JP2007171162A - Radar apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar apparatus for detecting a failure in switches for switching transmission and reception in a plurality of antennas. <P>SOLUTION: The radar apparatus includes a plurality of the antennas having the switches, and detects the failure in the switches, based on a comparison of a level of a signal received by each antenna. If level difference in the signal received is a predetermined value or larger, it is determined that at least one switch has failed and that it cannot be turned on. If the level difference in the received signal is smaller than the gain difference in each antenna and is substantially identical, it is determined that the compared switches substantially have failed and that it cannot be turned off. If the signal received is detected and has a predetermined level or larger when each switch is turned off, it is determined that at least one switch has failed and that it cannot be turned off. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radar apparatus provided with a switch for selecting one of signals received by each of a plurality of antennas, and more particularly to a radar apparatus capable of detecting a switch failure.

  As a method for determining the azimuth of the target, a phase monopulse method is known in which the azimuth of the target is calculated from the phase difference between reflected waves received by two antennas.

  FIG. 1 is a diagram for explaining a phase monopulse system. As shown in FIG. 1, a phase monopulse radar device receives reflected waves from an object with two receiving antenna waves, and determines the azimuth angle θ of the object from the reception phase difference φ between them using, for example, the following equation: To do.

θ = sin ⁻¹ (λφ / 2πd ₀ ) (1)
Where λ is the wavelength of the radar wave and d ₀ is the antenna interval.

  Using a transmission wave that is FM-modulated with a triangular wave, the beat signal generated by mixing a part of the transmission wave with the reception wave is relative to the distance to the object from the sum and difference of the frequencies in the upstream and downstream sections of the triangular wave. FM-CW radar that obtains speed is used as an on-vehicle radar. In this FM-CW radar, the aforementioned reception phase difference φ is calculated from the phase value of the peak appearing in the Fourier transform result of the beat signal.

  FIG. 2 is a block diagram showing a configuration of a phase monopulse FM-CW radar apparatus. In FIG. 2, three antennas AT0, AT1, and AT2 are arranged, and these are preferably arranged at unequal intervals, for example, when the wavelength of the carrier wave is λ, the interval between AT0 and AT1 is 5λ / 4, and AT1 and AT2 Are arranged to be 6λ / 4.

  A transmission signal that is FM-modulated with a triangular wave output from a voltage controlled oscillator (VCO) 10 is amplified by a transmission amplifier 14 and transmitted from an antenna via a circulator 16. In the radar apparatus shown in FIG. 2, transmission and reception are performed by selecting one of the three antennas AT0, AT1, and AT2 with the switches SW0, SW1, and SW2. A reception signal transmitted by the antenna selected by the switches SW0, SW1, and SW2 and received by the antenna selected by the switches SW0, SW1, and SW2 is amplified by the reception amplifier 26 through the circulator 16, and is transmitted to the transmission wave in the mixer 28. Mixed with a part, a beat signal is generated. The beat signal generated by the mixer 28 is converted into a digital signal by the A / D converter 32, subjected to fast Fourier transform (FFT) by the fast Fourier transform unit 34 and input to the CPU 36. Based on the frequency analysis of the beat signal, the CPU 36 calculates the orientation with the target, as well as the distance and relative speed.

  When obtaining the reception phase difference φ, two of the three antennas AT0, AT1, and AT2 are selected, and for each peak obtained from the reception signal (reflected wave) of each selected antenna, the corresponding peak A phase difference value (phase difference φ) is obtained. For example, a combination of the antenna AT0 and the antenna AT1, a combination of the antenna AT0 and the antenna AT2, and a combination of the antenna AT1 and the antenna AT2 can be taken.

Note that the following Patent Document 1 discloses a configuration in which an antenna is determined to be abnormal when the maximum reception level of the switched and received antenna does not exceed a predetermined level. Patent Document 2 below discloses a configuration in which an antenna failure is determined when an average value of differences in received voltages of a plurality of antennas is larger than a threshold value. Patent Document 3 below discloses a configuration in which reception levels from the past are averaged between those received by the same antenna element. Further, Patent Document 4 below discloses a configuration in which, when two transmission outputs are mixed and output due to a failure of a diode switch, only the beat frequency is detected from the mixed output and a failure of the diode switch is detected.
JP-A-11-205207 JP-A-5-327568 JP 2001-127680 A Japanese Patent Laid-Open No. 3-52427

  On the other hand, in the configuration of FIG. 2, since there is one transmission / reception path for three antennas, it is necessary to perform transmission / reception in each antenna in a time division manner. Therefore, at each measurement timing, one antenna that performs transmission and reception is selected by switching control of the switches SW0, SW1, and SW2.

  FIG. 3 is a diagram illustrating a time chart of a control signal of a switch for switching between transmission and reception of the antenna. In the example of FIG. 3, the switch switching control at the next timing t1 to t6 is repeated according to the switching of transmission and reception.

t1: Transmission by antenna AT0 t2: Reception by antenna AT0 t3: Transmission by antenna AT0 t4: Reception by antenna AT1 t5: Transmission by antenna AT0 t6: Reception by antenna AT2 In such switch switching control, normal due to a switch failure If the switch does not turn ON / OFF, accurate measurement cannot be performed. For example, at the reception timing t2 by the antenna AT0, the switches SW1 and SW2 of the antennas AT1 and AT2 need to be OFF. When the antenna AT1 is in the ON state due to the failure of SW1, the antenna AT0 and A beat signal based on a composite signal of signals received by both antennas AT1 will be generated. As described above, due to a failure of the switch, correct measurement cannot be performed if the switch is not turned OFF at the timing when it is turned OFF, or if it is not turned ON at the timing when it is turned ON.

  Accordingly, an object of the present invention is to provide a radar apparatus that can detect a failure of a switch that switches between transmission and reception in a plurality of antennas.

  In order to achieve the above object, the first configuration of the radar apparatus of the present invention includes a first antenna, a second antenna, a first switch connected to the first antenna, and the second antenna. A first switch received by the first antenna and a second signal received by the second antenna are connected to the first switch and the second switch, respectively. Signal processing means for obtaining the level of the first signal and the level of the second signal, and based on the level of the first signal and the level of the second signal, And a switch failure detecting means for detecting a failure of the second switch.

  According to a second configuration of the radar apparatus of the present invention, in the first configuration, the level of the first signal and the level of the second signal are each a plurality of first values obtained by a plurality of measurements. It is an average value of the level of the signal and the level of the plurality of second signals.

  According to a third configuration of the radar apparatus of the present invention, in the first configuration, the level of the first signal and the level of the second signal are the frequencies of the first signal and the second signal, respectively. It is the peak level of the frequency spectrum obtained by analysis.

  According to a fourth configuration of the radar apparatus of the present invention, in the third configuration, the peak level is a maximum peak level among a plurality of peaks appearing in a frequency spectrum.

  According to a fifth configuration of the radar apparatus of the present invention, in the third configuration, the peak level is a peak on a frequency spectrum corresponding to a predetermined target for which a distance or a relative speed is obtained. .

  According to a sixth configuration of the radar apparatus of the present invention, in any one of the first to fifth configurations, the switch failure detecting means is based on a gain difference between the first antenna and the second antenna. Correcting the level of the first signal and the level of the second signal, and based on the corrected level of the first signal and the level of the second signal, the first switch and the A failure of the second switch is detected.

  According to a seventh configuration of the radar apparatus of the present invention, in the sixth configuration, the gain difference includes the first signal path including the first switch and the second switch including the second switch. It includes a gain difference based on a signal path and a gain difference based on pattern characteristics of the first antenna and the second antenna.

  According to an eighth configuration of the radar apparatus of the present invention, in any one of the first to seventh configurations, the switch failure detecting means has a difference between a level of the first signal and a level of the second signal. When the value is equal to or greater than a predetermined value, it is determined that the failure is one in which one of the first switch and the second switch is not turned on.

  According to a ninth configuration of the radar apparatus of the present invention, in the sixth or seventh configuration, the switch failure detecting means is configured such that the level of the first signal and the level of the second signal are greater than the gain difference. When it is small and substantially the same, it is determined that the failure is such that the first switch and the second switch are not turned off.

  According to a tenth configuration of the radar apparatus of the present invention, in any one of the first to seventh configurations, the switch failure detecting means has a predetermined level or more when the first switch and the second switch are in an off state. When the first signal or the second signal is detected, it is determined that at least one of the first switch and the second switch does not turn off.

  According to an eleventh configuration of the radar apparatus of the present invention, in any one of the first to tenth configurations, the radar device includes a warning unit that performs a predetermined warning operation based on a failure detection of the switch failure detection unit. Features.

  A twelfth configuration of a radar apparatus according to the present invention includes a first antenna, a second antenna, a first switch connected to the first antenna, and a second switch connected to the second antenna. A switch and a first signal received by the first antenna and a second signal received by the second antenna are input via the first switch and the second switch, respectively, Based on signal processing means for determining the level of the first signal and the level of the second signal, and the level of the first signal and the level of the second signal, the first switch and the second signal Switch failure, failure of the first antenna and the second antenna, route between the first antenna and the first switch, and route between the second antenna and the second switch The switch that detects the failure of Characterized in that it comprises a switch failure detecting means.

  According to a thirteenth configuration of the radar apparatus of the present invention, in the twelfth configuration, the switch failure detecting means is configured such that a difference between the level of the first signal and the level of the second signal is not less than a predetermined value. In some cases, a failure in which one of the first switch and the second switch is not turned on, a failure in one of the first antenna and the second antenna, or the first antenna and the first switch It is determined that the failure is one of the failure between the path between the second antenna and the path between the second antenna and the second switch.

  A fourteenth configuration of the radar apparatus according to the present invention is characterized in that, in the twelfth or thirteenth configuration, a warning means for performing a predetermined warning action based on the failure detection of the switch failure detection means. And

  According to the present invention, in a radar apparatus having a plurality of antennas whose reception timings can be switched at least by a switch, it is possible to detect a switch failure such as a failure that does not turn on or a failure that does not turn off.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention.

  The configuration of the radar apparatus of the present embodiment is the same as that of FIG. 2, and the switch failure detection in the radar apparatus of the present embodiment is executed by the CPU 36 that analyzes the frequency of the beat signal. Switch failure detection is performed by comparing signal levels obtained for each ON / OFF control of each switch. The ON / OFF control of each switch is performed, for example, at the timing shown in FIG. The switch 36 also performs ON / OFF control of the switch. Specific examples will be described in detail below.

(First embodiment)
FIG. 4 is a flowchart of switch failure detection processing in the first embodiment of the present invention. In the first embodiment, a failure that does not turn on the switch is detected. First, the reception level of each antenna is measured (S100). In step S101, the maximum peak value of the reception levels of the respective antennas is obtained. If the difference between the maximum peak values is equal to or greater than a predetermined value, it is determined that one of the switches does not turn on (S102). If it is less than the predetermined value, it is determined as normal (S103).

  Specifically, when the maximum peak values of the switches SW0, SW1, and SW2 are B0, B1, and B2, respectively, the maximum value MAX (B0, B1, B2) and the minimum value of the maximum peak values B0, B1, and B2 The comparison in step S101 is performed using the following equation (1) that compares the difference between MIN (B0, B1, B2) and the predetermined value K.

(MAX (B0, B1, B2) −MIN (B0, B1, B2) <k (1)
The maximum peak value of the reception level is, for example, the level of the maximum peak among the peaks appearing in the frequency spectrum obtained from the frequency analysis result of the beat signal. By comparing the maximum peaks, the failure can be determined with the highest accuracy. In addition, it is necessary to compare the peak levels for the same target, but if the switch is normally turned on at the operation timing of each antenna, the antenna detects the same peak level for the same target. The maximum peak of the antenna can be considered as a level from the same target. Therefore, it is preferable to use the maximum peak for comparison because it is simple and highly accurate as a process. However, when it can be determined that the peak is from the same target, failure detection may be performed by comparing non-maximum peaks. .

  Preferably, before the peak comparison, it may be confirmed that the peaks used for the comparison are the same target. That is, in the case of FM-CW radar, the distance or relative speed corresponding to the peak used for comparison is obtained by a known calculation method, and it is confirmed that they are substantially the same (the difference is less than a predetermined value). To compare the peaks.

  On the other hand, if the antenna switch does not turn on at the operation timing of an antenna due to some abnormality (when it remains OFF), the peak level of the target cannot be obtained from that antenna, and the maximum peak value is normal. Compared with the maximum peak value in the antenna of a simple switch, it is greatly reduced.

  Thus, by comparing the peak values of the reception levels of the respective antennas, it is possible to detect a failure in which the switch is not turned on.

  The reception level of each antenna is measured multiple times, the average value of the peak values at each reception level is obtained, and failure determination is performed using the average value, thereby eliminating temporary changes such as noise and accuracy. A high determination can be made.

When there is a gain difference in each system of antennas AT0, AT1, and AT2, it is necessary to correct the peak value in consideration of the gain difference in the comparison of maximum peak values. The gain difference is, for example, the gain difference of the signal path from the receiving end of the antenna to the mixer 28 where the beat signal is generated (for example, each switch SW0, SW1, SW2 has an amplification function, and the gain is Since the peak values for the same target differ by the gain difference, it is preferable to compare the peak values in consideration of the gain difference. That is, when the gains of the signal paths from the antennas AT0, AT1, and AT2 are G0, G1, and G2, respectively, and the gain of the path from the antenna AT0 is used as a reference,
Gain difference of antenna AT0 offset0 = G0-G0 = 0
Antenna AT1 gain difference offset1 = G1-G0
Antenna AT2 gain difference offset2 = G2-G0
It becomes. Therefore, instead of the above equation (1), as shown in the following equation (2), the maximum peak values corrected by the gain difference of each antenna are compared.
(MAX (B0 + offset0, B1 + offset1, B2 + offset2) -MIN (B0 + offset0, B1 + offset1, B2 + offset2) <k (2)
Furthermore, the gain difference of each antenna AT0, AT1, AT2 itself may be added to the gain difference of the signal path. Depending on the individual difference of each antenna, the gain of the antenna itself may differ, and a more accurate gain difference can be obtained. In this case, a gain difference between signal paths including each antenna is obtained. However, when including the gain of the antenna, it is necessary to consider the pattern characteristics of the antenna.

  FIG. 5 is a diagram illustrating an example of pattern characteristics of the antenna. As shown in FIG. 5, when the pattern characteristics of each antenna are different, the gain with respect to the target angle is different. For example, the gains of the antennas AT0, AT1, and AT2 when the target angle is the angle θ1 are GP0, GP1, and GP2, respectively. Accordingly, the gain difference of the entire antenna system including the gain difference due to the difference in pattern characteristics is as follows.

Antenna AT0 gain difference offset0 = (G0 + GP0)-(G0 + GP0) = 0
Gain difference offset1 of antenna AT1 = (G1 + GP1)-(G0 + GP0)
Gain difference offset2 of antenna AT2 = (G2 + GP2)-(G0 + GP0)
In addition, when considering the gain difference based on the pattern characteristics of the antenna, it is necessary to obtain the target angle of the peak value used for comparison as described above. Therefore, in this case, since the target angle is not obtained at the stage where the beat signal is only frequency-converted, this failure detection processing is performed after obtaining the angle of the specific target by the known calculation using the phase monopulse method. Do.

  When the pattern characteristics of each antenna are substantially the same, the gains GP0, GP1, and GP2 of each antenna do not change greatly depending on the target angle, so the gain of the signal path including the antenna is measured in advance. The gains of the respective systems of the antennas AT0, AT1, AT2 are measured in advance when the radar apparatus is assembled and stored in the internal memory. Thereby, the gain difference between antennas can be obtained.

Also, when the pattern characteristics of each antenna are different, it is difficult to obtain an accurate gain if the target angle is within the range of the side lobe in the pattern characteristics, so the target angle is within the range of the main lobe of the pattern characteristics of each antenna. It is necessary to be.
(Second embodiment)
FIG. 6 is a flowchart of the switch failure detection process in the second embodiment of the present invention. In the second embodiment, a failure in which the antenna does not turn off is detected using the gain difference between the antennas obtained above. As in the first embodiment, first, the reception level of each antenna is measured (S200). In step S201, the maximum peak value of the reception levels of the two selected antennas is obtained, and the difference between the maximum peak values is substantially the same even though there is a gain difference, more specifically. If it is less than a predetermined value smaller than the gain difference between the two antennas, it is determined that the failure does not turn off the switches of both antennas (S202). If there is a difference of only a gain difference, it is determined as normal (S203).

  For example, if there is no difference corresponding to the offset offset1 of the antenna AT1 between the maximum peak value B0 of the antenna AT0 and the maximum peak value B1 of the antenna AT1, both switches SW0 and SW1 are It is determined that the failure does not turn off. Since both switches are not turned off, the peak value of the same signal obtained by combining the received signals from the antenna AT0 and the antenna AT1 is compared at both the timing when the switch SW0 is turned on and the timing when the switch SW1 is turned on. The difference disappears.

As described above, in the processing of the second embodiment, when the reception levels of the two selected antennas are substantially the same, both the switches of the two antennas are determined to be faulty.
(Third embodiment)
FIG. 7 is a flowchart of the switch failure detection process in the third embodiment of the present invention. Unlike the configuration of FIG. 2, the third embodiment is applied to a radar apparatus having a configuration in which a transmission system is separately provided as shown in FIG.

  FIG. 8 is a diagram illustrating another configuration of the radar apparatus. In the configuration of FIG. 8, antennas AT0, AT1, and AT2 are reception-only antennas, and a transmission-only antenna AT3 is provided separately. In such a configuration, the switches SW0, SW1, and SW2 of the receiving antennas AT0, AT1, and AT2 are all turned off in a state where a transmission signal is transmitted from the transmitting antenna AT3. At this time, if a peak of a predetermined level or higher occurs even though the reception level should be almost zero, it can be determined that any of the switches is not OFF. This is because the level of the received signal is detected because one of the switches remains in the ON state.

  Accordingly, referring back to FIG. 7, in the state where the transmission signal is transmitted from the transmission antenna AT3, the reception antenna is turned off (S300), and the reception level is measured in this state (S301). It is determined whether the reception level is not zero or, more specifically, whether there is a reception level equal to or higher than a predetermined level (S302). If there is, it is determined that one of the switches is not OFF (S303), and if not, it is determined that the switch is normal (S304).

(Fourth embodiment)
FIG. 9 is a flowchart of the switch failure detection process in the fourth embodiment of the present invention. The fourth embodiment is a modification of the first embodiment, and when the difference between the maximum peak values of the antennas is equal to or greater than a predetermined value, as in the first embodiment It is determined that the failure is an antenna-switch system failure, that is, either a switch failure, an antenna failure, or a switch-antenna path failure, without determining that the switch has failed.

  As described in the first embodiment, when the difference between the maximum peak values is equal to or larger than the predetermined value, it is considered that a reception signal from at least one antenna has not been obtained. Since the power switch is not turned on, it can be determined with a very high probability that the received signal has not been obtained (basically, it is safe to assume that only a switch failure occurs) Although the possibility of failure is very low with respect to switch failure, in addition to switch failure, failure of the antenna itself or failure of the path between the antenna and the switch can be assumed.

  The failure of the antenna itself may be, for example, a case where a reception signal is not output due to a failure of an internal circuit of the antenna. Further, the failure of the path between the antenna and the switch may be, for example, the disconnection of the signal line between the antenna and the switch.

  In this way, in addition to the failure of the switch, when the failure of the antenna and the failure of the path between the antenna and the switch are also assumed, by comparing the peak values of the reception levels of the respective antennas, In any case, it is determined that either a switch failure (specifically, a failure in which the switch does not turn on), an antenna failure, or a failure in the path between the antenna and the switch has occurred.

  That is, in FIG. 9, first, the reception level of each antenna is measured (S400). In step S401, the maximum peak value of the reception level of each antenna is obtained. If the difference between the maximum peak values is equal to or greater than a predetermined value, a switch failure in the antenna-switch system (specifically, the switch It is determined that it is either a failure that is not ON), a failure of the antenna, or a failure of the path between the antenna and the switch (S402). If it is less than the predetermined value, it is determined as normal (S403).

  FIG. 10 is a diagram illustrating an example in which the radar apparatus according to the embodiment of the present invention is mounted on a vehicle (automobile). The radar apparatus 100 is installed in a rear bumper of the vehicle 200, for example, and functions as a rear radar that detects the approach of the rear vehicle 300. Of course, the radar apparatus 100 may be installed not only in the rear of the vehicle but also in the front and the side, and may be installed not only in the automobile but also in other moving objects.

  The radar apparatus according to the embodiment of the present invention preferably detects when a switch failure is detected or when a switch failure, an antenna failure, or a switch-antenna path failure is detected, the driver (radar). A predetermined warning operation for notifying the device (when the device is installed in a car) is performed.

  For example, when the radar apparatus is mounted on an automobile, a warning operation includes a process for generating an alarm sound, a voice notification process, and a predetermined warning display process on a car meter panel or a navigation system screen. Such a warning operation is realized by the CPU 36 executing a computer program given in advance.

  The radar apparatus according to the embodiment of the present invention detects a switch failure (or a switch failure, an antenna failure, or a switch-antenna path failure) by comparing reception levels of a plurality of antennas. Therefore, it is not necessary to store a normal value of the reception level in advance (for example, before shipment), it is not necessary to consider the secular change of the radar apparatus, and it is possible to detect a failure even during traveling. Therefore, by performing the failure detection process in the embodiment of the present invention as needed or periodically, it is possible to quickly detect a failure and prevent malfunction due to a failure of the radar device. This will help ensure safety.

  In the processing of each of the embodiments described above, the receiving-side signal processing circuit (a circuit including reference numerals 26, 28, 32, 34, and 36 in the configuration of FIG. 2) is provided for a plurality of antennas. An example of the configuration has been described. In this configuration, since reception signals from a plurality of antennas cannot be processed simultaneously, it is necessary to control transmission / reception timing in a time division manner as described above. On the other hand, in a radar apparatus having a reception side signal processing circuit for each of a plurality of antennas, a plurality of reception side signal processing circuits can simultaneously process a reception signal from each antenna. The above embodiment of the present invention can also be applied to such a configuration.

  Further, the embodiment of the present invention can be applied to a radar apparatus having two or more antennas and switches.

It is a figure explaining a phase monopulse system. It is a block diagram which shows the structure of the FM-CW radar apparatus of a phase monopulse system. It is a figure which shows the time chart of the control signal of the switch for switching transmission / reception of an antenna. It is a flowchart of the switch failure detection process in the first embodiment of the present invention. It is a figure which shows the example of a pattern characteristic of an antenna. It is a flowchart of the switch failure detection process in the second embodiment of the present invention. It is a flowchart of a switch failure detection process in the third embodiment of the present invention. It is a figure which shows another structure of a radar apparatus. It is a flowchart of the switch failure detection process in the fourth embodiment of the present invention. It is a figure which shows the example which mounts the radar apparatus in embodiment of this invention in the vehicle.

Explanation of symbols

  10: Voltage controlled oscillator, 14: Transmitting amplifier, 16: Circulator, 22: Switch, 26: Receiving amplifier, 28: Mixer, 32: A / D converter, 34: Fast Fourier transform, 36: CPU, AT0: Antenna, AT1: Antenna, AT2: Antenna, SW0: Switch, SW1: Switch, SW2: Switch

Claims (14)

The first antenna,
A second antenna,
A first switch connected to the first antenna;
A second switch connected to the second antenna;
The first signal received by the first antenna and the second signal received by the second antenna are input via the first switch and the second switch, respectively, Signal processing means for determining the level of the signal and the level of the second signal;
A radar apparatus comprising: a switch failure detecting means for detecting a failure of the first switch and the second switch based on the level of the first signal and the level of the second signal. . In claim 1,
The level of the first signal and the level of the second signal are respectively average values of the levels of the plurality of first signals and the levels of the plurality of second signals obtained by a plurality of measurements. A characteristic radar device. In claim 1,
A radar apparatus, wherein the level of the first signal and the level of the second signal are peak levels of a frequency spectrum obtained by frequency analysis of the first signal and the second signal, respectively. . In claim 3,
The radar apparatus according to claim 1, wherein the peak level is a maximum peak level among a plurality of peaks appearing in a frequency spectrum. In claim 3,
The radar apparatus according to claim 1, wherein the peak level is a peak on a frequency spectrum corresponding to a predetermined target whose distance or relative speed is obtained. In any one of Claims 1 thru | or 5,
The switch failure detection means corrects the level of the first signal and the level of the second signal based on the gain difference between the first antenna and the second antenna, and the corrected first A radar apparatus, wherein a failure of the first switch and the second switch is detected based on a level of one signal and a level of the second signal. In claim 6,
The gain difference includes a gain difference between the path of the first signal having the first switch and the path of the second signal having the second switch, and the first antenna and the second antenna. A radar apparatus comprising a gain difference based on the pattern characteristics of In any one of Claims 1 thru | or 7,
The switch failure detection means is a failure in which one of the first switch and the second switch is not turned on when a difference between the level of the first signal and the level of the second signal is a predetermined value or more. A radar apparatus characterized by being determined to be present. In claim 6 or 7,
The switch failure detecting means, when the level of the first signal and the level of the second signal are smaller than the gain difference and substantially the same, the first switch and the second switch are A radar apparatus characterized by determining that the fault does not turn off. In any one of Claims 1 thru | or 7,
The switch failure detection means is configured to detect the first switch and the second switch when the first signal or the second signal of a predetermined level or more is detected when the first switch and the second switch are in an OFF state. A radar apparatus, characterized in that it is determined that the failure is such that at least one of the second switches is not turned off. In any one of Claims 1 thru | or 10.
A radar apparatus comprising: warning means for performing a predetermined warning operation based on failure detection of the switch failure detection means. The first antenna,
A second antenna,
A first switch connected to the first antenna;
A second switch connected to the second antenna;
The first signal received by the first antenna and the second signal received by the second antenna are input via the first switch and the second switch, respectively, Signal processing means for determining the level of the signal and the level of the second signal;
Based on the level of the first signal and the level of the second signal, a failure of the first switch and the second switch, a failure of the first antenna and the second antenna, and A radar apparatus, comprising: a switch failure detecting means for detecting a failure of a path between the first antenna and the first switch and a path between the second antenna and the second switch. In claim 12,
The switch failure detection means, when the difference between the level of the first signal and the level of the second signal is a predetermined value or more, a failure in which one of the first switch and the second switch is not turned on, Or one of the failure of one of the first antenna and the second antenna, or one of the path between the first antenna and the first switch and the path between the second antenna and the second switch. A radar apparatus, characterized in that it is determined that one of the failures. In claim 12 or 13,
A radar apparatus comprising: warning means for performing a predetermined warning operation based on failure detection of the switch failure detection means.

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