JP2639595B2 - Radar equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention transmits a pulse-like energy wave at predetermined angles one after another while rotating a directional transducer, and transmits the energy wave from a target of the energy wave. Related to a radar device that receives the echo information of a receiver, calculates the azimuth from the angle of rotation, calculates the distance from the time from the transmission of the energy wave to the reception of the echo, and displays the position of the target. A radar device and radar-like function that can increase the signal-to-noise ratio and prevent interference from other similar devices without sacrificing azimuth resolution, in particular. (A function of observing the position of a target by echo information from the target) (hereinafter simply referred to as a radar device in the present specification).

[Prior Art] Conventionally, as a method of increasing the S / N ratio in a radar device, a method disclosed in JP-A-52-10094 has been proposed.
Weighted averaging circuit> is known. FIG. 10 is a configuration diagram showing a weighted averaging circuit.

In FIG. 10, input echo information a is supplied to an adder. The input echo information a is delayed by a delay circuit for a time corresponding to the transmission interval of the pulsed energy wave, and
The multiplier attenuates the signal by multiplying it by a number smaller than 1, attenuates the echo information obtained by previous transmission, and adds the result to the adder to output an output signal b.

Processing of echo information at the same distance (the same reflection time) indicated by a dotted line will be described with reference to FIG. The radar device rotates clockwise, and echo information is input to the adder at predetermined angles of 1, 2, 3, 4,..., 7,. At the display position 4, the output signal b of the calculation result of 1 to 4 is displayed. Hereinafter, similarly, the output signal b of the calculation result of 2 to 5 is displayed at the display position of 5.

With such a configuration, echo information at the same distance obtained every time a pulsed energy wave is transmitted is added with a smaller weight as the information is longer, and is automatically discarded soon. Due to such integration, information that is not continuous at the same distance, such as noise, is suppressed, and information that is continuous at the same distance, such as echo information from a target, is emphasized.

[Problems to be Solved by the Invention] However, such a conventional weighted averaging circuit has the following two problems.

One is that the maximum point of the output signal changes depending on the number of times of continuous input echo information at the same distance. For example, as shown in FIG. 11 (B), when the input echo information is continuous twice as shown in FIG. 11 (A), and when it is continuous four times d, the output signals are e and f, respectively, as shown in FIG. 11 (B). And each maximum point is shifted. This means that the instantaneous angle of the rotating transducer and the maximum angle of the echo fluctuate, and the azimuth changes depending on the continuous number of input echo information, which is a serious problem for the laser apparatus.

Another problem is that the azimuth resolution deteriorates if a sufficient integration effect is to be obtained.

That is, in order to obtain a sufficient integration effect, it is obvious that the multiplier of the multiplier shown in FIG. 10 needs to be closer to 1, but the closer the multiplier is to 1, the more the output shown in FIG. It is also apparent that the attenuation range of the signal e or f is lengthened and the azimuth resolution is degraded.

[Means for Solving the Problems] In order to solve the above problems, in the radar apparatus of the present invention, there are provided: (a) a plurality of pieces of echo information for each predetermined angle obtained by transmitting a plurality of continuous pulsed energy waves; (B) an adder for simultaneously reading and adding the same time portions of the plurality of pieces of echo information recorded respectively; and (c) an adder for reading the plurality of pieces of echo information read simultaneously. A continuity determiner for determining continuity; and (d) a switch for controlling the output of the adder based on a determination output signal output from the continuity determiner, or a predetermined weight according to the output of the continuity determiner. And output adjustment means for giving the output to the output.

Further, in the radar device according to the second aspect, the continuity determiner that determines the continuity of the plurality of pieces of echo information includes: (e) one of the plurality of pieces of echo information read out simultaneously.
When one or a plurality of pieces of echo information do not exist at the same time, an echo detector that outputs a signal for turning off a switch that controls the output of the adder is provided.

Further, in the radar device according to the third aspect, together with the echo detector, (f) echo information of a predetermined level or more exists among a plurality of pieces of echo information read out simultaneously, and When at least one set of echo information does not exist adjacent to the other, a configuration is provided in which a high-level echo determiner that outputs a signal for turning off a switch that controls the output of the adder is provided.

[Operation] With this configuration, a plurality of pieces of echo information obtained by transmitting a plurality of continuous pulsed energy waves are respectively stored, and a plurality of pieces of recorded echo information are simultaneously read, and the same distance is read. Are added.

In addition, a portion of the recorded plurality of pieces of echo information at the same time (distance) is examined, and when a plurality of pieces of echo information do not normally exist near the center thereof, the output is turned off.

In addition, the same time portion of each of a plurality of stored echo information is examined, and like interference from other similar devices,
If the signal is higher than a predetermined level and is not continuous, the output is turned off.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. First
In the figure, storage elements 1a, 1b, 1c, 1d of a storage circuit 1 are for delaying input echo information by a time corresponding to a transmission interval of a pulsed energy wave. Therefore, the output g of the storage element 1a is the echo information obtained by the previous transmission, the output h of the storage element 1b is obtained two times, and similarly, i and j are obtained three times and four times before, respectively. The received echo information. These pieces of echo information are added by the adder 2, and the addition result is output as an output signal b through the switch 3.

These operations are the same as the description shown in FIG. 12,
The number of times corresponds to a predetermined angle at which the radar device rotates.

On the other hand, the echo information of g to j is sent to the continuity determiner 4, and the switch 3 is turned on or off by this determination output signal k.

Next, one embodiment of the continuity determiner 4 is shown in FIG. FIG. 2 shows an echo detector 5 which outputs off as an output signal m when the echo information h and i do not exist at the same time, and there are echo information g to j having a certain level or more, and When these are not continuous, the high-level echo determiner 6 that outputs an off signal as the output signal n, two output signals m (hereinafter, also simply referred to as “output m”), and an output signal n (hereinafter, referred to as “output m”). , Which is also simply referred to as “output n”).

As an example, FIG. 3 shows a circuit example of the echo detector 5 when the input echo information is a 2-bit binary signal and is configured by a positive logic circuit, and FIG. Shown respectively. The echo detector 5 in FIG.
It is composed of an OR circuit 8 and a NAND circuit 9 and outputs an OFF signal of logic level 1 as an output signal m when the echo information h and i do not exist at the same time.

In the high-level echo decision unit 6 shown in FIG.
The 2-bit echo information is input to the AND circuit 10 to extract 1 for both bits, that is, the highest level echo information p to s. This information is output by the AND circuit 11 and the NOR circuit 12 if the adjacent echo signal is not at the highest level, and the signal t is output as the logical level 1. On the other hand, if any of the echo information is at the highest level by the OR circuit 13, the signal u is output as the logical level 1. These two signals t
And u become an output signal n of the high-level echo determiner 6 through the AND circuit 14. That is, an OFF signal of logic level 1 is output as the output signal n only when any one of the echo information g to j is the highest level but none of the adjacent information is the highest level.

As shown in FIG. 2, the output signals m and n are supplied to the OFF OR gate 7.
Are ORed, and becomes a determination output signal k of the continuity determiner 4. That is, only when there is no information in the echo information h and i at the same time, or only when the highest level information exists in the echo information g to j, the determination output signal k of the continuity determiner 4 is as shown in FIG. Is turned off.

In this embodiment, the switch for controlling the output is provided after the integrator, but the integrator may control the front or the integrator itself. It goes without saying that various modifications such as systems and circuits can be applied within the scope of the gist of the present invention.

(Specific Operation Description) Next, an operation based on specific echo information g to j will be described.

In the present embodiment, the echo information at the same distance obtained every time the pulsed energy wave is transmitted is added by an appropriately set number. Therefore, an ideal integration effect without weight or the like is obtained. The number to be integrated may be determined from the directional characteristics of the transducer, the rotational speed, the transmission interval of the pulsed energy wave, and the like. This will be described with reference to FIG. 5 for the embodiment of FIG.

Suppose now that level 3 echo information is present at a predetermined distance every transmission as shown in FIG. 5 (a).

The result of the four additions is output from the adder 2 as shown in FIG. 5 (b). That is, the maximum output level of the adder 2 is level 3 × 4 = 12, and the number of detections for each transmission of the input echo information is five (1 to 5) of the input, and the addition result is eight (1 to 8). .

On the other hand, in the case of the same input signal in the conventional weighted averaging circuit shown in FIG. 10, the multiplier (weight) of the multiplier is assumed to be 0.8.
Then, the output signal b (hereinafter, also simply referred to as "output b") is multiplied by 0.8 and added, so that the output signal b is as shown in FIG. 5 (c). Therefore, as an integration effect, the output level of the weighted averaging circuit is 12, whereas the output level of the weighted averaging circuit is 12, and the number of detections for each transmission is greater in the weighted averaging circuit than in the weighted averaging circuit. Because
The azimuth resolution deteriorates.

In order to prevent the azimuth resolution from deteriorating, subtraction with a fixed value may be considered. Assuming that the fixed value is 3, the maximum output level is reduced to 9 (12-3) in FIG. 5B, and the number of detections is 6 (2 to 7), whereas FIG. ), The same applies to the number of detections.
It must be 5.5, but the maximum output level is 1
It is halved to 0−5.5 = 4.5.

Further, in order to obtain a large output by the weighted averaging circuit, the multiplier of the multiplier may be made close to 1, but it is obvious that the number of detections, that is, the azimuth resolution is further deteriorated.

As shown by the solid line and the dotted line in FIG. 5 (c), the weighted averaging circuit has a problem that the output level greatly changes depending on the number of continuous echo information, that is, the size of the target in the azimuth direction. In this embodiment, as shown in FIG. 5 (b), the number is limited by a predetermined number of additions and does not abnormally increase.

(Explanation of Operation of Claim 2) In Claim 2, the continuity judging device 4 is configured to control the integral output by detecting the echo near the center before integration, and to output no output when there is no echo information near the center. And Therefore, the azimuth resolution is not deteriorated.

If no output is provided unless there is a plurality of, for example, two pieces of echo information near the center, signals having no correlation such as noise can be removed, so that the S / N ratio can be improved separately from the integration effect. This will be described with reference to FIG.
A description will be given based on FIG. 6 and FIG.

It is now assumed that level 3 echo information has been input five consecutive times as shown in FIG. 5 (a). In this case, the output of the adder 2 spreads as shown in FIG.

However, the echo detector 5 of the continuity determiner 4 outputs the output m when there is an input at h and i at the center of the input echo information.
Is determined to have an echo, the output b is limited as shown in FIG. 5D, and the resolution is not deteriorated.

Also, if there is an interference signal or a single noise from another radar device as shown in FIG. 6A, the output of the adder 2 becomes as shown in FIG. The output m of No. 5 does not appear in the output b because it is not determined that there is echo information.

(Explanation of Operation of Claim 3) Further, in claim 3, when relatively high-level information is in an independent state without correlation, such as an interference signal directly coming in from another similar device, an output is performed. And a high-level echo determiner for preventing the generation of noise. Therefore, interference can be prevented without hindering the integration effect. This will be described with reference to FIGS. 7 to 9 for the embodiment of FIG.

It is now assumed that a signal having very little continuity, which is unknown whether it is weak echo information or noise, is input as shown in FIG. The output of the adder 2 in this case is as shown in FIG. 7 (b).

On the other hand, the echo detector 5 in the continuity determiner 4 determines that the output m has echo information only when the central inputs h and i are present at the same time. This means that the portion with information is emphasized and output.

Next, it is assumed that a single high-level echo is mixed in the echo information shown in FIG. 5A as shown in FIG. 8A.
The output of the adder in this case is as shown in FIG.

On the other hand, the high-level echo determiner 6 in the continuity determiner 4
When the high-level echo exists alone, the output b is turned off. Therefore, as shown in FIG. 8C, the output near the high-level echo that exists alone is turned off. That is, a high-level signal that exists alone, such as interference from another radar, is removed.

Next, as shown in FIG. 9A, it is assumed that a part of the echo information in FIG. 7A is a continuous high-level signal. The output of the adder is as shown in FIG. 9 (b).

On the other hand, the high-level echo determiner 6 in the continuity determiner 4
Determines that there is a continuous high-level echo between sections C and D in FIG. 9A, and the echo detector 5
Since it is determined that there is echo information at one point of (e), the output b becomes as shown in FIG.

When the high-level echoes are continuously present, the addition result is output, and the addition result of the continuous low-level echo is also output.

In general, the probability that an interference signal from another radar device is continuous like a high-level echo shown in FIG. 9A is very small.

[Effects of the Invention] In the present invention, firstly, echo information of the same distance obtained every time a pulsed energy wave is transmitted is added by an appropriately set number. Therefore, an ideal integration effect without weight or the like is obtained. The number to be integrated may be determined from the directional characteristics of the transducer, the rotational speed, the transmission interval of the pulsed energy wave, and the like.

Second, the present invention includes a continuity determination unit for echo information, checks a plurality of continuous echo information, and operates only with true echo information from a target. Can be avoided.

According to the second aspect, the continuity judging device is configured to control the integration output by detecting the echo near the center before the integration, and to output no output when there is no echo information near the center. Therefore, the azimuth resolution is not deteriorated.

If no output is provided unless there is a plurality of, for example, two pieces of echo information near the center, signals having no correlation such as noise can be removed, so that the S / N ratio can be improved separately from the integration effect.

Further, according to the third aspect, when relatively high-level information is in an independent state without correlation, such as an interference signal directly entering from another similar device, a high-level signal is output. It was configured to use an echo decision unit together.
Therefore, interference can be prevented without hindering the integration effect.

[Brief description of the drawings]

1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of one embodiment of a continuity determiner, FIG. 3 is a circuit diagram of an echo detector, and FIG. FIG. 5 is a waveform diagram for explaining the operation of one embodiment of the present invention, FIG. 6 is a waveform diagram for explaining the operation of one embodiment of the present invention, and FIG. FIG. 8 is a waveform diagram for explaining the operation of one embodiment of the present invention, FIG. 9 is a waveform diagram for explaining the operation of one embodiment of the present invention, and FIG. FIG. 11 is a waveform diagram for explaining the operation of FIG. 10, and FIG. 12 is a diagram for explaining the operation concept of the radar device. 1 ... memory circuit, 2 ... adder, 3 ... output adjusting means (switch), 4 ... continuity determiner, 5 ... echo detector, 6 ... high-level echo determiner.

Claims (3)

(57) [Claims] 1. A pulse-like energy wave is successively transmitted at predetermined angles while rotating a transducer having directivity,
In a radar device that receives echo information from the target of the energy wave by the receiver and displays the position of the target, a plurality of continuous pulses of energy waves are output from the plurality of continuous pulses of the energy wave. A storage circuit (1) for storing each piece of echo information, an adder (2) for simultaneously reading and adding portions of the plurality of pieces of echo information stored at the same time, and a storage circuit (1) for storing the plurality of pieces of echo information read simultaneously. A continuity determiner (4) for determining the continuity of a portion at the same time; and an output adjusting means (3) for controlling the adder output based on a determination output signal (k) output from the continuity determiner A radar device, characterized in that: 2. The continuity judging device (4), which is a switch for turning on or off the output adjusting means (3) and which determines the continuity of echo information, outputs the same time at the same time. The radar apparatus according to claim 1, further comprising an echo detector (5) that outputs a signal for turning off the switch when there is no echo information among a plurality of pieces of echo information at the same time. 3. The continuity judging unit (4), which is a switch for turning on or off the output adjusting means (3) and judges the continuity of echo information at the same time, is read simultaneously. When a plurality of pieces of echo information do not exist at the same time, an echo detector (5) that outputs a signal for turning off the switch is provided. When echo information of a predetermined level or more exists and at least one set of echo information of this level does not exist adjacent to the high level echo decision unit (6) for outputting a signal for turning off the switch, The radar device according to claim 1, further comprising: