JP4846481B2 - Radar equipment - Google Patents

Description

  The present invention relates to a radar apparatus having means for correcting a phase change caused by deterioration with time and temperature change, and is a radar apparatus having means for correcting a phase change by obtaining an absolute phase.

  One method of measuring the direction to an object in a radar apparatus is to use a phase difference between signals received by a plurality of antennas. The transmission signal radiated from the transmission antenna is reflected by the target, and the reflected transmission signal is received by the plurality of reception antennas. And the direction of a target can be calculated | required from the phase difference of the received signal received with each receiving antenna.

  In such a radar apparatus, there are variations in the characteristics of the parts constituting the channel of the radar apparatus, and the phase changes in the channel because of a change over time and a temperature change. For this reason, the phase difference between the receiving antennas also changes with time to cause an error, and an error also occurs in the measurement result in the direction to the target.

Patent Documents 1 and 2 are known as methods for correcting such a phase change.
FIG. 8 shows a radar apparatus described in Patent Document 1. The receiving antenna is arranged symmetrically with respect to the front. In this radar apparatus, the modulated correction signal is input to the channels CH10 and CH20 through the line L10, amplified by the low noise amplifiers LNA10 and LNA20, mixed with the signal from the oscillator OSC6 by the mixers MIX3 and MIX4, and converted to an intermediate frequency. After that, the phase is corrected by adjusting the phase shifter PS1 of the channel CH10. Therefore, the low noise amplifiers LNA10 and LNA20 and the mixers MIX3 and MIX4 are to be corrected. In this method, the phases of the oscillators OSC1, 5, 6, and 7 are not synchronized, but the mixers MIX3 and MIX4 are mixed with signals from the same oscillator OSC6, and the mixers MIX5 and MIX6 are mixed with signals from the same oscillator OSC7. Therefore, the relative phase difference between the channels CH10 and CH20 can be obtained correctly, and by adjusting the relative phase difference to be zero, it is possible to correct a phase change due to a change with time or a temperature change. In Patent Document 1, as a method for correcting the relative phase difference to zero, correction data is obtained directly in the signal processing means P1 without using a phase shifter, stored in a memory, and the correction data is used. A method for correcting the phase difference is also described.

  FIG. 9 shows a radar apparatus described in Patent Document 2. With reference to antenna R × 1, measured values φ2 to φ (n) of the phase difference between antenna R × 1 and each antenna R × 2 to R × (n) and the initial phase difference measured at the time of shipment of the radar device From Δ2 to Δ (n), the temperature changes of the low noise amplifiers LNA1 to LNA (m) and the phase changes Δ′1 to Δ ′ (m) due to changes with time are obtained. Then, phase correction is performed based on the values of Δ′1 to Δ ′ (m). That is, it is the phase change of the low noise amplifiers LNA1 to LNA (m) that is to be corrected.

As described above, the phase correction methods described in Patent Literature 1 and Patent Literature 2 obtain a change in phase difference from the relative phase of each channel, and correct the phase using the value.
JP2003-248054 JP 2001-166029 A

  However, in the method described in Patent Document 1, it is necessary to align the length from the oscillator OSC 6 to the mixer of each reception channel in order to match the phase of the carrier wave between the channels. For example, in the method of branching the lines and aligning the length as shown in FIG. 10, when there are many reception channels, the length from the oscillator OSC8 (corresponding to OSC6 in FIG. 8) to the mixer of each reception channel is equal. It is difficult to make a simple branch, and it is not easy to implement because it takes up space. Furthermore, the oscillator OSC6 requires a large output power. Similarly, the length of the line L10 for supplying the correction signal needs to be equal between the channels.

  Further, in the method described in Patent Document 2, it is necessary to detect an initial phase difference. Usually, when a radar apparatus is shipped, an inspector operates a switch or the like to use a reflected wave from a target object as a reference between antennas. The initial phase difference is detected. As described above, Patent Document 2 has a problem in that a calibration operation is required at the time of shipment.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a radar apparatus having means capable of correcting a phase change that does not require a calibration operation at the time of shipment and does not require the line lengths from an oscillator to a mixer to be uniform between channels. Is to realize.

1st invention has a transmission channel which radiates | emits the electromagnetic wave based on a transmission signal with respect to a target, and several receiving channels which receive the reflected wave and obtains a received signal, and measures the azimuth | direction of a target A radar device for demodulating a received signal with a demodulated carrier wave to convert it to an IF signal of IF frequency, a conversion line connected to a mixer for inputting a first carrier wave for conversion to an IF signal, A signal processing device for processing the IF signal, a correction line for inputting a correction signal from the connection point to each reception channel, and an IF signal obtained by converting the reception signal of the reflected wave received by the reception channel by the mixer detects the phase of the quadrature demodulation to the received signal as a detected phase by the second carrier, complement the IF signal correcting signal is converted by the mixer orthogonal demodulation to the second carrier A phase detection means for detecting the phase of use signals as the correction phase, the amplifier of the other receiving channel supplies a first carrier wave is amplified conversion line, an amplifier for supplying a first carrier wave amplified, As a carrier wave for obtaining a correction signal for the correction line, a switch for switching between the case where the input to the amplifier is supplied and the case where the output of the amplifier is supplied, When the output is switched, the first correction phase detected by the phase detection means and the switch are switched when the input to the amplifier is supplied to the correction line, and the first detection phase detected by the phase detection means. 2 Phase transition amount measuring means for measuring the difference from the corrected phase as the phase transition amount of the amplifier of each reception channel, and the reception channel detected by the phase detection means is received. A phase correction unit that corrects the detection phase of the received signal of the reflected wave by the correction phase detected by the phase detection unit and the phase transition amount of the amplifier measured by the phase transition amount measurement unit to obtain a true detection phase; , anda correction signal, a first carrier wave input to the amplifier which not input the output of the other amplifier of the amplifier, the second carrier, the phase is synchronized, the frequency of the correction signal and the first A radar device characterized in that the direction of a target is detected from each true detection phase obtained by a phase correction means of each channel , which is a signal having a carrier frequency difference equal to the frequency of the second carrier. is there.

  Here, the detection phase means a phase when the reception channel receives a reflected wave from the target and the phase of the reception signal is obtained by the phase detection means. The correction phase is a phase obtained by the phase detection means when a correction signal is input, and is a phase for correcting the detection phase.

Since the phase of the correction signal, the first carrier wave, and the second carrier wave are synchronized, the phase of the first carrier wave included in the correction signal at the connection point of the correction line and the phase of the first carrier wave input to the mixer Phase difference (hereinafter, this phase difference is referred to as “first carrier phase difference”) is zero, the correction phase is the phase transition of each receiving channel from the connection point of the correction line to the output of the mixer ( Absolute phase). If the first carrier phase difference is not zero, as in the second invention, the first carrier phase difference is obtained from the difference between the lengths of the correction line and the conversion line and the frequency of the first carrier, and stored. The absolute phase can be obtained by correcting the correction phase value using the first carrier phase difference. As described above, if the length of the conversion line and the length of the correction line are equal for each reception channel and the first carrier phase difference is zero, the correction phase is not affected by the line length. Can be branched by an amplifier and supplied to another receiving channel.

  Therefore, if the phase at the mixer input point of the demodulated carrier wave of the received signal is the same at each receiving channel, simply subtracting the absolute phase obtained as described above from the detected phase, the phase by the amplifier or mixer of the receiving channel Characteristics (including temperature change and change with time) can be compensated.

  The connection position of the correction line to the reception channel may be a connection position that includes a portion with a large phase change due to a change with time or a temperature change downstream of the connection position. The connection position is preferably closer to the reception point. The amount of phase change from the reception point to the connection position can be reduced, and correction can be made more accurately. It is also possible to connect to a receiving antenna.

  Further, the correction phase in each reception channel is measured independently in each channel as an absolute phase. Therefore, the phase of the first carrier wave input to each reception channel does not need to be synchronized between the reception channels. Therefore, it is not necessary to branch the conversion line and the correction line to make the lengths uniform as in the prior art, and the lengths of the conversion lines may be different.

  As the phase correction means, a method of feeding back an error to the phase shifter and correcting the phase shifter so that the phase value detected by the phase detection means becomes a predetermined value is also possible. The transmission signal may be a monopulse or FM-CW.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the phase of the correction signal and the first carrier wave are synchronized using a PLL. At this time, the second carrier wave may also be synchronized using the PLL, but a Costas method may be used.

  In a fourth aspect based on the first aspect or the second aspect, the first carrier and the second carrier are phase-synchronized using a PLL, and the correction signal is transmitted from the first carrier to the second carrier. A radar apparatus characterized by being on-off modulated. Since it is not necessary to create a correction signal separately, synchronization can be achieved more easily.

  When the demodulated carrier wave when demodulating the received signal is supplied to the mixer by the same line as the line supplying the first carrier wave, the relative phase relationship of the demodulated carrier wave between each channel is not known accurately. The direction of the target cannot be determined. Therefore, the phase of the demodulated carrier wave of each channel is stored, and the phase transition amount is further subtracted from the correction phase.

  Further, the present invention can be applied to a millimeter wave radar device.

According to the first to fourth aspects of the present invention, when the phase at the mixer input point of the demodulated carrier wave of the received signal is equal in each reception channel, the correction phase is simply subtracted from the detection phase. It is possible to compensate for phase changes (including temperature changes and changes with time) caused by amplifiers and mixers. Since the phases of the correction signal, the first carrier wave, and the second carrier wave are synchronized, the phase change from the connection point of the correction line of each reception channel to the mixer can be obtained absolutely. Therefore, the phase can be corrected for each reception channel. Further, by performing correction as needed, it is possible to improve the accuracy of detecting the orientation of the target, and it is not necessary to obtain and correct the initial phase at the time of shipment. In addition, since it is sufficient that the first carrier phase difference is known, it is not necessary to equalize the lengths of the correction line and the conversion line between the reception channels. Therefore, it is possible to use the amplifier, it is not necessary to use an oscillator of high power. Also, it is possible to obtain a more accurate angle by correcting the phase between the channels in the demodulation carrier.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a block diagram showing a reception channel section of a radar apparatus according to the present invention. The radar apparatus comprises a transmission channel CH6, reception channels CH1 to CH5, and a radar signal processing apparatus 1 as shown in the block diagram of FIG. . All the reception channels CH1 to CH5 have the same configuration as shown in FIG. In the radar apparatus according to the first embodiment, the transmission signal transmitted from the transmission channel CH6 is reflected by the target, the reception channels CH1 to CH5 receive the reflected signal, and the phase difference of the reception signal is used to determine the target signal. The direction can be measured.

  In the following description, the description is similarly applied to all the reception channels CH1 to CH5.

  As shown in FIG. 1, the reception channel section includes a reception antenna 10, a waveguide 11, a low noise amplifier 12, a mixer 13, an IF filter 14, an A / D converter 15, and a phase measurement section 2, which are connected in this order. Has been. A signal line L3 connecting the waveguide 11 and the low noise amplifier 12 is connected to a signal line for correction (correction line) L1 having a switch 17 at a connection position p, and the mixer 13 is used for frequency conversion (demodulation). The signal line (conversion line) L2 for propagating the first carrier wave is connected. The A / D converter 15 is connected to the radar signal processing apparatus 1 through the signal line L4, and the phase measuring unit 2 is also connected to the radar signal processing apparatus 1. The switch 17 is connected to a signal line L6. Here, the first carrier phase difference is stored in the memory of the radar signal processing device 1 for each of the reception channels CH1 to CH5. The first carrier phase difference is a phase difference between the phase of the first carrier at the connection position p and the phase of the first carrier at the mixer 13 input point. The first carrier phase difference is mainly caused by a difference in length between the signal line L1 and the signal line L2. It is assumed that the signal lines L1 and L2 are very little deteriorated with time and temperature is changed, and therefore the phase change is also extremely small.

  The phase measurement unit 2 is a quadrature demodulation unit that performs synchronous demodulation, and can measure the phase. The phase measuring unit 2 includes a mixer 20, a mixer 21, a π / 2 phase shifter 22, and a phase detector 23. The demodulation signal line L5 is connected to the mixer 21, the π / 2 phase shifter 22, and the phase detector 23. The π / 2 phase shifter 22 is connected to the mixer 20. In FIG. 1, the phase measuring unit 2 is shown in a block diagram, but is actually a digital circuit or a computer processing device. When the phase measuring unit 2 is a circuit that performs analog processing, the A / D converter 15 is not necessary.

  In this radar apparatus, by inputting a signal from the signal lines L1, L2, L5, and L6, the transition phase from the connection position p to the position q on the line between the mixer 13 and the IF filter 14 is detected, and the phase is detected. The detected phase of the received signal at the antenna 10 is corrected by the radar signal processing apparatus 1 using the value. The input signal (correction signal) from the signal line L1 can be regarded as a signal received from the reflected signal from the pseudo target located in front of the receiving antenna 10. Here, in order to obtain the phase values from the connection position p to the position q, the signals input from the signal lines L1, L2, L5, and L6 must be synchronized in phase.

  Therefore, in order to synchronize the phases of the signals input from the signal lines L1, L2, L5, and L6, a PLL is used as in the phase synchronization circuit 3 shown in the block diagram of FIG. The phase synchronization circuit 3 includes a phase comparator 24, a loop filter 25, a VCO (voltage controlled oscillator) 26, a 1 / M frequency divider 27, and a reference oscillator 28 made of a crystal resonator. The signal from the reference oscillator 28 is used as an input signal to the signal lines L1 and L2 by using the phase synchronization circuit 3 and the signal fed back from the 1 / M frequency divider 27 to the phase comparator 24 is extracted. Assume that the input signal is to the signal lines L5 and L6. By doing so, the phases of the input signals to the signal lines L1, L2, L5, and L6 can be synchronized. In the first embodiment, the frequency of the reference oscillator 28 is 5 MHz, and the frequency of the input signal to the signal lines L1 and L2 is 77 GHz. Therefore, the frequency of the input signal to the signal lines L5 and L6 is 5 MHz, which is the same as the frequency of the reference oscillator 28, and the value of M is 15400. The output signal of the VCO 26 is branched by an amplifier and supplied to the reception channels CH1 to CH5.

Next, phase correction by the radar apparatus according to the first embodiment will be described in detail.
The first carrier wave having a frequency of 77 GHz input to the signal line L1 is ON / OFF modulated by the switch 17 with a signal having a frequency of 5 MHz input to the signal line L6. The signal for correction obtained by the modulation passes through the signal line L1, passes through the signal line L3, is amplified by the low noise amplifier 12, and then is input to the signal line L2 by the mixer 13 (the signal having the frequency of 77 GHz). Mixed with one carrier wave and synchronously detected. Thereafter, only a signal having a frequency of 5 MHz is passed through the IF filter 14, converted into a digital signal by the A / D converter 15, and sent to the phase measuring unit 2.

  Here, the phase of the first carrier wave included in the modulated correction signal at the connection position p is β, and the phase of the first carrier wave input to the signal line L2 at the connection position of the signal line L2 and the mixer 13 is set. Is α and there is no phase transition of the transmission line, the signal output from the IF filter 14 is a signal of phase β-α at a frequency of 5 MHz. Further, when the absolute phase from the connection position p to the position q is Δ, and this is taken into consideration, the signal output from the IF filter 14 is a signal with a frequency of 5 MHz and a phase β−α + Δ.

  In the phase measuring unit 2, the digital signal having the frequency of 5 MHz and the phase β−α + Δ sent from the A / D converter 15 is mixed by the mixer 21 with the signal (second carrier wave) having the frequency of 5 MHz input to the signal line L 5. Further, the second carrier wave is quadrature demodulated by mixing the second carrier wave with the signal whose phase is changed by π / 2 by the π / 2 phase shifter 22 and the mixer 20, and the two signal components output from the mixers 20 and 21 are mixed. When the phase detector 23 obtains from (I, Q component), the corrected phase β−α + Δ can be obtained. However, this correction phase includes a phase difference (first carrier level) between the phase of the first carrier wave included in the correction signal at the connection position p and the phase of the first carrier wave at the connection position of the signal line L2 and the mixer 13. Phase difference) β-α is included. When the first carrier phase difference β-α is measured in advance and stored in the memory in the radar signal processing apparatus 1, and the correction phase β-α + Δ is corrected using the first carrier phase difference β-α, the correction phase is corrected. Becomes equal to the absolute phase Δ from the connection position p to the position q, and the accuracy is improved. Since the first carrier phase difference β-α is caused by the difference in length between the signal line L1 and the signal line L2, it is set to zero if the lengths of the signal line L1 and the signal line L2 are equal for each channel. Can do. The lengths of the signal lines L1 and L2 are the same in each reception channel, and may be different between the channels. The correction phase Δ is stored in a memory in the radar signal processing device 1.

On the other hand, assuming that the radio wave of phase γ ₀ is radiated from the transmission channel CH6, the antenna 10 receives the reflected wave of phase δ, and is mixed with the demodulated carrier wave of phase τ by the mixer 13, the detected phase δ + γ ₀ −τ + Δ is obtained. It is done. When the radar signal processing apparatus 1 performs a process of subtracting the correction phase Δ from the detected phase δ + γ ₀ −τ + Δ, the phase δ + γ ₀ −τ is obtained.

What is actually required to obtain the angle is a phase difference between the channels, that is, a difference of δ. Assuming that the corrected phases in the reception channels CH1 and CH2 are δ ₁ + γ ₀ −τ ₁ and δ ₂ + γ ₀ −τ ₂ , the difference is (δ ₂ −δ ₁ ) − (τ ₂ −τ _1). )

Therefore, in order to correct the value of τ, (1) the value of τ of each reception channel is made equal (the line length from the oscillator to the mixer of each reception channel is the same), and (2) each reception channel There are three methods of measuring and storing the value of γ ₀ -τ, and (3) measuring and storing the difference in τ for each reception channel. The methods (2) and (3) are advantageous in that the line lengths do not have to be the same, and the demodulated carrier wave can be distributed to other reception channels using an amplifier.

  If the value of τ is corrected by any of these three methods, the difference in δ can be obtained accurately, so that the arrival angle of the received signal can be obtained with high accuracy.

  In the above correction, by making the connection position p close to the antenna 10, the phase transition between the antenna 10 and the connection position p can be reduced, so that the correction can be made more accurately. In particular, if the connection position p is the antenna 10, it is more accurate. Further, if the distance from the antenna 10 to the connection position p is the same in each reception channel, the phase transition between the antenna 10 and the connection position p in each reception channel becomes equal, so the phase difference includes the phase transition. Since the effect does not work, it can be corrected accurately. Further, if the connection position p is different for each reception channel, the correction phase may be further corrected by the phase difference caused by the connection position p.

  The second embodiment is obtained by replacing the phase measuring unit 2 with the phase correcting unit 4 shown in FIG. 4 in the first embodiment. The digital signal sent from the A / D converter 15 is processed by the phase correction unit 4. Data of the corrected phase Δ obtained by the phase detector 23 is fed back to the phase shifter 29, and the phase is corrected so that the output becomes zero. Therefore, the phase corrected digital signal is sent to the data processing apparatus 1 through the signal line L4.

As shown in the block diagram of FIG. 5, the third embodiment is different from the first embodiment in that the switch 17 and the signal line L6 are not provided. Since the input signal to the signal line L1 (correction signal) and the input signal to the signal line L2 (first carrier wave) need to have different frequencies and phase synchronization, the phase shown in the block diagram of FIG. Two PLLs are used as in the synchronization circuit 5. This phase synchronization circuit 5 includes phase comparators 24a and 24b, loop filters 25a and 25b, VCOs (voltage controlled oscillators) 26a and 26b, 1 / M ₁ frequency divider 27a, 1 / M ₂ frequency divider 27b, crystal oscillation The reference oscillator 28 is a child. An output signal from the VCO 26a is used as an input signal to the signal line L2, and is fed back from the 1 / M ₁ frequency divider 27a to the phase comparator 24a. By extracting this signal and using it as an input signal to the signal line L5 and using an output signal from the VCO 26b as an input signal to the signal line L1, the phase of the correction signal and the first carrier wave are synchronized. Further, by changing the values of M ₁ and M ₂ , the frequency of the input signal to the signal line L1 and the frequency of the input signal to the signal line L2 are made different.

In the third embodiment, the frequency of the reference oscillator 28 is 5 MHz as in the first embodiment, the frequency of the input signal to the signal line L1 is 77.005 GHz, and the frequency of the input signal to the signal line L2 is 77 GHz. Therefore, the frequency of the input signal (second carrier wave) to the signal line L5 is 5 MHz, the value of M ₁ is 15400, and the value of M ₂ is 15401.

  The fourth embodiment is an example in which an input signal to the signal line L2 is branched and input by an amplifier, and FIG. 7 shows connections for the reception channels CH1 and CH2 among the reception channels CH1 to CH5. The two receiving channel sections are the same as those in the first embodiment, and the phase measuring section 2 is also the same, and is omitted. The first carrier wave is branched into an input to the signal line L1a and an input to the amplifier 18a. The first carrier wave input to the amplifier 18a is branched into a signal input to the signal lines L1a and L2a and a signal input to the reception channel CH2. The signal input to the reception channel CH2 is branched into a signal input to the signal line L1b and a signal input to the amplifier 18b. The signal input to the amplifier 18b is a signal input to the signal lines L1b and L2b. The signal is branched to a signal input to a reception channel CH3 (not shown). The signal line L1a is provided with switches 40a and 41a, and the signal line L1b is provided with switches 40b and 41b.

  In the reception channel CH1, the phase change by the amplifier 18a is obtained by comparing the correction phase measured with the switch 40a turned on and turned off with the switch 41a and the correction phase measured with the switch 40a turned off and turned on with the switch 41a. It is done. The phase change by the amplifier 18b is obtained in the same manner.

  When obtaining the detection phase, the switches 40a, 41a, 40b, and 41b are cut off, and a demodulated carrier wave is input instead of the first carrier wave. As the demodulating carrier wave, a signal whose frequency is modulated with a sawtooth wave is used for FM-CW, and the same signal as the first carrier wave is used for monopulse radar.

Let η be the relative phase between the channels of the first carrier wave input to the mixer 13 of each reception channel. Assuming that the signal lines L2 are equal between the respective reception channels, η is proportional to the phase change by the amplifier 18 of each reception channel. Assuming that the other phase values are the same as those in the first embodiment, the phase δ + γ ₀ −η is obtained as a value obtained by subtracting the correction phase from the detected phase in the reception channel CH1 of the fourth embodiment. From this point, correction is further made using the value of η, and the phase δ + γ ₀ can be obtained as in the first embodiment. If the lengths of the signal lines L2 are not equal between the respective reception channels, η including a phase difference corresponding to the line length difference is obtained in advance and stored for each reception channel.

  As described above, in the fourth embodiment, the phase change of the amplifier can be obtained, so that a configuration of branching by the amplifier can be adopted. Therefore, it is not necessary to use a high output oscillator.

  The present invention can be used for an automotive millimeter wave radar device and the like.

FIG. 3 is a block diagram illustrating a reception channel unit of the radar apparatus according to the first embodiment. 1 is a block diagram illustrating a radar apparatus according to a first embodiment. 1 is a block diagram illustrating a phase synchronization circuit according to a first embodiment. FIG. 6 is a block diagram illustrating a phase correction unit according to the second embodiment. FIG. 6 is a block diagram illustrating a reception channel unit of a radar apparatus according to a third embodiment. FIG. 5 is a block diagram illustrating a phase synchronization circuit according to a third embodiment. The block diagram which shows the example which branches the signal of Example 4 by amplifier. 1 is a block diagram showing a radar device described in Patent Document 1. FIG. FIG. 3 is a block diagram showing a radar apparatus described in Patent Document 2. The figure which shows the branch of the track | line from an oscillator.

1: Radar signal processing device 2: Phase measurement unit 3, 5: Phase synchronization circuit 4: Phase correction unit 10: Reception antenna 12: Low noise amplifier 13, 20, 21: Mixer 17, 40a, 40b, 41a, 41b: Switch 22: π / 2 phase shifter 23: phase detector 24, 24a, 24b: phase comparator 25, 25a, 25b: loop filter 26, 26a, 26b: VCO
27: 1 / M frequency divider 27a: 1 / M ₁ frequency divider 27b: 1 / M ₂ frequency divider 28: Reference oscillator 29: Phase shifter L1-L5: Signal line

Claims (4)

In a radar apparatus that has a transmission channel that radiates a radio wave based on a transmission signal to a target and a plurality of reception channels that receive the reflected wave and obtain a reception signal, and measures the orientation of the target,
A mixer for demodulating the received signal with a demodulated carrier wave and converting it to an IF signal of IF frequency;
A conversion line connected to the mixer for inputting a first carrier wave for conversion to the IF signal;
A signal processing device for processing the IF signal;
A correction line for inputting a correction signal from a connection point to each reception channel;
The IF signal obtained by converting the reception signal of the reflected wave received by the reception channel is quadrature demodulated by a second carrier wave to detect the phase of the reception signal as a detection phase, and the correction signal is Phase detection means for orthogonally demodulating the IF signal converted by the mixer with a second carrier wave and detecting the phase of the correction signal as a correction phase ;
An amplifier for supplying the amplified first carrier wave to the conversion line and supplying the amplified first carrier wave to an amplifier of another reception channel;
As a carrier wave for obtaining the correction signal for the correction line, a switch for switching between supplying an input to the amplifier and supplying an output of the amplifier;
The switch is switched when supplying the output of the amplifier to the correction line, the first correction phase detected by the phase detection means, and the switch to the correction line. A phase transition amount measuring means for measuring a difference from the second correction phase detected by the phase detection means by switching when supplying an input to the amplifier as a phase transition amount of the amplifier of each reception channel;
The detection phase of the reception signal of the reflected wave received by the reception channel detected by the phase detection means, the correction phase detected by the phase detection means, and the phase transition amount measurement means measured by the phase transition amount measurement means Correcting only the phase transition amount of the amplifier to obtain a true detection phase;
Have
The correction signal , the first carrier wave that is input to an amplifier that does not receive the output of another amplifier among the amplifiers, and the second carrier wave are synchronized in phase, and the frequency of the correction signal and the first carrier wave A difference in frequency of one carrier wave is equal to a frequency of the second carrier wave;
A radar apparatus , wherein the direction of the target is detected from each true detection phase obtained by the phase correction means of each channel .   Based on the difference between the length of the correction line and the length of the conversion line of each reception channel, the phase difference between the correction signal at the connection point and the first carrier wave at the mixer is determined for each reception channel. The radar apparatus according to claim 1, further comprising a storage unit configured to store the correction phase, wherein the correction phase is corrected by the phase difference.   The radar apparatus according to claim 1, wherein the phase of the correction signal and the first carrier wave are synchronized using a PLL. The first carrier and the second carrier are synchronized in phase using a PLL,
The radar apparatus according to claim 1, wherein the correction signal is obtained by on-off modulating the second carrier wave with the first carrier wave.

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