JP2870508B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radar device,
In particular, the present invention relates to a radar apparatus having a side lobe processing control circuit for controlling whether or not to perform side lobe processing.

[0002]

2. Description of the Related Art Conventionally, a side lobe canceller for suppressing an unnecessary wave such as an interference wave input from a side lobe direction has been used in a radar apparatus.

A side lobe canceller has an SLC (sidelobe) in addition to a main antenna (main antenna).
Canceler-based antennas (sub-antennas), and the respective antenna patterns (antenna directivity) are as shown in FIGS. Figures 5 and 6 show the main system and S
FIG. 3 is an antenna pattern characteristic diagram of an LC antenna. In this pattern characteristic diagram, the horizontal axis indicates the azimuth (degree), and the vertical axis indicates the gain (dB).

The main antenna is an antenna having directivity and has a main lobe (mainlobe) region A having a high gain and side lobe regions a1 to a a having a low gain on both sides thereof.
6. The signals input to the side lobe regions a1 to a6 are not necessary.

On the other hand, the SLC antenna is an almost omnidirectional antenna and has a pattern B in which the gain is almost constant in all directions.

FIG. 5 shows a case where an unnecessary wave is inputted from the angle of intersection C between the main antenna pattern A and the SLC antenna pattern B. FIG. 6 shows a point (null point) D where the gain is almost zero. This shows a case where an unnecessary wave is input. The operation when these unnecessary waves are input will be described later.

The principle of operation of the sidelobe canceller is as follows.
A received signal from the main antenna (hereinafter referred to as a main received signal) and a received signal from the SLC antenna (hereinafter referred to as S
(Referred to as an LC reception signal), an unnecessary wave is extracted as a correlated signal component, and the unnecessary wave is suppressed by subtracting it from the original signal.

The SLC processing method is roughly classified into an analog processing method for processing an analog signal at an intermediate frequency stage before phase detection, and a digital processing after phase detection and A / D (analog / digital) conversion. There is a digital processing method for processing a signal.

First, an analog processing method will be described with reference to FIG. FIG. 7 is a configuration diagram of a first example of a conventional sidelobe canceller.

[0010] The signal received by the main antenna 101 passes through a subtractor 103, and is then input to a mixer 107 together with the signal received by an SLC antenna 102. The output of the mixer 107 is input to the low-pass filter 106, and a correlation component is extracted. After the correlation component is amplified by the amplifier 105,
The signal is input to the multiplier 104. The received signal from the SLC antenna 102 is also input to the multiplier 104, and the result is input to the subtractor 103. Mixer 1 from subtractor 103
07, low-pass filter 106, amplifier 105, multiplier 10
A correlation loop that returns to the subtractor 103 through 4 is formed to suppress unnecessary waves.

An example of this type of SLC system is disclosed in
230102. FIG. 8 shows a configuration of a side lobe canceller of a second example disclosed in this publication, which is an improvement of FIG. 7 described above. This is characterized by having a hold circuit 108 in order to solve the problem that the correlation loop is not stable when a pulse-like discontinuous unnecessary wave is input, and holds the correlation component in this hold circuit 108. This has the effect of shortening the time until the correlation loop is stabilized.

A third example of the side rope shown in FIG.
The canceller is disclosed in Japanese Patent Application Laid-Open No. 5-107334, which is a further improvement of the second example, in which the antenna pattern in the unnecessary wave direction changes by beam scanning and the held correlation component is reset. A pulse generating circuit 109 for generating a reset pulse when necessary.

Next, the digital processing system will be described. The principle of the digital processing method is that after performing phase detection and A / D conversion on the main system reception signal and the SLC system reception signal, the optimum weight for the SLC system reception signal is obtained in real time, the unnecessary wave component is estimated, Is subtracted from the signal.

The calculation formula is as follows.

W = (E {Xa ^* · Xm}) / (E {Xa ^* · Xa}) (1) Y = Xm−W · Xa (2) where Xm is a main system reception signal and Xa Is an SLC system received signal, W is a weight, E ｛｝ is an average value calculation, Y is an SLC
The processing ability and * indicate conjugate complex numbers, respectively.

This digital processing method suppresses unnecessary waves by performing the above-described calculation, and has an advantage that time for stabilizing a correlation loop is not required unlike the analog method.

The contents of this digital processing system are as follows:
RADER HANDBOOK ", MERRILL
I, SKOLNIK, McGRAW-HIL PUBL
ISHING COMPANY, 1990. It is described in.

When the digital processing method is actually adopted, signal loss is always lost due to SLC processing operation accuracy and the like, and the target signal is also suppressed in the main lobe region. Control for turning on the SLC processing is performed only when the input is from the side lobe area. This control method will be described with reference to FIG.

FIG. 10 is a block diagram of a fourth example of a conventional side lobe canceller. First, the main system received signal after the phase detection and the A / D conversion is transmitted to the SLC processor 10 and the I / Q
(In-phase / Quadratic-phas
e) It is input to the synthesizer 5. The main received signal converted into an amplitude value by the I / Q combiner 5 is input to a comparator (1) 6, and if the amplitude of the main received signal is equal to or greater than a threshold (threshold), it is determined that an unnecessary wave is present. Then, the result is input to an on / off (ON / OFF) controller 9.

On the other hand, SLC after phase detection and A / D conversion
The system reception signal is input to the SLC processor 10 and the I / Q combiner 1. In the comparator (2) 3, the inside / outside of the main lobe area is determined based on the magnitude of the amplitude value of the output of the I / Q combiner 5 and the I / Q combiner 1. If the amplitude of the main system reception signal is larger than the amplitude of the SLC system reception signal, it is determined that the amplitude is within the main lobe region, otherwise, it is determined to be outside the main lobe region, and the result is input to the on / off controller 9.

The ON / OFF controller 9 outputs an ON control signal to the SLC processor 10 only when there is an unnecessary wave and is outside the main lobe region, and turns OFF otherwise. The SLC processor 10 turns on or off the SLC process according to a control signal from the on / off controller 9. When the SLC process is off, the main system reception signal is output as it is.

Another technique of this type is disclosed in Japanese Patent Laid-Open No. 2-712.
No. 86, JP-A-3-78680 and JP-A-3-78680
No. 78681, JP-A-62-263482 and JP-A-3-248078.

[0023]

However, in the conventional side lobe canceller, unnecessary waves in the direction corresponding to the direction corresponding to the intersection of the main system antenna pattern and the SLC system antenna pattern (intersection C in FIG. 5). Is input, there is a disadvantage that unnecessary waves remain without being suppressed.

This is because the determination of the unnecessary wave inside or outside the main lobe region is made based on the magnitude relationship between the main system reception signal and the SLC system reception signal. Therefore, the magnitude determination result frequently changes in the direction of intersection C, and the SLC process is turned on. This is because / off becomes unstable.

In FIG. 8, a hold circuit 108 is provided on the output side of the amplifier 105, which holds (holds) only a correlation component. However, it has no effect on unnecessary waves input in the direction of the intersection C.

Further, in the conventional side lobe canceller, when an unnecessary wave in a direction corresponding to the vicinity of the null point (null point D in FIG. 6) of the side lobe area is inputted, the unnecessary wave remains without being suppressed. There was also.

This is because the presence / absence of an unnecessary wave is determined based on the magnitude relationship between the received signal of the main system and the threshold value. Therefore, the magnitude determination result frequently changes near the null point D, and the ON / OFF of the SLC process is unstable. This is because

An object of the present invention is to provide a radar apparatus capable of reliably suppressing unnecessary waves input from the direction of intersection between the main antenna pattern and the SLC antenna pattern and the null point direction of the side lobe area. is there.

[0029]

In order to solve the above-mentioned problems, the present invention provides a main lobe region having a high gain and two main lobe regions.
A main antenna having a low sidelobe region of gain ;
An omnidirectional sub-antenna, first comparing means for comparing the level of the main signal obtained from the main antenna with a predetermined threshold value and outputting a result of the determination of the presence or absence of unnecessary waves ; a first holding means for holding a comparison result by the comparison means, the auxiliary antenna
Amplify the sub-signal obtained from the
The main antenna is higher than the side lobe gain of the main antenna.
Amplifying means set lower than the lobe gain and this amplification
Means for comparing the level of the signal obtained from the antenna with the level of the main signal, and obtaining the signal obtained from the two antennas.
Second comparing means for outputting a result of determination as to whether or not the signal is inputted to the idrobe, second holding means for holding the result of comparison by the second comparing means, and first and second holding means And a determination unit for determining whether or not to perform the side lobe process based on the two comparison results held in the control unit.

According to another aspect of the present invention, there is provided amplification means for amplifying a sub-signal obtained from the sub-antenna and inputting the amplified signal to the second comparison means, and wherein the main signal is input during the sampling time. Only when not performed, the first comparing means causes the first comparison means to compare the main signal with the threshold value even outside the sampling time, and the first holding means does not perform the holding operation. A control unit for controlling the comparing unit and the holding unit is further provided.

According to the present invention, the comparison results obtained by the first and second comparing means are temporarily held in the first and second holding means and then output to the judging means. A stable comparison result that does not change frequently is input. Therefore, the determination means can make a stable determination.

On the other hand, according to another invention, even when an unnecessary wave is inputted outside the sampling time, the unnecessary wave can be detected by the first comparing means, and the main system and the SLC are included in the second comparing means. Even if none of the system signals are input during the sampling time, the noise component of the SLC system signal is amplified by the amplifying means, and the result within the side lobe region is obtained as the second comparison result. The determining means can determine that there is an unnecessary wave.

[0033]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a configuration diagram of a preferred embodiment of a side lobe processing control circuit of a radar apparatus according to the present invention. The same components as those in the conventional example (FIG. 10) are denoted by the same reference numerals, and description thereof will be omitted.

This side lobe processing control circuit includes an SLC processor 10 for performing side lobe processing for convenience of explanation. However, the configuration of the side lobe processing control circuit does not include the SLC processor 10.

The main system received signal is a signal received by an antenna having directivity (not shown), and the SLC system received signal is a signal received by a non-directional antenna (not shown).

The main system reception signal and the SLC system reception signal are signals that have been subjected to phase detection and A / D conversion in advance.
That is, this circuit is a processing circuit using digital signals.

Referring to FIG. 1, a side lobe processing control circuit includes an I / Q combiner 5 to which a main system reception signal is input,
A comparator (1) 6 for comparing the output signal of the I / Q combiner 5 with a predetermined threshold, a hold circuit 7 for holding the output of the comparator (1) 6, and a comparator (1) 6 and a hold controller 8 for controlling a hold circuit 7, and an I / Q combiner 1 to which an SLC system received signal is input.
, An amplifier 2 for amplifying the output of the I / Q combiner 1, a comparator (2) 3 to which the output of the amplifier 2 and the output of the I / Q combiner 5 are input, and a comparator (2) 3 A hold circuit 4 for holding an output; a gate generator 11 for outputting a sampling gate signal for defining a sampling time for comparison to the comparators (1) 6 and (2) 3; ON / OFF (ON / O)
FF) controller 9.

Then, the main system reception signal, the SLC system reception signal, and the output of the on / off (ON / OFF) controller 9 are input to an external SLC processor 10.

Here, the threshold provided in the comparator (1) 6 is set to at least the noise level.

Next, the operation of the side lobe processing control circuit will be described with reference to FIG. FIG. 2 is a timing chart showing the operation of the side lobe processing control circuit.

First, the radar apparatus main body (not shown) generates a transmission trigger for each beam scanning (see FIG. 2H), and operates using the transmission trigger as a reference trigger.

Then, a transmission pulse is transmitted following the transmission trigger (see (I) in the figure), and thereafter, the main system and SLC system reception signals are input almost simultaneously (FIGS. (J) and (K)). )reference).

The sampling gate signal is output from the gate generator 11 almost simultaneously with the reception timing of the main and SLC reception signals.

Now, it is assumed that received signals of the main system and the SLC system are inputted to the side lobe processing control circuit. First, the main system received signal is input to the SLC processor 10 and also to the I / Q combiner 5.

The I / Q combiner 5 converts the I / Q separated main received signal into an amplitude value (level). Then, the main-system reception signal converted into the amplitude value is input to the comparator (1) 6.

The comparator (1) 6 compares the input main system reception signal with a predetermined threshold. And
When the amplitude value of the main system reception signal is determined to be equal to or larger than the threshold, the comparator (1) 6 outputs an ON signal indicating that an unnecessary wave is present as a determination result (see FIG. 2 (N)).
On the other hand, when it is determined that the amplitude value of the main system reception signal is less than the threshold, the comparator (1) 6 outputs an off signal indicating that there is no unnecessary wave as a determination result.

The judgment result from the comparator (1) 6 is input to the hold circuit 7 and held for a certain period of time (FIG. 2 (M)).
reference). The predetermined time period is before the next transmission pulse is emitted, and therefore before the next sampling gate signal is output (see FIG. 3L) and before the next comparison is performed.
The determination result is reset after the elapse of the predetermined time.

On the other hand, the received signal of the SLC system is input to the SLC processor 10 and also to the I / Q combiner 1.

The I / Q combiner 1 converts the I / Q separated SLC system received signal into an amplitude value. Then, the SLC-system reception signal converted into the amplitude value is input to the amplifier 2. The amplifier 2 is set so that the gain is slightly higher than the gains of the side lobes a1 to a6 of the main antenna pattern (see FIG. 5).

The output of the amplifier 2 and the output of the I / Q combiner 5 are input to a comparator (2) 3. The comparator (2) 3 receives the main system received signal input via the I / Q combiner 5 and the SLC input via the I / Q combiner 1 and the amplifier 2.
The amplitude values of the system reception signals are compared.

When the amplitude value of the SLC received signal is equal to or larger than the amplitude value of the main received signal, the comparator (2) 3 determines that the input signal has been input to the side lobe and determines the ON signal as a determination result. Output. On the other hand, when the amplitude value of the SLC reception signal is smaller than the amplitude value of the main reception signal, the comparator (2) 3 determines that the input signal has been input to the main lobe, and outputs an off signal as a determination result ( FIG.
reference).

The judgment result from the comparator (2) 3 is input to the hold circuit 4 and held for a certain period of time (FIG. 2 (M)).
reference). This fixed time is the same as the fixed time of the hold circuit 7.

The ON / OFF controller 9 outputs an ON signal only when an ON signal is input to both the ON / OFF controller 9 from the hold circuits 4 and 7 (see FIG. 2 (P)). That is, the judgment of the comparator (1) 6 is “there is an unnecessary wave”.
And the ON / OFF controller 9 outputs an ON signal only when the judgment of the comparator (2) 3 is “inside lobe”.

This ON signal is input to the SLC processor 10, where the SLC processing is performed and the result is output.

On the other hand, when an off signal is input to at least one of the hold circuits 4 and 7 to the on / off controller 9, the on / off controller 9 outputs an off signal.

This off signal is input to the SLC processor 10, and the SLC processor inhibits the SLC processing.

As described above, when the unnecessary signal is detected when the sampling gate signal is output, the SLC is surely performed.
Processing can be performed. However, in this configuration, if an unnecessary signal is input during a period in which the sampling gate signal is not output (see FIG. 2 (Q)), the SLC process cannot be performed.

Therefore, the present invention has a configuration in which the SLC process can be performed even when an unnecessary signal is input during a period when the sampling gate signal is not output.
The amplifier 2 and the hold controller 8 have the configuration.

When the amplitude value of the main system reception signal is smaller than the threshold value in the comparator (1) 6, the comparator (1) 6
Outputs an off signal, and stops the comparison operation when the sampling gate signal disappears in principle. If the amplitude value of the main system reception signal is less than the threshold, the hold controller 8 eliminates the sampling gate signal. Thereafter, the comparator (1) 6 is configured to be kept in a comparable state. Further, the hold controller 8 controls the hold circuit 7 to pass the comparison result without holding it after the sampling gate signal disappears.

On the other hand, an amplifier 2 is provided on the input side of the comparator (2) 3, and the SLC system received signal is amplified by the amplifier 2 and input to the comparator (2) 3. The amplifier 2
Is set to be slightly higher than the gains of the side lobes a1 to a6 of the main system antenna pattern as described above. Therefore, even when an unnecessary wave is not input to the comparator (2) 3, that is, when both the main system and the SLC system reception signal have a noise level, the SLC system reception signal is amplified by the amplifier 2. Therefore, the comparator (2) 3 determines that the amplitude value of the SLC reception signal is equal to or larger than the amplitude value of the main reception signal, and outputs an ON signal. And
The ON signal is held by the hold circuit 4.

Accordingly, when an unnecessary signal is input at a timing other than the timing at which the sampling gate signal is output (see FIG. 2 (Q)), the comparator (1) receives this signal and has an amplitude value equal to or larger than the threshold. An on signal is output, and the on signal passes through the hold circuit 7 and is input to the on / off controller 9.

On the other hand, in this case, since the comparator (2) 3 does not perform comparison except at the timing when this sampling gate signal is output, the previous comparison result, that is, the ON signal is held in the hold circuit 4. I have.

Accordingly, since the ON signal is input from both the hold circuits 7 and 4 to the ON / OFF controller 9, the ON / OFF controller 9 outputs the ON signal. Then, the ON signal is input to the SLC processor 10, where the SLC processing is performed. Thus, even when an unnecessary signal is input at a timing other than the timing at which the sampling gate signal is output, the SLC
Processing can be performed.

Next, a second embodiment will be described. This is a more specific example of the first embodiment. FIG. 3 is a configuration diagram of the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The difference between the second embodiment and the first embodiment is that the phase detectors 13 and 16, the A / D converter 14,
17, weight calculator 18, multiplier 19, subtractor 2
0, delay circuits 21 and 22, and a selector 23 are added. Of these, the weight calculator 18 to the selector 23 are S
It corresponds to the LC processor 10.

Both the reflected wave of the radio wave radiated into the space and the unnecessary wave are incident on the main antenna and the SLC antenna.

After the phase detector 13 and the A / D converter 14 perform phase detection and A / D conversion of the main system received signal, the delay circuit 21, the weight calculator 18, the subtractor 20, and the I / Q
Output to the synthesizer 5.

The phase detector 16 and the A / D converter 17
After phase detection and A / D conversion of the LC system received signal, the signal is output to the weight calculator 18, the multiplier 19 and the I / Q combiner 1.

The operation after the output of the I / Q combiners 5 and 1 is similar to that of the first embodiment, and the description is omitted.

The weight calculator 18 performs a correlation operation between the main system reception signal and the SLC system reception signal, and a multiplier 19 multiplies the output weight value by the SLC system reception signal, and a subtractor 20 multiplies the output value. The result is subtracted from the main system reception signal. The output of the subtractor 20 is the output after the SLC processing,
Along with the signal before SLC processing, delay circuits 21 and 22 are respectively provided.
After passing through, it is input to the selector 23. The selector 23 receives the signal of the delay circuit 21 when the off signal is input from the on / off controller 9, and outputs the signal of the delay circuit 22 when the on signal is input from the on / off controller 9. Select and output.

Next, the operation will be described more specifically with reference to a timing chart. FIG. 4 is a timing chart showing the operation of the second embodiment.

The radar apparatus according to the second embodiment has a beam scanning interval of 2080 μS (FIG. 4I,
(J)), and operates based on the transmission trigger. The transmission pulse is 80 μS (see (I) in the figure), and after the transmission is completed, the main system reception signal and the SLC system reception signal are input respectively. The reception time was 2000 μS ((J) in FIG.
(K)), which corresponds to a distance of about 80 NM.

The sampling time is set to 50 μS after the start of reception (refer to FIG. 3L), and the comparator (1) 6 determines the presence or absence of an unnecessary wave by comparing the magnitude of the main system reception signal with the threshold. (2) In 3 it is determined whether or not the received signal is in the main lobe area by comparing the magnitude of the main system received signal with the SLC system received signal.

The operation itself of the SLC process is always performed, and the selector 23 determines whether or not to select the operation of the SLC process. The output waveform of the delay circuit 21 is shown in FIG.
The output waveform of the delay circuit 22 is shown in FIG.
The output waveforms of No. 3 are shown in FIG.

If there is no unnecessary wave in the received signal, the comparator (1) 6 determines that there is no unnecessary wave because the main system received signal is smaller than the threshold.
3 selects the output signal of the delay circuit 21.

On the other hand, if a continuous unnecessary wave is input as shown in FIG. 9 (N), if the input direction is the direction of intersection C between the main antenna pattern and the SLC antenna pattern, or the side direction In the null point D direction of the lobe area, even if the comparison result of the comparator (1) 6 or the comparator (2) 3 is unstable at the moment, the sampling time is 50 μm.
If the comparison result is turned on at least once during S, the ON signal is held in the hold circuit 7 or 4, so that the selector 23
Can stably output the delayed SLC processing output signal (see (X) in the figure).

When a pulse-like unnecessary wave outside the sampling time as shown in FIG. 9 (Q) is input, the comparator (1) 6 may determine that there is no unnecessary wave within the sampling time. There is. In this case, as in the first embodiment, the comparator (1) 6 operates outside the sampling time,
Further, the hold controller 8 controls the comparator (1) 6 and the hold circuit 7 so that the hold circuit 7 outputs the determination result without holding it.

The comparator (2) 3 determines that the signal is out of the main lobe if there is no unnecessary wave within the sampling time since the SLC system received signal is amplified by the amplifier 2. As a result, the selector 23 outputs an SLC processing output signal only at the timing when the unnecessary wave is actually input for the pulse-like unnecessary wave (see FIG. 3 (R). (Y)).

[0079]

According to the present invention, the main antenna having directivity, the sub-antenna having no directivity, and the first signal for comparing the level of the main signal obtained from the main antenna with a predetermined threshold value and outputting the result. And a first holding means for holding the result of the comparison by the first comparing means, and comparing the level of the sub signal obtained from the sub antenna with the level of the main signal and outputting the result. A second comparing means, a second holding means for holding a result of comparison by the second comparing means, and a side lobe process based on the two comparison results held by the first and second holding means. Since the radar device includes the determination means for determining whether or not to perform the determination, unnecessary waves input from the direction of the intersection of the main system antenna pattern and the SLC system antenna pattern and the direction of the null point of the side lobe region are reliably suppressed. That Kill.

According to another aspect of the present invention, the radar device amplifies the sub-signal obtained from the sub-antenna and inputs the amplified signal to the second comparing unit. Only when the main signal is not input, the first comparing means causes the main signal to be compared with the threshold value outside the sampling time, and the first holding means does not perform the holding operation. As described above, since the apparatus further includes the control means for controlling the first comparing means and the holding means, unnecessary waves can be reliably suppressed even when unnecessary waves are input outside the sampling time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a preferred embodiment of a side lobe processing control circuit of a radar apparatus according to the present invention.

FIG. 2 is a timing chart showing an operation of the side lobe processing control circuit.

FIG. 3 is a configuration diagram of a second embodiment of the sidelobe processing control circuit.

FIG. 4 is a timing chart showing an operation of the second embodiment of the sidelobe processing control circuit.

FIG. 5 is an antenna pattern characteristic diagram of a main system antenna and an SLC system antenna.

FIG. 6 is an antenna pattern characteristic diagram of a main system antenna and an SLC system antenna.

FIG. 7 is a configuration diagram of a first example of a conventional sidelobe canceller.

FIG. 8 is a configuration diagram of the second example.

FIG. 9 is a configuration diagram of the third example.

FIG. 10 is a configuration diagram of the fourth example.

[Description of Signs] 2 Amplifier 3, 6 Comparator 4, 7 Hold circuit 8 Hold controller 9 ON / OFF controller 11 Gate generator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-198883 (JP, A) JP-A-5-107334 (JP, A) JP-A-2-1176771 (JP, A) JP-A-56-1988 74671 (JP, A) JP-A-6-273517 (JP, A) JP-A-62-230102 (JP, A) JP-A-2-71286 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01S 7/00-7/42 G01S 13/00-123/95

Claims (6)

(57) [Claims] 1. A main lobe region having a high gain and both sides thereof
A main antenna having a side lobe region having a low gain , an omnidirectional sub-antenna, and a main signal level obtained from the main antenna are compared with a predetermined threshold to determine whether there is an unnecessary wave.
First comparing means for outputting a constant result, the first holding means for holding a comparison result in the first comparison means, said auxiliary A
Amplify the sub-signal obtained from the antenna and gain
Is higher than the sidelobe gain of the main antenna.
Amplifying means set lower than the in-lobe gain
The level of the signal obtained from the amplifying means is compared with the level of the main signal, and the signals obtained from the two antennas are compared with each other.
A second comparing means for outputting a result of determination as to whether or not the signal is inputted to the side lobe, a second holding means for holding a result of the comparison by the second comparing means, A radar device for determining whether or not to perform a side lobe process based on two comparison results held in the holding device. 2. The method according to claim 1, wherein the determining unit stores a comparison result indicating that the level of the main signal is equal to or higher than the threshold value in the first holding unit, and stores the level of the sub signal in the second holding unit. 2. The radar apparatus according to claim 1, wherein when the comparison result indicating that the level is equal to or higher than the level of the main signal is held, it is determined that the side lobe processing is performed. 3. The radar apparatus according to claim 1, wherein the threshold is set to at least a noise level. 4. The apparatus according to claim 1, further comprising a sampling time setting means, wherein said first and second comparing means compare each of said signals at the sampling time.
4. The radar device according to any one of claims 1 to 3. 5. An amplifying means for amplifying a sub-signal obtained from said sub-antenna and inputting the amplified signal to said second comparing means, and only when said main signal is not input during said sampling time. The first comparing means and the holding means are configured to cause the first comparing means to compare the main signal with the threshold value even outside the sampling time, and to prevent the first holding means from performing a holding operation. The radar apparatus according to claim 4, further comprising control means for controlling. 6. The radar apparatus according to claim 1, wherein the first and second holding units reset the held comparison result before the next comparison is performed.