Laser radar anti-interference method, device, laser radar and readable storage medium

Abstract

The embodiment of the present application provides a laser radar anti-interference method, device, laser radar and readable storage medium, wherein the method includes: transmitting a target pulse sequence according to the preset transmission frequency of the laser radar and the random code value corresponding to each transmission pulse; generating a target sequence, and taking two adjacent transmission cycles of the target sequence as a measurement cycle, the target sequence includes a target pulse sequence and a target echo sequence returned by the target pulse sequence; filtering out interference signals within the target measurement cycle according to the reception time of the two echo signals of the target measurement cycle, the corresponding random code values ​​of the two transmission pulse signals of the target measurement cycle, the preset transmission cycle of the laser radar and the preset error value of the laser radar. The embodiment of the present application does not need to increase the transmission frequency of the laser radar, effectively solves the anti-interference problem of the laser radar, and improves the life of the laser. In addition, when the measurement distance remains unchanged, there is no need to increase the transmission power consumption of the laser.

Description

Technical Field

[0001] The present application relates to the field of radar, and in particular to a laser radar anti-interference method, device, laser radar and readable storage medium. Background Art

[0002] With the development of autonomous driving technology, lidar has become an indispensable and important sensor, and higher requirements have been placed on its cost, performance, reliability, and anti-interference.

[0003] The existing technology mainly achieves anti-interference through double or triple laser pulses, that is, one measurement point emits two or three laser pulses, and pulse coding is achieved by adjusting the time interval of the laser pulses, thereby realizing the anti-interference function of the laser radar. However, under the same measurement point frequency, this solution requires the laser radar's laser emission repetition rate to be doubled or tripled, resulting in a significant impact on the life of the laser. At the same time, in order to ensure that the measurement distance of the laser radar remains unchanged, the laser's emission power consumption needs to be increased. Summary of the invention

[0004] In order to solve the above technical problems, the embodiments of the present application provide a laser radar anti-interference method, device, laser radar and readable storage medium.

[0005] In a first aspect, an embodiment of the present application provides a laser radar anti-interference method, the method comprising:

[0006] According to the preset transmission frequency of the laser radar and the random code value corresponding to each transmission pulse, a target pulse sequence is transmitted;

[0007] generating a target sequence, and taking two adjacent transmission cycles of the target sequence as a measurement cycle, wherein the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence;

[0008] According to the receiving time of the two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitting pulse signals of the target measurement period, the preset transmitting period of the laser radar and the preset error value of the laser radar, the interference signal within the target measurement period is filtered out.

[0009] In one embodiment, filtering out interference signals within the target measurement period according to the reception time of two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar includes:

[0010] Calculating the reception time of two echo signals of the target measurement period;

[0011] Calculate a first judgment threshold and a second judgment threshold respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar;

[0012] Interference signals in the target measurement period are filtered out according to the receiving times of the two echo signals in the target measurement period, the first judgment threshold, and the second judgment threshold.

[0013] In one embodiment, filtering out interference signals within the target measurement period according to the reception times of the two echo signals of the target measurement period, the first judgment threshold, and the second judgment threshold includes:

[0014] Determine whether the reception time of the two echo signals of the target measurement period, the first judgment threshold and the second judgment threshold meet a preset judgment condition;

[0015] If so, determining that the reception time of the echo signal corresponding to the current transmission pulse of the target measurement period is the time when the echo signal returns within the target measurement period;

[0016] If not, the interference signal within the target measurement period is filtered out according to a preset algorithm.

[0017] In one implementation, the preset judgment condition is: a reception time interval between reception moments of two echo signals of the target measurement period is greater than the first judgment threshold and less than the second judgment threshold.

[0018] In one embodiment, the method further includes: determining a current emission pulse of the target measurement period according to a preset emission period of the laser radar and a measurement distance of the target detected by the laser radar.

[0019] In one embodiment, determining the current emission pulse of the target measurement period according to the preset emission period of the laser radar and the measurement distance of the target detected by the laser radar includes:

[0020] Calculating the maximum measurement distance of the preset transmission period;

[0021] If the measurement distance is less than or equal to the maximum measurement distance, determining the first transmission pulse signal in the target measurement period as the current transmission pulse of the target measurement period;

[0022] If the measurement distance is greater than the maximum measurement distance, the second transmission pulse signal in the target measurement period is determined as the current transmission pulse of the target measurement period.

[0023] In one embodiment, if the measurement distance is less than or equal to the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar, including:

[0024] According to the formula M1=Δt2-Δt1+T-t3, the first judgment threshold is calculated;

[0025] According to the formula M2=Δt2-Δt1+T+t3, the second judgment threshold is calculated;

[0026] Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt2 represents the random code value corresponding to the next transmission pulse of the current transmission pulse, Δt1 represents the random code value corresponding to the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

[0027] In one embodiment, if the measurement distance is greater than the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar, including:

[0028] According to the formula M1=Δt4-Δt3+T-t3, the first judgment threshold is calculated;

[0029] According to the formula M2=Δt4-Δt3+T+t3, the second judgment threshold is calculated;

[0030] Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt4 represents the random code value corresponding to the current transmission pulse, Δt3 represents the random code value corresponding to the previous transmission pulse of the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

[0031] In one implementation, the random code value ranges from -0.3us to 0.3us, and the preset error value ranges from 4ns to 10ns.

[0032] In one embodiment, the step of transmitting a target pulse sequence according to a preset transmission frequency of the laser radar and a random code value corresponding to each transmission pulse includes:

[0033] According to the preset transmission frequency of the laser radar, obtaining the initial transmission time corresponding to each of the transmission pulses;

[0034] Superimposing the corresponding random code value on the initial emission time corresponding to each of the emission pulses to obtain the actual emission time of each of the emission pulses;

[0035] The target pulse sequence is transmitted according to the actual transmission time of each of the transmission pulses.

[0036] In one embodiment, obtaining the initial emission time corresponding to each of the emission pulses according to the preset emission frequency of the laser radar includes:

[0037] Generate an initial pulse sequence according to a preset transmission frequency of the laser radar;

[0038] An initial emission time corresponding to each emission pulse is obtained from the initial pulse sequence.

[0039] In one embodiment, generating a target sequence comprises:

[0040] Receiving an echo signal returned after each of the transmitted pulses of the target pulse sequence reaches the target detected by the laser radar;

[0041] Based on the time sequence, a target sequence is generated according to each transmit pulse of the target pulse sequence and the echo signal corresponding to each transmit pulse.

[0042] In a second aspect, an embodiment of the present application provides a laser radar anti-interference device, the device comprising:

[0043] A transmitting module, used to transmit a target pulse sequence according to a preset transmitting frequency of the laser radar and a random code value corresponding to each transmitting pulse;

[0044] A generating module, used for generating a target sequence and taking two adjacent transmission cycles of the target sequence as a measurement cycle, wherein the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence;

[0045] The filtering module is used to filter out the interference signal within the target measurement period according to the reception time of the two echo signals of the target measurement period, the corresponding random code values ​​of the two transmission pulse signals of the target measurement period, the preset transmission period of the laser radar and the preset error value of the laser radar.

[0046] In a third aspect, an embodiment of the present application provides a laser radar, comprising a memory and a processor, wherein the memory is used to store a computer program, and when the computer program is run by the processor, the laser radar anti-interference method provided in the first aspect is executed.

[0047] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program, which, when running on a processor, executes the laser radar anti-interference method provided in the first aspect.

[0048] The laser radar anti-interference method provided in the above application adjusts the moment of each laser pulse emission under a relatively fixed repetition rate, which effectively solves the anti-interference problem of the laser radar without increasing the emission frequency of the laser, effectively improving the life of the laser and reducing the emission power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. In each of the drawings, similar components are numbered similarly.

[0050] Figure 1 A schematic diagram of a process of a laser radar anti-interference method provided in an embodiment of the present application is shown;

[0051] Figure 2 A schematic diagram of an initial pulse sequence provided by an embodiment of the present application is shown;

[0052] Figure 3 A schematic diagram showing a comparison between an initial pulse sequence and a target pulse sequence provided in an embodiment of the present application is shown;

[0053] Figure 4 A schematic diagram showing comparison of a target sequence corresponding to an initial pulse sequence and a target sequence corresponding to a target pulse sequence provided in an embodiment of the present application is shown;

[0054] Figure 5 A schematic diagram showing comparison of another target sequence corresponding to an initial pulse sequence and a target sequence corresponding to a target pulse sequence provided in an embodiment of the present application is shown;

[0055] Figure 6 A schematic diagram of the structure of a laser radar anti-interference device provided in an embodiment of the present application is shown;

[0056] Figure 7 A schematic diagram of the structure of a laser radar provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0058] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0059] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present application, are intended only to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0060] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0061] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0062] Example 1

[0063] The present application embodiment provides a laser radar anti-interference method. Figure 1 , the laser radar anti-interference method comprises:

[0064] Step S110, transmitting a target pulse sequence according to a preset transmission frequency of the laser radar and a random code value corresponding to each transmission pulse;

[0065] In a common laser radar system, the laser radar's transmitting module emits laser pulses at a fixed transmitting frequency, which can be seen in Figure 2 , Figure 2 The standard 500KHZ transmission system is shown, that is, the time interval between each laser pulse is 2us, from which the measured distance in a single measurement cycle is:

[0066] (2us*c) / 2≈300m Formula 1

[0067] Here, c represents the speed of light, and a single measurement cycle includes one round trip, so it needs to be divided by 2. Therefore, Figure 2 The maximum measurement distance of the radar system shown is 300m. If the distance exceeds 300m, it will not be possible to distinguish whether the signal is returned from the current measurement cycle or other measurement cycles (previous measurement cycles). In other words, the standard fixed transmission frequency radar system has poor anti-interference ability and cannot distinguish between correct signals and interference signals.

[0068] Based on this, the embodiment of the present application improves the radar system with a fixed transmission frequency, adds a random code value, and adjusts the timing of each transmission pulse. Figure 3 , Figure 3 A schematic diagram of comparing an initial pulse sequence and a target pulse sequence provided in an embodiment of the present application is provided. For example, taking a 500KHZ transmission system as an example, while the total number of transmission points remains unchanged, each transmission moment is adjusted left or right, and the adjustment amplitude (that is, the random coding value) is controlled within a preset adjustment range.

[0069] Preferably, the random coding value ranges from -0.3us to 0.3us. This ensures that the adjustment range is flexible but does not affect the measurement range. If it exceeds this range, there is a risk of affecting the measurement range. Within the adjustment range, the adjustment amplitude can be randomly changed, that is, each transmission pulse is randomly encoded based on the random coding value to transmit the target pulse sequence.

[0070] In an embodiment of the present application, based on the preset transmission frequency of the laser radar and the random coding value corresponding to each transmission pulse, transmitting a target pulse sequence includes: obtaining the initial transmission time corresponding to each transmission pulse according to the preset transmission frequency of the laser radar; superimposing the corresponding random coding value on the initial transmission time corresponding to each transmission pulse to obtain the actual transmission time of each transmission pulse; and transmitting the target pulse sequence according to the actual transmission time of each transmission pulse.

[0071] Furthermore, according to the preset transmission frequency of the laser radar, obtaining the initial transmission time corresponding to each transmission pulse includes: generating an initial pulse sequence according to the preset transmission frequency of the laser radar; and obtaining the initial transmission time corresponding to each transmission pulse from the initial pulse sequence.

[0072] Step S120, generating a target sequence, and taking two adjacent transmission cycles of the target sequence as a measurement cycle, the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence; wherein the target pulse sequence represents the transmission sequence, and the target echo sequence represents the returned sequence.

[0073] In an embodiment of the present application, generating a target sequence includes: receiving an echo signal returned after each transmitting pulse of the target pulse sequence reaches the target detected by the laser radar; based on the time sequence, generating the target sequence according to each transmitting pulse of the target pulse sequence and the echo signal corresponding to each transmitting pulse.

[0074] See also Figure 4 , Figure 4 A schematic diagram showing comparison of a target sequence corresponding to an initial pulse sequence and a target sequence corresponding to a target pulse sequence provided in an embodiment of the present application is shown; Figure 4 exist Figure 3 On the basis of the above, the echo signal after the laser emission is added. It is assumed that the echo signal in the figure is about 0.2us after the emission, that is, the target of the return signal is about 0.2us*c / 2=30m. When a fixed emission frequency is used, the position of the echo is relatively fixed, but when the emission time is randomly adjusted, the position of the echo signal will also change randomly. Therefore, the present application uses two adjacent emission cycles as a measurement cycle to calculate the position of the echo signal. For example, the first and second emission cycles are combined into measurement cycle T1, and the second and third emission cycles are combined into measurement cycle T2, and so on.

[0075] Step S130, filtering out interference signals within the target measurement period according to the reception time of the two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar and the preset error value of the laser radar.

[0076] The target measurement cycle here is the measurement cycle to be measured in step S120. In one embodiment, filtering out interference signals within the target measurement cycle according to the reception time of the two echo signals of the target measurement cycle, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement cycle, the preset transmission cycle of the laser radar, and the preset error value of the laser radar includes:

[0077] Calculate the receiving time of the two echo signals of the target measurement period; calculate the first judgment threshold and the second judgment threshold respectively according to the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar and the preset error value of the laser radar; filter out the interference signal within the target measurement period according to the receiving time of the two echo signals of the target measurement period, the first judgment threshold and the second judgment threshold.

[0078] Preferably, the preset error value ranges from 4ns to 10ns. This is due to the error considerations of the laser radar system. There are many reasons for the error, such as air refraction error, scanning angle error, etc. Considering the various errors that may occur, the generally more reasonable preset error value ranges from 4ns to 10ns.

[0079] In one embodiment, filtering out interference signals within the target measurement period according to the reception times of the two echo signals of the target measurement period, the first judgment threshold, and the second judgment threshold includes:

[0080] Determine whether the reception time of the two echo signals of the target measurement period, the first judgment threshold and the second judgment threshold meet a preset judgment condition;

[0081] If yes, determine that the reception time of the echo signal corresponding to the current transmission pulse of the target measurement period is the time when the echo signal returns within the target measurement period; if not, filter out the interference signal within the target measurement period according to a preset algorithm.

[0082] Specifically, two judgment thresholds may be calculated using some influencing parameters of the target measurement period, so as to calculate the normal signal and the interference signal according to the judgment thresholds.

[0083] Specifically, in one embodiment, the preset judgment condition is: the reception time interval between the reception moments of two echo signals of the target measurement period is greater than the first judgment threshold and less than the second judgment threshold.

[0084] In one embodiment, the method further includes: determining a current emission pulse of the target measurement period according to a preset emission period of the laser radar and a measurement distance of the target detected by the laser radar.

[0085] In one embodiment, determining the current emission pulse of the target measurement period according to the preset emission period of the laser radar and the measurement distance of the target detected by the laser radar includes:

[0086] Calculate the maximum measurement distance of the preset transmission cycle; if the measurement distance is less than or equal to the maximum measurement distance, determine the first transmission pulse signal in the target measurement cycle as the current transmission pulse of the target measurement cycle; if the measurement distance is greater than the maximum measurement distance, determine the second transmission pulse signal in the target measurement cycle as the current transmission pulse of the target measurement cycle.

[0087] The maximum measurement distance is determined by the preset transmission frequency of the laser radar, specifically, the preset transmission frequency multiplied by the speed of light divided by 2. This step is to achieve cross-cycle measurement to avoid receiving echoes from the previous transmission cycle in the current transmission cycle.

[0088] In one embodiment, if the measurement distance is less than or equal to the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar, including:

[0089] According to the formula M1=Δt2-Δt1+T-t3, the first judgment threshold is calculated;

[0090] According to the formula M2=Δt2-Δt1+T+t3, the second judgment threshold is calculated;

[0091] Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt2 represents the random code value corresponding to the next transmission pulse of the current transmission pulse, Δt1 represents the random code value corresponding to the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

[0092] Specifically, Figure 4 As shown, when the target is within the maximum measurement distance, the first transmitted pulse signal within the target measurement period T1 is determined as the current transmitted pulse of the target measurement period T1. Assuming that in the measurement period T1, the receiving time of the first echo signal is t1, and the receiving time of the second echo signal is t2, the receiving time of the echo signal corresponding to the current transmitted pulse signal is t1. Since the time interval between the two transmitted pulse signals within the target measurement period T1 and the time interval between the echo signals corresponding to the two transmitted pulse signals will not change suddenly, t2-t1≈Δt, where Δt is the time interval between the two transmitted pulse signals.

[0093] At the same time, assuming that the emission time of the current emission pulse signal differs from the standard preset emission frequency by Δt1 (i.e., the random code value Δt1 corresponding to the current emission pulse signal), Δt1=0, and the emission time of the next emission pulse signal differs from the preset emission frequency by Δt2 (i.e., the random code value Δt2 corresponding to the next emission pulse signal), Δt2=-0.2us, then the time interval Δt=Δt2-Δt1+T between the two emission pulse signals within the target measurement period T1 can be calculated, where T represents the preset emission period under the standard emission frequency, and the preset emission period T, the random code value Δt1 corresponding to the current emission pulse signal, and the random code value Δt2 corresponding to the next emission pulse signal are known, such as Figure 4As shown, within the target measurement period T1, the time interval between two transmitted pulse signals is Δt=Δt2-Δt1+T=-0.2-0+2=1.8us.

[0094] In addition, when making a judgment, because the laser radar system itself may have errors, a preset error value t3 needs to be reserved. The preset error value t3 can be determined based on the error value of the laser radar system.

[0095] Specifically, the first judgment threshold M1 can be calculated according to the following formula:

[0096] M1=Δt2-Δt1+T-t3 Formula 2

[0097] The second judgment threshold M2 is calculated according to the following formula 3:

[0098] M2=Δt2-Δt1+T+t3 Formula 3

[0099] If the receiving time interval between the receiving time of the first echo signal t1 and the second echo signal t2 of the target measurement period T1 is greater than the first judgment threshold M1 and less than the second judgment threshold M2, that is, in the target measurement period T1, when the condition of Δt2-Δt1+T-t3<t2-t1<Δt2-Δt1+T+t3 is satisfied, the receiving time of the first echo signal is determined to be t1 as the time when the echo signal returns within the target measurement period T1, that is, the receiving time of the echo signal corresponding to the current emission pulse of the target measurement period is determined to be the time when the echo signal returns within the target measurement period. When there are other interference signals, this condition will not be met, and the interference signals can be effectively filtered out according to the preset algorithm. Since Δt1 and Δt2 are constantly changing randomly, the effect of identification by random coding values ​​can be achieved. Compared with the traditional double-shot laser emission pulse, this method does not need to increase the emission frequency of the laser, thereby not affecting the life of the laser and increasing the emission power consumption.

[0100] The laser radar anti-interference method provided in the above embodiment, under the condition of relatively fixed repetition frequency, effectively determines the interference signal and filters it according to the preset algorithm by adjusting the moment of each laser pulse emission, thereby solving the laser radar anti-interference problem. In addition, compared with the existing laser pulse double emission method, there is no need to increase the emission frequency of the laser, which effectively reduces the emission power consumption and increases the life of the laser.

[0101] In one embodiment, if the measurement distance is greater than the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar, including:

[0102] According to the formula M1=Δt4-Δt3+T-t3, the first judgment threshold is calculated;

[0103] According to the formula M2=Δt4-Δt3+T+t3, the second judgment threshold is calculated;

[0104] Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt4 represents the random code value corresponding to the current transmission pulse, Δt3 represents the random code value corresponding to the previous transmission pulse of the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

[0105] In addition, the embodiment of the present application can also realize cross-cycle measurement, such as Figure 5 As shown, Figure 5 A schematic diagram of comparing another target sequence corresponding to an initial pulse sequence and a target sequence corresponding to a target pulse sequence provided in an embodiment of the present application is shown. When the measured distance of the measured target is far and exceeds the maximum measurement distance, it is assumed that the echo signal returned by the measured target is 2.4us away from the emission time. At this time, the measured distance of the measured target is equal to 2.4*c / 2=360m, where c is the speed of light. If a fixed 500KHZ repetition frequency is used, a measurement error will occur in the next measurement cycle, and the object will be misjudged as 2.4-2=0.4us, that is, 60m.

[0106] Therefore, when the method for randomly adjusting the transmission time provided in this embodiment is used to transmit the target pulse sequence, taking the target measurement period T2 as an example, the second transmission pulse signal in the target measurement period T2 is determined as the current transmission pulse of the target measurement period T2. It is assumed that the reception time of the first echo signal is calculated to be t3, and the reception time of the second echo signal is t4. Therefore, the reception time of the echo signal corresponding to the current transmission pulse signal is t4. At the same time, it is assumed that the transmission time of the current transmission pulse signal differs from the standard preset transmission frequency by Δt4 (that is, the random code value Δt4 corresponding to the current transmission pulse signal), Δt4=0.1us, and the reception time of the previous transmission pulse signal is t3. The emission time differs from the standard preset emission frequency by Δt3 (i.e., the random code value Δt3 corresponding to the previous emission pulse signal), Δt3=-0.2us. Since the time interval between the two emission pulse signals and the time interval of the echo signals corresponding to the two emission pulse signals within the target measurement period T2 will not change suddenly, it can be obtained that t4-t3≈Δt4-Δt3+T, wherein T represents the preset emission period under the standard emission frequency, the preset emission period T, the random code value Δt4 corresponding to the current emission pulse signal, and the random code value Δt3 corresponding to the previous emission pulse signal are known, so t4-t3≈0.1-(-0.2)+2=2.3us.

[0107] In addition, when making a judgment, because the laser radar system itself may have errors, a preset error value t3 needs to be reserved. The preset error value t3 can be determined based on the error value of the laser radar system.

[0108] Specifically, the new first judgment threshold M1 can be calculated according to the following formula:

[0109] M1=Δt4-Δt3+T-t3 Formula 4

[0110] The new second judgment threshold M2 is calculated according to the following formula:

[0111] M2=Δt4-Δt3+T+t3 Formula 5

[0112] If the receiving time interval between the receiving time of the first echo signal t3 and the second echo signal t4 of the target measurement period T2 is greater than the first judgment threshold M1 and less than the second judgment threshold M2, that is, in the target measurement period T2, when the condition of ΔΔt4-Δt3+T-t3<t4-t3<Δt4-Δt3+T+t3 is satisfied, the receiving time of the second echo signal is determined to be t4 as the time when the echo signal returns within the target measurement period T2, that is, the receiving time of the echo signal corresponding to the current transmission pulse of the target measurement period is determined to be the time when the echo signal returns within the target measurement period. When there are other interference signals, this condition will not be met, and the interference signals can be effectively filtered out according to the preset algorithm. Since Δt4 and Δt3 are constantly changing randomly, the effect of identification by random coding values ​​can be achieved.

[0113] This embodiment can realize cross-cycle measurement. When the measured target is far away, by judging whether the time when the echo signal returns satisfies the condition that it is greater than the first judgment threshold M1 and less than the second judgment threshold M2, it can be determined that the reception time of this echo signal is the time when the echo signal returns within the target measurement cycle. In this way, cross-cycle measurement can be realized, avoiding the measurement error caused by the distance of the measured target being greater than the maximum measurement distance of the laser radar in the prior art, thereby greatly improving the ranging range of the laser radar, and also playing a role in solving the anti-interference problem.

[0114] In summary, the laser radar anti-interference method provided in this embodiment adjusts the moment of each laser pulse emission under a relatively fixed repetition frequency, which effectively solves the anti-interference problem of the laser radar. At the same time, cross-cycle emission coding is realized, cross-cycle measurement can be realized, and the ranging range of the laser radar is greatly improved. This embodiment does not need to increase the emission frequency of the laser, which effectively improves the life of the laser and reduces the emission power consumption.

[0115] Example 2

[0116] This embodiment also provides a laser radar anti-interference device, see Figure 6 , the laser radar anti-interference device 600 includes:

[0117] The transmitting module 610 is used to transmit a target pulse sequence according to a preset transmitting frequency of the laser radar and a random code value corresponding to each transmitting pulse;

[0118] A generating module 620 is used to generate a target sequence and use two adjacent transmission cycles of the target sequence as a measurement cycle, wherein the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence;

[0119] The filtering module 630 is used to filter out the interference signal within the target measurement period according to the reception time of the two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar and the preset error value of the laser radar.

[0120] The laser radar anti-interference device provided in this embodiment can implement the laser radar anti-interference method provided in Example 1. To avoid repetition, it will not be repeated here.

[0121] The laser radar anti-interference device provided in this embodiment adjusts the moment of each laser pulse emission under a relatively fixed repetition frequency, effectively solving the laser radar anti-interference problem. At the same time, cross-cycle emission coding is realized, cross-cycle measurement can be realized, and the ranging range of the laser radar is greatly improved. This embodiment does not need to increase the emission frequency of the laser, effectively improving the life of the laser and reducing the emission power consumption.

[0122] Example 3

[0123] This embodiment also provides a laser radar 700, see Figure 7 , Figure 7 The laser radar 700 shown includes a transmitter 710, a receiver 720, a memory 730 and a processor 740, wherein the memory stores a computer program, and the computer program executes the laser radar anti-interference method as described in Example 1 when the processor is running.

[0124] The laser radar provided in this embodiment adjusts the moment of each laser pulse emission under a relatively fixed repetition frequency, which effectively solves the anti-interference problem of the laser radar. At the same time, cross-cycle emission coding is realized, which can realize cross-cycle measurement and greatly improve the ranging range of the laser radar. This embodiment does not need to increase the emission frequency of the laser, effectively improving the life of the laser and reducing the emission power consumption.

[0125] Example 4

[0126] This embodiment also provides a computer-readable storage medium storing a computer program. When the computer program is run on a processor, the laser radar anti-interference method as described in Embodiment 1 is executed.

[0127] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or terminal including the element.

[0128] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0129] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose and protection scope of the present application, all of which are within the protection of the present application.

Claims

1. A laser radar anti-interference method, characterized in that: The method comprises: According to the preset transmission frequency of the laser radar and the random code value corresponding to each transmission pulse, a target pulse sequence is transmitted; generating a target sequence, and taking two adjacent transmission cycles of the target sequence as a measurement cycle, wherein the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence; According to the receiving time of two echo signals of the target measurement period, the corresponding random code values ​​of the two transmission pulse signals of the target measurement period, the preset transmission period of the laser radar and the preset error value of the laser radar, the interference signal within the target measurement period is filtered out; The method of filtering out interference signals within the target measurement period according to the receiving time of two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar includes: Calculating the reception time of two echo signals of the target measurement period; Calculate a first judgment threshold and a second judgment threshold respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar; filtering out interference signals within the target measurement period according to the reception time of the two echo signals of the target measurement period, the first judgment threshold, and the second judgment threshold; Determining a current emission pulse of the target measurement period according to a preset emission period of the laser radar and a measurement distance of a target detected by the laser radar includes: Calculating the maximum measurement distance of the preset transmission period; If the measurement distance is less than or equal to the maximum measurement distance, determining the first transmission pulse signal in the target measurement period as the current transmission pulse of the target measurement period; If the measurement distance is greater than the maximum measurement distance, determining the second transmission pulse signal in the target measurement period as the current transmission pulse of the target measurement period; If the measurement distance is greater than the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar, including: According to the formula M1=Δt4-Δt3+T-t3, the first judgment threshold is calculated; According to the formula M2=Δt4-Δt3+T+t3, the second judgment threshold is calculated; Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt4 represents the random code value corresponding to the current transmission pulse, Δt3 represents the random code value corresponding to the previous transmission pulse of the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

2. The method according to claim 1, characterized in that The filtering out interference signals within the target measurement period according to the reception time of the two echo signals of the target measurement period, the first judgment threshold and the second judgment threshold includes: Determine whether the reception time of the two echo signals of the target measurement period, the first judgment threshold and the second judgment threshold meet a preset judgment condition; If so, determining that the reception time of the echo signal corresponding to the current transmission pulse of the target measurement period is the time when the echo signal returns within the target measurement period; If not, the interference signal within the target measurement period is filtered out according to a preset algorithm.

3. The method according to claim 2, characterized in that The preset judgment condition is: the receiving time interval between the receiving moments of two echo signals in the target measurement period is greater than the first judgment threshold and less than the second judgment threshold.

4. The method according to claim 1, characterized in that: If the measurement distance is less than or equal to the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar, including: According to the formula M1=Δt2-Δt1+T-t3, the first judgment threshold is calculated; According to the formula M2=Δt2-Δt1+T+t3, the second judgment threshold is calculated; Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt2 represents the random code value corresponding to the next transmission pulse of the current transmission pulse, Δt1 represents the random code value corresponding to the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

5. The method according to claim 1, characterized in that The random code value ranges from -0.3us to 0.3us, and the preset error value ranges from 4ns to 10ns.

6. The method according to any one of claims 1 to 5, characterized in that The method of transmitting a target pulse sequence according to a preset transmission frequency of the laser radar and a random code value corresponding to each transmission pulse includes: According to the preset transmission frequency of the laser radar, obtaining the initial transmission time corresponding to each of the transmission pulses; Superimposing the corresponding random code value on the initial emission time corresponding to each of the emission pulses to obtain the actual emission time of each of the emission pulses; The target pulse sequence is transmitted according to the actual transmission time of each of the transmission pulses.

7. The method according to claim 6, characterized in that The step of obtaining the initial emission time corresponding to each emission pulse according to the preset emission frequency of the laser radar includes: Generate an initial pulse sequence according to a preset transmission frequency of the laser radar; An initial emission time corresponding to each emission pulse is obtained from the initial pulse sequence.

8. The method according to claim 7, characterized in that The generating of the target sequence comprises: Receiving an echo signal returned after each of the transmitted pulses of the target pulse sequence reaches the target detected by the laser radar; Based on the time sequence, a target sequence is generated according to each transmit pulse of the target pulse sequence and the echo signal corresponding to each transmit pulse.

9. A laser radar anti-interference device, characterized in that: The device comprises: A transmitting module, used to transmit a target pulse sequence according to a preset transmitting frequency of the laser radar and a random code value corresponding to each transmitting pulse; A generating module, used for generating a target sequence and taking two adjacent transmission cycles of the target sequence as a measurement cycle, wherein the target sequence includes the target pulse sequence and a target echo sequence returned by the target pulse sequence; A filtering module, used to filter out interference signals within the target measurement period according to the reception time of two echo signals of the target measurement period, the corresponding random code values ​​of the two transmission pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar; The method of filtering out interference signals within the target measurement period according to the receiving time of two echo signals of the target measurement period, the corresponding random code values ​​of the two transmitted pulse signals of the target measurement period, the preset transmission period of the laser radar, and the preset error value of the laser radar includes: Calculating the reception time of two echo signals of the target measurement period; Calculate a first judgment threshold and a second judgment threshold respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar; filtering out interference signals within the target measurement period according to the reception time of the two echo signals of the target measurement period, the first judgment threshold, and the second judgment threshold; Determining a current emission pulse of the target measurement period according to a preset emission period of the laser radar and a measurement distance of a target detected by the laser radar includes: Calculating the maximum measurement distance of the preset transmission period; If the measurement distance is less than or equal to the maximum measurement distance, determining the first transmission pulse signal in the target measurement period as the current transmission pulse of the target measurement period; If the measurement distance is greater than the maximum measurement distance, determining the second transmission pulse signal in the target measurement period as the current transmission pulse of the target measurement period; If the measurement distance is greater than the maximum measurement distance, the first judgment threshold and the second judgment threshold are calculated respectively according to the random code values ​​corresponding to the two emission pulse signals of the target measurement period, the preset emission period of the laser radar, and the preset error value of the laser radar, including: According to the formula M1=Δt4-Δt3+T-t3, the first judgment threshold is calculated; According to the formula M2=Δt4-Δt3+T+t3, the second judgment threshold is calculated; Among them, M1 represents the first judgment threshold, M2 represents the second judgment threshold, Δt4 represents the random code value corresponding to the current transmission pulse, Δt3 represents the random code value corresponding to the previous transmission pulse of the current transmission pulse, T represents the preset transmission period of the laser radar, and t3 represents the preset error value of the laser radar.

10. A laser radar, characterized in that: It comprises a transmitter, a receiver, a memory and a processor, wherein the memory stores a computer program, and when the computer program is run by the processor, the laser radar anti-interference method described in any one of claims 1 to 8 is executed.

11. A computer-readable storage medium, characterized in that: It stores a computer program, which, when running on a processor, executes the laser radar anti-interference method described in any one of claims 1 to 8.

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