Obstruction detection method and device of channel, electronic equipment, medium and product

Abstract

Embodiments of the present application provide a channel occlusion detection method and device, electronic equipment, medium and product. The method comprises: receiving a plurality of first signals sent by a satellite, preprocessing the plurality of first signals to obtain a plurality of second signals after preprocessing, and based on a preset double-channel sliding window algorithm, determining a first energy ratio of the second signals involved in the execution of the current double-channel sliding window algorithm according to the plurality of second signals. If the first energy ratio is greater than a preset energy ratio threshold, a helicopter rotor occluded channel is detected. If the first energy ratio is less than or equal to the preset energy ratio threshold, a helicopter rotor non-occluded channel is detected. The present application can more stably and accurately detect whether the helicopter rotor occludes the channel, and has better robustness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal processing, and in particular to a channel occlusion detection method and device, electronic equipment, medium and product. BACKGROUND

[0002] During the rotation of the rotor of a helicopter, the rotor may periodically occlude a communication antenna carried on the fuselage. If the channel is occluded, it will cause periodic fading of the signal transmission, affecting flight safety and task execution. Therefore, it is necessary to detect whether the rotor of the helicopter occludes the channel.

[0003] In related technologies, when detecting whether the rotor of the helicopter occludes the channel, the received radio frequency signal at the airborne end is first processed to obtain a baseband digital signal, and the signal average power is calculated in real time, and then the calculation result of the signal average power is compared with a preset threshold value. If it is higher than the preset threshold value, it is detected that the received signal is not occluded, otherwise it is detected that the received signal is occluded.

[0004] However, the above method has poor robustness. SUMMARY

[0005] The embodiments of the present application provide a channel occlusion detection method, device, electronic equipment, medium and product to achieve the technical effect of improving detection robustness.

[0006] In a first aspect, the embodiments of the present application provide a channel occlusion detection method, comprising:

[0007] Receiving a plurality of first signals sent by a satellite, the plurality of first signals being continuous signals;

[0008] Preprocessing the plurality of first signals to obtain a plurality of second signals after preprocessing;

[0009] Based on a preset double-channel sliding window algorithm, determining a first energy ratio of the second signals involved in the execution of the current double-channel sliding window algorithm according to the plurality of second signals; the preset double-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm, and the second signal involved in the execution of the second sliding window algorithm is the adjacent signal of the second signal involved in the execution of the first sliding window algorithm in a later period;

[0010] If the first energy ratio is greater than a preset energy ratio threshold value, it is detected that the rotor of the helicopter occludes the channel;

[0011] If the first energy ratio is less than or equal to the preset energy ratio threshold value, it is detected that the rotor of the helicopter does not occlude the channel.

[0012] In a possible implementation, the pre-processing of the plurality of first signals to obtain a plurality of second signals after pre-processing includes:

[0013] The plurality of first signals are converted to obtain a plurality of third signals after conversion processing;

[0014] The plurality of third signals are gain-processed to obtain a plurality of second signals after gain processing.

[0015] In a possible implementation, the first signal includes real part data and imaginary part data; the conversion processing of the plurality of first signals to obtain a plurality of third signals after conversion processing includes:

[0016] For any first signal, the real part data and the imaginary part data of the first signal are respectively subjected to absolute value calculation to obtain first absolute value data corresponding to the real part data and second absolute value data corresponding to the imaginary part data;

[0017] The maximum value data and the minimum value data are determined from the first absolute value data and the second absolute value data;

[0018] The minimum value data is subjected to mean value processing to obtain data after mean value processing;

[0019] The maximum value data and the data after mean value processing are added to obtain the third signal after conversion processing of the first signal.

[0020] In a possible implementation, the gain processing of the plurality of third signals to obtain a plurality of second signals after gain processing includes:

[0021] A plurality of continuous third signals involved in a current gain processing process are determined;

[0022] The plurality of continuous third signals involved are subjected to summation processing to obtain a first energy sum;

[0023] A preset energy threshold value is divided by the first energy sum to determine a gain coefficient;

[0024] The plurality of continuous third signals involved are respectively multiplied by the gain coefficient to obtain second signals corresponding to the plurality of third signals after gain processing.

[0025] In a possible implementation, the first energy ratio of the second signal involved in a current double-channel sliding window algorithm based on a preset double-channel sliding window algorithm is determined according to the plurality of second signals, and the first energy ratio includes:

[0026] determine, based on the first sliding window algorithm, a second energy sum of the second signals involved in execution of the current first sliding window algorithm;

[0027] determine, based on the second sliding window algorithm, a third energy sum of the second signals involved in execution of the current second sliding window algorithm; wherein the second signals involved in execution of the second sliding window algorithm are adjacent signals of the second signals involved in execution of the first sliding window algorithm in a later period;

[0028] calculate, according to the second energy sum and the third energy sum, a ratio between the second energy sum and the third energy sum, and the ratio is the first energy ratio.

[0029] In a possible implementation, the determining, based on the first sliding window algorithm, of the second energy sum of the second signals involved in execution of the current first sliding window algorithm comprises:

[0030] determining, based on the first sliding window algorithm, a plurality of continuous second signals involved in execution of the current first sliding window algorithm;

[0031] performing summation processing on the plurality of continuous second signals to obtain the second energy sum.

[0032] In a possible implementation, the determining, based on the second sliding window algorithm, of the third energy sum of the second signals involved in execution of the current second sliding window algorithm comprises:

[0033] determining, based on the second sliding window algorithm, a plurality of continuous second signals involved in execution of the current second sliding window algorithm;

[0034] performing summation processing on the plurality of continuous second signals to obtain the third energy sum.

[0035] In a possible implementation, the method further comprises:

[0036] if the helicopter rotor shielding channel is detected, updating preset index data from initial data to preset data, the preset index data being index data used to indicate a shielding state;

[0037] based on a preset double-channel sliding window algorithm and a preset window sliding step, re-determining, according to the plurality of second signals, a second energy ratio of the second signals involved in execution of the current double-channel sliding window algorithm;

[0038] determining a target energy ratio threshold according to the preset energy ratio threshold.

[0039] if the second energy ratio is less than the target energy ratio threshold, it is determined that the channel blocked by the helicopter rotor has recovered to an unblocked state;

[0040] if the second energy ratio is greater than or equal to the target energy ratio threshold, it is determined that the channel is still blocked by the helicopter rotor.

[0041] In a second aspect, an embodiment of the present application provides a channel blocking detection device, comprising:

[0042] a receiving module configured to receive a plurality of first signals transmitted by a satellite, the plurality of first signals being continuous signals;

[0043] a processing module configured to pre-process the plurality of first signals to obtain a plurality of second signals after pre-processing;

[0044] The processing module is further configured to determine, based on a preset double-channel sliding window algorithm, a first energy ratio of the second signals involved in the execution of the current double-channel sliding window algorithm according to the plurality of second signals; the preset double-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm, and the second signals involved in the execution of the second sliding window algorithm are adjacent signals of the second signals involved in the execution of the first sliding window algorithm in a later period;

[0045] The processing module is further configured to detect that a channel is blocked by a helicopter rotor if the first energy ratio is greater than a preset energy ratio threshold.

[0046] The processing module is further configured to detect that the channel is not blocked by the helicopter rotor if the first energy ratio is less than or equal to the preset energy ratio threshold.

[0047] In a third aspect, an embodiment of the present application provides an electronic device, comprising a memory and a processor.

[0048] The memory stores computer execution instructions.

[0049] The processor executes the computer execution instructions stored in the memory, so that the processor executes the first aspect and / or various possible implementation manners of the first aspect.

[0050] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by a processor to implement the first aspect and / or various possible implementation manners of the first aspect.

[0051] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the first aspect and / or various possible implementation manners of the first aspect.

[0052] The channel occlusion detection method, the electronic device, the storage medium and the program product provided by the embodiments of the present application can receive a plurality of first signals sent by a satellite, and pre-process the plurality of first signals to obtain a plurality of second signals after pre-processing. Based on a preset double-channel sliding window algorithm, the first energy ratio of the second signals involved in the execution of the current double-channel sliding window algorithm is determined according to the plurality of second signals. If the first energy ratio is greater than a preset energy ratio threshold, a helicopter rotor occluded channel is detected. If the first energy ratio is less than or equal to the preset energy ratio threshold, a helicopter rotor non-occluded channel is detected. Through continuous processing of multiple signals, the signal quality is optimized by pre-processing, and then the energy ratio is analyzed by using the double-channel sliding window algorithm. The dynamic change trend of the signal is comprehensively considered, the signal is considered from multiple dimensions, the limitation of single threshold judgment is greatly reduced, various disturbances and signal fluctuations in complex environments have stronger resistance, and therefore the helicopter rotor occluded channel can be more stably and accurately detected, and the robustness is better. BRIEF DESCRIPTION OF DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and serve to explain the principles of the present application together with the specification.

[0054] Figure 1 An application scenario schematic diagram is provided for the embodiments of the present application.

[0055] Figure 2A A flowchart of a channel occlusion detection method is provided for the embodiments of the present application.

[0056] Figure 2B A channel occlusion detection schematic diagram is provided for the embodiments of the present application.

[0057] Figure 3 A flowchart of a method for obtaining a third signal is provided for the embodiments of the present application.

[0058] Figure 4 A flowchart of a method for obtaining a second signal is provided for the embodiments of the present application.

[0059] Figure 5 A flowchart of a method for determining a first energy ratio is provided for the embodiments of the present application.

[0060] Figure 6A detection process schematic diagram provided for an embodiment of the present application;

[0061] Figure 7 A structure schematic diagram of a channel occlusion detection device provided for an embodiment of the present application;

[0062] Figure 8 A structure schematic diagram of an electronic device provided for an embodiment of the present application.

[0063] The above-described figures have shown the explicit embodiments of the present application, which will be described in more detail hereinafter. These figures and textual descriptions are not intended to limit the scope of the concept of the present application by any means, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0064] The exemplary embodiments will be described in detail herein with reference to the attached drawings. In the following description, the same numbers are used to indicate the same or similar components. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present application, as detailed in the appended claims.

[0065] When the helicopter rotor rotates, it periodically occludes the signal transmission path between the airborne end and the communication node such as a satellite, resulting in intermittent occlusion of the channel, causing signal attenuation, interruption or bit error rate increase, etc., thereby affecting the stability and reliability of navigation, communication and other functions. For example, in satellite navigation, rotor occlusion can cause positioning accuracy to decrease, and during data transmission, information loss is likely to occur. Therefore, it is necessary to detect whether the helicopter rotor occludes the channel.

[0066] In the related art, when detecting whether the helicopter rotor occludes the channel, the radio frequency signal received by the airborne end is first processed to obtain a baseband digital signal, and the average power of the baseband digital signal is calculated in real time. The average power is compared with the threshold value preset by the airborne end modem. If it is higher than the threshold value, it is determined that the signal is not occluded, otherwise it is determined to be occluded.

[0067] However, in the above manner, it only depends on the average power of the baseband digital signal to make the judgment, and the average power is easily affected by various interference factors, such as sudden electromagnetic noise encountered during flight, electronic interference of airborne equipment itself, etc., which can cause instantaneous abnormal fluctuations of the signal average power, and may cause the unblocked signal to be misjudged as blocked due to the temporary power being lower than the threshold, or the blocked signal to be misjudged as unblocked due to the accidental factor of the power being temporarily higher than the threshold. Moreover, the preset threshold is fixed and cannot adapt to the dynamic changes in different flight environments and different signal strengths. When the signal itself has normal amplitude fluctuations, it is difficult for the fixed threshold to accurately distinguish between normal fluctuations and power changes caused by rotor shielding, thereby reducing the reliability and stability of the detection and resulting in poor robustness.

[0068] In the related art, there is also a way of predicting the shielding of the rotor of a helicopter based on Kalman filtering. When the helicopter receives the blocked signal, a sliding average operation is performed on the signal power, and based on a preset power threshold, the shielding period length and the shielding time length in the shielding period are counted. According to the initial shielding state of the rotor, the shielding period and the shielding rate of the rotor are calculated, and the predicted values of the shielding period and the shielding rate of the next period are obtained through Kalman filtering. Then, the predicted value of the gap time length of the next period is calculated, that is, the prediction of the rotor shielding is completed.

[0069] However, the above method relies on the sliding average, statistics and Kalman filtering of the signal power, and the signal power is easily affected by shielding mutations, environmental noise, channel interference, etc., resulting in poor power value stability and poor robustness.

[0070] Therefore, in order to solve the problem of poor robustness in the related art, it is found in the research process that preprocessing the initial signal sent by the satellite can convert the alternating signal into a non-negative signal, eliminate the fluctuation interference caused by the positive and negative alternation of the signal, and reduce the influence of the polarity change in the original signal on the subsequent calculation. Moreover, it can amplify the effective signal component and suppress the noise, so that the useful signal features are more prominent, thereby reducing the influence of sudden electromagnetic noise, airborne electronic interference, etc. during flight on the signal. The energy ratio is calculated by using a double-channel sliding window algorithm, and the judgment is made by the relative relationship of the signal energy in the window, rather than the absolute value of the single average power. This relative ratio can effectively offset the influence of the overall intensity fluctuation of the signal. Based on the comparison of the energy ratio and the threshold, the ratio form can better adapt to the dynamic changes of the signal strength, reduce the inadaptability of the fixed threshold to different environments, thereby reducing the misjudgment, improving the reliability and stability of the detection, and further improving the robustness.

[0071] In order to better understand the method of the present application, the following will be described by an exemplary application scenario, please refer to Figure 1 , Figure 1An application scenario schematic diagram provided by an embodiment of the present application includes a helicopter 01 and a satellite 02.

[0072] The onboard equipment in the helicopter 01 receives a plurality of first signals sent by the satellite 02. After receiving the first signals, the onboard equipment in the helicopter 01 pre-processes the first signals to obtain a plurality of second signals after pre-processing. Then, based on a preset double-channel sliding window algorithm, the first energy ratio of the second signals included in the current double-channel sliding window algorithm is determined according to the second signals, and then whether the helicopter rotor blocks the channel is detected according to the relationship between the first energy ratio and a preset energy ratio threshold.

[0073] It can be understood that the number, type and function of the helicopter 01 and the satellite 02 in the present application are not limited, and the above examples are only used for illustration. The specific application situation can be determined.

[0074] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0075] Please refer to Figure 2A , Figure 2A A flowchart of a channel blocking detection method provided by an embodiment of the present application is shown. The execution subject of the method can be a channel blocking detection device, which can be realized by a computer program. It can also be realized by a medium storing a related computer program, such as a U disk and / or an optical disk, or it can also be realized by an entity device integrated or installed with a related computer program, such as an electronic device. As shown in the figure, the method can include the following steps: Figure 2A

[0076] S201, receiving a plurality of first signals sent by a satellite.

[0077] In this embodiment, the plurality of received first signals are continuous signals, and the first signals can be baseband digital signals.

[0078] In order to facilitate understanding of the method of the present embodiment, the following will be combined with Figure 2B , Figure 2B A channel blocking detection schematic diagram provided by an embodiment of the present application is shown.

[0079] S202, pre-processing a plurality of first signals to obtain a plurality of second signals after pre-processing.

[0080] ​Optionally, the plurality of first signals are converted to obtain a plurality of third signals after conversion processing.

[0081] As shown in FIG. 1, the plurality of first signals S1 transmitted by the satellite are converted by the conversion module in the signal preprocessing module, which can also be referred to as absolute value processing, and the plurality of third signals after conversion processing are output to the gain control module in the signal preprocessing module. Figure 2B

[0082] Optionally, the plurality of third signals are gain-processed to obtain a plurality of second signals after gain processing.

[0083] The gain control module is between the conversion module and the dual-channel sliding window summation module. The input is the third signal S2 after conversion processing, and the output is the second signal S3 after gain adjustment.

[0084] The gain control module can automatically adjust the amplifier gain by calculating the gain coefficient through a summer or the like according to the intensity of the input signal, so that the output signal is kept within a suitable preset dynamic range. In this way, the consistency of the signal in amplitude can be improved, thereby reducing the adverse effects of instantaneous amplitude fluctuations caused by environmental changes, such as distance changes or channel fading, on the occlusion detection, and reducing the accuracy of the calculation results of the subsequent sliding window summation module and energy ratio calculation module due to excessively strong or weak signals.

[0085] S203, based on a preset dual-channel sliding window algorithm, determining a first energy ratio value of the second signals involved in the execution of the current dual-channel sliding window algorithm according to the plurality of second signals.

[0086] Through the dual-channel sliding window summation module, based on a preset dual-channel sliding window algorithm, a first energy ratio value of the second signals included in the execution of the algorithm is determined according to the plurality of second signals. The number of second signals included in the execution of the algorithm is related to the length of the window set in the algorithm.

[0087] The dual-channel sliding window summation module can be composed of two sliding window summators, including a first sliding window summator and a second sliding window summator, which are respectively used to determine the energy sum of the second signals included in the execution of the algorithm according to the plurality of second signals.

[0088] According to the energy sums E1 and E2 determined by the two sliding window summators respectively, the energy ratio R is calculated by a divider in the energy ratio calculation module.

[0089] S204, detecting whether the helicopter rotor occludes the channel according to the relationship between the first energy ratio value and a preset energy ratio value threshold.

[0090] ​The occlusion of the helicopter rotor to the channel is detected according to a size relationship between the first energy ratio and a preset energy ratio threshold through a decider in the occlusion judgment module.

[0091] In the above embodiment of the present application, a plurality of first signals transmitted by a satellite are received, and the plurality of first signals are preprocessed to obtain a plurality of second signals after preprocessing. Based on a preset double-channel sliding window algorithm, a first energy ratio of the second signal involved in the execution of the current double-channel sliding window algorithm is determined according to the plurality of second signals, and then the occlusion of the helicopter rotor to the channel is detected according to the relationship between the first energy ratio and the preset energy ratio threshold. The method of the embodiment can eliminate the influence of signal polarity fluctuation and enhance the effective signal characteristics by preprocessing the first signals continuously transmitted by the satellite, thereby reducing the interference of environmental noise and electronic interference. The first energy ratio of the second signal is calculated by combining the double-channel sliding window algorithm, and the relative energy relationship is replaced by a single power absolute value judgment, which can offset the influence of signal overall intensity fluctuation and reduce the misjudgment caused by instantaneous interference. At the same time, the occlusion is detected based on the relationship between the energy ratio and the preset threshold, which can adapt to the dynamic changes of different flight environments and signal strengths, avoid the inadaptability of the fixed power threshold, thereby improving the accuracy, stability and anti-interference ability of the helicopter rotor occlusion channel detection, and enhancing the detection robustness.

[0092] Further, on the basis of the above embodiment, the following embodiment explains the process of converting and processing the plurality of first signals to obtain a plurality of third signals after conversion processing, please refer to Figure 3 , Figure 3 A flowchart of a method for obtaining a third signal provided by the embodiment of the present application, which can include the following steps:

[0093] S301, for any first signal, the real part data and the imaginary part data of the first signal are respectively subjected to absolute value calculation to obtain first absolute value data corresponding to the real part data and second absolute value data corresponding to the imaginary part data.

[0094] In an actual communication system, the first signal is usually a complex signal including real part data and imaginary part data. In the related art, when the first signal is converted and processed, the real part data and the imaginary part data are usually squared respectively, and then the results after squaring are added to obtain an addition result, and then the square root of the addition result is taken.

[0095] For details, please refer to the following formula (1):

[0096]

[0097] Among them, The nth third signal is represented as represents the n-th first signal; represents the real part; represents the imaginary part.

[0098] As can be seen from the above formula (1), the modulus of the complex signal needs to be calculated, which involves square operation of the real part data and the imaginary part data, summation, square root operation, and two kinds of hardware, multiplication and square root, to realize such high-cost and high-time-consuming operation. The multiplier circuit structure is complex, and the square root operation needs a special hardware module, which will increase the hardware resource occupation and delay.

[0099] Therefore, a new conversion processing mode is proposed in the embodiment, which respectively calculates the absolute values of the real part data and the imaginary part data of the first signal to obtain the first absolute value data corresponding to the real part data and the second absolute value data corresponding to the imaginary part data.

[0100] S302, the maximum value data and the minimum value data are determined from the first absolute value data and the second absolute value data.

[0101] Further, the maximum value and the minimum value are determined from the determined first absolute value data and the second absolute value data.

[0102] If the maximum value and the minimum value are equal, one of them is randomly taken as the maximum value data and the minimum value data.

[0103] S303, the minimum value data is processed by mean value to obtain the data after mean value processing.

[0104] The half of the minimum value data is taken as the data after mean value processing by processing the minimum value data by mean value.

[0105] S304, the maximum value data is added to the data after mean value processing to obtain the third signal after conversion processing of the first signal.

[0106] Further, the maximum value data is added to the data after mean value processing to finally obtain the third signal after conversion processing of the first signal.

[0107] The steps in the embodiment are specifically described in the following formula (2):

[0108]

[0109] As can be seen from the formula (2), the formula (2) can be calculated by taking absolute value, comparing size, addition and division, wherein the division by 2 can be realized by shifting, which is simple in hardware. By taking the absolute value of the real part data and the imaginary part data first, the size is determined by the comparator, and then the maximum value is added to half of the minimum value by the adder. The whole process does not need multiplication and square root, but only relies on simple logical comparison, addition and shifting operation, which can significantly reduce the complexity of hardware implementation.

[0110] In the embodiment, when the absolute value of the real part data of the first signal is equal to the absolute value of the imaginary part data, the error reaches the maximum, and the maximum error at this time is as shown in formula (3):

[0111]

[0112] As can be seen, the method of the embodiment can effectively simplify the hardware implementation process although it introduces certain error.

[0113] In the above embodiment of the application, for any first signal, the absolute value of the real part data and the imaginary part data of the first signal is calculated respectively to obtain the first absolute value data corresponding to the real part data and the second absolute value data corresponding to the imaginary part data. From the first absolute value data and the second absolute value data, the maximum value data and the minimum value data are determined, the minimum value data is processed by mean value to obtain the data processed by mean value, and the maximum value data is added to the data processed by mean value to obtain the third signal after conversion processing of the first signal. The method of the embodiment reduces the complex operations such as square and square root used in the modulus calculation of the related technology, and only simple operations such as taking absolute value, comparing size, mean value processing and addition are used to complete the calculation, thereby reducing the complexity of hardware implementation and reducing the operation delay and resource occupation.

[0114] Further, on the basis of the above embodiment, the process of gain processing of a plurality of third signals to obtain a plurality of second signals processed by gain is described in the following embodiment. Please refer to Figure 4 , Figure 4 A flowchart of a method for obtaining a second signal provided by the embodiment of the application, which can include the following steps:

[0115] S401, determine the continuous plurality of third signals involved in the current gain processing process.

[0116] In the embodiment, the continuous plurality of third signals involved in the current gain processing process can be determined according to the length of the preset window.

[0117] Assuming that the length of the preset window is L1, the execution of the current gain processing can include L1 third signals.

[0118] S402, summing the involved continuous multiple third signals to obtain a first energy sum.

[0119] For details, see the following formula (4):

[0120]

[0121] Among them, The first energy sum is represented by E1; The length of the preset window, that is, the number of third signals that can be processed.

[0122] S403, divide the preset energy threshold value by the first energy sum to determine the gain coefficient.

[0123] For details, see the following formula (5):

[0124]

[0125] Among them, The gain coefficient is represented by G; The preset energy threshold value is represented by E0.

[0126] S404, multiply the involved continuous multiple third signals by the gain coefficient respectively to obtain the second signals corresponding to the multiple third signals after gain processing.

[0127] After determining the gain coefficient G The multiple third signals included in the window are multiplied by the gain coefficient G respectively, and the gain processing of the third signals included in the window is completed.

[0128] For details, see the following formula (6):

[0129]

[0130] Among them, The nth second signal is represented by Yn.

[0131] After completing the gain processing of the third signals included in the window, the third signals included in the next window are processed by gain processing by sliding the window by a preset length, for example Length.

[0132] For details, see the following formula (7):

[0133]

[0134] wherein, representing window sliding length, the energy sum of the third signal included.

[0135] further through the preset energy threshold value divided by the energy sum of the third signal included after window sliding, a new gain coefficient is obtained , and the third signal in the window after sliding is multiplied by the gain coefficient . In this way, until the gain processing of all third signals is completed.

[0136] In the above embodiments of the application, the continuous multiple third signals involved in the current gain processing process are determined, the continuous multiple third signals included are summed to obtain a first energy sum. The preset energy threshold value is divided by the first energy sum to determine the gain coefficient, and then the continuous multiple third signals included are multiplied by the gain coefficient to obtain the second signal corresponding to the multiple third signals after gain processing. The method of the embodiment can dynamically calculate the gain coefficient based on the energy sum of the continuous multiple third signals and the preset energy threshold value, and then uniformly adjust each third signal, which can flexibly match the signal changes of different intensities, reduce the problems of signal over-saturation or over-distortion under fixed gain, and thus adaptively adjust the signal intensity to keep the signal in a suitable processing range.

[0137] Further, on the basis of any of the above embodiments, the following embodiments illustrate the process of determining the first energy ratio of the second signal involved in the current double-channel sliding window algorithm based on the preset double-channel sliding window algorithm according to multiple second signals.

[0138] Please refer to Figure 5 , Figure 5 is a flowchart of a method for determining a first energy ratio provided by an embodiment of the application. The method can include the following steps:

[0139] S501, based on the first sliding window algorithm, determining the second energy sum of the second signal involved in the current first sliding window algorithm.

[0140] In the embodiment, the preset double-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm, the first sliding window algorithm is implemented by a first sliding window summer, and the second sliding window algorithm is implemented by a second sliding window summer.

[0141] Based on the first sliding window algorithm, the continuous multiple second signals involved in the current first sliding window algorithm process are determined, and the continuous multiple second signals are summed to obtain a second energy sum.

[0142] The continuous multiple second signals involved in the current first sliding window algorithm process can be determined by the length of the window preset by the first sliding window summer corresponding to the algorithm, for example, the length can be L2, L2 can be set as 1 / N of the total length N of the second signal input into the double-channel sliding window summer module, and N can be flexibly configured according to actual application.

[0143] The calculation of the second energy sum is specifically shown in the following formula (8):

[0144]

[0145] Among them, The second energy sum is represented by E2; The length of the window preset by the first sliding window summer, that is, the number of second signals that can be processed; The i-th second signal is represented by xi.

[0146] The second energy sum in the window of the first sliding window summer is obtained Then, Output to the energy ratio calculation module, and slide the window by M units, where M is a preset window sliding step. When M is selected to be a small step, a higher time resolution can be obtained, and when M is selected to be a large step, a lower time complexity can be obtained, so that it can be flexibly selected according to actual requirements.

[0147] S502, based on the second sliding window algorithm, the third energy sum of the second signal involved in the current second sliding window algorithm process is determined.

[0148] Based on the second sliding window algorithm, the continuous multiple second signals involved in the current second sliding window algorithm process are determined, and the continuous multiple second signals are summed to obtain a third energy sum.

[0149] In this embodiment, the continuous multiple second signals involved in the current second sliding window algorithm process can be determined by the length of the window preset by the second sliding window summer corresponding to the algorithm, for example, the length can be L2, which is the same as the length of the window preset by the first sliding window summer.

[0150] The second signal involved in the execution of the second sliding window algorithm process is the adjacent signal of the second signal involved in the execution of the first sliding window algorithm process in the subsequent period. The second signal input into the second sliding window summer is accessed after being delayed by L2, so that the summation interval of the second sliding window summer is always the subsequent adjacent period of the first sliding window summer.

[0151] This design ensures that the energy ratio calculation is always based on adjacent and non-overlapping time periods, which can reduce misjudgments. Specifically, the two windows are not calculated independently, but based on adjacent intervals in time, which can more accurately capture the continuous change trend of signal energy. If only a single window or non-adjacent windows are used, the signal characteristics may be misjudged due to transient interference, noise fluctuations, and other isolated events. The comparison of adjacent periods can filter short-term abnormalities and focus on the real energy change law, such as sustained attenuation caused by channel occlusion, to reduce false judgments caused by isolated data fluctuations to reduce misjudgments.

[0152] For example, if the signal suddenly weakens, the calculation result of the first sliding window summer alone may mistakenly believe that it is an occlusion, but in combination with the data of the subsequent period of the second sliding window summer, it is found that it is a burst interference, which can exclude the misjudgment of occlusion, and if the front and rear windows are continuously weakened, it is more likely to be a real occlusion. In this way, through the correlation comparison of adjacent periods, the misjudgment of a single window caused by transient interference is reduced.

[0153] The calculation of the third energy sum is specifically shown in the following formula (9):

[0154]

[0155] wherein, represents the third energy sum.

[0156] The third energy sum in the window of the second sliding window summer is obtained Then, output to the energy ratio calculation module, and the window is slid by M units to continue the calculation.

[0157] S503, according to the second energy sum and the third energy sum, the ratio between the second energy sum and the third energy sum is calculated, and the ratio is the first energy ratio.

[0158] Specifically, please refer to the following formula (10):

[0159]

[0160] wherein, represents the first energy ratio.

[0161] In the above embodiments of the present application, the second energy sum of the second signal involved in the current first sliding window algorithm process is determined based on the first sliding window algorithm, and the third energy sum of the second signal involved in the current second sliding window algorithm process is determined based on the second sliding window algorithm. Then, according to the second energy sum and the third energy sum, the ratio between the second energy sum and the third energy sum is calculated, and the ratio is the first energy ratio. In the method of the present embodiment, the second energy sum and the third energy sum of the second signal are respectively obtained through the first and second sliding window algorithms, and the ratio of the two is calculated as the first energy ratio, which can accurately capture the relative change trend of the signal energy. Compared with the single power value judgment, this method based on the energy ratio of adjacent time periods can effectively offset some interference, thereby improving the accuracy of the detection result.

[0162] Further, on the basis of any of the above embodiments, the process of detecting whether the helicopter rotor shields the channel is described.

[0163] In the present embodiment, the index data is set as an index data for indicating the shielding state, which may, for example, be a register state for recording the detection result. When the register state is "0", it indicates shielding, and when the register state is "1", it indicates no shielding, wherein the initial state is set as "1".

[0164] If it is detected that the first energy ratio is greater than the preset energy ratio threshold, it is determined that the helicopter rotor shields the channel, and if it is detected that the first energy ratio is less than or equal to the preset energy ratio threshold, it is determined that the helicopter rotor does not shield the channel.

[0165] For example, it is assumed that the preset energy ratio threshold T is generally a constant greater than 1. If it is detected that the first energy ratio is greater than T, it is determined that the second signal included in the preset window of the second sliding window summer occurs shielding in the corresponding time period. The decision maker of the shielding decision module outputs "0", and the register state is updated from the initial state "1" to "0". If it is detected that the first energy ratio is less than or equal to T, it is determined that the second signal included in the preset window of the second sliding window summer does not occur shielding in the corresponding time period. The register state remains unchanged and is still "1" in the initial state.

[0166] If it is determined according to the current detection result that the helicopter rotor shields the channel, the shielding of the channel can also be judged to be restored according to the second signal in the subsequent sliding window summer.

[0167] If it is detected that the helicopter rotor shields the channel, the preset index data is updated from the initial data to the preset data, i.e., the register state is "0", wherein the preset index data is the index data for indicating the shielding state, i.e., the register state.​

[0168] Based on the preset double-channel sliding window algorithm and the preset window sliding step, the second energy ratio of the second signal involved in the current double-channel sliding window algorithm is re-determined according to the plurality of second signals. The specific implementation process is similar to the determination process of the first energy ratio, and will not be repeated. Please refer to the above embodiment.

[0169] According to the preset energy ratio threshold, the target energy ratio threshold is determined. Optionally, the target energy ratio threshold in the embodiment can be the inverse of the preset energy ratio threshold, for example, 1 / T.

[0170] If the second energy ratio is less than the target energy ratio threshold 1 / T, it is determined that the channel blocked by the helicopter rotor has recovered to the unblocked state, the decision output is "1", and the register state is updated from "0" to "1". If the second energy ratio is greater than or equal to 1 / T, it is determined that the channel is still blocked by the helicopter rotor, and the register state remains unchanged, still "0".

[0171] In order to better understand the embodiment, the following flow chart is briefly described, please refer to Figure 6 , Figure 6 A detection process schematic diagram provided by the embodiment of the application can include the following steps:

[0172] S601, initializing the register state as "1".

[0173] S602, determining whether the first energy ratio is greater than the energy ratio threshold.

[0174] S603, if it is less than or equal to, the decision output is "1", and the initialization state of the register is maintained as "1".

[0175] S604, if it is greater than, the decision output is "0", and the initialization state of the register is updated from "1" to "0".

[0176] S605, the double-channel sliding window algorithm is slid and the second energy ratio is determined.

[0177] S606, determining whether the second energy ratio is less than the target energy ratio threshold.

[0178] S607, if it is greater than or equal to, the decision output is "0", and the state of the register is maintained as "0".

[0179] S608, if it is less than, the decision output is "1", and the initialization state of the register is updated from "0" to "1".

[0180] The double-channel sliding window algorithm continues to slide the window and repeats the above steps.

[0181] For specific implementation details of each step, please refer to the embodiment Figure 6 The above content is not repeated for brevity.

[0182] In the above embodiment of the present application, the initial state of whether the occlusion is recorded intuitively by the register state, and the comparison between the first energy ratio and the energy ratio threshold value can quickly determine whether the occlusion occurs and update the state. When the occlusion is detected, the second energy ratio is obtained by means of window sliding, and the target energy ratio threshold value is compared to determine whether the occlusion is restored. The state switching is also realized by updating the register state. The double-threshold setting reduces the misjudgment, and the dynamic update is maintained by the register state, thereby realizing the reliable detection of the helicopter rotor occlusion channel.

[0183] Please refer to Figure 7 , Figure 7 A structure diagram of a channel occlusion detection device provided by the embodiment of the present application is shown in Figure 7 The device provided by the embodiment can include:

[0184] The receiving module 701 is configured to receive a plurality of first signals sent by a satellite, and the plurality of first signals are continuous signals.

[0185] The processing module 702 is configured to pre-process the plurality of first signals to obtain a plurality of second signals after pre-processing.

[0186] The processing module 702 is further configured to determine, based on a preset double-channel sliding window algorithm, a first energy ratio of a second signal involved in a process of executing a current double-channel sliding window algorithm according to the plurality of second signals. The preset double-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm, and the second signal involved in the process of executing the second sliding window algorithm is an adjacent signal of the second signal involved in the process of executing the first sliding window algorithm in a later period.

[0187] The processing module 702 is further configured to detect a helicopter rotor occlusion channel if the first energy ratio is greater than a preset energy ratio threshold value.

[0188] The processing module 702 is further configured to detect a helicopter rotor non-occlusion channel if the first energy ratio is less than or equal to the preset energy ratio threshold value.

[0189] In a possible implementation manner, the processing module 702 is specifically configured to:

[0190] The plurality of first signals are converted and processed to obtain a plurality of third signals after conversion and processing.

[0191] The plurality of third signals are gain processed to obtain a plurality of second signals after gain processing.

[0192] In a possible implementation, the first signal includes real part data and imaginary part data, and the processing module 702 is specifically configured to:

[0193] For any first signal, the real part data and the imaginary part data of the first signal are respectively subjected to absolute value calculation to obtain first absolute value data corresponding to the real part data and second absolute value data corresponding to the imaginary part data.

[0194] The maximum value data and the minimum value data are determined from the first absolute value data and the second absolute value data.

[0195] The minimum value data is subjected to mean value processing to obtain data after mean value processing.

[0196] The maximum value data and the data after mean value processing are subjected to addition processing to obtain a third signal after conversion processing of the first signal.

[0197] In a possible implementation, the processing module 702 is specifically configured to:

[0198] The continuous plurality of third signals involved in the current gain processing process are determined.

[0199] The continuous plurality of third signals involved are subjected to summation processing to obtain a first energy sum.

[0200] The preset energy threshold value and the first energy sum are subjected to division processing to determine a gain coefficient.

[0201] The continuous plurality of third signals involved are respectively multiplied by the gain coefficient to obtain second signals corresponding to the plurality of third signals after gain processing.

[0202] In a possible implementation, the processing module 702 is specifically configured to:

[0203] Based on the first sliding window algorithm, a second energy sum of the second signal involved in the current first sliding window algorithm process is determined.

[0204] Based on the second sliding window algorithm, a third energy sum of the second signal involved in the current second sliding window algorithm process is determined.

[0205] According to the second energy sum and the third energy sum, a ratio between the second energy sum and the third energy sum is calculated, and the ratio is a first energy ratio.

[0206] In a possible implementation, the processing module 702 is specifically configured to:

[0207] Based on the first sliding window algorithm, determine the continuous multiple second signals involved in the execution of the current first sliding window algorithm.

[0208] Sum the continuous multiple second signals involved to obtain a second energy sum.

[0209] In a possible implementation, the processing module 702 is specifically configured to:

[0210] Based on the second sliding window algorithm, determine the continuous multiple second signals involved in the execution of the current second sliding window algorithm.

[0211] Sum the continuous multiple second signals involved to obtain a third energy sum.

[0212] In a possible implementation, the processing module 702 is specifically configured to:

[0213] If the helicopter rotor blocks the channel, the preset index data is updated from the initial data to the preset data, and the preset index data is index data used to indicate the blocking state.

[0214] Based on the preset double-channel sliding window algorithm and the preset window sliding step, the second energy ratio of the second signal involved in the execution of the current double-channel sliding window algorithm is re-determined according to the multiple second signals.

[0215] According to the preset energy ratio threshold, determine the target energy ratio threshold.

[0216] If the second energy ratio is less than the target energy ratio threshold, it is determined that the channel blocked by the helicopter rotor has recovered to an unblocked state.

[0217] If the second energy ratio is greater than or equal to the target energy ratio threshold, it is determined that the helicopter rotor still blocks the channel.

[0218] The channel blocking detection device provided in this embodiment can perform the channel blocking detection method provided in the method embodiment, and has similar implementation principles and technical effects, which will not be described here.

[0219] Figure 8 A structural schematic diagram of an electronic device provided in an embodiment of the present application is shown in FIG. 8. As shown in FIG. 8, the electronic device provided in this embodiment includes at least one processor 801 and a memory 802. Optionally, the electronic device further includes a communication component 803. The processor 801, the memory 802, and the communication component 803 are connected through a bus 804. Figure 8

[0220] ​In the implementation process, the at least one processor 801 executes the computer-executable instructions stored in the memory 802, so that the at least one processor 801 performs the method described above.

[0221] The specific implementation process of the processor 801 can refer to the method embodiments described above, which have similar implementation principles and technical effects, and details are not described here.

[0222] In the above embodiments, it should be understood that the processor can be a central processing unit (English: Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (English: Digital Signal Processor, DSP), application specific integrated circuits (English: Application Specific Integrated Circuit, ASIC), etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the application can be directly embodied as hardware processor execution, or executed by a combination of hardware and software modules in the processor.

[0223] The memory can include a random access memory (Random Access Memory, RAM), and can also include a non-volatile memory (Non-volatile Memory, NVM), for example, at least one disk memory.

[0224] The bus can be an industry standard architecture (Industry Standard Architecture, ISA) bus, a peripheral component interconnect (Peripheral Component, PCI) bus, or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of the present application does not limit only one bus or one type of bus.

[0225] The present application also provides a computer program product, comprising a computer program, which is executed by a processor to implement the method described above.

[0226] The present application also provides a computer-readable storage medium, which stores computer-executable instructions, and when the processor executes the computer-executable instructions, the method described above is implemented.

[0227] The above-mentioned readable storage medium can be realized by any type of volatile or nonvolatile storage devices or their combinations, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0228] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0229] The division of units is only a logical functional division, and in actual implementation, there can be another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0230] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0231] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0232] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the embodiments of the method of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0233] It can be understood by those skilled in the art that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various media that can store program codes.

[0234] Finally, it should be noted that: those skilled in the art will easily think of other embodiments of the present application after considering the specification and practicing the application disclosed herein. The present application is intended to cover any variations, uses or adaptations of the present application that follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed in the present application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

Claims

1. A method for detecting channel obstruction, characterized in that, include: Receive multiple first signals transmitted by a satellite, wherein the multiple first signals are consecutive signals; The plurality of first signals are preprocessed to obtain a plurality of preprocessed second signals; Based on a preset dual-channel sliding window algorithm, the first energy ratio of the second signals involved in the execution of the current dual-channel sliding window algorithm is determined according to the plurality of second signals. The preset dual-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm. The second signal involved in the execution of the second sliding window algorithm is the adjacent non-overlapping signal of the second signal involved in the execution of the first sliding window algorithm in the later time period. If the first energy ratio is greater than the preset energy ratio threshold, then the helicopter rotor is detected to be blocking the channel. If the first energy ratio is less than or equal to the preset energy ratio threshold, then the helicopter rotor is detected as not blocking the channel.

2. The method according to claim 1, characterized in that, The preprocessing of the plurality of first signals to obtain a plurality of preprocessed second signals includes: The plurality of first signals are converted to obtain a plurality of third signals after conversion. The multiple third signals are subjected to gain processing to obtain multiple second signals after gain processing.

3. The method according to claim 2, characterized in that, The first signal includes real data and imaginary data; the conversion processing of the plurality of first signals to obtain a plurality of converted third signals includes: For any first signal, the absolute values ​​of the real part data and the imaginary part data of the first signal are calculated respectively to obtain the first absolute value data corresponding to the real part data and the second absolute value data corresponding to the imaginary part data; From the first absolute value data and the second absolute value data, determine the maximum value data and the minimum value data; The minimum value data is averaged to obtain the averaged data; The maximum value data is added to the mean value data to obtain the third signal after the first signal conversion processing.

4. The method according to claim 2, characterized in that, The step of performing gain processing on the plurality of third signals to obtain a plurality of second signals after gain processing includes: Identify the multiple consecutive third signals involved in the current gain processing; The first energy sum is obtained by summing the multiple consecutive third signals involved. The gain coefficient is determined by dividing the preset energy threshold value by the sum of the first energy values. The multiple consecutive third signals involved are multiplied by the gain coefficient respectively to obtain the second signal corresponding to the multiple third signals after gain processing.

5. The method according to claim 1, characterized in that, The preset dual-channel sliding window algorithm, based on the plurality of second signals, determines the first energy ratio of the second signals involved in the execution of the current dual-channel sliding window algorithm, including: Based on the first sliding window algorithm, determine the second energy sum of the second signals involved in the execution of the current first sliding window algorithm; Based on the second sliding window algorithm, determine the third energy sum of the second signals involved in the execution of the current second sliding window algorithm; Based on the second total energy and the third total energy, calculate the ratio between the second total energy and the third total energy, where the ratio is the first energy ratio.

6. The method according to claim 5, characterized in that, The step of determining the second energy sum of the second signals involved in the execution of the current first sliding window algorithm based on the first sliding window algorithm includes: Based on the first sliding window algorithm, determine a series of consecutive second signals involved in the execution of the current first sliding window algorithm; The summation of the multiple consecutive second signals involved is performed to obtain the second total energy.

7. The method according to claim 5, characterized in that, The determination of the third energy sum of the second signals involved in the execution of the current second sliding window algorithm, based on the second sliding window algorithm, includes: Based on the second sliding window algorithm, determine a series of consecutive second signals involved in the execution of the current second sliding window algorithm; The summation of the multiple consecutive second signals involved is performed to obtain the third energy summation.

8. The method according to claim 7, characterized in that, Also includes: If the helicopter rotor is detected to block the channel, the preset index data is updated from the initial data to the preset data, which is the index data used to indicate the blocking status. Based on the preset dual-channel sliding window algorithm and the preset window sliding step size, the second energy ratio of the second signals involved in the execution of the current dual-channel sliding window algorithm is re-determined according to the multiple second signals. The target energy ratio threshold is determined based on the preset energy ratio threshold. If the second energy ratio is less than the target energy ratio threshold, it is determined that the channel blocked by the helicopter rotor has been restored to an unblocked state; If the second energy ratio is greater than or equal to the target energy ratio threshold, then it is determined that the helicopter rotor is still blocking the channel.

9. A channel obstruction detection device, characterized in that, include: A receiving module is used to receive multiple first signals transmitted by a satellite, wherein the multiple first signals are continuous signals; The processing module is used to preprocess the plurality of first signals to obtain a plurality of preprocessed second signals; The processing module is further configured to determine, based on a preset dual-channel sliding window algorithm and the plurality of second signals, a first energy ratio of the second signals involved in the execution of the current dual-channel sliding window algorithm. The preset dual-channel sliding window algorithm includes a first sliding window algorithm and a second sliding window algorithm. The second signal involved in the execution of the second sliding window algorithm is the adjacent non-overlapping signal of the second signal involved in the execution of the first sliding window algorithm in the later time period. The processing module is further configured to detect that the helicopter rotor is blocking the channel if the first energy ratio is greater than a preset energy ratio threshold. The processing module is further configured to detect that the helicopter rotor does not block the channel if the first energy ratio is less than or equal to the preset energy ratio threshold.

10. An electronic device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-8.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-8.

12. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-8.

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