JPS62174676A - Beam scanning radar equipment - Google Patents

Abstract

PURPOSE:To detect a multi-degree echo by detecting the multi-degree echo at long distance where no unnecessary echo is mixed. CONSTITUTION:One specific or plural succeeding bits are transmitted and received in every elevation step at a longer transmission repetition period than other hits. Namely, a multi-degree detector 20 quantizes and detects a video by a slicer 21 with a prescribed threshold value in the time zone of the period extension part of the output video of a transmitter receiver 10. Then, the quantized video outputted by the slicer 21 is shaped by a removal pulse generating circuit 22 to generate a removal pulse. A multi-degree echo removing device 30, on the other hand, delays the output video of the transmitter receiver 10 by a delay circuit 31 corresponding to the transmission repetitive period and a gate circuit 32 removes the multi-degree echo stably with the removal pulse outputted by the multi-degree echo detector 22, so that the wrong removal of a primary echo is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for removing multiple echoes mixed in a received signal of a beam scanning radar device.

[Conventional technology]

Conventionally, there was a device for this mallet as shown in the third example.

In the figure, (1) is an input terminal, (2) is an output terminal, (
(g) is a transmitter/receiver, (b) is a multi-order echo detector consisting of a delay circuit A of 1151), a slicer (φ4), and a cancellation pulse generation circuit (b), and (b) is a multi-order echo canceller.

The fourth factor and the fifth factor are the third evil equipment-〇Operation explanation 1, and the operation will be explained using these. Normally, in a beam scanning radar device, the elevation plane is divided into arbitrary elevation angle steps (fourth step) to obtain the required coverage area for a target with a single radar cross section as shown in Figure 4. The figure shows an example of 5 steps), and for each elevation step, the elevation step numbers 1 to 5 can be set using an arbitrary number of hits (for convenience of explanation, 8 hits).
This is done repeatedly by scanning the beam. (The beam scanning order may be scanned from elevation step number 5 to 1.) In addition, the transmission repetition period satisfies the required coverage shown in Figure 4, and the time required for beam scanning is minimized. Therefore, it is common to select a period corresponding to the maximum detection distance corresponding to each elevation angle step. At this time, as shown in No. 40, if a target larger than the specified radar cross section is located at a distance equal to or longer than the transmission repetition period, the destruction of that target increases like a ward. This indicates that the target is received at a level that is sufficient for detection, and this indicates that the target B of 511a, b
As shown by the relationship of echoes B1+B2, these echoes are mixed into the received signal as multi-order echoes, which are unnecessary for the device and result in erroneous detection. Conventional devices generally use staggered transmission/reception processing as described below as a method for dealing with this problem.

From the above, the transmission/reception is performed from the input terminal (1) to the antenna (Fig. The echoes transmitted from the antenna (not shown) and received by the antenna (not shown) are input from the input terminal (1) and subjected to receiving processing such as low noise amplification, frequency conversion, and video detection.
As shown in Figure C, the results of video integration of 8 hits are output. For convenience of explanation, we will use the fifth target as the target to receive here.
As shown in figure a, the distance R received as the primary echo
The eye mA of a person and the distance JO received as a secondary echo
When assuming two types of target B in B, enter “transmission/reception @-”
It is obvious that the power is obtained at point 51b and the output of the transceiver Q0 is obtained as shown in FIG. 5C.

In the multi-order echo detector stage, the output video of the transceiver is
The video shown in FIG. 5d is obtained by delaying the video by the delay circuit Φη by ΔR corresponding to the circumferential constraint change due to the stagger. Next, slicer e′
4. In w, the output video of the transceiver (7) and the delay circuit G
Each output video of υ is quantized using a prescribed threshold 46, and a quantized video is output. In the elimination Hals generator system,
Slicer competition, take the AND of the output video of the mansion, and figure 5C
Elimination pulses are generated at two locations: a time when B1 shown in FIG. 5 and B2 shown in FIG. 5d match, and a time delayed by ΔR from this time. On the other hand, in the multi-order echo remover..., the delay port f
From the output video (shown in FIG. 6d) which has been delayed by ΔR in Mr611, the secondary echo B1. , B2 are removed, and only A, which is the primary echo, is outputted from the output terminal (2) as a received signal (shown in FIG. 5e). In this way, multi-order echoes mixed into the received signal are removed.

[Problems to be Solved by the Invention] Since the conventional device is configured as described above, it has the following problems.

(1) When there are unnecessary echoes from the ground, sea surface, etc. in a short distance area and unnecessary echoes from rain clouds distributed over a wide area, the primary echo may be mistakenly removed.

(2) In the case of a device using a pulse compression method, the transmission pulse time is relatively long and the secondary echo B1 shown in No. 51Wc
．． If either B2 is superimposed during the transmission time period, it becomes impossible to detect the secondary echo, which makes it impossible to remove it.

This invention was made to solve the above-mentioned problems, and it is possible to stably remove multi-order echoes, and
To obtain a beam scanning radar device capable of suppressing a first-order echo error removal rate to a low level.

The purpose is to

[Means for Solving the Problems] The beam scanning radar device according to the present invention sets the transmission repetition period for a specific one or a plurality of consecutive humans at a period longer than other humans at each elevation angle step. This device performs transmission and reception processing, detects multi-order echoes during the extended period of the output video, generates a cancellation pulse, and uses this cancellation pulse to remove the multi-order echoes mixed into the output video of the transmitter/receiver. be.

[Effect]

The beam scanning radar device of the present invention extends the transmission repetition period only for one specific person or several consecutive people at each elevation angle step, and detects multi-order echoes in a long-distance area where unnecessary echoes are not mixed. In addition, since the transmission repetition period of the last human is selected so that the multi-order echo does not overlap with the transmission time period, it is possible to stably detect and remove the multi-order echo, and to improve the stability of the detection and removal of the first-order echo. The error removal rate can be kept low.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is the input terminal, (2) is the output terminal, and σ
q is a transmitter/receiver, good is a multi-order echo detector consisting of a c2υ slicer and a removal pulse generation circuit, and q is a multi-order echo detector consisting of a zero delay circuit and a gate circuit. It is an echo remover.

The second white is a white for explaining the operation of the apparatus shown in FIG. 1, and the operation will be explained using this white. Since the general operation of the beam scanning radar device and the generation of multiple echoes are the same as in the case of FIG. 3, the explanation will be omitted, and only the different parts will be explained. As shown in the second row, the transmitter/receiver αQ transmits 8 hits per elevation angle step, and extends the transmission repetition period only for the last hit (3rd bit), and connects the input terminal (1) to the antenna (not shown). Send from At this time, the third bit period RD is set to be equal to or greater than the maximum distance of the target for multi-order echoes, taking into account the installation altitude of the device, the upper limit of flight altitude of the aircraft, the system gain of the device, etc. be. Next, the transceiver αQ inputs the echo received by the antenna (not shown) from the input terminal (1) and generates a low-noise amplification signal 1.
After performing reception processing such as frequency conversion and video detection,
The result of video integration of 8 hits is output as shown in the figure below. Here, when assuming the same target as in the case of the third factor (shown in the second factor d) as the receiving target, the transmitter/receiver C1
) is shown in Figure 2, and the output of the transmitter/receiver σQ is shown in Figure 2C.
It is obvious that what can be obtained as shown in .

In the multi-order echo detector 4, the transmitter/receiver αQ shown in 2nd C
The video is quantized and detected using a slicer υ using a predetermined threshold value in the time period of the period extension part of the output video. Next, the quantized video output from the slicer (b) is shaped by a removal pulse generation circuit 4 (for example, using a specified value of the signal pulse width, a value twice that value, etc.) to generate a removal pulse.

On the other hand, in the multi-order echo canceller q, the output video of the transmitter/receiver CIQ is delayed by a period Rc (shown in Fig. 2, c) in the delay circuit Cη, and the multi-order echo detector (4) is processed by the gate circuit. Multi-order echo Bl (
) shown in FIG. 2C to obtain the output shown in the second factor d. At this time, the video of the multi-order echo detection section (shown in Figure 2C) is not used as the radar output video. here,
As for the delay time of the delay circuit, the transmission repetition period becomes @ for each elevation angle step, so one shift corresponding to this is required. Therefore, in the delay circuit υ, as is clear from the four factors, the transmission repetition period at the elevation step 5, that is, the lowest elevation beam, is generally the maximum, so the memory used as the delay multiplier is It would be a good idea to prepare accordingly. Also,
In the cancellation pulse generation circuit eυ, the cancellation pulse is shaped in order to reliably remove multi-order echoes, so the delay time in the delay circuit c1 is set slightly larger than the corresponding transmission repetition period. It is desirable to keep it.

Furthermore, in the above embodiments, for convenience of explanation, the specific hit is the final hit, but it is not necessarily limited to the final hit or the single hit.

In addition, in the above embodiment, the case where the transceiver (LO) is not staggered is shown, but if staggered, the period change due to the stagger is applied to the cancellation pulse generation circuit for multi-order echo video as shown in Section 51c. This can be removed by adding a circuit that can generate a removal pulse during a time period corresponding to .

〔Effect of the invention〕

As described above, according to the present invention, multi-order echoes can be detected in a long distance area where unnecessary echoes are not mixed in, and the multi-order echoes are configured so as not to be superimposed on the transmission 1' west time zone. , multi-order echoes can be stably removed, and
This has the effect that the error cancellation rate of the primary echo can be kept low.

[Brief explanation of drawings]

1- is a system diagram showing a beam scanning radar device according to a one-sentence embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. figure,
The fifth factor is an explanatory diagram of the operation of the conventional beam correction radar device of No. 3C. α0...Transmission/reception building, ■...Multi-order echo detector, (Foundation)...Slicer, (B)...Removal pulse generation circuit,
Ring...Multi-order echo remover, 6η...Delay circuit, working...
...Gate circuit. In the figures, the same reference numerals indicate the same or equivalent parts. Patent issuer: Toru Yamano, Director, Technology Research Headquarters, Defense Agency, Figure 1: Jθ 0 Nu゛ c, +
Fig. 3 Fig. 4 Fig. 1

Claims (1)

[Claims] Divide the beam scan in the elevation plane into arbitrary elevation steps,
In addition, in a beam scanning radar device that transmits and receives an arbitrary number of hits for each elevation angle step, the transmission repetition period is set to be longer than other hits only for a specific one or a plurality of consecutive hits for each elevation angle step. A transmitter/receiver that performs transmission/reception processing, and a target located at a distance corresponding to the transmission repetition period of a person other than the period extension hit in the time period of the extended part of the period extension hit in the received signal output for each elevation angle step of the transceiver. A multi-order echo detector consisting of a slicer that quantizes and detects echoes (so-called multi-order echoes) using a specified threshold, and a cancellation pulse generation circuit that creates multi-order echo cancellation pulses from the quantized video output from the slicer. , the delay circuit that delays the output of the received signal by a time equivalent to the transmission repetition period of the person other than the period extension hit, and gates the output of the delay circuit with the multi-order echo cancellation pulse output from the multi-order echo detector. 1. A beam scanning radar device comprising a multi-order echo remover constituted by a gate circuit for removing multi-order echoes, thereby being able to remove multi-order echoes mixed into a received signal.