JP2850872B2 - Sonobuoy signal processor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sonobuoy signal processing apparatus, and more particularly to a sonobuoy signal processing apparatus for displaying cardioid processed signal gram data and azimuth data of a plurality of channels.

[0002]

2. Description of the Related Art Conventionally, a sonobuoy signal processing apparatus for performing a cardioid process has an omni sensor which detects three signals output from a DIFAR sonobuoy, that is, signals from all directions, as shown in FIG. (OMNI) signal, NS signal having directivity in the north-south direction, and EW signal having directivity in the east-west direction are frequency-analyzed in a frequency analysis circuit to obtain frequency domain data, that is, a level for a frequency at a certain time. The data is converted into data, and each data in the frequency domain obtained in this way is synthesized, and N, S,
Create signals with improved directivity gain in each direction of E and W,
The signal is processed in a display processing circuit to convert it to gram data, that is, display format data (for example, FIG. 6) in which the vertical axis represents time, the horizontal axis represents frequency, and the level is represented by shading, and displayed on a display. .

The north component is the sum signal of the omni (OMNI) signal and the NS (north south) signal, the east component is the sum signal of the omni signal and the EW (west east) signal, and the south component is The signal of the sum of the omni signal and the inverted NS signal, and the west component is the signal of the sum of the omni signal and the inverted EW signal.

However, in such a system, N,
When displaying gram data of passive audio signals of four channels (CH) of S, E, and W, indicators 551, 552, 553, and 554 for four channels are required, and the direction of each signal is N, Only the approximate directions of S, E and W were known.

[0005]

As described above, the conventional cardioid processing type sonobuoy signal processing apparatus does not have four displays 551, 552, 553, and 554 to display four-channel gram data. At the same time, since data in all directions cannot be viewed, display of 551, 552, 553, and 554 times as large as the sonobuoy channel is required to display data from DIFAR sonobuoys of a plurality of channels. Therefore, as the number of channels increases, the number of displays also increases, causing problems in equipment space and costs.

Further, the conventional cardioid processing type sonobuoy signal processing apparatus cannot determine the true azimuth of the signal since only the approximate target azimuths such as N, S, E, and W can be identified, so that the position of the target is limited. Was not enough.

[0007] Suppose that N,
Even if each beam of S, E, and W can be set to an arbitrary direction, in order to specify a plurality of targets having different directions, the number of beams is required by the number of targets, and accordingly, the number of indicators is increased. However, the problem that a plurality of devices are required cannot be solved.

Therefore, for example, Japanese Patent Application Laid-Open No. 5-302970
As disclosed in Japanese Unexamined Patent Application Publication No. 5-190040 and Japanese Patent Application Laid-Open No. 5-194040, there has been proposed a method in which the azimuth of the target is determined, the beam azimuth is automatically controlled, and the position of the target is limited.
However, this method cannot solve the problem that when there are a plurality of targets having different directions, the number of beams is required by the number of targets, and the number of displays is required accordingly.

As disclosed in JP-A-63-265183 and JP-A-63-191982, a method of calculating the azimuth of each analysis frequency component has also been proposed. A wide frequency band sound source detection device based on this method includes a directional passive sonobuoy for receiving underwater sound waves,
A frequency analysis unit that receives the noise signal of the north-south component, the noise signal of the east-west component, and the noise signal having the omnidirectional component from this directional passive sonobuoy, and performs a frequency analysis,
Compare the phase of the noise signal of the north-south direction component and the noise signal of the east-west direction component with the phase of the noise signal of the omnidirectional direction component. After the frequency analysis, the positive sign is applied to the in-phase signal and the negative sign is applied to the opposite-phase signal. A phase comparison unit that adds the north-south component noise signal and the east-west component noise signal to each other, an integration unit that integrates the output signal of the phase comparison unit with time, and an output of the north-south component miscellaneous signal of the integration unit. An azimuth detecting unit for detecting the direction of the sound source from the output of the noise signal of the east-west component, and a cumulative unit for adding the integrated output of the north-south component noise signal and the east-west component noise signal within a predetermined frequency range and azimuth range And the presence of the sound source, it is possible to detect the presence and direction of the unknown sound source.
Therefore, as compared with the conventional apparatus, there is an advantage that two or more sonobuoys are arranged in a limited range, and it is not necessary to constantly control and grasp the distance, and the apparatus can be easily operated. It can be expected to have an extremely large effect on marine use such as navigation and detection.

However, in this method, signal detection is
A single component of each of MNI, NS, and EW is used, and the signal processing gain of the cardioid processing method cannot be sufficiently obtained.

Accordingly, an object of the present invention is to compress signal data subjected to cardioid processing in each direction into one channel so that signal data of a plurality of channels can be displayed with a small amount of display resources, and the processing gain of the cardioid processing is reduced. It is an object of the present invention to provide a sonobuoy signal processing device capable of specifying the azimuth of each frequency component without deteriorating the signal.

[0012]

According to the present invention, DIFAR
In a cardioid processing circuit to which OMNI, NS, and EW signals, which are sonobuoy outputs, are input, three signals are combined, and a cardioid-shaped directivity combination having a directional gain for each fixed direction is performed. In the frequency analysis circuit, the cardioid processing data in each direction is frequency-analyzed and converted into frequency domain data. The signal detection circuit performs signal detection on these frequency domain data, and a detection bit is added to the detected signal data. The signal selection circuit selects signal detection data for each frequency component from the plurality of signal detection data based on the detection bit. The azimuth data assigning circuit assigns an azimuth to the selected signal detection data for each frequency region, and displays the signal detection data to which the azimuth has been assigned collectively on one display.

The signal selection circuit selects the signal data when only one detection signal is added with the detection bit, and selects the signal data when two or more signal detection data is added with the detection bit. If the signal detection data with the highest level is selected and there is no signal detection data to which the detection bit is added, the signal detection data with the lowest signal level is selected from the signal detection data in each direction, and these are frequency components. Display on each display.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing in detail a signal detection circuit, a signal selection circuit, and a direction data provision circuit in FIG. Reference is made to FIG. 3 showing a characteristic diagram of the display example of FIG. 2 during one time of frequency, and FIG. 4 showing a characteristic diagram of one-side frequency.

1 to 3, a sonobuoy signal processing device according to the present embodiment receives cardioid processing data (every 1 ° C.) by receiving a DIFAR sonobuoy output, that is, an omni (OMNI) signal, an NS signal, and an EW signal. An obtained cardioid processing circuit 1000, a frequency analysis circuit 1001 for creating frequency domain data based on each cardioid processing data, signal detection circuits 4001 to 4360 for removing noise components based on the frequency domain data,
It includes a single signal selection circuit 8000, a direction data providing circuit 9000, and a display 10000.

OMNI, which is a DIFAR sonobuoy output,
The NS and EW signals are converted to a cardioid processing circuit 1000.
Is input to These three signals are combined to create cardioid processed data 1 to 360.

Frequency analysis circuits 1001 to 1360 are connected to the cardioid processing data 1 to 360, respectively.
Frequency analysis processing units 2001 to 236 in 01 to 1360
0 is provided. The received cardioid processing data 1, 2,... 360 are subjected to frequency analysis, and frequency domain data 3001 to 360 are created.

The frequency analysis circuits 1001 to 1360 include:
Signal detection circuits 4001 to 4360 are respectively connected,
Next, these signal detection circuits 4001 to 4360 include 1
Signal selection circuits 8000 are connected,
000 is connected to an azimuth data adding circuit 9000,
The display 10000 is connected to the azimuth data providing circuit 9000.

The signal detection circuits 4001 to 4360 correspond to FIG.
As shown in the block diagram of FIG.
A noise averaging process 5001 to 5360 for calculating an average level of noise based on 3360, and a signal detection processing unit 60 for setting a threshold level based on the average level of noise and detecting a signal based on the threshold level
01 to 6360 and a detection bit assignment processing section 700 for assigning a detection bit indicating that the signal is a signal to the detected signal.
1 to 7360.

A signal selection circuit 8000 extracts a signal to which a detection bit is added from the outputs of the 360 signal detection circuits 4001 to 4360, and a detection bit extraction processing unit 8001 based on the detection bit extraction result. Level detection processing section 800 for detecting the highest level of output
2 and a lowest level detection processing block 8003 for detecting the lowest level.

The azimuth data adding circuit 9000 includes a detection processing section extraction processing section 8001, a highest level detection processing section 8002
And an orientation data assignment processing unit 9001 for assigning orientation data to the output for each frequency component from the lowest level extraction processing unit 8003, and a display unit that synthesizes display data based on each frequency component data output with an orientation. 10000 includes a display data synthesizing unit 9002 for displaying gram data and azimuth data.

Next, the operation of this embodiment will be described. In the cardioid processing circuit 1000, OMNI, NS, and EW signals, which are DIFAR sonobuoy outputs, are input, and these three signals are combined to provide a cardioid-shaped cardioid having a directional gain in one-degree increments from one direction. Processing data 1 to 360 are created. At this time, creation of a cardioid signal of an arbitrary azimuth α degree (α = 1 to 360) (as shown in FIG. 2) is based on the following equation. Cardioid signal of α-degree azimuth = OMNI signal + NS signal × cos α + EW signal × sin α

The cardioid processing data 1 to 360 are
The signals are input to the frequency analysis circuits 1001 to 1360 for each channel. In each of the frequency analysis circuits 1001 to 1360, frequency analysis processing units 2001 to 2360 are provided.
60 is subjected to frequency analysis by frequency analysis circuits 2001 to 2360 to generate frequency domain data 3001 to 360.
The frequency domain data 3001 to 360 are input to the signal detection circuits 4001 to 4360 for each channel.

In the operation of each of the signal detection circuits 4001 to 4360, first, the noise averaging processing sections 5001 to 5360
, The respective frequency domain data 3001 to 33
For 60, calculate the noise average. Next, the signal detection processing units 6001 to 6360 set a threshold level value from the noise average value, and detect data having a signal level higher than the threshold level value as signal data. Then, a detection bit assignment processing unit 7001
At 7360, a detection bit indicating that it is signal detection data is added only to the detected signal data. The data of each frequency component of each channel in which the detection bit is added to the signal detection data is input to the signal selection circuit 8000 in a lump.

In the signal selection circuit 8000, first, in the detection bit extraction processing unit 8001, the signal detection circuit 400
From the outputs of 1 to 4360, the signal level and detection bit of each channel are extracted for each frequency component. Based on the detection bit extraction result, the following three means are selected.

The first means, when there is only one signal detection data to which the detection bit is added, outputs the level information of the signal detection data to the azimuth data addition processing unit 9000.

When there are a plurality of pieces of signal detection data to which detection bits are added, the second means outputs the signal detection data to which a plurality of detection bits are added to the highest level detection processing section 8002. Then, the highest level detection processing section 8002 detects the signal detection data having the maximum signal level, and outputs the level information of the signal detection data having the maximum signal level to the azimuth data addition processing section 9001.

The third means outputs, to the lowest level detection processing section 8003, the signal level of the angular azimuth signal detection data to which the detection bit is not added when there is no signal detection data to which the detection bit is added. . Then, the lowest level detection processing unit 8003 detects the signal detection data with the minimum signal level among the signal detection data in each direction, and sends the level information of the signal detection data with the minimum signal level to the direction data addition processing unit 9000. Output.

Next, the operation of the azimuth data providing circuit 9000 will be described. First, in the azimuth data addition processing unit 9001, azimuth data is added to the output for each frequency component from the detection processing unit extraction processing unit 8001, the highest level detection processing unit 8003, and the lowest level extraction processing unit 8003, and the display data synthesis processing is performed. Output to the unit 9002. Next, in the display data synthesis processing unit 9002, the level data for each frequency component to which the azimuth is assigned is synthesized into display data for one channel, and this is output to the display 10000. And display the azimuth data.

[0030]

As described above, according to the sonobuoy signal processing apparatus of the present invention, data of each direction is compressed to one channel (CH) while sufficiently securing the directivity gain which is an advantage of cardioid processing. This saves display resources and reduces the burden of operator data confirmation, and provides azimuth information for each frequency that cannot be obtained by normal cardioid processing. Thus, the above-mentioned problems are all solved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the functions of a sonobuoy signal processing device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating functions of a signal detection circuit, a signal selection circuit, and a direction data provision circuit of the sonobuoy signal processing device according to the embodiment of the present invention.

FIG. 3 is a time-frequency characteristic diagram of the display device according to the embodiment of the present invention.

FIG. 4 is a characteristic diagram of one direction and one frequency in the display according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing processing of a conventional sonobuoy signal processing device.

FIG. 6 is a plan view showing a display on a display of a conventional sonobuoy signal processing device.

[Explanation of symbols]

 551 to 554 Display 1000 Cardioid processing circuit 1001 to 1360 Frequency analysis circuit 2001 to 2360 Frequency analysis processing section 4001 to 4360 Signal detection circuit 5001 to 5360 Noise averaging processing section 6001 to 6360 Signal detection processing section 7001 to 7360 Detection bit addition processing section 8000 Signal selection circuit 8001 Detection bit extraction processing section 8002 Highest level detection processing section 8003 Lowest level detection processing section 9000 Direction data addition circuit 9001 Direction data addition processing section 9002 Display data synthesis processing section 10000 Display

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15 / 00-15/96

Claims (4)

(57) [Claims] An OMNI signal received by an omnidirectional receiver, an NS signal received by a receiver having directivity in the north-south direction, and an EW signal received by a receiver having directivity in the east-west direction. And a DIFAR sonobuoy output composed of three signals, and a cardioid processing circuit for performing a cardioid shape indicating synthesis for each fixed azimuth, and a frequency analysis of the cardioid processing data for each azimuth for conversion to frequency domain data. A frequency analysis circuit; a signal detection circuit that performs signal detection on the frequency domain data for each direction subjected to frequency analysis processing; a signal selection circuit that selects a display signal based on the data of these signal detections; And a display for displaying the signal selection data to which the azimuth is assigned. Sonobuoy signal processor. 2. A noise average processing means for measuring a noise level from the frequency domain data for each direction and calculating a noise average value for each frequency component, and a threshold level value from the noise average value for each direction. And signal detection means for detecting data having a level higher than the threshold level value as signal data, and detection bit assignment processing means for assigning a detection bit only to the detected signal data and outputting signal detection data. The sonobuoy signal processing device according to claim 1. 3. The signal selection circuit retrieves data for each frequency component from the frequency domain data for each azimuth, and if there is only one signal detection data to which a detection bit is added, the signal is detected. First means for sending detection data to the azimuth data providing circuit; and when there are a plurality of signal detection data provided with the detection bits, the signal detection data provided with the plurality of bits is sent to the highest level detection processing means. Second means for sending out, and third means for sending out signal detection data of each direction to which no detection bit is added to the minimum level detection processing means when there is no signal detection data to which the detection bit is added. Detection bit extraction processing means for selecting the processing of a total of three means, and a signal based on signal detection data to which a plurality of detection bits transmitted in the case of the second means are added. The highest level detection processing means for detecting the signal detection data having the maximum bell and transmitting the signal detection data having the maximum signal level to the azimuth data providing circuit, and the detection bit transmitted in the case of the third means is provided. 2. A minimum level detection processing means for detecting signal detection data having the minimum signal level from the signal detection data of each azimuth which is not present and transmitting the signal detection data having the minimum signal level to the azimuth data providing circuit. Sonobuoy signal processor. 4. The azimuth data providing circuit determines which azimuth cardioid processing data is the signal detection data for each frequency component output from the signal selection circuit, and adds the azimuth data to the output signal detection data. 2. The sonobuoy signal processing device according to claim 1, comprising: azimuth data providing processing means for providing; and display data synthesizing processing means for arranging signal detection data provided with the azimuth in ascending order of frequency components and creating display data.