KR20220096549A - Stepped fm modulated pulse signal count for synthetic aperture radar system - Google Patents

Abstract

The present invention relates to a step-modulation pulse signal count for a radar system. A radar system including an RF transmission unit having a transmission pulse check circuit comprises: a transmission driving module including an output unit for outputting an RF signal composed of long pulses and short pulses and a DAM transmission engine for outputting a timing signal earlier than the RF output by a first set time; and an up-conversion module for driving an LED indicating normality or abnormality by processing two different pairs of RFs with three input bits and one output bit, wherein the DAM transmission engine of the transmission driving module includes a reception check mode for outputting a signal inverted from an operation model when the timing signal is output, and the up-conversion module delays the first set time by more than 10 times and determines whether the short pulses and long pulses are normal or abnormal using delay logic. According to the present invention, the step-modulation pulse signal count for a radar system can drive a check LED by detecting missed transmission pulses.

Description

STEPPED FM MODULATED PULSE SIGNAL COUNT FOR SYNTHETIC APERTURE RADAR SYSTEM

The present invention relates to step modulated pulse signal counting for radar systems.

Radar can be largely divided into continuous wave radar and pulse wave radar depending on the radio waves used. Continuous wave radar refers to continuously radiating radio waves whose amplitude does not change at a specific frequency, while pulse wave radar refers to radiating radio waves whose amplitude increases instantaneously at a specific frequency and returns for a short time.

Radar that uses pulse waves emits waves with different amplitudes in an instant, so you can easily measure the distance to the opponent by knowing when the reflected wave has returned. Here, by using the Doppler effect, not only 3D information such as the opponent's speed and altitude, but also noise caused by the terrain can be removed. However, there are problems in that it is difficult to make a high-power pulse wave, a warm-up is required, and the resolution is lower than that of a continuous wave.

Continuous wave radar has a disadvantage in that it cannot measure when the reflected wave returns because the same radio wave continuously comes in by generating radio waves with the same frequency and amplitude and detecting the reflected wave. Accordingly, the continuous wave radar has a problem in that it is difficult to measure the distance between the objects.

Since the transmission driving assembly of the radar system uses the diversity method, two variable pulses are operated as a pair, and due to the characteristics of the equipment, normal and faulty conditions must be indicated using the LED of each circuit card.

There is a need to solve the problem that the transmission pulse is missing and received.

Republic of Korea Registration Notice No. 10-1320508 Republic of Korea Registration Notice No. 10-1437747

An object of the present invention is to provide a step-modulated pulse signal coefficient for a radar system capable of driving a check LED by detecting a missing transmission pulse in order to solve the above problems.

The present invention relates to a radar system including an RF transmitter including a transmit pulse check circuit,

a transmission driving module including an output unit for outputting an RF signal composed of a long pulse and a short pulse and a DAM transmission engine for outputting a timing signal earlier than the RF output by a first set time; and

It includes; an up-conversion module that processes two different pairs of RF with three input BIT and one output bit and drives an LED indicating whether it is normal or not;

The DAM transmission engine of the transmission driving module includes a reception check mode for outputting a signal reversed from an operation mode when the timing signal is output,

The up-conversion module provides a step-modulated pulse signal coefficient for a radar system, characterized in that it delays the first set time by 10 times or more, and determines whether short pulses and long pulses are normal using delay logic.

According to an embodiment of the present invention, it is possible to provide a step-modulated pulse signal coefficient for a synthetic aperture radar system capable of driving a check LED by detecting a missing transmit pulse.

1 is a diagram illustrating a transmission timing of a radar system according to the present invention.
FIG. 2 is a diagram illustrating timing signals of one transmission driving module (DAM) and four RF generators.
3 is an enlarged view showing a reception check mode.
4 is a circuit diagram showing the configuration of AD8317, which is a LOG detector/controller.
5 and 7 show a test circuit, respectively.
6 and 8 are diagrams showing 0.1 μs pulse test results of the test circuits of FIGS. 5 and 7, respectively.
9 is a conceptual diagram of UCM according to an embodiment of the present invention.
10 is a diagram illustrating a UCM LED driving circuit.
11 is a graph showing the operation of the UCM LED driving circuit of FIG.
12 is a graph showing the delay of 74HCT221.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are only exemplified for the purpose of explaining the embodiments according to the concept of the present invention, and the embodiment according to the concept of the present invention These may be embodied in various forms and are not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention may have various changes and may have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes changes, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, a first component may be named a second component, Similarly, the second component may also be referred to as the first component.

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle. Expressions describing the relationship between elements, for example, “between” and “between” or “directly adjacent to”, etc. should be interpreted similarly.

The terminology used herein is used only to describe specific embodiments, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, and includes one or more other features or numbers, It should be understood that the possibility of the presence or addition of steps, operations, components, parts or combinations thereof is not precluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present specification. does not

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. Like reference numerals in each figure indicate like elements.

The transmitter for step-modulated pulse signal counting according to an embodiment of the present invention includes one transmission drive module (DAM) and four RF generators, an up-conversion module (UCM), WGM, reference signal synthesis module (SGM), and LSM. do. Hereinafter, a transmission timing according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 .

1 shows transmission timing for a radar system. TXPW represents the final output signal. FIG. 2 shows timing signals of one transmission driving module (DAM) and four RF generators, and FIG. 3 is an enlarged view showing the reception check mode.

All timing signals start 1 μsec before the final output signal. The output signal is composed of a long pulse (LP) and a short pulse (SP). The long and short pulses are variable pulses. The average value of the long pulses is 86 μs, and the variable range of the short pulses is 0.1 μs to 7 μs.

The STALO3 signal is supplied from the reference signal synthesis module (SGM) to the upconversion module (UCM) and operates like the timing signal of the reference signal synthesis module (SGM) of FIG. 2, and the RF output delay of the reference signal synthesis module (SGM) is about 600 n seconds. The UCM operates like the timing signal of the UCM shown in FIG. 2 by a combination of a long pulse and a short pulse, and the filter is cut internally by selecting the long pulse and the short pulse.

The DAM includes a reception check mode as shown in FIG. 3 . The reception check mode is driven as shown in Table 1 below.

4 is a circuit diagram showing the configuration of AD8317, which is a LOG detector/controller, and Table 2 shows the AD8317 usage conditions.

The minimum width of a short pulse is 0.1μs, and when a pulse of 0.1us is input, it should be output at a level sufficient to drive a logic IC using the VSET function of the AD8317 log detector.

In order to determine the R value so that the output of the AD8317 can meet the input condition of the CMOS IC at a pulse of 0.1us, a test circuit is constructed as shown in FIG. 5 and a test is performed. 6 is a view showing a 0.1 μs pulse test result of the test circuit of FIG. 5 .

As shown, if the voltage of pin 4 of AD8317 is set to 1.1V, “H” is detected at about -41dBm of input frequency 6.8GHz CW standard. As shown in FIG. 6 , even though the MM74HC541MIC is a CMOS IC, when the VSET value of pin 4 of AD8317 is set to a low level, the pulse width is deformed as the AD8317 input level approaches the VSET value. The orange line in Fig. 6 represents the output of the AD8317, and the green line represents the output of the MM74HC541MIC. These problems cause problems in circuit cards as follows and impose restrictions on circuit design. First, the minimum operating pulse width is 0.1us, and the output pulse width of AD8317 Log Detector becomes narrower as a low level input to 0.1us pulse becomes. As shown in FIG. 6 , there is a problem in that the input range of the CMOS IC of the LED driving circuit is narrowed due to the narrowed pulse width, and due to this, there is a problem in that the resolution of the RF level check signal becomes unclear during 0.1us pulse operation. There is a problem that the CMOS IC cannot operate.

As shown in Figure 6, when the output of MM74HC541 on the right does not operate normally at -28dBm input to AD8317, when a resistance of 330Ω is added as shown in Figure 7, as shown in Figure 8, The output of MM74HC541 operates normally at -37dBm input to AD8317.

When a coupler and an attenuator are used in the configuration of the input/output check circuit, the input/output is 0.1us +5dBm when the “L” level detection area of the logic IC becomes the “L” area at the higher RF level input as a result of the test on the left side of FIG. It is difficult to construct a circuit that detects an abnormal signal at -10dBc or higher. In the circuit of FIG. 7, the difference between the “L” region of the CW standard and the “L” of the 0.1usRF pulse width is about 3dBc, so it can be sufficiently used in the detection circuit under the above conditions.

9 is a conceptual diagram of UCM according to an embodiment of the present invention. As shown, with 3 input BIT and 1 output BIT. By processing two different pairs of RF pulses, the LED indicates whether there is a normal fault. The shortest pulse is 0.1us.

The check LED driving circuit must satisfy the following conditions. Normal status should be displayed in power ON and standby mode (only STALO1 signal is input and all signals are OFF). If there is an error in at least one of the short pulse and the long pulse, a fault is indicated. If the level falls by more than -10dBc based on input/output RF, it is indicated as a failure. For both short and long pulses, the LED driving circuit should operate normally even when the minimum pulse width is 0.1us or more. According to the AD8317 test result, the input logic IC of the LED driving circuit should use a CMOS IC. Table 3 below is the TTL input condition, and Table 4 is the CMOS input condition.

10 is a diagram showing a UCM LED driving circuit, FIG. 11 is a graph showing the operation of the UCM LED driving circuit of FIG. 10, and FIG. 12 is a graph showing a delay of 74HCT221. 11A shows missing detection counts. The LED driving circuit of UCM shown in FIG. 10 uses 74221 and 7474 as main ICs. The basic configuration uses 74221 to delay 0.1us to several us, and 7474 is used for this delayed logic to determine whether short pulses and long pulses are normal. As shown in FIG. 11 , the RC time constant of No. ① in the circuit diagram of FIG. 11 is designed to be sufficiently larger than the time constant of No. ② at the moment when DC power is supplied in the power ON section. According to ① and ② of FIG. 11, 7474 of Table 5 below maintains the power ON section and the power OFF section. ③ shows “H” operation when the FPGA of the local signal synthesis circuit card operates and the DDS generates a frequency and the RF signal is supplied to the UCM. After the power is turned on, the FPGA of the local signal synthesis module operates and the RF signal (STALO1) When it becomes UCM, it is displayed as normal.

In the normal section of FIG. 11, the RC time constant of 74221 of ④⑤⑥ of FIG. 10 is delayed by 4.5us (AD8317 output signal delay), and ⑦ is delayed by 2 to 2.5us (UCM_EN delay) as shown in FIG. The input and output of ⑦74221 of FIG. 10 are opposite to ④⑤⑥ of the above item. 7 of FIG. 11 is used as a CLK input of 7474 of FIG. 10 . Therefore, as shown in FIG. 12 , it is possible to determine normal failure. In conclusion, it can be seen that normal failure is determined in the middle region of the 4.5us delayed ④⑤⑥ signal.

In the short pulse failure section of FIG. 11, as in A of FIG. 11, when the short pulse fails, the output of ⑨ (the first D Flip-Flops) is “L” by the delay output ⑦ of the UCM_EN of FIG. do. After this operation, the LP pulse is output normally, but the “L” output above moves to ⑩ (the second D Flip-Flops) to output “L”. If any one of the short pulse and the long pulse is defective, the entire section in which the short pulse and the long pulse are combined is marked as a failure.

Therefore, if the processing of short pulses of 0.1us is delayed by several ms, it is possible to solve the problem that failures are not identified when pulses of different lengths are used, and to solve the problem of sliding the RF Detector in the FPGA. do.

Claims (1)

A radar system including an RF transmitter including a transmit pulse check circuit, comprising: an output unit for outputting an RF signal composed of a long pulse and a short pulse; and a DAM transmission engine for outputting a timing signal that is earlier than the RF output by a first set time a transmission driving module, and an up-conversion module that processes two different pairs of RF with 3 input BIT and 1 output BIT to drive an LED indicating whether it is normal, wherein the DAM transmission engine of the transmission driving module includes a reception check mode that outputs a signal inverted from the operation mode when the timing signal is output, and the up-conversion module delays the first set time by 10 times or more, and uses delay logic to determine the normality of short pulses and long pulses Step-modulated pulse signal counting for a radar system, characterized in that it determines the presence or absence.

Images