A detection threshold dynamic control system and method for a radar sensor

Abstract

The present invention discloses a detection threshold dynamic control system and method of a radar sensor. The system includes a radar system module, an A / D acquisition module, a signal processing module, and a serial port module. If the digitized signal value is less than the noise value + threshold, it is considered that no moving target is detected, then T is accumulated, and after a preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than or equal to the noise value + threshold, it is considered that a moving target is detected, T=1 and the timing is restarted, and the signal processing module reduces the detection threshold of the radar. After a preset delay time, if T<the preset specified value, the system outputs a high level. The present invention adjusts the size of the radar threshold according to whether a moving target appears or not. When a moving target appears within a preset range, the sensing accuracy of the radar is improved, the tiny movements of the moving target are accurately identified, and the output of the level is controlled in real time based on this sensing result; when there is no moving target within the preset range, the predetermined threshold is maintained to reduce the computing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of radar sensing, and more specifically, to a detection threshold dynamic control system and method for a radar sensor. Background Art

[0002] Radar sensing technology is increasingly being used, and some radar sensing modules need to be used to identify multiple scenarios at the same time, such as identifying the approaching movement of a moving object while also identifying the tiny movements of the object after it approaches. Such technology should be applied to the switch of induction lights, but traditional radar information systems are mainly based on hardware platforms such as FPGA and DSP. The cost of developing products is high and the application algorithms are complex, requiring the MCU to have great computing power. Such high technical costs are not suitable for ordinary lighting products in the consumer market, which makes it difficult to promote radar sensing technology to daily products. Summary of the invention

[0003] The primary purpose of the present invention is to address the problems existing in the prior art and provide a detection threshold dynamic control system and method for a radar sensor, which uses an algorithm to match multiple scenes with radar detection thresholds one by one, identifies moving targets by dynamically adjusting the threshold, and accurately controls the output level.

[0004] The technical effects to be achieved by the present invention are achieved through the following technical solutions:

[0005] A detection threshold dynamic control system of a radar sensor, comprising the following modules:

[0006] Radar system module: detects moving targets within a preset range in real time through fixed-frequency microstrip transmitting and receiving antennas, and outputs intermediate frequency signals for AD digital-to-analog conversion;

[0007] A / D acquisition module: performs AD digital-to-analog conversion on the intermediate frequency signal, and acquires the digital signal value after the digital-to-analog conversion;

[0008] Signal processing module: Process the digitized signal value, initialize the parameter timing variable T=0, if the digitized signal value is less than the noise value + threshold, it is considered that no moving target is detected, then T accumulates the timing, after the preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than the noise value + threshold, it is considered that a moving target is detected, T=1 and the timing is restarted, the signal processing module reduces the detection threshold of the radar, after the preset delay time, if T<the preset specified value, the system outputs a high level;

[0009] Serial port module: Utilizing the serial port peripherals of the MCU, the serial port module is used to set the detection parameters of the radar system module, including the size of the detection threshold, the preset range, and the delay time.

[0010] Preferably, it includes an MCU processing module communicatively connected to the radar system module, and the MCU processing module includes the A / D acquisition module and the signal processing module.

[0011] Preferably, T cumulative timing and T=1 will both trigger timing, and the MCU will make a numerical determination on T after reaching the preset delay time; if T<preset specified value, the MCU triggers the system to output a high level; if T≥preset specified value, the MCU clears T and restores the detection threshold of the intermediate frequency signal, and outputs a low level; the preset specified value>1.

[0012] Preferably, the degree of continuity of the digital signal value acquisition is judged by the signal processing module integrating the digital signal value N times to obtain an average value of the DC voltage value and an average value of the signal amplitude integral value, and performing DC voltage value filtering and signal amplitude integral value filtering on the average value of the DC voltage value and the average value of the signal amplitude integral value during the accumulation timing T, and calculating the adaptive noise value to determine whether a moving target is currently present.

[0013] Preferably, the lowest value of the detection threshold is a critical value at which the radar system module will not be falsely triggered when there is no moving target within a preset range; the highest value of the detection threshold is a value corresponding to the maximum amplitude of the radar intermediate frequency signal.

[0014] Preferably, the radar system module adopts a 9.85 GHz X-band radar chip.

[0015] Preferably, the signal processing module is connected to a timer, and the timer is provided with the timing variable T.

[0016] The detection threshold dynamic control method of the radar sensor of the present invention comprises the following steps:

[0017] S1. Use the radar system module to detect moving targets within a preset range in real time;

[0018] S2, using an A / D acquisition module to perform AD digital-to-analog conversion on the intermediate frequency signal, and acquire a digitized signal value after the digital-to-analog conversion;

[0019] S3. Use the signal processing module to process the digitized signal value, initialize the parameter timing variable T=0, if the digitized signal value is less than the noise value + threshold, it is regarded as no moving target is detected, then T accumulates the timing, after the preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than the noise value + threshold, it is regarded as a moving target is detected, T=1 and the timing is restarted, the signal processing module reduces the detection threshold of the radar, after the preset delay time, if T<the preset specified value, the system outputs a high level.

[0020] Preferably, the lowest value of the detection threshold is a critical value at which the radar system module will not be falsely triggered when there is no moving target within a preset range.

[0021] Preferably, when the radar system module identifies a moving target, it triggers the timing of the detection cycle, and the MCU makes a numerical determination on T after the detection cycle is reached.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] When the radar system module senses a moving target within the preset range, the system will reduce the detection threshold of the radar and continue to detect the moving target within the detection period. If the moving target is detected to exist continuously, a high level is output; if the moving target is interrupted within a certain detection period, the timing parameters are cleared and the set threshold of the radar is restored, and a low level is output.

[0024] The present invention adjusts the size of the radar threshold according to the presence or absence of a moving target. In scenarios where moving targets such as people may appear within a preset range such as a walkway, the radar's sensing accuracy is improved, thereby accurately identifying the tiny movements of the moving target, and using this sensing result to control the system to respond in real time; in scenarios where there are no moving targets within the preset range, the radar's preset threshold is maintained to reduce the radar's computing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of a detection threshold dynamic control system of a radar sensor according to the present invention;

[0027] Figure 2 It is a flow chart of a detection threshold dynamic control method of a radar sensor described in the present invention. DETAILED DESCRIPTION

[0028] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] See also Figure 1The detection threshold dynamic control system of a radar sensor according to the present invention comprises the following modules:

[0030] Radar system module: detects moving targets within a preset range in real time through fixed-frequency microstrip transmitting and receiving antennas, and outputs intermediate frequency signals for AD digital-to-analog conversion;

[0031] A / D acquisition module: performs AD digital-to-analog conversion on the intermediate frequency signal, and acquires the digital signal value after the digital-to-analog conversion;

[0032] A / D acquisition module: performs AD digital-to-analog conversion on the intermediate frequency signal, and acquires the digital signal value after the digital-to-analog conversion;

[0033] Signal processing module: Process the digitized signal value, initialize the parameter timing variable T=0, if the digitized signal value is less than the noise value + threshold, it is considered that no moving target is detected, then T accumulates the timing, after the preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than the noise value + threshold, it is considered that a moving target is detected, T=1 and the timing is restarted, the signal processing module reduces the detection threshold of the radar, after the preset delay time, if T<the preset specified value, the system outputs a high level;

[0034] Serial port module: Utilizing the serial port peripherals of the MCU, the serial port module is used to set the detection parameters of the radar system module, including the size of the detection threshold, the preset range, and the delay time.

[0035] It should be noted that the lowest value of the detection threshold is the critical value at which the radar system module will not be falsely triggered when there is no moving target within the preset range; the highest value of the detection threshold is the value corresponding to the maximum amplitude of the radar intermediate frequency signal. The signal processing module should adjust the threshold within the above range.

[0036] Among them, it includes an MCU processing module that is communicatively connected to the radar system module, the MCU processing module includes the A / D acquisition module and the signal processing module, the signal processing module is connected to a timer, and the timer is provided with the timing variable T.

[0037] T cumulative timing and T=1 will trigger timing. The MCU will make a numerical determination on T after reaching the preset delay time; if T<preset specified value, the MCU will trigger the system to output a high level; if T≥preset specified value, the MCU will clear T and restore the detection threshold of the intermediate frequency signal, and output a low level; the preset specified value>1.

[0038] The detection period refers to the judgment time interval for determining whether there is a moving target each time. For example, a detection period of 300 ms means that it is determined whether there is a moving target every 300 ms. The judgment period is related to factors such as the power supply situation of the system, the product shell of the application, and the use environment, and needs to be determined after debugging according to the actual scenario.

[0039] The radar system module needs to continuously detect whether there is a moving target within the detection period. If the moving target is interrupted, T starts to accumulate and time. In this way, within the preset delay time, T is likely to exceed the preset specified value. If T > the preset specified value after the delay time, a low level is output. During the process of continuously detecting the moving target, it is necessary to filter and denoise the digital signal value to ensure the detection accuracy. Specifically, the signal processing module performs N integrations on the digital signal value to obtain the average value of the DC voltage value and the average value of the signal amplitude integral value, and continuously filters the average value of the DC voltage value and the average value of the signal amplitude integral value respectively during the process of T accumulating and timing, and calculates the adaptive noise value to determine whether there is a moving target currently.

[0040] Among them, the average value of the signal amplitude integral value = N * Value_b, Value_b is the signal amplitude of each detection, Value_b = |Value_a - average|; N is the number of integrations.

[0041] The filtering of the DC voltage value includes: defining a filtering coefficient P and performing recursive arithmetic average processing on the DC voltage value.

[0042] The filtering of the signal amplitude integral value includes: defining a noise fluctuation range value M, M is a variable, and M = Value_c >> 3; defining a filtering coefficient as N, the value of N depends on the filtering coefficients R and S; performing limit filtering on the average value of the signal amplitude integral value and the average value of the signal amplitude integral value of the previous T times, with the amplitude being the noise fluctuation range value M, and then performing recursive average filtering processing according to the filtering coefficient N.

[0043] The calculation of the adaptive noise value includes:

[0044] When the current is at a low potential / the lamp is off, according to the difference between the noise value and the signal amplitude integral value, the noise coefficient is divided into Q levels, and each level corresponds to a different filtering coefficient R. When N > R, the signal amplitude integral value is used as the new noise value and recursive average filtering is performed;

[0045] When the potential is high / the lamp is on, according to the difference between the noise value and the signal amplitude integral value, the noise coefficient is divided into T levels, and each level corresponds to a different filtering coefficient S. When S < N, the signal amplitude integral value is used as the new noise value, and recursive average filtering is performed on the noise value;

[0046] Define the threshold value H. If the signal amplitude integral value > noise value + threshold value H, the output is high level, indicating that there is a moving target within the sensing range. Otherwise, the output is low level, indicating that there is no moving target.

[0047] See also Figure 2 The control method provided by the present invention comprises the following steps:

[0048] S1. Use the radar system module to detect moving targets within a preset range in real time;

[0049] S2, using an A / D acquisition module to perform AD digital-to-analog conversion on the intermediate frequency signal, and acquire a digitized signal value after the digital-to-analog conversion;

[0050] S3. Use the signal processing module to process the digitized signal value and initialize the parameter timing variable T=0. Use the signal processing module to process the digitized signal value and initialize the parameter timing variable T=0. If the digitized signal value is less than the noise value+threshold value, it is regarded as that no moving target is detected, then T is accumulated and timed. After a preset delay time, if T≥the preset specified value, the system outputs a low level. If the digitized signal value is greater than or equal to the noise value+threshold value, it is regarded as that a moving target is detected, T=1 and the timing is restarted. The signal processing module reduces the detection threshold of the radar. After a preset delay time, if T<the preset specified value, the system outputs a high level.

[0051] The radar system module of the present invention adopts a 9.85GHz X-band radar chip. Based on the Doppler effect, the present invention adopts a fixed-frequency, directional transmitting and receiving antenna to detect moving targets. This X-band radar chip is formed by combining chip integration technology and microwave antenna, and has the characteristics of small size, long sensing distance, no wall penetration, and high stability.

[0052] The present invention adjusts the size of the radar threshold according to the frequency of occurrence of moving targets. In scenarios where moving targets such as people may appear within a preset range such as a walkway, the radar's sensing accuracy is improved, thereby accurately identifying the tiny movements of the moving targets, and using this sensing result to control the system to respond in real time; in scenarios where there are no moving targets within the preset range, the radar's preset threshold is maintained to reduce the radar's computing cost.

[0053] According to the low-energy operation characteristics of the present invention, an 8-bit single-chip microcomputer can be used as the MCU, which can better meet the cost requirements of ordinary daily necessities such as lighting products, and help solve the bottleneck that millimeter-wave radar signal processing systems are difficult to popularize in daily necessities.

[0054] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. A detection threshold dynamic control system for a radar sensor, characterized in that: Includes the following modules: Radar system module: detects moving targets within a preset range in real time through fixed-frequency microstrip transmitting and receiving antennas, and outputs intermediate frequency signals for AD digital-to-analog conversion; A / D acquisition module: performs AD digital-to-analog conversion on the intermediate frequency signal, and acquires the digital signal value after the digital-to-analog conversion; Signal processing module: Process the digitized signal value, initialize the parameter timing variable T=0, if the digitized signal value is less than the noise value + threshold, it is considered that no moving target is detected, then T accumulates the timing, after the preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than the noise value + threshold, it is considered that a moving target is detected, T=1 and the timing is restarted, the signal processing module reduces the detection threshold of the radar, after the preset delay time, if T<the preset specified value, the system outputs a high level; Serial port module: Utilizing the serial port peripherals of the MCU, the serial port module is used to set the detection parameters of the radar system module, including the size of the detection threshold, the preset range, and the delay time.

2. The detection threshold dynamic control system of a radar sensor according to claim 1, characterized in that: It includes an MCU processing module that is communicatively connected to the radar system module, and the MCU processing module includes the A / D acquisition module and the signal processing module.

3. The detection threshold dynamic control system of a radar sensor according to claim 2, characterized in that: T cumulative timing and T=1 will trigger timing. The MCU will make a numerical determination on T after reaching the preset delay time; if T<preset specified value, a high level will be output; if T≥preset specified value, the MCU will clear T and restore the detection threshold of the intermediate frequency signal, and output a low level; the preset specified value>1.

4. The detection threshold dynamic control system of a radar sensor according to claim 1, characterized in that: The signal processing module integrates the digitized signal value N times to obtain an average value of the DC voltage value and an average value of the signal amplitude integral value, and performs DC voltage value filtering and signal amplitude integral value filtering on the average value of the DC voltage value and the average value of the signal amplitude integral value during the accumulation timing T, and calculates the adaptive noise value to determine whether a moving target is currently present.

5. The detection threshold dynamic control system of a radar sensor according to claim 1, characterized in that: The lowest value of the detection threshold is a critical value at which the radar system module will not be falsely triggered when there is no moving target within the preset range; the highest value of the detection threshold is a value corresponding to the maximum amplitude of the radar intermediate frequency signal.

6. The detection threshold dynamic control system of a radar sensor according to claim 1, characterized in that: The radar system module adopts a 9.85GHz X-band radar chip.

7. The detection threshold dynamic control system of a radar sensor according to claim 1, characterized in that: The signal processing module is connected to a timer, and the timer is provided with the timing variable T.

8. A method for dynamically controlling a detection threshold of a radar sensor, characterized in that: The detection threshold dynamic control system of the radar sensor according to any one of claims 1 to 7 comprises the following steps: S1. Use the radar system module to detect moving targets within a preset range in real time; S2, using an A / D acquisition module to perform AD digital-to-analog conversion on the intermediate frequency signal, and acquire a digitized signal value after the digital-to-analog conversion; S3. Use the signal processing module to process the digitized signal value, initialize the parameter timing variable T=0, if the digitized signal value is less than the noise value + threshold, it is regarded as no moving target is detected, then T accumulates the timing, after the preset delay time, if T≥ the preset specified value, the system outputs a low level; if the digitized signal value is greater than the noise value + threshold, it is regarded as a moving target is detected, T=1 and the timing is restarted, the signal processing module reduces the detection threshold of the radar, after the preset delay time, if T<the preset specified value, the system outputs a high level.

9. The method for dynamically controlling the detection threshold of a radar sensor according to claim 8, characterized in that: The lowest value of the detection threshold is a critical value at which the radar system module will not be falsely triggered when there is no moving target within the preset range.

10. The method for dynamically controlling the detection threshold of a radar sensor according to claim 8, characterized in that: When the radar system module identifies a moving target, it triggers the timing of the detection cycle, and the MCU determines the value of T after the detection cycle is reached.

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