JP3414316B2 - Aircraft monitoring equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive secondary surveillance radar device (hereinafter referred to as a passive SSR: Secondary Surveyillance).
It's called Radar. ) And a passive SSR system (hereinafter, ADS-B: Automatic Dependent Monitoring System).
ent Surveillance-Broadcast. ) And ground control system (SMGCS: Surface Movement Guidance)
Call it Control. ), The aircraft monitoring apparatus and the aircraft monitoring method.

[0002]

2. Description of the Related Art Conventionally, by intercepting an SSR response radio wave transmitted from an SSR transponder mounted on an aircraft in response to an SSR interrogation radio wave emitted from another SSR site having a transmitter, the position of this aircraft is detected. There is known a passive SSR that detects a. This type of passive SS
In R, it is used to monitor an aircraft in order to fly an air route, around an airport, or to safely operate an aircraft traveling on the airport surface.

In the case of the passive SSR, unlike the conventional SSR, since there is no transmission timing, it is not possible to perform reception processing synchronized with the transmission timing. Therefore, the received power level varies depending on the position of the aircraft (distance from the passive SSR to the aircraft), which causes variation in the pulse width of the received signal, which causes a reduction in the target detection rate and a reduction in erroneous decoding of the identification code. Was there. As an example, there is a power level difference of 46 dB between the received power level of the response signal from the aircraft present at a short distance (1 nautical mile) and the received power level of the response signal from the aircraft present at a long distance (200 nautical mile).

A device using the passive SSR system is
There are many buildings such as mountains, buildings around the airport, terminal buildings in the airport, aircraft hangars, etc., and the response signal of the aircraft is affected by multipath interference, which may cause a decrease in the target detection rate and a reduction in erroneous identification code decoding. Was becoming. Passive SSR
By the time the signal is received in (1), the signal received by being reflected (multipath) to the building or the like and the directly received signal (the signal received without the original reflection) are mixed and received. Therefore, the reflected reception signal causes problems such as generation of a pseudo target and interference.

In the prior art, the software processing of the radar information processing apparatus collects information on the azimuth and distance at which a pseudo target is generated by reflection in advance for a long period of time, and this information is registered in a database of the radar information processing apparatus. I used to perform correlation processing with registration information to suppress pseudo targets,
Since the generation position of the pseudo target changes the reflection point depending on the flight course and the flight altitude of the aircraft, the pseudo target cannot be completely suppressed by the method of the prior art. Further, when this conventional technique is applied to an airport surface monitoring system, a complicated pseudo target occurs in all directions in a place where many buildings such as an airport terminal building / aircraft hangar are scattered, such as in an airport. It is very difficult to create a database for a radar information processing device.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an aircraft monitoring apparatus and an aircraft monitoring method in which the target detection rate is lowered and the identification code decoding rate is improved. In point.

[0007]

The present invention has the following constitution in order to solve the above problems. The gist of the invention according to claim 1 is to monitor the aircraft as a target based on a received signal from the aircraft, and to perform the navigation from the received signal.
In an aircraft monitoring device for extracting a target signal from an aircraft and monitoring the aircraft, a logarithmic amplifier / which extracts a received signal from the aircraft as a logarithmic video signal based on a predetermined threshold value. A detector and a threshold for controlling the threshold value so as to follow fluctuations in the reception level of a reception signal from the aircraft, and for controlling the threshold value to perform waveform shaping of the logarithmic video signal to obtain an output video signal. and hold controller, a reference time generator for generating a reference time, and a target detecting unit for generating a target data assigned with the reference time in the position information of the aircraft derived from the output video signal, before
Each time the target signal is extracted, the time at that point
The same aircraft as the time giving unit for giving the target signal of
A plurality of said target signals which are considered to be target signals from
The target signal with the later time given by the time giving unit
Signal as a pseudo target signal and a multipath suppressor
The present invention resides in an aircraft monitoring device characterized by being provided . The gist of the invention according to claim 2 is that the threshold controller detects a maximum value of the amplitude of the logarithmic video signal, and sets a value lower than the maximum value by a predetermined level as the threshold value. The aircraft monitoring device according to claim 1. A third aspect of the present invention is an aircraft monitoring method for monitoring a target aircraft based on a received signal from an aircraft, wherein the received signal from the aircraft is a logarithmic video signal based on a predetermined threshold value. And controlling the threshold value to follow the reception level fluctuation of the reception signal from the aircraft, and the output video signal is subjected to waveform shaping of the logarithmic video signal by the controlled threshold value. A step of obtaining and a step of generating a reference time,
Target data derived from the output video signal is generated
Each time, the time at that point is added to this target data
And that step, comparing the applied time of the plurality of target data
It is considered that the target data from the same aircraft as the process
Of the plurality of target data
Rejected target data with a delayed time as pseudo target data
Further comprising the step of existing in an aircraft monitoring method according to claim.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the outline of the present invention will be described. The present invention is directed to the passive SSR, the ADS-B using the passive SSR method, and the SMGCS as described above.
Is used as part of the function to build.

The signal received by the aircraft monitoring device of the present invention is a collision prevention system (ACA) currently in operation between aircraft equipped with SSR mode S transponders.
Using the function of S), the position information of the aircraft is transmitted from the aircraft to the ground-based aircraft monitoring device in an omnidirectional broadcast format.

The aircraft surveillance system of the present invention is a passive SS.
Used for R, ADS-B and SMGCS,
Since the response signal from the omnidirectional aircraft is received by the omnidirectional antenna device, many interference signals due to the multipath phenomenon are received by being reflected by an obstacle (reflecting object) such as a building. A feature of the present invention is that a threshold control function is provided in order to remove an interference signal due to the multipath phenomenon, and the target detection rate is reduced and erroneous decoding of the identification code is avoided.

Further, when the passive SSR is operated as the ADS-B, the reception power level of the response signal from the aircraft has a characteristic inversely proportional to the square of the existing distance (R) of the aircraft. The above-mentioned characteristics are the received power level of the response signal from the aircraft existing at a short distance (1 nautical mile) and the long distance (2
The received power level of the response signal from the aircraft existing at (00 nautical miles) has a power level difference of 46 dB. Therefore, in the case of the device using the passive SSR system, the reception processing synchronized with the transmission timing cannot be performed, and therefore the difference in the reception power level causes the fluctuation of the reception signal pulse width, which lowers the target detection rate. It may cause misreading of the identification code.

Therefore, the present invention is characterized in that a pulse width of a received signal is restored by providing a threshold control function and performing threshold control to follow fluctuations in the received power level.

Furthermore, the present invention utilizes the fact that the reflected wave has the following characteristics, and also suppresses the pseudo target by multipath. 1. The reflected wave of the aircraft response due to multipath has a longer radio wave propagation path than the true direct wave, so the reception time is delayed. 2. The received power level of the reflected wave of the aircraft response due to multipath is attenuated more than the received power level of the true direct wave.
(Reflected by a reflective object and power is attenuated.)

From the above first characteristic of multipath, as shown in FIG. 1, the reception time is stamped on the response signal of the aircraft by the time from the reference time generator 10, and the target detector 8 time stamps the reception time. This result is characterized in that the multipath suppressing unit 9 suppresses target data having a late reception time by comparing with the above-mentioned time stamp time for the aircraft having the same identification information of the response signal from the aircraft. .

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the aircraft monitoring device according to the present embodiment includes an antenna 1 for receiving, a receiving device 20 that is a processing unit for a received signal, and a target detection device 30 that decodes the received signal. The receiving device 20
In contrast to the block diagram of the conventional device shown in FIG. 2, a threshold controller 7 which is a feature of the present invention is provided.

The receiving device 20 has an RF for amplifying the received signal.
An amplifier 2, a bandpass filter 3 for generating a received signal,
Mixing / IF amplifier 4 which mixes a signal from an oscillator 6 and a received signal to convert it to an intermediate frequency signal, and a logarithmic amplifier / detector 5 which performs video detection after logarithmically amplifying the intermediate frequency signal from the mixing / IF amplifier 4. , And a threshold controller 7 for shaping the waveform of the logarithmic video signal from the logarithmic amplifier / detector 5.

The threshold controller 7, as shown in FIGS. 3, 5 and 6, receives the logarithmic video signal sent from the logarithmic amplifier 5, and the logarithmic video signal is supplied to the delay line 21, the peak hold circuit 22, It is input to the comparator 26. This logarithmic video signal is a delay line 21.
Is supplied to the comparator 23 and is delayed for a predetermined time,
Entered in. The logarithmic video signal is supplied to the peak hold circuit 22 in parallel, and then the amplitude (maximum value) of the logarithmic video signal is sampled and input to the comparator 23.

Further, in the above-described peak hold circuit 22, a sampling timing signal for sampling the amplitude (maximum value) of the logarithmic video signal is generated by the sampling timing circuit 25 and input to the peak hold circuit 22. ing.

The comparator 26 compares the logarithmic video signal with the reference voltage, performs preprocessing for generating a sampling timing signal from the logarithmic video signal, and converts it into a quantized signal. The reset timing circuit 24 is configured to generate a timing pulse for canceling the hold state of the amplitude (maximum value) of the logarithmic video signal in the peak hold circuit 22 and input it to the peak hold circuit 22.

The target detecting device 30 comprises a target detecting section 8, a multipath suppressing section 9, and a reference time generating section 10.
Details of the target detecting unit 8, the multipath suppressing unit 9, and the reference time generating unit 10 will be described later.

Next, the operation of this embodiment will be described. First, the operation of the threshold controller 7 will be described with reference to the block diagram of FIG. 3 and the timing diagram of FIG.

The threshold controller 7 inputs a logarithmic video signal and produces a delayed logarithmic video signal through the delay line 21. Further, in order to obtain the amplitude information of the logarithmic video signal by parallel processing, the peak hold circuit 22 samples the amplitude (maximum value) of the logarithmic video signal to generate a peak hold reference signal. Further, in order to remove the receiver noise by parallel processing, the quantized video signal is generated by comparing the logarithmic video signal with the reference voltage in the comparator 26. This quantized video signal is supplied to the sampling timing circuit 25.
Then, the peak hold circuit 22 generates a peak hold pulse for sampling and holding the amplitude (maximum value) of the logarithmic video. The reset timing circuit 24 inputs the peak hold pulse and generates a hold reset pulse for resetting the peak hold reference signal.

After the processing described above, the two signals of the delayed logarithmic video signal and the peak hold reference signal are input to the comparator 23, and only the signal having the delayed logarithmic video signal larger than the peak hold reference signal is inputted to the comparator 23. To produce an output video signal.

Next, the details of the operation of this embodiment will be described with reference to the timing chart of FIG. The timing diagram of FIG. 5 shows circuit operation waveforms for restoring the pulse width of the received signal. Restoring the pulse width means converting the output video signal of the logarithmic amplifier 5 into a normal linear video signal. Normally, the pulse width is the half amplitude point in the voltage amplitude (see FIG.
However, the signal passing through the logarithmic amplifier 5 has a characteristic that the pulse width is apparently widened.

When the logarithmic video signal is processed with a constant reference value as in the conventional apparatus, the pulse width of the original signal varies due to the change in the received power level of the received signal. When the received power level is low (response signal from a long distance), the pulse width is narrow, and when the received power level is high (response signal from a short distance), the pulse width is wide. From the above, in order to keep the pulse width constant, it is necessary to always perform waveform shaping by slicing at a level as low as 6 dB from the peak value of the logarithmic video signal. A reference signal for performing this slicing (a low level corresponding to a 6 dB voltage) is used as a peak hold signal.

Therefore, the output video signal restored to the true pulse width (T1 in FIG. 5) can be obtained by being processed by the comparator 23 as shown in the comparator input in FIG. Furthermore, regarding the operation of suppressing the generation of the pseudo target due to the multipath in the target detection device 30,
Description will be given according to the block diagram of FIG.

The output video signal from the receiving device 20 is processed by the target detector 11 and the code decoder 12 in order to convert it into the target data, and the processed data is sent to the target data generator 13. The target detector 11 calculates the position information of the aircraft and supplies it to the code decoder 12. The code decoder 12 adds the position information of the aircraft to the code decoding result. The target data generator 13 adds the time from the reference time generation unit 10 to the target data, and the target processor generates the target data.
And the pseudo target judging device 15.

The tracking processor 14 is a target data generator 13
The target data generated in step 2 is stored, a table is created for each target data, and the aircraft identification code and time stamp time are managed. The storage table management in the tracking processor 14 performs tracking for each target, and manages the continuity of the received signal for a true target, and uses it as an index for pseudo target determination. The reason for this is that in the case of the pseudo target, the response signal does not always reflect to the same reflecting object each time, so the response signal is not continuously received. The index A for this continuity is calculated.

The index A is incremented each time a response signal is received, and is decremented when it is not received, and a response signal with a large count is the true target.
However, a threshold value (changeable parameter value) is set for this count number, and a preset value is determined according to the operating environment in which this device is installed. That is, the target data having a value equal to or larger than the threshold value is used as the index A for determining the true target. This index is supplied to the target data suppressor 16.

The pseudo target judging device 15 compares the time stamped times with respect to the target data having the same identification code of the target data from the target data generator 13.
The index B, which is a pseudo target, is given to the target data with the later time. (The index B is valid when it is 1.) Next, the above-described index is added to the target data from the target data generator 13, and the target data is supplied to the target data suppressor 16.

The target data suppressor 16 uses the index A,
Whether or not the target data is the pseudo target is determined from the index B as follows. This determination condition rejects the target data of (index A: invalid) and (index B: valid), and suppresses it as a pseudo target.

As described above, the pseudo pulse width is restored by suppressing the fluctuation of the pulse width due to the fluctuation of the reception power level of the response signal, and the difference between the reception times and the target reception continuity are managed to reduce the pseudo. It is possible to suppress the target and detect the target stably.

Since the aircraft monitoring device according to the embodiment is configured as described above, it has the following effects.
That is, the aircraft monitoring device of the present embodiment is provided with a threshold control function of the receiver in order to keep the pulse width of the received signal constant in order to improve the target detection rate and the identification code decoding rate, and the received power level. The target detection rate and the identification code erroneous decoding rate can be improved by performing the pulse width restoration of the received signal by performing the threshold control to follow the fluctuation.

Further, in order to improve the reliability of the pseudo target due to the multipath, the characteristic of the multipath phenomenon due to the reflecting object is utilized, and the reception time is delayed because the reflected wave has a longer radio wave propagation path than the direct wave. By comparing the time stamps of the response signals of the aircraft having the same aircraft identification information, it is possible to know the pseudo target due to multipath.

By providing the above two functions,
It is possible to improve the target detection rate and the identification code erroneous decoding rate and suppress the occurrence of a pseudo target due to multipath, which are difficult with the conventional passive SSR. This can increase the reliability of the target data of the aircraft monitoring device, reduce the load on the air traffic control information processing device that processes the target data of the aircraft monitoring device, and improve the safety of radar air traffic control operations. it can.

In the present embodiment, the present invention is not limited to the aircraft monitoring device described above, but can be applied to an aircraft monitoring device suitable for applying the present invention. Further, the number, position, shape, etc. of the above-mentioned constituent members are not limited to the above-mentioned embodiment, and a suitable number, position, in implementing the present invention,
It can have a shape or the like. In addition, in each figure, the same components are denoted by the same reference numerals.

[0037]

Since the present invention is configured as described above, it is possible to realize an aircraft monitoring apparatus and an aircraft monitoring method that have a lower target detection rate and an improved identification code decoding rate.
Has the effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic circuit configuration of an aircraft monitoring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of an example of a conventional aircraft monitoring device.

FIG. 3 is a block diagram showing a circuit configuration of a threshold controller according to an embodiment.

FIG. 4 is a timing diagram for explaining the operation of the embodiment.

FIG. 5 is a timing chart for explaining details of the operation of the embodiment.

FIG. 6 is a block diagram showing a circuit configuration of a target detection device of one embodiment.

[Explanation of symbols]

1 antenna 2 RF amplifier 3 bandpass filter 4 Mixing / IF amplifier 5 logarithmic amplifier / detector 6 oscillators 7 Threshold controller 8 Target detection section 9 Multipath suppression unit 10 Reference time generator 11 Target detector 12 Code Decoder 13 Target data generator 14 Tracking processor 15 Pseudo target determiner 16 Target data suppressor 20 Receiver 21 delay line 22 Peak hold circuit 23 Comparator 24 Reset timing circuit 25 Sampling timing circuit 26 Comparator 30 Target detection device

Continuation of the front page (56) References Japanese Patent Laid-Open No. 1-136085 (JP, A) Japanese Patent Laid-Open No. 1-173889 (JP, A) Japanese Patent Laid-Open No. 9-90030 (JP, A) Japanese Patent Laid-Open No. 9-230040 (JP) , A) JP 5-1222025 (JP, A) JP 5-142341 (JP, A) JP 2000-206239 (JP, A) JP 61-169787 (JP, A) JP 6 -27234 (JP, A) J. Kohei 5-28534 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01S ⁷ /00-7/42 G01S 13/00-13/95 G08G 5/00

Claims (3)

(57) [Claims] 1. The target aircraft is monitored based on a received signal from the aircraft, and the received signal is monitored in front of the received signal.
The target signal from the aircraft is extracted to monitor the aircraft.
In an aircraft monitoring device that performs, a logarithmic amplifier / detector that extracts a reception signal from the aircraft as a logarithmic video signal based on a predetermined threshold value, and a variation in the reception level of the reception signal from the aircraft with the threshold value. A threshold controller for waveform-shaping the logarithmic video signal according to the controlled threshold value to obtain an output video signal, a reference time generator for generating a reference time, and the output video A target detection unit that generates target data in which the reference time is added to the position information of the aircraft obtained from a signal, and the time at that time each time the target signal is extracted.
The same time division as that for the target signal and the same aviation
A plurality of said target signals considered to be target signals from the machine
The target signal with the later time given by the time giving unit
Signal as a pseudo target signal and a multipath suppressor
Aircraft monitoring device, characterized in that it comprises. 2. The threshold controller detects the maximum value of the amplitude of the logarithmic video signal, and sets a value lower than the maximum value by a predetermined level as the threshold value. Aircraft surveillance equipment. 3. A method for monitoring an aircraft, which is a target based on a signal received from the aircraft, wherein the signal received from the aircraft is extracted as a logarithmic video signal based on a predetermined threshold value. A step of controlling the threshold value so as to follow fluctuations in a reception level of a reception signal from the aircraft, and waveform-shaping the logarithmic video signal with the controlled threshold value to obtain an output video signal; Generating a time of day and generating target data derived from the output video signal
It is given the time that put in the time to the target data for each that
And a step of comparing the application times of a plurality of the target data , a plurality of target data considered to be the same target data from the same aircraft.
Of the target data, the time given by the process
Process of rejecting target data with slow target as pseudo target data
Aircraft monitoring method characterized by comprising and.