JPH0412831B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a PPI sonar that digitizes and displays the intensity of reflected waves.

Conventional technology Since sonar uses ultrasonic waves to measure the object to be detected, it has a drawback due to the measurement method itself that it is not possible to shorten the time required for exploration in one direction.
It is noticeable on PPI sonar. In other words, in full-circle scanning, exploration must be performed many times in different directions, and one round of scanning cannot be completed in a short period of time. This means that it cannot be applied to objects to be detected that move quickly.

Therefore, we calculated based on actually measured data that the time required for scanning the entire circumference can be shortened by making fewer measurements of the entire circumference, that is, scanning at coarse angular intervals, and as a result, the display becomes difficult to read. A method has been proposed to make the display easier to see by supplementing the information using interpolated data.

Problems to be Solved by the Invention The actual measurement sweep, which is a sequence of actually measured data, and the interpolation sweep, which is a sequence of interpolated data, are designed so that their display speed is in time when the range is set to a short exploration distance. be done. For example, in a configuration where four interpolation sweeps are used to fill in the blanks between measured sweeps, and the exploration distance at that time is 150 m, the measured sweeps are obtained at approximately 200 mS time intervals, so each interpolation sweep is 40 m.
Display is performed at time S. (The remaining 40 mS is the drawing time for the actual measurement sweep).

If the search distance is changed to 300m, actual measurement sweeps can only be obtained at intervals of 400mS. Nevertheless, the measured sweep and 4
Since the interpolation sweep of a book is displayed within a time of 200 mS, a blank time of 200 mS is created.
For example, if the measured sweep is obtained at intervals of 5 degrees, the display for 5 degrees will be displayed quickly, then the display will stop updating for a while, the display for 5 degrees will be displayed again, and then it will stop. This repeats itself, resulting in an unsightly display with discontinuous updates.

The present invention was conceived to eliminate the above-mentioned unsightly display, and is a PPI that can smoothly and continuously update the display regardless of the setting range.
The purpose is to provide sonar.

Means for Solving the Problems In order to achieve the above object, the PPI sonar of the present invention includes a range setting section that sets the search distance and outputs the setting result, and a range setting section that sets the search distance and outputs the setting result, and a range setting section that sets the intensity signal from the receiving section that receives reflected waves. An A/D converter unit that digitizes and outputs received data at time intervals according to the output of the setting unit, and a signal that outputs interpolated data by performing calculations on two pairs of received data that correspond to the same distance. a processing section; a display section that displays an actual measurement sweep that is an array of received data; and an interpolation sweep that is an array of interpolated data; and a timer section that changes according to the output.

Effect The time required to obtain the received data for the actual measurement sweep starts corresponding to the search distance set by the range setting section, so each interpolation sweep is processed at approximately equal time intervals within the time interval for obtaining the actual measurement sweep. In order to perform the display, the timer section controls the start of the interpolation sweep display according to the output of the range setting section.

Embodiment FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the present invention. In the figure, the output of the transducer 41 that receives the reflected wave of the key impulse is as follows:
The signal is guided to the receiver 11, amplified, detected, and sent to the A/D converter 12 as an intensity signal. The transmitter 22 generates a key impulse and sends it to the transducer 4.
1 causes the transducer 41 to vibrate. The transducer drive unit 23 is a mechanical drive device for rotating the transducer 41, changing the inclination angle, or storing the transducer 41 inside the hull when not in use. It operates according to signals from the control section 21.

Further, the control unit 21 controls the timing at which the transmitting/receiving unit 22 emits the key impulse and the timing at which the receiving unit 11 performs amplification and detection, according to the output of the range setting unit 24, which is comprised of a range setting switch etc. provided for the pulse. It's on.

The A/D converter 12 sequentially digitizes the intensity signal from the receiver 11 at time intervals corresponding to the range setting and outputs it as received data. This received data is guided to the signal processing section 13. The signal processing unit 13 includes a buffer memory 33 that stores all received data corresponding to key impulses at two adjacent angles, a data ROM 31 that stores interpolated data groups, and a signal processing main unit that is configured by software. The coordinate conversion section 32 outputs the received data and interpolated data to the coordinate transformation section 14.

The timer unit 26 is configured by software and receives the output from the range setting unit 24.
A control output for controlling the display timing of the interpolation sweep is sent to the signal processing main section 32 (the timer section 26 will be explained in detail later).

The above two pieces of data given in polar coordinates are written into the video memory 15 arranged in orthogonal coordinates after coordinate transformation. The video clock unit 25 sequentially generates read addresses in accordance with the scan timing of the display unit 17 and sends them to the video memory 15, and the read data is converted into serial data by the video signal converter 16. After that, it is sent to the display section 17. Further, two horizontal and vertical synchronization signals are sent from the video clock section 25 to the display section 17.

FIG. 2 is an explanatory diagram showing the relationship between the measured sweep and the interpolation sweep. The figure shows a case where interpolation sweep calculations are performed along two directions (in an actual machine, interpolation sweep calculations are performed in more directions, for example, 10 directions, so that the display is continuous).

The key impulse is emitted in the direction 61, and its reflected waves are sequentially A/D converted at regular time intervals and become received data, which becomes received data at a position that moves away from the center O as time passes. When receiving data up to the outer periphery 81 indicating the longest distance is obtained, the transducer 41 is rotated to emit a key impulse in the direction 62 and receive data is obtained (in the actual machine, this rotation angle is set to 5 degrees).
At this time, area 8 sandwiched between direction 61 and direction 62
2 has no received data. Therefore, the received data at the same distance in directions 61 and 62, that is, the center O
Focusing on the received data 63 and 64 located at the same distance from , interpolated data 73 and 74 are calculated from these two received data 63 and 64.

Regarding the order of calculation of interpolation data, for example, when the rotation direction of the key impulse is clockwise,
First, the interpolation data 75 and 76 start from the center O of the direction 71 toward the outer periphery 81, and when the calculation up to the interpolation data 77 is completed, the interpolation data is similarly calculated along the direction 72. The interpolated data calculated in this way has the same number as each received data in the directions 61 and 62, and is an actual measurement sweep obtained from the reflected wave of a key impulse emitted in the directions 71 and 72. An interpolated sweep is obtained in such an order.

FIG. 3 is a timing chart showing the main timings of the PPI sonar of the present invention.

The interpolation sweep is displayed as an interpolation sweep that spreads in 10 directions for the area 82 shown in Figure 2, so the direction of the measured sweep obtained by the reflected wave is set as 0, and the directions are sequentially clockwise from 1 to 10. There is. Although FIG. 2 shows two interpolation sweep directions, only the first two directions are shown and the following eight directions of interpolation sweep are omitted for explanation.

The key impulse 91 shows the case of a 150m range, for example, and the interval t1 between the pulses is approximately
200 mS, and within that time, the actual measurement sweep in the direction 61 shown in Fig. 2 is displayed S0, followed by the interpolated sweep 71 displayed S1, the interpolated sweep 72 displayed S2, and so on, and finally the 10th one. Interpolation sweep display S10 is performed.

The display starts according to the output 101a indicating the start of the timer section output 93, and the time interval t2a
is t1/11, that is, 200/11 mS. The time t3 required to display each sweep S is t3<t2a to provide some margin.

The key impulse 94 shows a case where the range is changed by the range setting section 24 and set to the 300 m range, and the key impulse interval is
t4 is twice t1. At this time, if the display is performed at the same timing as in the case of the 150m range, the display will end within time t1, and time t5 will be a blank time where the display is not updated, so the timer section 26 starts the display. The time interval t2b of the output 101b indicating
Set it to twice t2a. The display then shows output 101b indicating the start of this doubled time interval t2b.
will be held in accordance with the timing of P0 indicates the display timing of the actual measurement sweep, and P1 to P10 indicate the display timing of the interpolation sweep.

If the range becomes longer, the time interval t2 of the output 101 indicating the start is made longer compared to the range. Furthermore, when the range is shorter than 150 m, the key impulse firing interval is maintained at t1, so that there is no delay in display.

Note that since the timer unit 26 is configured by software, the timing is generated by generating an interrupt at a fixed time interval, and outputting an output 101 indicating the start every time the number of interrupts is counted by a fixed number of times.
A method has been adopted to send out.

Note that the present invention is not limited to the above embodiments,
For example, regarding interpolation sweep, we explained the case where the direction is 10, but it can be applied to models that display interpolation sweep in any number of directions that makes the display most legible, depending on the relationship between the angular interval of key impulses and display density. It is possible to do so.

Further, regarding the display section 17, the present invention can be similarly applied to a model having a display section that is scanned from the center toward the outer periphery.

Further, the timer section 26 may be provided with a timing circuit or the like that can vary the setting of time intervals, and the display may be performed according to the output thereof.

Effects of the Invention The PPI sonar of the present invention is equipped with a timer section to control the display timing of the interpolation sweep according to the output of the range setting section, so that the display can be smoothly and continuously regardless of the setting range. It becomes possible to update.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the relationship between an actual measurement sweep and an interpolation sweep, and FIG. 3 is a block diagram showing the electrical configuration of an embodiment of the present invention.
This is a timing circuit chart showing the main timing of PPI sonar. 12... A/D conversion section, 13... Signal processing section,
17...display section, 24...range setting section, 26...
...Timer section.

Claims (1)

[Claims] 1. Time-series received data obtained by A/D converting the intensity of reflected waves from within the exploration distance based on key impulses emitted at regular angular intervals at regular time intervals. The arranged measured sweeps and the interpolated sweeps in which interpolated data obtained by performing calculations on each pair of received data corresponding to the same distance on the adjacent measured sweeps are displayed on the same display section. In PPI sonar where multiple interpolated sweeps are displayed in the angular area sandwiched between two adjacent actual measurement sweeps that are the basis for calculating this interpolated sweep, the search distance is set and the setting result is output. 1. A PPI sonar comprising: a range setting section for changing the display start timing of each of a measured sweep and a plurality of interpolation sweeps according to an output of the range setting section.