JPH0528980U - Radar equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Stable removal of multiple echoes and 1
An object of the present invention is to obtain a radar device capable of suppressing the false detection rate of the next echo to be low. [Constitution] The video quantized by the slicer 6 is converted into a message by the message creating circuit 10 and is input to the microprocessor 15. The transmission cycle is changed to a short cycle and a long cycle for the same elevation angle, and the short cycle is changed. A plurality of distances corresponding to the repetition cycle of are set, and the process of performing coincidence test with the echo of the long cycle is performed. [Effect] Based on the long-period echo, there is an effect that the short-period multi-order echo can be removed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a method for removing a multi-order echo mixed in a reception signal of a radar device.

[0002]

[Prior Art]

 Conventionally, this type of device has been shown in FIG. In the figure, 1 is an input terminal, 2 is an output terminal, 3 is a transceiver, 4 is a multi-order echo detector composed of a delay circuit 5 and slicers 6a and 6b and a removal pulse generator 7 and 8 is a It is a multi-order echo remover.

FIG. 6 is an operation explanatory view of the apparatus of FIG. 5, and the operation will be described using these. Normally, transmission is repeated with a predetermined number of hits (3 hits for convenience of illustration) at a predetermined transmission repetition period so that a required coverage area can be obtained for a target with a specified radar cross-sectional area. To do. In particular, regarding the transmission repetition period, it is general to select a period corresponding to the maximum detection distance in order to satisfy the predetermined coverage and improve the data rate. At this time, if the target larger than the specified radar cross section is more than the distance corresponding to the transmission repetition period, the coverage area of the target is expanded. This indicates that the target is received at a reception level that is sufficient for detection, and the echo B with respect to the target B in FIGS.₁, B₂As shown in the relationship, the multi-order echo is mixed in the received signal, which is unnecessary and erroneously detected by the device. In a conventional device, a stagger transmission / reception process described below is generally used as a method for coping with this. The transceiver 3 has 3 hits as shown in FIG. 6b, and transmits the echo received from the antenna (not shown) from the input terminal 1 with the stagger ratio (Rc + ΔR) / Rc. Input from the input terminal 1, low noise amplification, frequency conversion, video detection, etc. are performed, and the result of video integration of 3 hits is output as shown in FIG. 6c. As a target to be received here, for convenience of description, when a target A at a distance RA received as a primary echo and a target B at a distance RB received as a secondary echo are assumed as shown in FIG. The three inputs are obtained as shown in FIG. 6b and the output of the transceiver 3 as shown in FIG. 6c. In the multi-order echo detector 4, the output video of the transceiver 3 is delayed by the delay circuit 5 by ΔR corresponding to the period change due to the stagger to obtain the video shown in FIG. 6d. Next, in the slicers 6a and 6b, the output video of the transceiver 3 and the output video of the delay circuit 5 are quantized by the respective predetermined threshold values and the quantized video is output. In the removal pulse generator 7, the output video of the slicers 6a and 6b is logically ANDed, and B shown in FIG.₁And B shown in FIG. 6d ₂ The removal pulse is generated at two points, that is, the time when and coincide with each other and the time delayed by ΔR from this time. On the other hand, in the multi-order echo remover 8, the secondary echo B is output by the removal pulse of the output of the multi-order echo detector 4 from the output video (shown in FIG. 6d) delayed by ΔR in the delay circuit 5.₁, B₂Is removed and only the primary echo A is output from the output terminal 2 as a received signal (shown in FIG. 6e). As described above, the multi-order echo mixed in the received signal is removed.

[0004]

[Problems to be solved by the device]

Since the conventional device is configured as described above, it has the following problems. (1) If there are unnecessary echoes from the nearby sea surface, ground, etc. or unnecessary echoes from rain clouds distributed over a wide area, the primary echo may be mistakenly removed. (2) In the case of the device using the pulse compression method, the transmission pulse width is relatively long and the secondary echo B ₁ or B ₂ shown in FIG. 6c overlaps with the transmission time zone. Becomes difficult to detect and cannot be removed.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a radar apparatus capable of stably removing multi-order echoes and suppressing a false detection rate of primary echoes to a low level. And

[0006]

Means for Solving the Problems A radar device according to the present invention changes a transmission repetition period into a short period and a long period for the same elevation angle, and includes a short period echo based on a long period echo. It is designed to remove the multiple ecos.

[0007]

[Action]

 The radar device according to the present invention eliminates the multi-order echo contained in the short-period echo based on the echo over the short-period period among the long-period echoes.

[0008]

【Example】

 Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is an input terminal, 2 is an output terminal, 3 is a transceiver, 6 is a slicer, 9 is a message creating circuit, 11 is an input circuit, 12 is a CPU, 13 is a memory, and 14 is an output circuit. It is a multi-order echo canceling circuit composed of Reference numeral 15 is a microprocessor.

Next, the operation will be described. In FIG. 1, a received echo input from an antenna (not shown) is input from an input terminal, low-noise amplification, frequency conversion, video detection, etc. are performed in the transceiver 3, and a video integrated result is output. .. FIG. 7 shows the operation explanatory diagram. The slicer 6 quantizes the output of the transceiver 3 with a specified threshold value and outputs a quantized video. This quantized video is input to the multi-order echo removing circuit 9 while the primary echo and the multi-order echoes of secondary and higher order are kept together. This quantized video is converted into a message (whether there is a hit, video amplitude, distance, etc.) by the message creating circuit 10 and input to the microprocessor 15. The microprocessor 15 executes the multi-order echo removal processing according to the flowchart shown in FIG. First, in the process 16 of calculating the target range of the short period beam, a plurality of distances corresponding to the repetition period are set. The explanatory view is shown in FIG. 2A shows an example in which the secondary echo is processed. For example, if it is set that a secondary echo is present, and when the target is detected at 18 NM and 40 NM when the cycle of the short-period beam is Rs = 52 NM, the targets are also set at 70 NM and 92 NM. Next, a step 17 of removing the short range target from the long range target is performed. This is a process in which a target within a short cycle among targets of a long cycle is not output to the next process. 2b is removed when this process is executed. Next, step 18 of performing a coincidence test with the long-period beam is executed. In this process, the match between the target set in step 16 and the target processed in step 17 is tested. In step 19, a multi-order echo mark is set to the target on the short cycle side of the matched pair. As explained with reference to a and b in FIG. 2, since a match is found with the pair, a multi-order eco mark is set. Next, the short-period beam multi-order echo removing step 20 is executed. This process is a process of deleting a target of a short period having a multi-order echo mark in the above process. Next, step 2 1 of setting the target remaining in the previous step in the multi-order echo cancellation output buffer is executed. FIG. 2C is an explanatory diagram of the short-period beam output after performing this processing.

Example 2. Although the tolerance is not set in the multi-order echo canceling circuit in the above embodiment, by providing the coincidence test tolerance setting circuit 30 as shown in FIG. 4, the tolerance can be easily set as a parameter. The tolerance can be easily set in the next echo removing circuit, and the same effect as that of the above-described embodiment can be obtained.

[0011]

[Effect of the device]

 As described above, according to the present invention, the difficulty of removing the multi-order echo due to the unnecessary echo and the difficulty of detecting the multi-order echo due to the long pulse width are eliminated, and the multi-order echo can be removed relatively easily. effective. In addition, the microprocessor control has an effect that a multi-order echo canceling circuit can be easily configured.

[Brief description of drawings]

FIG. 1 is a system diagram showing a radar device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of a multi-order echo canceling circuit according to an embodiment of the present invention.

FIG. 3 is a flow chart showing the operation of an embodiment of the present invention.

FIG. 4 is a system diagram of a radar device showing a second embodiment of the present invention.

FIG. 5 is a system diagram showing a conventional radar device.

FIG. 6 is an operation explanatory view of a conventional radar device.

FIG. 7 is a diagram for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

1 Input Terminal 2 Output Terminal 3 Transceiver 4 Multi-order Echo Detector 5 Delay Circuit 6 Slicer 7 Removal Pulse Generation Circuit 8 Multi-order Echo Remover 9 Multi-order Echo Removal Circuit 10 Message Creation Circuit 11 Input Circuit 12 CPU 13 Memory 14 Output Circuit 15 Microprocessor 16 Process for calculating target range of short period beam 17 Process for removing short period range target from target within long period 18 Long period beam and coincidence verification process 19 Multi-order echo mark setting process 20 Short period beam multi order Echo removal process 21 Multi-order echo removal output buffer setting process 30 Match test tolerance setting circuit

Claims (1)

[Scope of utility model registration request] 1. A radar apparatus comprising a transceiver and a CFAR circuit and a multi-order echo canceling circuit in the subsequent stage,
A radar device, characterized in that the transmission cycle of the transceiver is changed to a short cycle and a long cycle with respect to the same elevation angle to remove a multi-order echo.