CN109254292B

CN109254292B - Sonar ranging method and device and execution equipment

Info

Publication number: CN109254292B
Application number: CN201710571921.7A
Authority: CN
Inventors: 陈有生; 丁胜东
Original assignee: Guangzhou Xaircraft Technology Co Ltd
Current assignee: Guangzhou Xaircraft Technology Co Ltd
Priority date: 2017-07-13
Filing date: 2017-07-13
Publication date: 2021-06-15
Anticipated expiration: 2037-07-13
Also published as: CN109254292A; CN112285718B; CN112285718A

Abstract

The application provides a sonar ranging method, belongs to the technical field of unmanned aerial vehicles, and is used for solving the problems of low accuracy and poor stability of measuring results in the sonar ranging method in the prior art. The method comprises the following steps: acquiring an echo signal sequence obtained by current sampling in a sonar ranging process, wherein the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time; filtering echo signals in the echo signal sequence to determine a filtering result of current sampling; and outputting the measurement distance according to the filtering processing result of the echo signal sampled for M times latest, wherein M is an integer greater than or equal to 2. The sonar ranging method disclosed in the embodiment of the application determines the measurement distance by the echo signal obtained according to continuous multiple sampling, and compared with the method of determining the measurement distance only according to the sampling signal once in the prior art, the influence of the measurement environment on single sampling is effectively weakened, so that the accuracy of the measurement result is higher, and the stability is higher.

Description

Sonar ranging method and device and execution equipment

Technical Field

The application relates to the technical field of unmanned aerial vehicles, in particular to a sonar ranging method and device and an execution device.

Background

The sonar ranging method is used for measuring distance based on the characteristic that echo waves are reflected by a measured object when the sound waves are transmitted in a medium, and is widely applied to underwater ranging. Sonar ranging mainly includes: transmitting sound waves, collecting echo waves and outputting a measuring distance according to the collected echo waves. The method for measuring the distance comprises the steps of transmitting sound waves and collecting echoes, wherein the steps of transmitting the sound waves and collecting the echoes are generally realized by combining hardware equipment with certain configuration parameters, the technology is basically mature, and the technology is stable, so that a specific method for outputting the measured distance according to the collected echoes becomes a key for improving the accuracy of distance measurement. In the prior art, when a distance is measured according to an acquired echo output, a threshold voltage is usually set, a hardware comparator is used to compare whether the amplitude voltage of the echo is greater than the threshold voltage value, and the distance corresponding to the echo with the first amplitude greater than the threshold voltage value is taken as the measured distance. The sonar ranging method in the prior art is suitable for simple application or environment, and aiming at some complex environments, for example, a sonar sensor is installed on an unmanned aerial vehicle, and when the distance between the unmanned aerial vehicle and the ground or surrounding obstacles is measured, an accurate measurement result cannot be obtained. Because unmanned aerial vehicle's the high-frequency vibration itself, the high-speed strong electromagnetic interference who rotates the production of motor, the noise interference that the high-speed cutting air of screw produced, simultaneously, can form complicated plane of reflection around unmanned aerial vehicle, above-mentioned factor will lead to the unable accurate distance between unmanned aerial vehicle of accurate measurement and the object that awaits measuring of sonar range finding method among the prior art.

Therefore, the sonar distance measurement method in the prior art at least has the problems of low accuracy and poor stability of the measurement result.

Disclosure of Invention

The embodiment of the application provides a flight control method, and solves the problems of low accuracy and poor stability of a measuring result in a sonar ranging method in the prior art.

First aspect, this application embodiment provides a sonar ranging method, includes:

acquiring an echo signal sequence obtained by current sampling in a sonar ranging process, wherein the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time;

filtering echo signals in the echo signal sequence to determine a filtering processing result of current sampling;

and outputting the measurement distance according to the filtering processing result of the echo signal sampled for M times latest, wherein M is an integer greater than or equal to 2.

Second aspect, this application embodiment still provides a sonar ranging device, includes:

the echo signal sequence acquisition module is used for acquiring an echo signal sequence obtained by sampling at the current time in the sonar ranging process, and the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time;

the filtering processing module is used for filtering the echo signals in the echo signal sequence acquired by the echo signal sequence acquisition module and determining the filtering processing result of the current sampling;

and the distance output module is used for outputting the measurement distance according to the filtering processing result of the echo signal sampled for M times latest, wherein M is an integer greater than or equal to 2.

In a third aspect, an embodiment of the present application further provides an execution device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the execution device further includes:

a sonar sensor for emitting and receiving sound waves;

the processor, when executing the computer program, implements the sonar ranging method of any one of claims 1 to 15.

Like this, the sonar ranging method disclosed in the embodiment of the present application, through the echo signal sequence that obtains of obtaining sonar ranging process current time sampling, including the echo signal who arranges from the past to the back according to the first-later order of sampling time in the echo signal sequence, then, to at least one echo signal carries out filtering process to according to the echo signal's of continuous M times latest sampling filtering process result, output measuring distance, the measuring result accuracy that exists when having solved the sonar ranging among the prior art is low and the relatively poor problem of stability. This application compares with only confirming the measuring distance according to sampling signal once among the prior art through the echo signal that obtains according to sampling many times in succession, has effectively weakened the influence that single sampling received measuring environment for measuring result's accuracy is higher, and stability is higher.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments of the present application will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive exercise.

Fig. 1 is a flowchart of a sonar distance measuring method according to a first embodiment of the present application;

fig. 2 is a flowchart of a sonar ranging method according to the second embodiment of the present application;

fig. 3 is a schematic diagram of echo signals sampled by the sonar ranging method according to the second embodiment of the present application;

fig. 4 is a flowchart of a sonar ranging method according to the third embodiment of the present application;

fig. 5 is one of the structural schematic diagrams of a sonar distance measuring device according to the fourth embodiment of the present application;

fig. 6 is a second schematic structural view of a sonar distance measuring device according to a fourth embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making an invasive task, are within the scope of the present application.

The sonar ranging method disclosed in the embodiment of the application is suitable for flight equipment such as unmanned aerial vehicles and aircrafts, and is collectively called as execution equipment in the embodiment of the application. In order to facilitate the reader to understand the solution, in the following embodiments, the technical solution is described in detail by taking the execution device as an unmanned aerial vehicle as an example.

The first embodiment is as follows:

as shown in fig. 1, the embodiment of the present application discloses a sonar distance measuring method, including: step 100 to step 120.

And step 100, acquiring an echo signal sequence obtained by current sampling in a sonar ranging process, wherein the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time.

In the sonar ranging process, the sonar sensor is started to emit sound waves at first. When the sound wave encounters an object to be measured in the propagation process, the sound wave signal is reflected and becomes an echo signal. During specific implementation, signals received by the receiving end of the sonar sensor are sampled through AD sampling, and the amplitude of echo signals can be obtained.

In the process of sonar distance measurement, a plurality of sampling points are preset according to the estimated distance of an object to be measured or the effective measurement range of a sonar sensor and the propagation speed of sound waves in the air, for example, sampling is performed every 1 second, and the sampling distance of the preset sampling points is d ═ v × t/2, where v is the propagation speed of sound waves in the air and has the unit of meter/second, t is sampling time, and d is the sampling distance of the sampling points, that is, the sampling distance of echo signals.

In specific implementation, because an object to be measured has a plurality of reflecting surfaces, or a sound wave meets an obstacle in the process of propagation, and a multi-echo phenomenon occurs, the sonar sensor usually receives a plurality of echo signals. I.e. after transmitting a sound wave, a plurality of echo signals may be sampled.

And step 110, performing filtering processing on the echo signals in the echo signal sequence, and determining a filtering processing result of the current sampling.

After all echo signals of one sample are acquired, the acquired echo signals need to be filtered first. In specific implementation, when the acquired echo signals are filtered, if only one echo signal is sampled at this time, the echo signals are directly used for subsequent distance measurement. If more than one echo signal is sampled at the time, merging processing or multiple echo filtering is carried out on all the echo signals obtained by sampling, or echo merging is firstly carried out, and then multiple echo filtering is carried out on the echo signals obtained after echo merging. In a specific implementation, the multiple echoes include: secondary echo, tertiary echo, quaternary echo, etc.

When echo filtering is performed, whether the echo signal includes multiple echoes can be judged according to the echo signal obtained by one-time sampling. Preferably, whether the echo signal includes multiple echo signals is judged according to the echo signal obtained by sampling at least twice continuously.

And obtaining the effective echo signal determined by the sampling after echo combination and/or echo filtration for multiple times. In specific implementation, several echoes with the largest energy are selected from the effective echoes determined by the current sampling and are used for determining the measuring distance subsequently.

And step 120, outputting the measured distance according to the filtering processing result of the echo signal sampled for M times latest.

Wherein M is an integer of 2 or more.

In the embodiment of the present application, the measurement distance is output according to the filtering processing result of the nearest echo signal sampled for a plurality of times continuously.

In a specific implementation, first, an initial echo is determined according to the filtering processing results of the echo signals sampled in the previous times. And then, determining the output measuring distance according to the echo signal filtering processing result of the current sampling and the initial echo.

And when the initial echo is determined, determining the initial echo according to the echo signal with the maximum energy in the filtering processing result obtained by continuous multiple sampling. And if the difference value of the sampling distances between the echo signals with the maximum energy in the filtering processing results obtained by continuous multiple times of sampling is smaller than a preset distance value, taking the average value of the sampling distances of the echo signals with the maximum energy in the filtering processing results obtained by the multiple times of sampling as the sampling distance of the initial echo. And if the distance between the echo signal with the maximum energy in the filtering processing result obtained by any sampling and the echo signal with the maximum energy in the filtering processing results obtained by other measurements is larger than or equal to the preset distance value, deleting the echo signal with the maximum energy in the filtering processing result obtained by the earliest sampling, retaining the echo signal with the maximum energy in the filtering processing results obtained by the subsequent sampling, and continuously sampling the latest echo signal to obtain the echo signal with the maximum energy in the filtering processing results for determining the initial echo.

And after the initial echo is determined, taking the echo signal with the sampling distance closest to the initial echo in the echo signal filtering processing result of the current sampling as the current alternative echo signal. And if the difference value between the sampling distance of the current alternative echo signal and the initial echo is larger than a preset value, considering that the current measurement is wrong, and directly taking the sampling distance of the echo signal with the maximum energy in the filtering processing result of the echo signal sampled at the current time as the output measurement distance. And if the difference value between the sampling distance of the current time alternative echo signal and the initial echo is smaller than or equal to the preset value, taking the sampling distance of the current time alternative echo signal as the output measuring distance.

The sonar ranging method disclosed in the embodiment of the application comprises the steps of obtaining an echo signal sequence obtained by sampling at the current time in the sonar ranging process, including echo signals arranged from front to back according to the sequence of sampling time in the echo signal sequence, then, filtering at least one echo signal, outputting a measured distance according to the filtering result of the echo signal sampled for M times latest in succession, and solving the problems of low accuracy and poor stability of the measured result existing in the prior art in the sonar ranging process. This application is through confirming the measuring distance according to the echo signal that continuous many times sampling obtained, compares with confirming the measuring distance according to sampling signal once among the prior art, has effectively weakened the influence of single sampling by the measuring environment for measuring result's accuracy is higher, and stability is higher.

Example two:

as shown in fig. 2, the embodiment of the present application discloses a sonar distance measuring method, including: step 200 to step 230.

And 200, acquiring an echo signal sequence obtained by current sampling in the sonar ranging process, wherein the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time.

There is the blind area, preferred, sets up the sampling distance according to sonar sensor's measuring range in the sonar range finding.

For example, the range of the distance measured by the sonar sensor is 20cm-800cm, which means that the minimum distance measured by the sonar sensor is 20cm, and the distance below 20cm cannot be measured and is a blind area; distances greater than 800cm cannot be measured, again as blind areas. The reason that closely the blind area exists is because control sonar sensor when vibrations transmission sound wave finishes, sonar sensor can not terminate vibrations immediately, still has a small amount of residual waves to send, if control sonar sensor stops to start AD converter immediately when launching the sound wave and carry out the echo sampling, the sound wave of control sonar sensor transmitting terminal transmission this moment can directly reach the receiving terminal to be gathered by the AD converter, thereby make the unable accurate measurement of distance in the blind area. Because the collected sound wave in the blind area is actually directly transmitted from the transmitting end to the receiving end, and the distance between the transmitting end and the receiving end is very small, the sound attenuation is very small, and therefore, the amplitude of the echo in the range of the blind area is very large and is generally larger than that of the normal echo. The range of the blind area is generally a fixed value, and once a sonar sensor is manufactured, the characteristics are determined, and the range of the blind area is also determined.

In specific implementation, after the preset time after the emission of the sound waves is stopped, the echo starts to be acquired at the preset time interval. In the embodiment of the present application, the sampling point is a time point of sampling an echo signal, and the preset sampling point is a sampling time point spaced by a preset time interval from a preset time after the emission of the acoustic wave is stopped. The echo signals acquired at different preset time points are echo signals reflected after sound waves propagate for different distances, so that whether the echo signals are echo signals reflected after encountering an obstacle or an object to be detected can be judged according to the amplitude values of the echo signals corresponding to different sampling points.

In specific implementation, the amplitude threshold a is preset first. Then, each sampling value of the echo signal is detected from the first preset sampling point after the blind area, whether the sampling value is larger than a preset amplitude threshold value A or not is judged, if the sampling value is larger than the amplitude threshold value A, the values of the sampling points with the amplitudes larger than A are accumulated until the amplitude of the echo signal is smaller than the amplitude threshold value A, and accumulation is finished at the moment. And taking the distance between the sampling point corresponding to the accumulation ending time and the sampling point corresponding to the accumulation starting time as the width of the current echo signal. And converting the position of the corresponding sampling point when the accumulation is started to be used as the sampling distance of the current echo signal (d is v t/2, the unit of d is the sampling distance is meter, v is the propagation speed of the sound wave in the air and is equal to 340 meters per second, and t is the time corresponding to the sampling point of which the echo is greater than the amplitude threshold A, and the unit is second). And accumulating the sampling points to obtain an accumulated value corresponding to the energy of the echo signal. In specific implementation, each acquired echo signal includes: amplitude, width, sampling distance and the like.

In an implementation, after a sound wave is transmitted, a plurality of echo signals may be collected, as shown in fig. 3, wherein a noise echo 310, a valid echo signal 320, a secondary echo 330, a tertiary echo 340, and the like may be included, and all the collected echo signals form an echo sequence. The echo signals in the echo sequence are arranged from front to back according to the sequence of the sampling distance from small to large.

Echo signals obtained by sampling at the receiving end of the sonar sensor comprise effective echo signals of an object to be measured and also comprise noise and/or multiple echo signals, so that the echo signals need to be filtered firstly before distance calculation. In specific implementation, the filtering processing is performed on the echo signal in the echo signal sequence, and a filtering processing result of the current sampling is determined, including: if the number of the echo signals is one, directly taking the echo signals as a filtering processing result; otherwise, filtering the echo signals in the echo signal sequence, and taking the filtered echo signals as a filtering result; wherein the filtering process includes: echo combining and/or multiple echo filtering.

And if no echo signal exists in the echo signal sequence, directly outputting a measurement error.

If only one echo signal in the echo signal sequence is present, directly outputting the echo signal for subsequent processing, and if two or more echo signals are included in the echo signal sequence, performing filtering processing on all echo signals in the echo signal sequence, for example: echo combining may be performed only on the echo signals; multiple echo filtering can be carried out on the echo signal; the echo signals can be subjected to echo combination firstly, and then multiple echo filtering is performed on the combined echo signals. In this embodiment, a specific process of filtering will be described by taking echo merging on the echo signals and then performing multiple echo filtering on the merged echo signals as an example.

In specific implementation, the preset amplitude threshold is set empirically or determined according to the average of the amplitudes of all echo signals in the echo signal sequence. For example, an amplitude threshold is set empirically, and if the AD sampling module does not sample the echo signal after setting the amplitude threshold, which indicates that the amplitude threshold is set higher, the amplitude threshold is appropriately lowered, and the measurement is continued. If the amplitude threshold value is set, the AD sampling module samples excessive echo signals with low amplitude, and the amplitude threshold value is set to be low, and excessive noise signals are collected, so that the amplitude threshold value can be improved according to the average value of the sampled echo signals, for example, the amplitude threshold value is adjusted to be 1.5 times of the average value, the noise signals are preliminarily filtered, the number of the obtained echo signals is reduced, and the filtering efficiency and the accuracy are improved.

In specific implementation, if the number of echo signals is less than 1 after one echo sampling is finished, it indicates that no echo signal is detected in the current measurement, which may be caused by too long or too close distance of measurement, the subsequent filtering processing and distance calculation processes are stopped, and the direct output measurement fails. And if the number of detected echoes is more than 1, performing next step processing on the detected echoes.

And 210, performing echo combination on the echo signals in the echo signal sequence.

Performing echo combining on the echo signals, comprising: determining whether the adjacent echo signals are echo signals to be combined or not according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence; and if the echo signals are determined to be the echo signals to be combined, combining the adjacent echo signals. The echo signals in the echo signal sequence are arranged from front to back according to the sequence of the sampling distances from small to large, and the sampling distance of the echo signals arranged in front is smaller. In specific implementation, the strength of the echo signal includes: amplitude or energy.

In specific implementation, the merging the adjacent echo signals includes: taking the sum of the energies of the adjacent echo signals as the energy of the combined echo signal; and updating the energy of the previous echo signal in the adjacent echo signals in the echo signal sequence through the energy of the combined echo signals, and deleting the next echo signal in the adjacent echo signals from the echo signal sequence. The merging the adjacent echo signals further comprises: taking the sampling distance difference value between the adjacent echo signals as the width of the combined echo signal; and updating the width of the previous echo signal in the adjacent echo signals in the echo signal sequence through the width of the combined echo signal.

In specific implementation, determining whether the adjacent echo signals are echo signals to be combined according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence includes: and if the sampling distance difference value between the adjacent echo signals is smaller than the preset distance difference value, and the intensity of the former echo signal is smaller than that of the latter echo signal, merging the adjacent echo signals. Taking the distance to the plant as an example, the sound wave first encounters the leaves of the plant, then encounters the branches and the ground in the propagation process, the leaves, the branches and the ground of the plant all reflect the echo signals, the leaves reflect the echo signals firstly and have small intensity, and the branches and the ground reflect the echo signals finally and have large intensity. When the method is specifically implemented, firstly, a distance threshold value is set according to the height of a plant to be measured; and then, carrying out echo combination on all echo signals in the echo sequence obtained by one-time sampling. Taking the example of representing the signal strength by the amplitude of the echo signal, it is assumed that the echo signal sequence includes 5 echo signals, and the sequence from front to back is: s₁、s₂、 s₃、s₄And s₅The specific method for performing echo combination on all echo signals in the echo sequence obtained by sampling comprises the following steps: first, judge s₁Is less than s₂The amplitude of (d); if so, further judging s₁And s₂If the difference between the sampling distances is smaller than the preset distance difference, otherwise, continuing to judge s₂Whether the amplitude of (a) is less than s₃The amplitude of (c). If s is₁And s₂Is less than a predetermined distance difference, then s is obtained₁And s₂Combining to obtain combined echo signal s₁', then, after further mergingOf the echo signal s₁' and s₂The amplitude and the sampling distance of the signal are judged.

In pair s₁And s₂When merging, s is₁As the combined echo signal s₁' sampling distance, will s₁And s₂As the combined echo signal s₁' energy of, will s₁And s₂The difference of the sampling distances is used as the combined echo signal s₁' width; by means of combined echo signals s₁' updates s₁And delete s₂After the signals are combined once, the echo signal sequence includes 4 echo signals, which are sequentially from front to back: s₁’、s₃、s₄And s₅. Then, the same method is adopted, and the echo combination from the front to the back is continuously carried out on the echo signal sequence until all the echo signals traverse once.

In specific implementation, the preset distance difference is determined by any one of the following modes: the preset distance difference value is determined according to the height of the object to be measured; and the preset distance difference is determined according to the estimated maximum distance between different obstacles to be detected. For example, when the unmanned aerial vehicle measures the height of the laminated obstacles through sonar, a preset distance difference value may be set as a height difference between different obstacles.

And step 220, performing multiple echo filtering on the echo signals after the echo merging processing to obtain a filtering processing result.

The multiple echoes, such as secondary echo and tertiary echo, are waves which are reflected by the sonar receiving end after the acoustic waves are transmitted and are shielded by an object to be measured. When the distance is near, because transmitted wave power is great, the echo does not attenuate through once turning back, has carried out the second or has turned back many times to be received many times by sonar receiving end, formed many times of echo. In the absence of any disturbance, the secondary or multi-echoes have a relationship, e.g. d₁For the measured primary echo, d₂To measure secondary echoes, d₃To detect the triple echo, then

However, due to the complexity of the environment, noise exists in the measurement process, and the noise and the real echo may also satisfy the relationship, so that the echo signal cannot be accurately judged only according to the formula.

In an embodiment of the present application, the echo is filtered for multiple times, including: determining the probability of containing multiple echo signals in the echo signal sequence; determining a valid echo signal of the last acquired echo signals according to the probability determined by at least two consecutive samples. In specific implementation, the determining the probability that the echo signal sequence includes multiple echo signals includes: and determining the probability of the echo signal sequence including multiple echo signals according to the number of the echo signals included in the echo signal sequence and the sampling distance of each echo signal.

According to the number of the echo signals included in the echo signal sequence and the sampling distance of each echo signal, the probability that the echo signal sequence includes multiple echo signals is determined to include the following four conditions.

In the first case, the number of echo signals in the echo signal sequence is greater than or equal to three.

In the following, taking an example that an echo signal sequence obtained after echo combining includes 3 echo signals, it is assumed that the 3 echo signals are respectively recorded as: s₁、s₂And s₃The sampling distances of the 3 echo signals are respectively denoted as d₁、d₂And d₃. Determining the probability that the echo signal sequence comprises multiple echo signals according to the number of the echo signals in the echo signal sequence and the sampling distance of each echo signal, wherein the determining comprises the following steps: if the sampling distances of the first three echo signals in the echo signal sequence are matched with a first preset condition, setting the probability of containing multiple echo signals in the echo signal sequence as a probability value corresponding to the first preset condition, and initializing the sampling distance of an effective echo signal as d₁(ii) a Otherwise, setting the echo signal sequence to contain multiple echo signalsThe probability is 0; wherein the first preset condition comprises any one of the following conditions:

and

d₁is the sampling distance of the first echo signal, d₂Is the sampling distance of the second echo signal, d₃Is the sampling distance of the third echo signal.

For example, when the sampling distances of the first, second and third echo signals in the echo signal sequence satisfy the formula

Then it is initially assumed that a secondary echo signal and a tertiary echo signal, i.e. s, are present in the echo signal sequence₂Possibly a secondary echo signal, s₃Possibly a triple echo signal. In this case, the probability P of the presence of multiple echoes is set to 0.34, and the sampling distance d of the valid echo signal is initialized₀＝ d₁。

For another example, if the secondary echo signal is lost due to interference or other reasons, but there are three echo signals and four echo signals, the sampling distance of the echo signal at this time satisfies the formula

Then the secondary echo signal and the tertiary echo signal, i.e. s, are initially assumed to be present in the echo signal sequence₂Possibly a triple echo signal, s₃Possibly four echo signals. In this case, the probability P of the presence of multiple echoes is set to 0.15, and the sampling distance d of the valid echo signal is initialized₀＝d₁。

For example, if the third echo signal is lost due to interference or other reasons, but there is a second echo signal and a fourth echo signal, the sampling distance of the echo signal at this time satisfies the formula

Then it is initially assumed that a second echo signal and a fourth echo signal, i.e. s, are present in the echo signal sequence₂Possibly a secondary echo signal, s₃Possibly four echo signals. In this case, the probability P of the presence of multiple echoes is set to 0.15, and the sampling distance d of the effective echo signal is initialized₀＝d₁。

In specific implementation, when the sampling distances of the echo signals are matched with different first preset conditions, the interference degrees in the measurement environments where the echo signals in the echo signal sequence are located are different, and therefore, the probabilities of the echo signals including multiple echoes are also different. The probability is determined according to the interference condition implied in the corresponding preset condition, and the probability set by the preset condition with the more slight interference condition is larger.

In a second case, the number of echo signals in the echo signal sequence is greater than or equal to four.

In the following, taking an example that an echo signal sequence obtained by echo combination includes 4 echo signals, it is assumed that the 4 echo signals are respectively recorded as: s₁、s₂、s₃And s₄The sampling distances of the 4 echo signals are respectively denoted as d₁、d₂、d₃And d₄. Determining the probability of the echo signal sequence including multiple echo signals according to the number of the echo signals included in the echo signal sequence and the sampling distance of each echo signal, including: if the sampling distances of the first four echo signals in the echo signal sequence are matched with a second preset condition, setting the probability of the echo signal sequence containing multiple echo signals as a probability value corresponding to the second preset condition, and initializing the sampling distance of an effective echo signal as the sampling distance of the echo signal of the first non-noise echo; otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0; wherein the second preset condition comprises any one of the following:

and

d₁is the sampling distance of the first echo signal, d₂Is the sampling distance of the second echo signal, d₃Is the sampling distance of the third echo signal, d₄Is the sampling distance of the fourth echo signal.

For example, if a noise echo is included before the first effective echo signal, and the sampling distances of the second, third and fourth echo signals satisfy the following formula

Then it is initially assumed that a secondary echo signal is present in the echo signal sequence, and that a tertiary echo signal, i.e. s, is present₁As noise echoes, s₃Possibly a secondary echo signal, s₄Possibly four echo signals. In this case, the probability P of the presence of multiple echoes is set to 0.25, and the sampling distance d of the valid echo signal is initialized₀＝d₂。

For another example, if a noise echo is included before the second effective echo signal, and the sampling distances of the first, third and fourth echo signals satisfy the following formula

Then it is initially assumed that a secondary echo signal and a tertiary echo signal, i.e. s, are present in the echo signal sequence₂As noise echoes, s₃Possibly a secondary echo signal, s₄Possibly a triple echo signal. In this case, the probability P of the presence of multiple echoes is set to 0.25, and the sampling distance d of the effective echo signal is initialized₀＝d₁。

For another example, if a noise echo is included before the third effective echo signal, and the sampling distances of the first, second, and fourth echo signals satisfy the following formula

Then it is initially assumed that a secondary echo signal and a tertiary echo signal, i.e. s, are present in the echo signal sequence₃As noise echoes, s₂Possibly a secondary echo signal, s₄Possibly a triple echo signal. In this case, the probability P of the presence of multiple echoes is set to 0.25, and the sampling distance d of the effective echo signal is initialized₀＝d₁。

In a specific implementation, whether the echo signal sequence includes a noise echo and which echo signal is a noise echo may be determined according to the intensity of the echo signal. Alternatively, whether to include a noise echo and which signal is a noise echo may be determined according to whether there is an integer multiple relationship between sampling distance differences between echo signals, for example: and if the sampling distance of one echo signal is not approximate integral multiple of the sampling distance of any other echo signal, and the sampling distance of no other echo signal is approximate integral multiple of the echo signal, determining that the echo signal is the noise echo. Typically, the noise echo is an echo signal having an echo signal intensity smaller than an average of echo signal intensities in the echo signal sequence, the intensities including: amplitude or energy.

In a third case, the number of echo signals in the echo signal sequence is equal to two.

In the following, taking an example that an echo signal sequence obtained after echo combining includes 2 echo signals, it is assumed that the 2 echo signals are respectively recorded as: s₁And s₂The sampling distances of the 2 echo signals are respectively denoted as d₁、 d₂. Determining the probability that the echo signal sequence comprises multiple echo signals according to the number of the echo signals in the echo signal sequence and the sampling distance of each echo signal, wherein the determining comprises the following steps: if the sampling distance of the echo signal in the echo signal sequence matches a third preset condition, setting the probability of the echo signal sequence containing multiple echo signals as a probability value corresponding to the third preset condition, and initializing effective echo according to the echo signal in the echo signal sequenceA sampling distance of the wave signal; otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0; wherein the third preset condition includes any one of:

and

d₁is the sampling distance, d, of the first echo signal₂Is the sampling distance of the second echo signal.

The initializing the sampling distance of the effective echo signal according to the echo signal in the echo signal sequence comprises: if the sampling distance of each echo signal in the echo signal sequence meets the condition

The sampling distance for initializing a valid echo signal is d₁(ii) a If the sampling distance of each echo signal in the echo signal sequence meets the condition

The sampling distance for initializing a valid echo signal is d₂-d₁。

For example, only two echo signals are included in the echo signal sequence, and neither echo signal is a noise echo if the sampling distance of each echo signal in the echo signal sequence satisfies the condition

It is initially assumed that a secondary echo signal is present in the echo signal sequence, in which case the probability P of containing multiple echo signals is set to 0.25, and a sampling distance d of valid echo signals is initialized₀＝d₁。

As another example, only two echo signals are included in the echo signal sequence, and neither echo signal is a noise echo if the sampling distance of each echo signal in the echo signal sequence satisfies the condition

Then it is preliminarily assumed that there is a secondary echo in the echo signal sequence, in which case the probability P of including multiple echo signals is set to 0.25, and the sampling distance d of the valid echo signal is initialized₀＝d₂-d₁. By setting the condition, the sampling distance of the effective echo signal can be determined under the condition that the effective echo signal cannot be sampled due to the fact that the effective echo signal is located in the blind area when the measuring distance is relatively close.

In a fourth case, the number of echo signals in the sequence of echo signals is equal to one.

When only one echo signal d is in the echo signal sequence₁When the second echo does not exist in the echo signal sequence, the probability P of the echo signal sequence containing multiple times is set to be 0, and the sampling distance of the effective echo signal is initialized to be d₀＝d₁。

The four conditions are mutual exclusion conditions and cannot exist simultaneously, and only one probability value can be obtained according to an echo signal sequence obtained by one-time sampling. And then, measuring again, acquiring an echo signal sequence of the sampling point, determining the probability that the echo signal sequence obtained by current sampling contains secondary echo signals according to the three conditions, and accumulating and judging the probability obtained by each sampling. If the probability after accumulation is more than 1 after several times of continuous sampling, determining that multiple echoes exist in the echo signal sequence obtained by the current sampling, and directly outputting d₀Measuring distance for current sonar ranging; and if the probability determined according to the echo signal sequence obtained by sampling at any time is 0, clearing the probability obtained by sampling for a plurality of times. If it cannot be determined that the echo signal sequence obtained by current sampling comprises multiple echoes, namely the probability is less than 1 after accumulation or the probability is subjected to zero clearing treatment, selecting several echo signals (for example, at most 3 echo signals) with the largest energy in the filtered echo signal sequence corresponding to the current sampling as filtering treatmentThe result is used for subsequent calculation of the measured distance.

And step 230, outputting the measured distance according to the filtering processing result of the echo signal sampled for M times latest.

Wherein M is an integer of 2 or more.

In the embodiment of the present application, the measurement distance is output according to the filtering processing result of the nearest echo signal sampled for a plurality of times continuously. In specific implementation, first, the initial echo is determined according to the filtering processing result of the echo signals sampled in the previous times. And then, determining the output measuring distance according to the echo signal filtering processing result of the current sampling and the initial echo.

In specific implementation, outputting the measurement distance according to the filtering processing result of the echo signal sampled for M times latest includes: selecting a preset number of echo signals with the maximum energy in the echo signal filtering processing result of the current sonar ranging sampling as a current filtering processing result; if the initial echo is determined, outputting a measurement distance according to the current filtering processing result and the initial echo; and if the initial echo is not determined, determining the initial echo according to the echo signal with the maximum energy in the filtering processing results of the latest sampling of the M times, wherein the filtering processing results of the latest sampling of the M times include the current filtering processing result.

And when the initial echo is determined, determining the initial echo according to the echo signal with the maximum energy in the filtering processing result obtained by continuous multiple sampling.

In specific implementation, determining the initial echo according to an echo signal with the largest energy in filtering processing results of M consecutive latest samples includes: if the sampling distance difference value between echo signals with the maximum energy obtained by sampling at the previous time and the next time in the filtering processing results of the latest sampling of the continuous M times is smaller than or equal to a second preset distance threshold value, taking the average value of the sampling distances of the echo signals with the maximum energy in the filtering processing results of the continuous M times as the sampling distance of the initial echo; otherwise, deleting the echo signal with the maximum energy in the filtering processing result of the earliest time, and sampling the echo signal again to update the echo signal with the maximum energy in the filtering processing result of continuous M times of sampling.

In this embodiment, taking M equal to 2 as an example, the technical solution of determining the initial echo is further defined.

Before measurement is started, initial echo is initialized to be empty, an alternative echo queue is emptied, the number of data in the alternative echo queue is cleared, and then sampling of echo signals is started. After the filtering processing result of the current sampling is output, the echo signals with the maximum energy in the current sampling result are sequentially put into the alternative echo queue, and then whether the number of the data in the alternative echo queue reaches 2 times or not is judged, namely whether 2 alternative echo signals are stored in the alternative echo queue or not is judged. If not, adding 1 to the number of the alternative echo queue data, and continuing to sample for the next time. If 2 alternative echo signals are stored in the alternative echo queue, the sequence is s_aAnd s_bThe sampling distances are respectively d_aAnd d_bJudging the alternative echo signal s in the alternative echo queue_aAnd s_bDifference value d of sampling distance between_a-d_bIf the distance is less than or equal to a second preset distance threshold, if so, s is determined_aAnd s_bIs measured (i.e., (d))_a+d_b) And/2) as the sampling distance of the initial echo. If the alternative echo signal s_aAnd s_bDifference value d of sampling distance between_a-d_bIf the signal is larger than the second preset distance threshold value, deleting the alternative echo signal s obtained by sampling firstly_aAnd subtracting 1 from the number of the alternative echo queue data, and continuing to sample for the next time.

In specific implementation, if the sampling distance difference between two echo signals obtained by sampling twice in the alternative echo queue is greater than a second preset distance threshold, the alternative echo signal obtained by sampling at the earliest time is deleted, and a new alternative echo signal is continuously sampled, so that the echo signal with the largest energy obtained by sampling at the latest time is always recorded in the alternative echo queue.

After the filtering processing result is output by sampling each time, the echo signals with the maximum energy in the echo signal filtering processing result of the current sonar ranging sampling are selected as the current filtering processing result, wherein the preset number (such as 3 echo signals) is selected as the maximum energy. Then, judging whether the initial echo is determined, if not, determining the initial echo by combining the current filtering processing result and the previous filtering processing results; and if the initial echo is determined, outputting the measurement distance according to the current filtering processing result and the initial echo.

According to the current filtering processing result and the initial echo, outputting the measuring distance comprises: selecting an echo signal with a sampling distance closest to the initial echo from the current filtering processing result as a current alternative echo signal; if the difference value of the sampling distance between the current alternative echo signal and the initial echo is smaller than or equal to a first preset distance threshold, taking the sampling distance of the current alternative echo signal as an output measurement distance; otherwise, the sampling distance of the echo signal with the maximum energy in the current filtering processing result is used as the output measuring distance.

In specific implementation, the 3 echo signals with the maximum energy selected from the echo signal filtering processing result of the current sampling are taken as s₅、s₆And s₇For example, the echo signal with the largest energy and the echo signal closest to the sampling distance of the initial echo are determined.

If the echo signal with the maximum energy is s₅The echo signal closest to the sampling distance of the initial echo is s₆Then s will₆As the current time candidate echo signal. If the current time alternative echo signal s₆If the difference value between the sampling distance and the initial echo is larger than the preset value, the current measurement is considered to be wrong, and the echo signal s with the maximum energy in the current sampled echo signal filtering processing result is directly filtered₅As the output measured distance. If the current time alternative echo signal s₆If the difference value between the sampling distance and the initial echo is less than or equal to a preset value, the current alternative echo signal s is obtained₆As the output measured distance.

If the echo signal with the maximum energy is s₅The echo signal closest to the sampling distance of the initial echo is also s₅Then s will₅As the output measured distance.

By this time, sonar ranging has been completed once.

In specific implementation, in order to improve the accuracy of ranging, the sampling distance of the initial echo, which is a reference for calculating the measurement distance, needs to be updated continuously, and therefore, after the sampling distance of the current candidate echo signal is taken as the output measurement distance, the method further includes: and updating the sampling distance of the initial echo through the sampling distance of the current alternative echo signal. Whether the sampling result is accurate or not is judged by continuously updating the latest measured sampling distance as the basis for judging the sampling result in the next measurement, the latest measurement result can be always used as the judgment basis, the fault tolerance can be carried out on the position jitter of the sonar sensor in the sonar ranging process, and the ranging accuracy is further improved.

The sonar ranging method disclosed in the embodiment of the application obtains the echo signal sequence through obtaining the present sampling in the sonar ranging process, including the echo signal who arranges from the front to the back according to the precedence of sampling time in the echo signal sequence, then, it is right echo signal in the echo signal sequence carries out echo merging and echo filtration processing many times to according to the echo signal's of continuous M times latest sampling filter processing results, output measurement distance, the measurement result accuracy that exists is low and the relatively poor problem of stability when having solved the sonar ranging among the prior art. This application is through confirming the measuring distance according to the echo signal that continuous many times sampling obtained, compares with confirming the measuring distance according to sampling signal once among the prior art, has effectively weakened the influence that single sampling received measuring environment for measuring result's accuracy is higher, and stability is higher. By carrying out echo combination on echo signals obtained by sampling, the robustness of the ranging method when a plurality of reflecting surfaces exist in an object to be measured during sonar ranging is improved. The echo signals obtained by sampling are subjected to multiple echo filtering, so that the primary echo signals can be accurately determined, and the accuracy of the measurement result is further improved by taking the primary echoes as the reference for calculating the distance.

The initial echo is determined by combining the echo signals obtained by continuous sampling for several times, and then the sampling distance comparison is carried out on the echo signals obtained by current sampling and the initial echo, so that the influence of single sampling result abnormity on the distance measurement result can be effectively avoided, and the accuracy and the stability of the distance measurement are further improved.

Example three:

based on embodiment one and embodiment two, as shown in fig. 4, this application embodiment discloses a sonar ranging method, including: step 400 to step 460.

And step 400, obtaining an echo signal sequence obtained by current sampling in the sonar ranging process, wherein the echo signal sequence comprises echo signals arranged from front to back according to the sequence of sampling time.

And acquiring an echo signal sequence obtained by sampling at the current time in the sonar ranging process, wherein the echo signal sequence comprises echo signals arranged from front to back according to the sequence of sampling time, and the specific implementation mode is referred to as embodiment two, and details are not repeated here.

And 410, performing echo combination on the echo signals in the echo signal sequence.

For a specific implementation of performing echo combination on the echo signals in the echo signal sequence, refer to example two, which is not described herein again.

And step 420, performing multiple echo filtering on the echo signals after the echo merging processing to obtain a filtering processing result.

For a specific implementation of performing multiple echo filtering on the echo signal after the echo combining processing to obtain a filtering processing result, refer to embodiment two, which is not described herein again.

And step 430, outputting the measured distance according to the filtering processing result of the echo signal sampled for M times latest.

A specific implementation of outputting the measured distance according to the filtering processing result of the echo signal sampled for M consecutive times is shown in example two, which is not described herein again.

After the initial echo is determined, in each subsequent sampling process, for the current filtering processing result, if the difference value between the sampling distance of the current alternative echo signal and the initial echo is less than or equal to a first preset distance threshold, the sampling distance of the current alternative echo signal is used as the output measurement distance, and then the previous measurement results need to be further tracked and judged, so that the continuous measurement on the basis of the wrong measurement result is avoided.

Step 440, judging whether the current candidate echo signal is an echo signal with the largest energy in the current filtering processing result, if so, executing step 450; otherwise, step 460 is performed.

After the step of taking the sampling distance of the current time candidate echo signal as the output measurement distance, the method further includes: if the current alternative echo signal is not the echo signal with the maximum energy in the current filtering processing result, adding the echo signal with the maximum energy in the current filtering processing result into a preset alternative echo queue for re-determining an initial echo according to the echo signal with the maximum energy in the continuous M filtering processing results in the alternative echo queue; otherwise, emptying the preset alternative echo queue.

In specific implementation, if the current candidate echo signal is only the echo signal closest to the initial echo, but not the echo signal with the largest energy, it is considered that the currently sampled echo signal may be inaccurate, and the currently identified initial echo needs to be corrected through the obtained echo signal with the largest energy measured for several consecutive times.

In specific implementation, an alternative echo queue may be preset, and the echo signal with the largest energy obtained by each measurement may be stored in the alternative echo queue. After outputting a measurement distance each time, judging whether the current alternative echo is the echo signal with the maximum energy obtained by the current sampling, if so, confirming that the current sampling is accurate, and emptying an alternative echo queue; if not, confirming that the current sampling is not accurate, and further re-determining the initial echo according to the echo signal with the maximum energy of the continuous measurements stored in the alternative echo queue.

Step 450, emptying the preset alternative echo queue.

And emptying the alternative echo signals stored in the preset alternative echo queue, and finishing the measurement.

Step 460, re-determining the initial echo according to the echo signal with the maximum energy in the filtering processing results of M consecutive times in the candidate echo queue.

The specific method for re-determining the initial echo according to the echo signal stored in the candidate echo queue refers to the specific method for determining the initial echo according to the echo signals obtained from the previous sampling when the ranging is started, and is not described herein again.

And finishing the measurement.

The sonar ranging method disclosed in the embodiment of the application tracks the output measuring distance which is not the sampling distance of the maximum energy echo signal by continuously monitoring the measuring result obtained by sampling at each time, corrects the measuring error in time and further improves the accuracy of the measuring result.

Example four:

correspondingly, refer to fig. 5, this application still discloses a sonar ranging device, includes:

the echo signal sequence acquisition module 500 is configured to acquire an echo signal sequence obtained by sampling at the current time in a sonar ranging process, where the echo signal sequence includes echo signals arranged from front to back according to the sequence of sampling time;

a filtering processing module 510, configured to perform filtering processing on the echo signal in the echo signal sequence acquired by the echo signal sequence acquiring module 500, and determine a filtering processing result of the current sampling;

and a distance output module 520, configured to output a measured distance according to a filtering processing result of the echo signal sampled for M consecutive times, where M is an integer greater than or equal to 2.

Optionally, as shown in fig. 6, the distance output module 520 includes:

a current filtering processing result obtaining selection unit 5201, configured to select, as a current filtering processing result, a preset number of echo signals with the largest energy in the echo signal filtering processing results of the current sonar ranging sampling;

a distance output unit 5202, configured to output a measured distance according to the current filtering processing result and the initial echo if the initial echo is determined;

the initial echo determining unit 5203 is configured to determine, if the initial echo is not determined, the initial echo according to an echo signal with the largest energy in the filtering processing results of the M consecutive latest samples, and use the initial echo for subsequently outputting the measurement distance, where the filtering processing results of the M consecutive latest samples include the filtering processing result of the current time.

Optionally, the distance output unit 5202 is further configured to:

selecting an echo signal with a sampling distance closest to the initial echo from the current filtering processing result as a current alternative echo signal;

if the difference value of the sampling distance between the current alternative echo signal and the initial echo is smaller than or equal to a first preset distance threshold, taking the sampling distance of the current alternative echo signal as an output measurement distance; otherwise, the sampling distance of the echo signal with the maximum energy in the current filtering processing result is used as the output measuring distance.

Optionally, the distance output unit 5202 is further configured to:

and updating the sampling distance of the initial echo through the sampling distance of the current alternative echo signal.

Optionally, the distance output unit 5202 is further configured to:

if the current alternative echo signal is not the echo signal with the maximum energy in the current filtering processing result, adding the echo signal with the maximum energy in the current filtering processing result into a pre-equipment echo selecting queue for re-determining an initial echo according to the echo signal with the maximum energy in the continuous M filtering processing results in the alternative echo queue; otherwise, emptying the preset alternative echo queue.

By continuously monitoring the measurement result obtained by sampling each time, the situation that the output measurement distance is not the sampling distance of the maximum energy echo signal is tracked, the measurement error is corrected in time, and the accuracy of the measurement result is further improved.

Optionally, the initial echo determining unit 5203 is further configured to:

if the difference value of the sampling distances between the echo signals with the maximum energy obtained by sampling at the previous time and the next time in the filtering processing results of the latest sampling of the continuous M times is smaller than or equal to a second preset distance threshold, taking the average value of the sampling distances of the echo signals with the maximum energy in the filtering processing results of the continuous M times as the sampling distance of the initial echo;

otherwise, deleting the echo signal with the maximum energy in the filtering processing result of the earliest time, and sampling the echo signal again for the first time so as to update the echo signal with the maximum energy in the filtering processing result of continuous M times of sampling.

Optionally, the filtering processing module 510 is further configured to:

if the number of the echo signals is one, directly taking the echo signals as a filtering processing result; otherwise, filtering the echo signals in the echo signal sequence, and taking the filtered echo signals as a filtering result;

wherein the filtering process includes: echo combining and/or multiple echo filtering.

Optionally, as shown in fig. 5, the filtering processing module 510 further includes:

an echo combining unit 5101, configured to perform echo combining on the echo signals;

the echo combining unit 5101 is further configured to:

determining whether the adjacent echo signals are to-be-combined echo signals or not according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence;

if the echo signals are determined to be echo signals to be combined, combining the adjacent echo signals;

wherein the intensity of the echo signal is amplitude or energy.

Optionally, the determining, according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence, whether the adjacent echo signals are echo signals to be combined includes:

and if the sampling distance difference value between the adjacent echo signals is smaller than the preset distance difference value, and the intensity of the former echo signal is smaller than that of the latter echo signal, combining the adjacent echo signals.

In specific implementation, the merging the adjacent echo signals includes:

taking the sum of the energies of the adjacent echo signals as the energy of the combined echo signal;

and updating the energy of the previous echo signal in the adjacent echo signals in the echo signal sequence through the energy of the combined echo signals, and deleting the next echo signal in the adjacent echo signals from the echo signal sequence.

a multiple echo filtering unit 5102 for performing multiple echo filtering on the echo;

the multi-echo filtering unit is further configured to:

determining the probability of containing multiple echo signals in the echo signal sequence;

and determining effective echo signals in the echo signals acquired last time according to the probability determined by at least two continuous sampling.

Optionally, the determining the probability that the echo signal sequence includes multiple echo signals includes:

and determining the probability of the echo signal sequence including multiple echo signals according to the number of the echo signals included in the echo signal sequence and the sampling distance of each echo signal.

In specific implementation, if the number of the echo signals in the echo signal sequence is greater than or equal to three, determining the probability that the echo signal sequence includes multiple echo signals according to the number of the echo signals included in the echo signal sequence and the sampling distance of each echo signal includes: if the sampling distances of the first three echo signals in the echo signal sequence are matched with a first preset condition, setting the probability of the echo signal sequence containing multiple echo signals as a probability value corresponding to the first preset condition, and initializing the sampling distance of an effective echo signal as d₁(ii) a Otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0;

wherein the first preset condition comprises any one of the following conditions:

and

d₁is the sampling distance of the first echo signal, d₂For the sampling distance of the second echo signal, d₃Is the sampling distance of the third echo signal.

In another embodiment, if the number of echo signals in the echo signal sequence is greater than or equal to four, the determining, according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal, the probability that the echo signal sequence includes multiple echo signals includes:

if the sampling distances of the first four echo signals in the echo signal sequence are matched with a second preset condition, setting the probability of the echo signal sequence containing multiple echo signals as a probability value corresponding to the second preset condition, and initializing the sampling distance of an effective echo signal as the sampling distance of the echo signal of the first non-noise echo; otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0;

wherein the second preset condition comprises any of the followingOne item is as follows:

and

d₁is the sampling distance of the first echo signal, d₂For the sampling distance of the second echo signal, d₃Is the sampling distance of the third echo signal, d₄Is the sampling distance of the fourth echo signal.

In another embodiment, if the number of echo signals in the echo signal sequence is equal to two, the step of determining the probability that the echo signal sequence includes multiple echo signals according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal includes:

if the sampling distance of the echo signal in the echo signal sequence matches a third preset condition, setting the probability of the echo signal sequence containing multiple times of echo signals as a probability value corresponding to the third preset condition, and initializing the sampling distance of an effective echo signal according to the echo signal in the echo signal sequence; otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0;

wherein the third preset condition includes any one of:

and

d₁is the sampling distance of the first echo signal, d₂The sampling distance of the second echo signal;

the initializing the sampling distance of the effective echo signal according to the echo signal in the echo signal sequence comprises:

if the sampling distance of each echo signal in the echo signal sequence meets the condition

The sampling distance for initializing a valid echo signal is d₁；

The sampling distance for initializing a valid echo signal is d₂-d₁。

In specific implementation, when the number of echo signals in the echo signal sequence is equal to one, the probability that the echo signal sequence contains multiple echo signals is set to be 0, and the echo signals in the echo signal sequence are used as effective echo signals.

The utility model provides a sonar ranging device, the echo signal sequence that obtains through acquireing sonar range finding in-process sampling at this time, including the echo signal who arranges from the front to back according to sampling time's precedence in the echo signal sequence, then, it is right echo signal among the echo signal sequence carries out echo merging and echo filtration processing many times to according to the echo signal's of continuous M times latest sampling the filtering process result, output measurement distance, the measuring result accuracy that exists when having solved the sonar range finding among the prior art is low and the relatively poor problem of stability. This application is through confirming the measuring distance according to the echo signal that continuous many times sampling obtained, compares with confirming the measuring distance according to sampling signal once among the prior art, has effectively weakened the influence that single sampling received measuring environment for measuring result's accuracy is higher, and stability is higher. By carrying out echo combination on echo signals obtained by sampling, the robustness of the ranging method when a plurality of reflecting surfaces exist in an object to be measured during sonar ranging is improved. The echo signals obtained by sampling are subjected to multiple echo filtering, so that the primary echo signals can be accurately determined, and the accuracy of the measurement result is further improved by taking the primary echoes as the reference for calculating the distance.

The device embodiment and the method of the present application correspond to each other, and the specific implementation manner of each module in the device embodiment is referred to as the method embodiment, which is not described herein again.

Correspondingly, the application also discloses an executing device, wherein the executing device is provided with a sonar sensor; the sonar sensor is used for transmitting and receiving sound waves; the execution device is further provided with a central processing unit and a memory, the memory is used for storing the program of the sonar distance measuring method according to the first embodiment to the third embodiment, and the central processing unit comprises each module and unit according to the fourth embodiment of the front speed and is used for executing the program stored in the memory so as to execute each step of the sonar distance measuring method according to the first embodiment to the third embodiment. The execution device may be a drone or an aircraft.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be appreciated by those of ordinary skill in the art that in the embodiments provided herein, the units described as separate components may or may not be physically separate, may be located in one place, or may be distributed across multiple network elements. In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a U disk, a removable hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can appreciate changes and substitutions without inventive step in the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A sonar distance measurement method is characterized by comprising the following steps:

filtering echo signals in the echo signal sequence to determine a filtering result of current sampling;

outputting a measurement distance according to the filtering processing result of the echo signal sampled for M times latest, wherein M is an integer greater than or equal to 2;

wherein, the step of outputting the measured distance according to the filtering processing result of the echo signal sampled latest M times includes:

selecting a preset number of echo signals with the maximum energy in the echo signal filtering processing result of the current sonar ranging sampling as a current filtering processing result;

if the initial echo is not determined, determining the initial echo according to the filtering processing result of the echo signal sampled for M times latest; and

if the initial echo is determined, outputting a measurement distance according to the current filtering processing result and the initial echo;

wherein, the step of outputting the measurement distance according to the current filtering processing result and the initial echo comprises:

2. The method according to claim 1, wherein the step of determining an initial echo according to the filtering processing result of the M-time latest sampled echo signals comprises:

and determining the initial echo according to the echo signal with the maximum energy in the filtering processing results of the latest sampling of M times, wherein the filtering processing results of the latest sampling of M times include the current filtering processing result.

3. The method according to claim 1 or 2, wherein the step of taking the sampling distance of the current time alternative echo signal as the output measured distance further comprises:

4. The method of claim 3, wherein the step of taking the sampled distance of the current time candidate echo signal as the output measured distance is further followed by:

if the current alternative echo signal is not the echo signal with the maximum energy in the current filtering processing result, adding the echo signal with the maximum energy in the current filtering processing result into a preset alternative echo queue for re-determining an initial echo according to the echo signal with the maximum energy in the continuous M filtering processing results in the alternative echo queue; otherwise, emptying the preset alternative echo queue.

5. The method of claim 2, wherein the step of determining the initial echo according to the echo signal with the largest energy in the filtering results of M consecutive latest samples comprises:

if the difference value of the sampling distances between the echo signals with the maximum energy obtained by the previous and subsequent sampling in the filtering processing results of the latest sampling for the continuous M times is smaller than or equal to a second preset distance threshold, taking the average value of the sampling distances of the echo signals with the maximum energy in the filtering processing results of the continuous M times as the sampling distance of the initial echo;

otherwise, deleting the echo signal with the maximum energy in the filtering processing result of the earliest time, and sampling the echo signal again to update the echo signal with the maximum energy in the filtering processing result of continuous M times of sampling.

6. The method according to claim 1, wherein the step of performing filtering processing on the echo signals in the echo signal sequence to determine a filtering processing result of a current sample comprises:

7. The method of claim 6, wherein the step of echo combining the echo signals comprises:

determining whether the adjacent echo signals are echo signals to be combined or not according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence;

wherein the intensity of the echo signal is amplitude or energy.

8. The method according to claim 7, wherein the step of determining whether the adjacent echo signals are echo signals to be combined according to the intensity and the sampling distance of the adjacent echo signals in the echo signal sequence comprises:

and if the sampling distance difference value between the adjacent echo signals is smaller than the preset distance difference value, and the intensity of the former echo signal is smaller than that of the latter echo signal, merging the adjacent echo signals.

9. The method of claim 7, wherein the step of combining the adjacent echo signals comprises:

10. The method of claim 6, wherein the step of echo filtering the echoes a plurality of times comprises:

11. The method of claim 10, wherein the step of determining the probability of the echo signal sequence comprising multiple echo signals comprises:

12. The method according to claim 11, wherein if the number of echo signals in the echo signal sequence is greater than or equal to three, the step of determining the probability that the echo signal sequence includes multiple echo signals according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

if the sampling distances of the first three echo signals in the echo signal sequence are matched with a first preset condition, setting the probability of containing multiple echo signals in the echo signal sequence as a probability value corresponding to the first preset condition, and initializing the sampling distance of an effective echo signal as d₁(ii) a Otherwise, setting the probability of containing multiple echo signals in the echo signal sequence to be 0;

and

13. The method according to claim 11, wherein if the number of echo signals in the echo signal sequence is greater than or equal to four, the step of determining the probability that multiple echo signals are included in the echo signal sequence according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

wherein the second preset condition comprises any one of the following:

and

14. The method according to claim 11, wherein if the number of echo signals in the echo signal sequence is equal to two, the step of determining the probability that multiple echo signals are included in the echo signal sequence according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

wherein the third preset condition includes any one of:

and

The sampling distance for initializing a valid echo signal is d₁；

The sampling distance for initializing a valid echo signal is d₂-d₁。

15. A sonar ranging device, its characterized in that includes:

the echo signal sequence acquisition module is used for acquiring an echo signal sequence obtained by sampling at the current time in the sonar ranging process, wherein the echo signal sequence comprises echo signals which are arranged from front to back according to the sequence of sampling time;

the filtering processing module is used for filtering the echo signals in the echo signal sequence acquired by the echo signal sequence acquisition module and determining the filtering processing result of the current sampling; the distance output module is used for outputting a measurement distance according to a filtering processing result of the echo signal sampled for M times latest, wherein M is an integer greater than or equal to 2;

wherein the distance output module includes:

the current filtering processing result obtaining and selecting unit is used for selecting the echo signals with the maximum energy in the echo signal filtering processing results of the current sonar ranging sampling as the current filtering processing results;

an initial echo determining unit, configured to determine an initial echo according to a filtering processing result of the echo signal sampled for the M times most recently if the initial echo is not determined;

a distance output unit, configured to output a measured distance according to the current filtering processing result and the initial echo if the initial echo is determined, including:

16. The apparatus according to claim 15, wherein the process of determining an initial echo from the result of the filtering process on the M-time most recently sampled echo signal by the initial echo determination unit includes:

17. The apparatus of claim 15 or 16, wherein the distance output unit is further configured to:

18. The apparatus of claim 17, wherein the distance output unit is further configured to:

19. The apparatus of claim 16, wherein the initial echo determination unit is further configured to:

20. The apparatus of claim 15, wherein the filter processing module is further configured to:

21. The apparatus of claim 20, wherein the filter processing module further comprises:

the echo combining unit is used for performing echo combination on the echo signals;

the echo combining unit is further configured to:

wherein the intensity of the echo signal is amplitude or energy.

22. The apparatus of claim 21, wherein the determining whether the adjacent echo signals are echo signals to be combined according to the intensities and sampling distances of the adjacent echo signals in the echo signal sequence comprises:

23. The apparatus of claim 21, wherein said combining the adjacent echo signals comprises:

24. The apparatus of claim 20, wherein the filter processing module further comprises:

the multi-echo filtering unit is used for filtering the echo for multiple times;

the multi-echo filtering unit is further configured to:

25. The apparatus of claim 24, wherein the determining the probability of the sequence of echo signals comprising multiple echo signals comprises:

26. The apparatus according to claim 25, wherein if the number of echo signals in the echo signal sequence is greater than or equal to three, the determining the probability that the echo signal sequence includes multiple echo signals according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

and

d₁for the sampling distance of the first echo signal，d₂Is the sampling distance of the second echo signal, d₃Is the sampling distance of the third echo signal.

27. The apparatus according to claim 25, wherein if the number of echo signals in the echo signal sequence is greater than or equal to four, the determining the probability that the echo signal sequence includes multiple echo signals according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

wherein the second preset condition comprises any one of the following:

and

28. The apparatus according to claim 25, wherein if the number of echo signals in the echo signal sequence is equal to two, the step of determining the probability that multiple echo signals are included in the echo signal sequence according to the number of echo signals included in the echo signal sequence and the sampling distance of each echo signal comprises:

wherein the third preset condition includes any one of:

and

The sampling distance for initializing a valid echo signal is d₁；

The sampling distance for initializing a valid echo signal is d₂-d₁。

29. An execution device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, further comprising:

a sonar sensor for emitting and receiving sound waves;

the processor, when executing the computer program, implements the sonar ranging method of any one of claims 1 to 14.