-vehicle radar device, comprising: a signal processing unit that obtains a distance and a relative speed of the target object based on a signal. 4. A delay means provided between the voltage-controlled oscillation means and the IQ detection means for delaying the phase of the frequency of the LO electromagnetic wave by π / 2 is further provided. The in-vehicle radar device according to claim 2 or 3. 5. Further comprising a delay means provided between the receiving means and the IQ detecting means for delaying the phase of the frequency of the electromagnetic wave received by the receiving means by π / 2. The in-vehicle radar device according to claim 2 or 3, which is characterized in that.