JP2007078463A - Monitoring radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a monitoring radar system capable of providing a reception filter characteristic having a high attenuation characteristic and a low dispersion of a group delay characteristic, by simple constitution, so as to enhance reception sensitivity to a response signal. <P>SOLUTION: Respective IF signals are converted from an analog signal into a digital signal by A/D converters 51-1 to 51-3, before passing the respective IF signals through bandpass filters 53-1 to 53-3, followed to be converted into digital signals (I-signal, Q-signal) of complex mode by I/Q detectors 52-1 to 52-3, and the digital signals are passed thereafter through the bandpass filters 53-1 to 53-3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a secondary monitoring radar apparatus for air traffic control, for example, and more particularly to a technique for improving reception sensitivity with respect to a response signal.

The secondary surveillance radar device for air traffic control transmits an interrogation signal (1030 MHz) to a transponder (response device) on an aircraft as shown in Patent Document 1, for example, and the interrogation signal decoded by the transponder The aircraft is identified by receiving a corresponding response signal (1090 MHz).
JP-A 61-11683.

  By the way, the secondary monitoring radar apparatus is required to use a reception filter for the purpose of receiving as weak a response signal as possible from the transponder and reproducing the response signal faithfully. As a filter characteristic of the reception filter, a characteristic having a large attenuation characteristic (a large inclination of the attenuation characteristic) and a small variation in the group delay characteristic is required. However, a reception filter that satisfies this requirement is realized by an analog circuit, and it is difficult to obtain ideal characteristics.

  Further, when the secondary monitoring radar apparatus includes a multi-receiver used in the monopulse angle measurement method, the amplitude / phase characteristics between the systems (sum pattern, difference pattern) are improved in order to improve angle measurement accuracy. Must be the same. In this case, the amplitude / phase characteristics between each system are measured, and based on the measurement results, the feeder length between the antenna and the receiver is adjusted, the amplitude level is adjusted by the attenuator in the receiver, and the phase characteristics by the phaser. Is adjusted by human work. For this reason, it takes a lot of labor and time to complete the adjustment, it is difficult to ensure the adjustment accuracy, and it is difficult to ensure the long-term stability in operation.

  Accordingly, a first object of the present invention is to provide a monitoring radar device capable of realizing a reception filter characteristic having a large attenuation characteristic and a small variation in group delay characteristic with a simple configuration in order to improve reception sensitivity with respect to a response signal. It is to provide.

  The second object of the present invention is to make it possible to adjust the amplitude and phase characteristics of the received signal quickly and appropriately without requiring manual operation in order to improve the reception sensitivity with respect to the response signal. An object of the present invention is to provide a surveillance radar device capable of ensuring long-term stability.

In order to achieve the above object, the present invention is configured as follows.
In a surveillance radar device that sends an interrogation signal toward an object, receives a response signal from the object to the interrogation signal at a receiving unit, converts the IF signal to an IF frequency at a frequency conversion unit, and passes a bandpass filter to obtain a video signal An analog / digital conversion means for converting the output signal of the frequency conversion section from an analog signal to a digital signal, and an orthogonal conversion means for orthogonally converting the digital signal obtained by the analog / digital conversion means and outputting the result to a bandpass filter. It is what I did.

  According to this configuration, before the response signal converted to the IF frequency is passed through the bandpass filter, the response signal in the IF frequency band is converted from an analog signal to a digital signal, and the digital signal is orthogonally converted to obtain a complex digital The signal (I signal, Q signal) is passed through a bandpass filter. Therefore, the bandpass filter can be created by a digital FIR (Finit Impulse Response) filter, thereby realizing a reception filter characteristic having a large attenuation characteristic and a small variation in the group delay characteristic.

  It is characterized by further comprising a removing means for removing unwanted wave components from the output signal of the frequency converting section between the frequency converting section and the analog / digital converting means.

  According to this configuration, unnecessary wave components are removed from the response signal converted to the IF frequency prior to the conversion to the digital signal, so that even better reception filter characteristics can be realized.

  In a monitoring radar device that sends an interrogation signal toward an object, receives a response signal from the object to the interrogation signal at the receiving unit, converts the IF signal to an IF frequency at the frequency converting unit, and obtains a video signal. The analog / digital conversion means for converting the output signal from the analog signal to the digital signal, the orthogonal conversion means for orthogonally converting the digital signal obtained by the analog / digital conversion means, and the amplitude characteristic and phase characteristic of the response signal are the best A memory for storing the reference amplitude information and the reference phase information obtained so that the amplitude and phase of the digital signal converted by the analog / digital means are corrected according to the reference amplitude information and the reference phase information stored in the memory. And a correction means for performing the correction.

  According to this configuration, before the video signal generation processing, the response signal in the IF frequency band is converted from an analog signal to a digital signal, and the digital signal is orthogonally converted to form a complex format digital signal (I signal, Q signal). A video signal is generated from the digital signal, and the amplitude and phase of the digital signal are corrected using reference amplitude information and reference phase information stored in the memory. Therefore, by simply storing the reference amplitude information and reference phase information in the memory, the amplitude and phase characteristics of the received signal can be adjusted quickly and appropriately without human intervention. It is possible to ensure the stability of

  The interrogation signal is sent to the object, the response signal to the interrogation signal is received from the object at the receiving unit, and the sum signal of the received signals obtained at a plurality of locations of the receiving unit is received by the first system. In a secondary monitoring radar apparatus that branches a signal difference signal to a second system and converts each system into an IF frequency by a frequency conversion unit to obtain a video signal, the sum signal of the first system and the difference signal of the second system Pilot signal superimposing means for superimposing pilot signals each having known amplitude and phase characteristics, analog / digital conversion means for converting the output signal of the frequency converter from an analog signal to a digital signal, and the analog / digital conversion means A pilot signal is extracted from the orthogonal transformation means for orthogonally transforming the digital signal obtained in step 1 and the video signals of the first and second systems, respectively. Based on the detection means for detecting the difference in amplitude / phase characteristics between the first and second systems, and the difference obtained by the detection means, the amplitude and phase of the digital signal converted by the analog / digital conversion means are corrected. And a correction means.

  According to this configuration, a pilot signal having a known amplitude / phase characteristic is superimposed on the sum signal and the difference signal of the received signal, and the pilot signal superimposed on the sum signal and the difference signal is used. Thus, the difference between the amplitude and phase characteristics between the systems is detected, and the amplitude and phase of the digital signal between the systems are adjusted. Therefore, it is possible to easily adjust the amplitude / phase characteristics of the received signal without using a special measuring instrument or the like.

  As described above in detail, according to the present invention, in order to improve the reception sensitivity with respect to the response signal, a monitoring radar apparatus capable of realizing a reception filter characteristic having a large attenuation characteristic and a small variation in group delay characteristic with a simple configuration. Can be provided.

  In addition, it is possible to provide a monitoring radar apparatus that can adjust the amplitude and phase characteristics of the received signal quickly and appropriately without requiring manpower, thereby ensuring long-term stability in operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing the configuration of the secondary monitoring radar apparatus according to the first embodiment of the present invention.

  In FIG. 1, an interrogation signal necessary for identifying an aircraft (not shown), for example, is generated from the transmitter 1. This interrogation signal is sent to the aircraft by the antenna device 3 via the circulator 2.

  Then, a response signal to the interrogation signal is received by the antenna device 3 from the transponder of the aircraft. The antenna device 3 adds received signals at a plurality of locations to generate a sum pattern RF (radio frequency) signal, and subtracts each received signal to generate a difference pattern RF signal.

  The sum pattern RF signal obtained by the antenna device 3 is supplied to the receiver 4 via the circulator 2, and the difference pattern RF signal is supplied directly to the receiver 4.

  On the other hand, the omni-pattern transmission signal generated from the transmitter 1 is sent to the aircraft by the antenna device 3 via the circulator 6, and the omni-pattern RF signal obtained by the antenna device 3 is transmitted to the circulator 6. To be supplied to the receiver 4.

  FIG. 2 is a block diagram showing a connection configuration between the receiver 4 and the signal processing unit 5.

  That is, for each RF signal (sum pattern, difference pattern, omni pattern) received by the antenna device 3, a desired reception frequency is selected by the bandpass filters 41-1 to 41-3 provided in each system, After being amplified by the high-frequency amplifiers 42-1 to 42-3 and converted into IF (intermediate frequency) signals by the mixers 43-1 to 43-3 and the local oscillator 44, unnecessary signals at the IF stage are bandpass filters. Each IF signal (sum pattern, difference pattern, omni pattern) is obtained by removing at 45-1 to 45-3.

  The obtained IF signals (sum pattern, difference pattern, omni pattern) are input to the signal processing device 5 and converted from analog signals to digital signals by A / D (analog / digital) converters 51-1 to 51-3. Then, the I / Q video signals are obtained by the I / Q detectors 52-1 to 52-3. Each I / Q video signal (sum pattern, difference pattern, omni pattern) passes through bandpass filters 53-1 to 53-3 for the purpose of ensuring minimum reception sensitivity and faithful reproduction of the received signal, and a video creation circuit 54 -1 to 54-3 generate each video signal (sum pattern, difference pattern, omni pattern).

  Further, the I / Q video signal (sum) and the I / Q video signal (difference) are generated into a video signal (monopulse) by the monopulse video creation circuit 55.

Next, the operation in the above configuration will be described.
Previously, a configuration as shown in FIG. 3 was considered as a receiver of the secondary monitoring radar apparatus. In FIG. 3, the same parts as those in FIG.

  Each IF signal (sum pattern, difference pattern, omni pattern) that has passed through the band-pass filters 45-1 to 45-3 is video-detected by the respective video detection circuits 71-1 to 71-3, and a video signal (sum pattern, As a difference pattern and an omni pattern, the IF signal (sum) and the IF signal (difference) are further processed by a π / 2 hybrid circuit 72, a video detection circuit 73, and a monopulse video creation circuit 74 to create a video signal (monopulse) for signal processing It was output to the device.

  The reception filter characteristics of the secondary monitoring radar device are realized by band-pass filters 45-1 to 45-3 in the IF signal stage. However, it is very difficult to provide these bandpass filters 45-1 to 45-3 with reception filter characteristics having large attenuation characteristics and small variations in group delay characteristics, and the circuit configuration becomes complicated. It will be.

  Therefore, in the first embodiment, the reception filter characteristics are RF-stage bandpass filters 41-1 to 41-3, IF-stage bandpass filters 45-1 to 45-3, and digital-stage bandpass filters 53-. Paying attention to the fact that it is realized by combining the attenuation characteristics 1 to 53-3, the bandwidths of the filters 41-1 to 41-3, 45-1 to 45-3, and 53-1 to 53-3 are as follows. RF stage bandpass filters 41-1 to 41-3> IF stage bandpass filters 45-1 to 45-3> digital stage bandpass filters 53-1 to 53-3.

  As a result, the reception filter characteristics for ensuring the minimum reception sensitivity and obtaining the faithful reproduction of the received signal are determined by the characteristics of the digital stage band-pass filters 53-1 to 53-3.

  Therefore, by creating digital stage band-pass filters 53-1 to 53-3 with digital FIR (Finit Impulse Response) filters, the attenuation characteristics are large (the inclination of the attenuation characteristics is large), and the group delay characteristics vary. A small reception filter characteristic can be realized.

  Further, by configuring the band pass filters 53-1 to 53-3 with digital FIR filters, it becomes possible to make the filter characteristics between the systems (sum pattern, difference pattern, omni pattern) the same, and between the systems. Variations in characteristics can be eliminated.

  As described above, in the first embodiment, each IF signal is analogized by the A / D converters 51-1 to 51-3 before each IF signal is passed through the bandpass filters 53-1 to 53-3. The signal is converted to a digital signal, converted into a complex digital signal (I signal, Q signal) by I / Q detectors 52-1 to 52-3, and passed through bandpass filters 53-1 to 53-3. It is configured as follows.

  Accordingly, the bandpass filters 53-1 to 53-3 can be created by digital FIR filters, thereby realizing a reception filter characteristic having a large attenuation characteristic and a small variation in the group delay characteristic.

(Second Embodiment)
FIG. 4 is a block diagram showing a connection configuration between the receiver and the signal processing device of the secondary monitoring radar device according to the second embodiment of the present invention. In FIG. 4, the same parts as those in FIG.

  In the second embodiment, the bandpass filters 45-1 to 45-3 are deleted. Therefore, in such a second embodiment, since the reception filter characteristics are realized only by the bandpass filters 53-1 to 53-3, the circuit is inferior to the first embodiment in terms of accuracy, but the circuit The configuration can be simplified.

(Third embodiment)
FIG. 5 is a block diagram showing a connection configuration between a receiver and a signal processing device of a secondary monitoring radar device according to the third embodiment of the present invention. In FIG. 5, the same parts as those in FIG.

  In the third embodiment, an amplitude / phase correction circuit 81 is interposed between the I / Q detector 52-2 and the bandpass filter 53-2 of the difference pattern system. A memory 82 is connected to the amplitude / phase correction circuit 81.

  The memory 82 stores reference amplitude data and reference phase data based on the sum pattern so that the amplitude / phase characteristics between the systems (sum pattern, difference pattern) are the same.

  The amplitude / phase correction circuit 81 receives the I / Q video signal output from the I / Q detector 52-2, and inputs the I / Q signal based on the reference amplitude data and the reference phase data stored in the memory 82. To correct the amplitude and phase.

  As described above, in the third embodiment, the I / Q detector 52 uses the reference amplitude data and the reference phase data stored in the memory 81 prior to the video signal generation processing by the video creation circuit 54-1. The amplitude and phase of the I / Q signal output from -2 are corrected.

  Therefore, only by storing the reference pattern amplitude data and the reference phase data of the sum pattern in the memory 82, the amplitude / phase characteristics between the systems can be adjusted quickly and appropriately without human intervention. Long-term stability during operation can be ensured.

  In the third embodiment, the example in which the reference amplitude data and the reference phase data of the sum pattern are stored in the memory 82 has been described. However, the reference amplitude data that provides the best amplitude / phase characteristics of the difference pattern signal. The reference phase data may be stored.

(Fourth embodiment)
FIG. 6 is a block diagram showing a connection configuration between a receiver and a signal processing apparatus of a secondary monitoring radar apparatus according to the fourth embodiment of the present invention. In FIG. 6, the same parts as those in FIG.

  In the fourth embodiment, an amplitude correction circuit 83 is inserted between the A / D converter 51-2 and the I / Q detector 52-2, and the I / Q detector 52-2 and the bandpass are connected. A phase correction circuit 84 is interposed between the filter 53-2 and the filter 53-2. At this time, a memory 82 is connected to the amplitude correction circuit 83 and the phase correction circuit 84, and the reference amplitude data and reference phase data of the sum pattern are stored in the memory 82.

  The amplitude correction circuit 83 receives the digital signal output from the A / D converter 51-2 and corrects the amplitude of the digital signal based on the reference amplitude data stored in the memory 82. The phase correction circuit 84 receives the I / Q video signal output from the I / Q detector 52-2 and corrects the phase of the I / Q signal based on the reference phase data stored in the memory 82. To do.

  As described above, in the fourth embodiment, the same effects as those of the third embodiment can be obtained, and the amplitude correction circuit 83 and the phase correction circuit 84 are separately provided. The processing burden is reduced compared to the third embodiment.

(Fifth embodiment)
FIG. 7 is a block diagram showing a connection configuration between the receiver and the signal processing device of the secondary monitoring radar device according to the fifth embodiment of the present invention. In FIG. 7, the same parts as those in FIG.

  In the fifth embodiment, an amplitude / phase correction circuit 81 is interposed between the I / Q detector 52-1 and the bandpass filter 53-1 of the sum pattern system. A memory 82 is connected to the amplitude / phase correction circuit 81.

  The memory 82 stores reference amplitude data and reference phase data based on the difference pattern so that the amplitude / phase characteristics between the systems (sum pattern, difference pattern) are the same.

  The amplitude / phase correction circuit 81 receives the I / Q video signal output from the I / Q detector 52-1, and inputs the I / Q signal based on the reference amplitude data and the reference phase data stored in the memory 82. To correct the amplitude and phase.

  Thus, even in the fifth embodiment, the same operational effects as those in the third embodiment can be obtained.

(Sixth embodiment)
FIG. 8 is a block diagram showing a connection configuration between the receiver and the signal processing device of the secondary monitoring radar device according to the sixth embodiment of the present invention. In FIG. 8, the same parts as those in FIG.

  In the sixth embodiment, an amplitude correction circuit 83 is inserted and connected between the A / D converter 51-1 and the I / Q detector 52-1, and the I / Q detector 52-1 and the bandpass are connected. A phase correction circuit 84 is inserted and connected between the filter 53-1. At this time, a memory 82 is connected to the amplitude correction circuit 83 and the phase correction circuit 84, and the reference amplitude data and reference phase data of the difference pattern are stored in the memory 82.

  The amplitude correction circuit 83 receives the digital signal output from the A / D converter 51-1 and corrects the amplitude of the digital signal based on the reference amplitude data stored in the memory 82. The phase correction circuit 84 receives the I / Q video signal output from the I / Q detector 52-1, and corrects the phase of the I / Q signal based on the reference phase data stored in the memory 82. To do.

  Thus, even in the sixth embodiment, the same operational effects as in the fourth embodiment can be obtained.

(Seventh embodiment)
FIG. 9 is a block diagram showing a connection configuration between a receiver and a signal processing device of the secondary monitoring radar device according to the seventh embodiment of the present invention. In FIG. 9, the same parts as those in FIG.

  In the seventh embodiment, an amplitude / phase correction circuit 85 is provided between the I / Q detectors 52-1 and 52-2 and the band-pass filters 53-1 and 53-2 of the sum pattern and difference pattern systems. Insertion is connected. A memory 82 is connected to the amplitude / phase correction circuit 85.

  The memory 82 stores reference amplitude data and reference phase data based on the sum pattern and the difference pattern so that the amplitude / phase characteristics between the systems (sum pattern, difference pattern) are the same.

  The amplitude / phase correction circuit 85 receives the I / Q video signals output from the I / Q detectors 52-1 and 52-2, and based on the reference amplitude data and the reference phase data stored in the memory 82. The amplitude and phase of the I / Q signal are corrected.

  As described above, even in the seventh embodiment, the same effects as those of the third embodiment can be obtained.

(Eighth embodiment)
FIG. 10 is a block diagram showing a connection configuration between the receiver and the signal processing device of the secondary monitoring radar device according to the eighth embodiment of the present invention. In FIG. 10, the same parts as those in FIG.

  In the eighth embodiment, an amplitude correction circuit 86 is provided between the A / D converters 51-1 and 51-2 and the I / Q detectors 52-1 and 52-2 in the system of the sum pattern and the difference pattern. The phase correction circuit 87 is inserted and connected between the I / Q detectors 52-1 and 52-2 and the band pass filters 53-1 and 53-2. A memory 82 is connected to the amplitude correction circuit 86 and the phase correction circuit 87.

  The memory 82 stores reference amplitude data and reference phase data based on the sum pattern and the difference pattern so that the amplitude / phase characteristics between the systems (sum pattern, difference pattern) are the same.

  The amplitude correction circuit 86 receives the digital signal output from the A / D converters 51-1 and 51-2 and corrects the amplitude of the digital signal based on the reference amplitude data stored in the memory 82. The phase correction circuit 87 also receives the I / Q video signal output from the I / Q detectors 52-1 and 52-2, and receives the I / Q signal based on the reference phase data stored in the memory 82. Correct the phase.

  As described above, even in the eighth embodiment, the same effect as that of the third embodiment can be obtained.

(Ninth embodiment)
FIG. 11 is a block diagram showing the configuration of the secondary monitoring radar apparatus according to the ninth embodiment of the present invention. In FIG. 11, the same parts as those in FIG.

  In the ninth embodiment, the pilot signal generator 100 is connected to the antenna apparatus 3. The pilot signal generator 100 generates a pilot signal having a known amplitude / phase characteristic. The pilot signal is superimposed on the sum pattern and difference pattern RF signals by the antenna apparatus 3.

  FIG. 12 is a block diagram showing a connection configuration between the receiver 4 and the signal processing unit 5. In FIG. 12, the same parts as those in FIG.

  In the ninth embodiment, an amplitude / phase correction circuit 91 is interposed between the I / Q detector 52-2 and the bandpass filter 53-2 in the difference pattern system. The amplitude / phase correction circuit 91 is controlled by a pilot signal detection circuit 92.

  The pilot signal detection circuit 92 extracts a pilot signal superimposed on each video signal output from the video creation circuits 54-1 and 54-2, and the amplitude and phase between the systems of the sum pattern and the difference pattern by these pilot signals. A difference in characteristics is detected, and the detection result is output to the amplitude / phase correction circuit 91 as amplitude / phase correction information.

  Then, the amplitude / phase correction circuit 91 corrects the amplitude and phase of the I / Q video signal output from the I / Q detector 52-2 based on the amplitude / phase correction information.

  As described above, in the ninth embodiment, pilot signals having known amplitude / phase characteristics are superimposed on the sum pattern and difference pattern RF signals, respectively, and are added to the sum pattern and difference pattern video signals. Using the superimposed pilot signal, the pilot signal detection circuit 92 detects the difference in amplitude / phase characteristics between the respective systems, and the amplitude / phase correction circuit 91 outputs from the I / Q detector 52-2. The amplitude and phase of the I / Q video signal to be corrected are corrected to match the amplitude and phase of the video signal between systems.

  Therefore, it is possible to easily adjust the amplitude / phase characteristics between the sum pattern and difference pattern systems without using a special measuring instrument or the like.

(Other embodiments)
Although the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment.

  The present invention can also be applied to a general surveillance radar.

1 is a block diagram showing a configuration of a secondary monitoring radar apparatus according to a first embodiment of the present invention. The block diagram which shows the connection structure of the receiver and signal processing part in the said 1st Embodiment. The block diagram which shows the receiver of the secondary monitoring radar apparatus considered before. The block diagram which shows the connection structure of the receiver and signal processing apparatus of the secondary monitoring radar apparatus concerning 2nd Embodiment of this invention. The block diagram which shows the connection structure of the receiver and signal processing apparatus of the secondary monitoring radar apparatus concerning 3rd Embodiment of this invention. The block diagram which shows the connection structure of the receiver and signal processing apparatus of the secondary monitoring radar apparatus concerning 4th Embodiment of this invention. The block diagram which shows the connection structure of the receiver and signal processing apparatus of the secondary monitoring radar apparatus concerning 5th Embodiment of this invention. The block diagram which shows the connection structure of the receiver of the secondary monitoring radar apparatus and signal processing apparatus concerning 6th Embodiment of this invention. The block diagram which shows the connection structure of the receiver and signal processing apparatus of the secondary monitoring radar apparatus concerning 7th Embodiment of this invention. The block diagram which shows the connection structure of the receiver of the secondary monitoring radar apparatus and signal processing apparatus concerning 8th Embodiment of this invention. The block diagram which shows the structure of the secondary monitoring radar apparatus concerning the 9th Embodiment of this invention. The block diagram which shows the connection structure of the receiver and signal processing part in said 9th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmitter, 2 ... Circulator, 3 ... Antenna apparatus, 4 ... Receiver, 5 ... Signal processing apparatus, 41-1 to 41-3, 45-1 to 45-3, 53-1 to 53-3 ... Band Pass filter, 42-1 to 42-3 ... high frequency amplifier, 43-1 to 43-3 ... mixer, 44 ... local oscillator, 51-1 to 51-3 ... A / D (analog / digital) converter, 52- 1 to 52-3 ... I / Q detector, 54-1 to 54-3 ... video creation circuit, 55 ... monopulse video creation circuit, 81, 85, 91 ... amplitude / phase correction circuit, 82 ... memory, 83, 86 ... Amplitude correction circuit, 84, 87 ... Phase correction circuit, 92 ... Pilot signal detection circuit, 100 ... Pilot signal generator.

Claims (12)

Surveillance radar that sends an interrogation signal toward an object, receives a response signal from the object to the interrogation signal at a reception unit, converts the IF signal to an IF frequency at a frequency conversion unit, and passes a band filter to obtain a video signal In the device
Analog / digital conversion means for converting the output signal of the frequency converter from an analog signal to a digital signal;
A surveillance radar apparatus comprising orthogonal conversion means for orthogonally converting a digital signal obtained by the analog / digital conversion means and outputting it to the bandpass filter.   The monitoring radar apparatus according to claim 1, further comprising a removing unit that removes an unnecessary wave component from the output signal of the frequency conversion unit between the frequency conversion unit and the analog / digital conversion unit. In a monitoring radar device that sends an interrogation signal toward an object, receives a response signal to the interrogation signal from the object at a receiving unit, converts it to an IF frequency at a frequency conversion unit, and obtains a video signal.
Analog / digital conversion means for converting the output signal of the frequency converter from an analog signal to a digital signal;
Orthogonal conversion means for orthogonally converting a digital signal obtained by the analog / digital conversion means;
A memory for storing reference amplitude information and reference phase information obtained so that the amplitude characteristic and phase characteristic of the response signal are best;
A monitoring radar apparatus comprising correction means for correcting the amplitude and phase of a digital signal converted by the analog / digital means in accordance with reference amplitude information and reference phase information stored in the memory.   The correction means corrects the amplitude of the output signal of the analog / digital means according to the reference amplitude information stored in the memory, and the phase of the output signal of the orthogonal transform means according to the reference phase information stored in the memory. The monitoring radar device according to claim 3, wherein:   4. The monitoring radar apparatus according to claim 3, wherein the correction unit corrects the amplitude and phase of the output signal of the orthogonal transform unit in accordance with reference amplitude information and reference phase information stored in the memory. A plurality of reception systems are provided, and the first reception system of the plurality of reception systems processes the sum signal of each reception signal obtained at a plurality of locations of the reception unit, and is different from the first reception system. When processing the difference signal of each of the height and azimuth of the receiving unit in the two receiving systems,
4. The surveillance radar device according to claim 3, wherein the correction means is provided in one of the first and second reception systems. A plurality of reception systems are provided, and the first reception system of the plurality of reception systems processes the sum signal of each reception signal obtained at a plurality of locations of the reception unit, and is different from the first reception system. When processing the difference signal of the plurality of received signals in the two receiving systems,
4. The surveillance radar device according to claim 3, wherein the correction unit is provided in each of the first and second reception systems. Sending an interrogation signal toward the object, receiving a response signal to the interrogation signal from the object at the receiving unit, and summing the received signals obtained at a plurality of locations of the receiving unit to the first system, In a monitoring radar device that branches a difference signal of each received signal to a second system and converts the received signal to an IF frequency by a frequency converter for each system to obtain a video signal
Pilot signal superimposing means for superimposing pilot signals having known amplitude / phase characteristics on the sum signal of the first system and the difference signal of the second system;
Analog / digital conversion means for converting the output signal of the frequency converter from an analog signal to a digital signal;
Orthogonal conversion means for orthogonally converting a digital signal obtained by the analog / digital conversion means;
Detecting means for extracting a pilot signal from each of the video signals of the first and second systems, and detecting a difference in amplitude / phase characteristics between the first and second systems based on the pilot signals;
A monitoring radar apparatus comprising: a correction unit that corrects the amplitude and phase of the digital signal converted by the analog / digital conversion unit based on a difference obtained by the detection unit.   The correction means corrects the amplitude of the output signal of the analog / digital means provided in one of the first and second systems, and corrects the phase of the output signal of the orthogonal transform means. The monitoring radar device according to claim 8.   9. The monitoring radar device according to claim 8, wherein the correction unit corrects an amplitude and a phase of an output signal of the orthogonal transform unit provided in one of the first and second systems.   The correction means corrects the amplitude of the output signal of the analog / digital means provided in each of the first and second receiving systems, and corrects the phase of the output signal of the orthogonal transform means. Item 9. The surveillance radar device according to Item 8.   9. The monitoring radar device according to claim 8, wherein the correction unit corrects an amplitude and a phase of an output signal of the orthogonal transform unit provided in each of the first and second reception systems.

Images