Height calculation method and system for improving stability, storage medium and equipment

Abstract

The invention discloses a height calculation method and system for improving the stability of a blind area and an overrun area, a storage medium and equipment, and belongs to the technical field of radar altimeters, and the method comprises the steps: obtaining a beat frequency signal through a chirp sequence waveform; obtaining frequency spectrum data of the beat frequency signal, and performing constant false alarm detection according to the frequency spectrum data to obtain a group of height candidate values; and deciding the group of height candidate values, and outputting a final height discrimination result which comprises the working area where the radar altimeter is located, the current height value and the credibility of the current height value. According to the method, the chirp sequence waveform is adopted, and the stability of the radar altimeter in the blind area and the over-limit area is improved by judging the blind area and the over-limit area of the radar altimeter and calculating the credibility of the current height, so that the reliability and the stability of aircraft control are improved.

Description

Technical Field

[0001] This application belongs to the technical field of radar altimeters, and particularly relates to an altitude calculation method, system, storage medium, and device for improving the stability in blind zones and overrun zones. Background Art

[0002] A radar altimeter is an instrument that measures the ground altitude based on the principle of radio wave reflection. An aircraft is equipped with a radar wave transmitter and a receiver. The transmitter emits radar waves towards the ground, and the receiver receives the echo reflected from the ground. By measuring the time difference between the transmitted wave and the echo, the distance from the aircraft to the ground, that is, the relative altitude, can be calculated. The radio altimeter is particularly important during the takeoff and approach landing phases of an aircraft. The altimeter has a wide range of applications in the aviation field and is one of the important tools for pilots and automatic flight control to perform flight operations and navigation.

[0003] Common radar altimeters generally use the frequency-modulated continuous wave (FMCW) system. In an FMCW radar, the frequency of the transmitted signal varies linearly with time. The received echo signal has a time offset τ relative to the transmitted signal due to propagation delay. This time offset (i.e., the delay time τ) is proportional to the distance to the target. When the transmitted signal and the echo signal are mixed in the radar receiver, a beat frequency signal is generated, and this frequency is directly related to the target distance. Since the radar altimeter is often used during takeoff and landing, the influence of the Doppler velocity also needs to be considered. Therefore, in the practical application of FMCW radar altimeter design, a triangular waveform is often used. Figure 1 It is a schematic diagram of a specific example of the triangular wave waveform used in a radar altimeter in the prior art. As Figure 1 shown, within one period of the triangular wave signal, the signal frequency linearly increases from the starting frequency to the ending frequency, and then linearly decreases back to the starting frequency, completing a full cycle. Each period of the triangular wave signal contains two linear segments, corresponding to the positive frequency modulation stage and the negative frequency modulation stage of the waveform respectively. The signs of the distance components in the beat frequency signals of these two waveforms are the same, while the signs of the velocity components are opposite. By adding the measurement results of the two stages and dividing by 2, a distance measurement that is not affected by velocity can be obtained.

[0004] Almost all radar altimeters have their own effective altitude measurement ranges. Beyond this range, the measurement results of the radar altimeter are unstable, untrustworthy, and uncontrollable. This is determined by the working principle and design parameters of the radar altimeter. The ranges where the radar altimeter cannot work properly include two categories: one is the radar blind zone. When the distance between the altimeter and the ground is too close, it cannot work properly. Due to the limited distance between the transmitting and receiving antennas of the radar, a part of the transmitted signal will be directly coupled into the receiving antenna. In addition, the transmitted signal will also be coupled into the receiving link through some other paths. These two types of couplings will both cause an interference signal to exist in the received signal, with a relatively large peak near the 0 frequency. We can call it the interference beat frequency, and this peak will exist regardless of the actual altitude between the radar and the ground, which will pose a huge challenge to the discrimination of the radar blind zone and even the over-limit zone because it is impossible to determine whether the low-frequency peak of fb is caused by the ground echo or by the transceiver leakage of the radar; the second category is when the altitude is greater than the radar range. When the distance between the altimeter and the ground is too far, the echo signal is weak, resulting in the inability to reliably detect the ground echo. What makes the problem more complicated is that when the radar is in the blind zone or outside the range, its echo characteristics may be similar.

[0005] Finally, even when the altitude between the radar and the ground is in the normal working area, there may be a situation where there is no peak or the peak is too small in the working area. This is because the surface reflection intensity will randomly fluctuate. The radar echo is the sum of the surface reflection waves within a certain range. Even if there are minor changes between the radar and this section of the surface, this summation may change significantly. The resulting phenomenon is that the target amplitude of the radar echo randomly fluctuates, and there is even a probability of showing the echo characteristics of the blind zone or the over-limit zone, that is, there is no effective peak.

[0006] Therefore, effectively determining the working interval of the radar, or effectively indicating whether the radar is in the normal working interval, adding a confidence flag to the radar output, etc., can greatly improve the reliability of the radar operation, avoid outputting incorrect information to the aircraft, causing incorrect actions of the aircraft, and improve safety. It can be said that the stable determination and indication of the radar blind zone and the over-limit zone are one of the core indicators of the working reliability of the radar altimeter. Summary of the Invention

[0007] In view of the above technical problems existing in the prior art, the present application provides a height calculation method, system, storage medium, and device for improving the stability of the blind zone and the over-limit zone. By using the chirp sequence waveform, through the judgment of the blind zone and the over-limit zone of the radar altimeter and the calculation of the credibility of the current altitude, the stability of the radar altimeter in the blind zone and the over-limit zone is improved, and the amount of information and reliability of the altimeter output are greatly increased, thereby improving the reliability and stability of aircraft control.

[0008] To achieve the above object, the first technical solution adopted by this application is: to provide a height calculation method for improving the stability of the blind area and the overrun area, which includes: obtaining a beat frequency signal by using a chirp sequence waveform; obtaining the spectral data of the beat frequency signal, and performing constant false alarm detection based on the spectral data to obtain a set of height candidate values; and making a decision on the set of height candidate values and outputting a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the credibility of the current height value.

[0009] The second technical solution adopted by this application is: to provide a height calculation system for improving the stability of the blind area and the overrun area, which includes: a radio frequency front-end module for obtaining a beat frequency signal by using a chirp sequence waveform; a signal processing module for obtaining the spectral data of the beat frequency signal and performing constant false alarm detection based on the spectral data to obtain a set of height candidate values; and a decision-making module for making a decision on the set of height candidate values and outputting a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the credibility of the current height value.

[0010] The third technical solution adopted by this application is: to provide a computer-readable storage medium storing computer instructions, where the computer instructions are operated to execute the height calculation method for improving the stability of the blind area and the overrun area in Solution 1.

[0011] The fourth technical solution adopted by this application is: to provide a computer device including a processor and a memory, where the memory stores computer instructions, and the processor operates the computer instructions to execute the height calculation method for improving the stability of the blind area and the overrun area in Solution 1.

[0012] The beneficial effects that can be achieved by the technical solutions of this application are: by using the chirp sequence waveform for the height measurement of the radar altimeter instead of the conventional triangular wave waveform, it avoids the matching problem of the up and down modulation of the two measurement points of the triangular wave in the case of multiple reflection points on the ground. A blind area and overrun area determination logic is specifically introduced to perform working area discrimination, and the discrimination result is carried in the output, including two additional pieces of information: which area the height is in and the credibility of the height, which can greatly improve the stability and reliability of the output of the radar altimeter, thereby avoiding outputting incorrect information to the aircraft and causing incorrect actions of the aircraft, and improving safety. Description of the Drawings

[0013] Figure 1 is a schematic diagram of a specific example of the triangular wave waveform used by the radar altimeter in the prior art;

[0014] Figure 2 is a schematic flowchart of a specific implementation manner of the height calculation method for improving the stability of the blind area and the overrun area of this application;

[0015] Figure 3 It is a schematic diagram of a specific example in the height calculation process of this application;

[0016] Figure 4 It is a schematic diagram of a specific example of the chirp sequence waveform of this application;

[0017] Figure 5 It is a schematic diagram of a specific example of the processing flow of the digital signal of the beat frequency signal in this application;

[0018] Figure 6 It is a schematic diagram of a specific example of performing one-dimensional Fourier transform and two-dimensional Fourier transform in this application;

[0019] Figure 7 It is a schematic diagram of a specific example of the range-Doppler map (RD-MAP, range-Doppler data) in this application;

[0020] Figure 8 It is a schematic diagram of the process of a specific embodiment of the height calculation method for improving the stability of the blind area and the overrun area in this application;

[0021] Figure 9 It is a schematic diagram of a specific implementation manner of the height calculation system for improving the stability of the blind area and the overrun area in this application. Specific Embodiment

[0022] The following elaborates on the preferred embodiments of this application in conjunction with the accompanying drawings, so that the advantages and features of this application can be more easily understood by those skilled in the art, thereby making the protection scope of this application more clearly defined.

[0023] This application aims to improve the reliability of the output of the radar altimeter, especially the stability of the output when the millimeter-wave radar altimeter is in the blind area, overrun area, and complex surface area.

[0024] Figure 2 It is a schematic diagram of the process of a specific implementation manner of the height calculation method for improving the stability of the blind area and the overrun area in this application.

[0025] In Figure 2 In a specific implementation manner shown, the height calculation method for improving the stability of the blind area and the overrun area in this application includes process S201 of obtaining a beat frequency signal using a chirp sequence waveform.

[0026] Figure 3 It is a schematic diagram of a specific example in the height calculation process of this application.

[0027] In a specific embodiment of the present application, obtaining a beat frequency signal using a chirp sequence waveform includes: transmitting a chirp sequence waveform transmission signal through a radar altimeter, mixing the echo signal with the transmission signal to obtain a beat frequency signal.

[0028] Specifically, as Figure 3 shown, a chirp sequence waveform is generated by a radar system, passed through a power amplifier PA, and then fed into an antenna. The antenna radiates the modulated waveform into space. During the propagation of the waveform in space, if it encounters the ground, a part of the energy will be reflected back. The reflected wave can generally be amplified by a low-noise amplifier LNA and then fed into a mixer. The mixer performs a mixing operation on the echo and the transmission waveform to obtain a beat frequency (also known as difference frequency) signal. Among them, the antenna can be in the form of a horn, a patch antenna, or a waveguide slot antenna, etc.

[0029] Figure 4 is a schematic diagram of a specific example of the chirp sequence waveform of the present application.

[0030] As Figure 4 shown, the present application uses a chirp sequence waveform instead of a common triangular wave signal. In one period of the frequency modulation sequence signal, the signal starts from a fixed starting frequency, linearly increases to a higher frequency, and then suddenly returns to the starting frequency to start the next period. The frequency modulation sequence signal usually requires dozens or even hundreds of linear frequency modulation signal sequences to complete a full measurement. The frequency modulation slope of each chirp signal is often much higher than that of the triangular wave signal, and the duration is also relatively short. Therefore, it is also called a chirp sequence (chirp sequence) waveform. The advantage of the chirp sequence waveform is that the speed and distance measurements are naturally separated. In the case of multiple reflection points (targets), there is no matching problem of the upper and lower modulation measurement points of the triangular wave.

[0031] In Figure 2 a specific embodiment shown, the height calculation method for improving the stability of the blind area and the overrun area of the present application includes process S202, obtaining the spectral data of the beat frequency signal, and performing constant false alarm detection based on the spectral data to obtain a set of height candidate values.

[0032] In this specific embodiment, it is necessary to calculate the amplitude according to the spectral data, and then perform constant false alarm detection to obtain a set of height candidate values.

[0033] In a specific embodiment of the present application, before obtaining the spectral data of the beat frequency signal, it further includes: conditioning the beat frequency signal and performing analog-to-digital conversion to obtain the digital signal of the beat frequency signal.

[0034] In this specific embodiment, the beat frequency signal is sent into an analog-to-digital converter (ADC) after being conditioned by circuits such as amplification and filtering, and is converted into a digital signal.

[0035] As Figure 3 shown, after obtaining the digital signal of the echo beat frequency signal, the digital signal needs to be sent into a signal processor for processing and analysis. The processing and analysis include conventional processing steps of a radar altimeter such as common Fourier transform and constant false alarm rate detection (CFAR), and preliminary altitude data is obtained.

[0036] In a specific embodiment of the present application, obtaining the spectral data of the beat frequency signal includes: performing a one-dimensional Fourier transform on each chirp of the digital signal of the beat frequency signal to obtain the range spectrum of each chirp; and performing a two-dimensional Fourier transform on each range bin of the range spectra of all chirps within the current frame to obtain the range-velocity spectrum.

[0037] Figure 5 is a schematic diagram of a specific example of the processing flow of the digital signal of the beat frequency signal in the present application.

[0038] Figure 6 is a schematic diagram of a specific example of performing a one-dimensional Fourier transform and a two-dimensional Fourier transform in the present application.

[0039] Figure 7 is a schematic diagram of a specific example of the range-Doppler map (RD-MAP, range-Doppler data) in the present application.

[0040] As Figure 5 shown, for the chirp echo sequence data of the sawtooth wave (i.e., the digital signal of the beat frequency signal), first perform a one-dimensional Fourier transform 1D-FFT on each chirp (as Figure 6 shown), to obtain the range spectrum of each chirp, and then perform a two-dimensional Fourier transform 2D-FFT on each range bin of the range spectra of N chirps within the current frame (as Figure 6 shown), and the so-called RD-MAP, that is, the range-velocity spectrum (as Figure 7 shown) can be obtained. The range-velocity spectrum is a two-dimensional matrix, and each element of the matrix represents the echo energy of a certain small range of distances and a certain small range of velocities.

[0041] After obtaining the RD-MAP (i.e., the spectral data of the beat frequency signal), performing CFAR detection on the RD-MAP can obtain a set of candidate values of ground reflection points, and at the same time, a set of candidate altitude values can be obtained.

[0042] In Figure 2In a specific embodiment shown, the height calculation method for improving the stability of the blind area and the over-limit area of the present application includes process S203, making a decision on a set of height candidate values and outputting a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the confidence level of the current height value.

[0043] In this specific embodiment, as Figure 5 shown, after a set of height candidate values obtained through CFAR detection pass through the decision module, a final height discrimination result is output.

[0044] In a specific embodiment of the present application, making a decision on a set of height candidate values and outputting a final height discrimination result includes: based on the spectrum data of the current frame beat frequency signal and the historical height value, through algorithms and logical judgments, determining the working area where the radar altimeter is located, and calculating the confidence level of the current height value.

[0045] In this specific embodiment, the present application additionally designs a blind area and over-limit area judgment module. The inputs of this module include the spectrum data of the current frame beat frequency signal and the historical height measurement result. This module uses these two types of data through algorithms and logical judgments to generate judgments on whether the radar altimeter is in the blind area, normal working area, or over-limit area, and calculates the confidence level of the current height measurement. The radar altimeter finally outputs these two additional pieces of information for the aircraft to use, which can greatly increase the amount of information of the height input of the aircraft, thereby improving the reliability and stability of control.

[0046] In a specific embodiment of the present application, making a decision on a set of height candidate values and outputting a final height discrimination result further includes: if a spectral peak with a confidence level greater than the confidence threshold is detected in the normal working area, then the radar altimeter is located in the normal working area, and the height corresponding to the spectral peak is used as the current height value; if no spectral peak with a confidence level greater than the confidence threshold is detected in the normal working area, then the radar altimeter is not in the normal working area.

[0047] In this specific embodiment, when the radar is operating in the normal working area, the height corresponding to the higher spectral peak with a confidence level greater than the confidence threshold is used as the current height value; when no spectral peak with a confidence level greater than the confidence threshold is detected in the normal working area, it is necessary to rule out whether there is a flickering problem in the working area, which is mainly completed through joint tracking or filtering of multiple-frame measurements. If the current frame flickers, resulting in a very low peak that is not detected, then only the situation of the previous and subsequent frames can be jointly judged, which is generally a "filtering" operation.

[0048] In a specific embodiment of the present application, making a decision on a set of candidate height values and outputting a final height discrimination result further includes: when the radar altimeter is not in the normal working area, if there is a spectral peak with non-zero Doppler in the blind area, it is determined that the radar altimeter is in the blind area, and the minimum range value of the radar altimeter is used as the current height value; if there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the pre-trained threshold data.

[0049] Specifically, when no spectral peak with a credibility greater than the credibility threshold is detected in the normal working area and the problem of working area flicker is excluded, it is necessary to decide whether the radar altimeter is in the blind area or the over-range area. The decision method is: if there is a spectral peak with non-zero Doppler in the blind area, it can be determined that the radar altimeter is in the blind area, because at this time, the ground echo beat frequency and the coupling interference beat frequency are in the same range cell, but the coupling interference beat frequency has no Doppler energy. When the radar working table is in the blind area, the radar altimeter outputs a blind area indication flag indicating that the radar is in the blind area, and the output height is locked at a fixed value within the blind area. Generally, the minimum range value of the radar working table is used as the current height value, so as not to jump higher due to misjudgment. If there is no spectral peak with non-zero Doppler in the blind area, further hypothesis testing of the blind area is required. At this time, threshold detection is performed on the blind area amplitude according to the pre-trained threshold data to determine whether the radar working table is in the blind area or the over-range area. In a specific embodiment of the present application, if there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the pre-trained threshold data, including: if there is a spectral peak in the blind area with an amplitude greater than the pre-trained threshold data, it is determined that the radar altimeter is in the blind area, and the minimum range value of the radar altimeter is used as the current height value; if there is no spectral peak in the blind area with an amplitude greater than the pre-trained threshold data, it is determined that the radar altimeter is in the over-range area, and the maximum range value of the radar altimeter is used as the current height value.

[0050] In this specific embodiment, when there is no spectral peak with non-zero Doppler in the blind area, further hypothesis testing of the blind area is performed. If the hypothesis is successful, it is determined that the radar working table is in the blind area. If the hypothesis fails, it is determined that the radar is working in the over-range area. When the radar working table is in the over-range area, the radar altimeter outputs an over-range area indication flag indicating that the radar height exceeds the range, and the output height is locked at a fixed value within the over-range area. Generally, the maximum range value of the radar altimeter is used as the current height value.

[0051] In addition, when the radar working table is in a complex surface area, there are multiple strong reflection points on the ground below the radar. At this time, the radar output height is stabilized at the nearest ground point, so as not to output an incorrect height value due to the wrong matching of a common triangular wave altimeter.

[0052] In a specific embodiment of the present application, the height calculation method for improving the stability of the blind area and the overrun area of the present application further includes: when there is no ground surface with height mutation in the working scenario, using the tracking logic to determine whether the radar altimeter is in the blind area or the overrun area through historical height values.

[0053] In this specific embodiment, in the above judgment logic, for different application scenarios, the tracking logic can be introduced. When there is no ground surface with height mutation in the working scenario, it is possible to determine whether the radar altimeter is in the blind area or the overrun area through historical height values.

[0054] Figure 8 It is a schematic flow chart of a specific embodiment of the height calculation method for improving the stability of the blind area and the overrun area of the present application.

[0055] As Figure 8 shown, the height calculation method for improving the stability of the blind area and the overrun area of the present application includes: First, start the transmission and reception measurement process of the radar once to obtain the beat frequency signal, then obtain the RD-MAP data of the beat frequency signal and calculate the amplitude, then perform CFAR detection, and input the detection result into the decision logic module for discrimination of the working area and height-related calculation, and finally output the measurement result of this time. Among them, inputting the detection result into the decision logic module for discrimination of the working area and height-related calculation and processing includes: First, judge whether there is a peak with a credible height in the normal working area. If so, use the height corresponding to the peak in the normal working area as the output and output the normal working area indication flag. If not, judge whether there is a height peak with non-zero Doppler in the blind area. If so, determine that the radar altimeter is in the blind area, use the minimum value of the radar altimeter range as the output, and output the blind area indication flag. If not, perform threshold detection on the blind area amplitude according to the threshold data obtained by pre-training. If the blind area peak is greater than the threshold data, determine that the radar altimeter is in the blind area, use the minimum value of the radar altimeter range as the output, and output the blind area indication flag. If not, determine that the radar altimeter is in the overrun area, use the maximum value of the radar altimeter range as the output, and output the over-range indication flag.

[0056] In the height calculation method for improving the stability of the blind area and the overrun area of the present application, by using the chirp sequence waveform for the height measurement of the radar altimeter instead of the conventional triangular wave waveform, the matching problem of the up and down modulation of the triangular wave at two measurement points in the case of multiple reflection points on the ground surface is avoided. The determination logic for the blind area and the overrun area is specifically introduced for working area discrimination, and the discrimination result is carried in the output, including two additional pieces of information: which area the height is in and the credibility of the height, which can greatly improve the stability and reliability of the output of the radar altimeter, thereby avoiding outputting incorrect information to the aircraft and causing incorrect actions of the aircraft, and improving safety.

[0057] Figure 9It is a schematic diagram of a specific embodiment of the height calculation system for improving the stability of the blind area and the overrun area in this application.

[0058] In Figure 9 In a specific embodiment shown, the height calculation system for improving the stability of the blind area and the overrun area in this application includes: a radio frequency front-end module 901 for obtaining a beat frequency signal by using a chirp sequence waveform; a signal processing module 902 for obtaining spectral data of the beat frequency signal and performing constant false alarm detection based on the spectral data to obtain a set of height candidate values; and a decision module 903 for making a decision on the set of height candidate values and outputting a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the credibility of the current height value.

[0059] In a specific embodiment of this application, obtaining the spectral data of the beat frequency signal includes: performing one-dimensional Fourier transform on each chirp of the digital signal of the beat frequency signal to obtain the range spectrum of each chirp; and performing two-dimensional Fourier transform on each range bin of the range spectra of all chirps in the current frame to obtain the range-velocity spectrum.

[0060] In a specific embodiment of this application, making a decision on a set of height candidate values and outputting a final height discrimination result includes: judging the working area where the radar altimeter is located through algorithms and logical judgments based on the spectral data of the current frame beat frequency signal and the historical height value, and calculating the credibility of the current height value.

[0061] In a specific embodiment of this application, making a decision on a set of height candidate values and outputting a final height discrimination result further includes: if a spectral peak with a credibility greater than the credibility threshold is detected in the normal working area, the radar altimeter is located in the normal working area, and the height corresponding to the spectral peak is used as the current height value; if no spectral peak with a credibility greater than the credibility threshold is detected in the normal working area, the radar altimeter is not in the normal working area.

[0062] In a specific embodiment of this application, making a decision on a set of height candidate values and outputting a final height discrimination result further includes: when the radar altimeter is not in the normal working area, if there is a spectral peak with non-zero Doppler in the blind area, it is determined that the radar altimeter is located in the blind area, and the minimum value of the radar altimeter's range is used as the current height value; if there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the pre-trained threshold data.

[0063] In a specific embodiment of the present application, if there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the pre-trained threshold data, including: if there is a spectral peak in the blind area with an amplitude greater than the pre-trained threshold data, it is determined that the radar altimeter is in the blind area, and the minimum value of the range of the radar altimeter is used as the current altitude value; if there is no spectral peak in the blind area with an amplitude greater than the pre-trained threshold data, it is determined that the radar altimeter is in the over-limit area, and the maximum value of the range of the radar altimeter is used as the current altitude value.

[0064] In a specific embodiment of the present application, the altitude calculation system for improving the stability of the blind area and the over-limit area of the present application further includes: a module for using the tracking logic to determine whether the radar altimeter is in the blind area or the over-limit area through the historical altitude value when there is no surface with sudden altitude change in the working scenario.

[0065] In the altitude calculation system for improving the stability of the blind area and the over-limit area of the present application, by using the chirp sequence waveform for the altitude measurement of the radar altimeter instead of the conventional triangular wave waveform, the matching problem of the measurement points modulated up and down twice by the triangular wave in the case of multiple reflection points on the surface is avoided. The determination logic for the blind area and the over-limit area is specifically introduced to perform the working area discrimination, and the discrimination result is carried in the output, including two additional pieces of information: which area the altitude is in and the credibility of the altitude, which can greatly improve the stability and reliability of the output of the radar altimeter, thereby avoiding the output of incorrect information to the aircraft and causing incorrect actions of the aircraft, and improving safety.

[0066] In a specific embodiment of the present application, a computer-readable storage medium stores computer instructions, and the computer instructions are operated to execute the altitude calculation method for improving the stability of the blind area and the over-limit area described in any embodiment. Among them, the storage medium can be directly in the hardware, in a software module executed by a processor, or in a combination of both.

[0067] The software module can reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium.

[0068] The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general-purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration. In an alternative, the storage medium may be integral with the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in the user terminal as discrete components.

[0069] In a specific embodiment of the present application, a computer device includes a processor and a memory, and the memory stores computer instructions, wherein the processor operates the computer instructions to execute the height calculation method for improving the stability of the blind area and the overrun area described in any embodiment.

[0070] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections between each other may be through some interfaces, and the indirect couplings or communication connections of the devices or units may be in electrical, mechanical or other forms.

[0071] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0072] The above are only embodiments of the present application, and do not thereby limit the patent scope of the present application. Any equivalent structural transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present application.

Claims

1. A height calculation method for improving the stability in blind areas and over-limit areas, characterized in that, Including: Obtaining a beat frequency signal by using a chirp sequence waveform; Obtaining spectral data of the beat frequency signal, and performing constant false alarm detection according to the spectral data to obtain a set of height candidate values; And Making a decision on the set of height candidate values and outputting a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the credibility of the current height value.

2. The height calculation method for improving the stability of blind spots and overrun areas according to claim 1, characterized in that The making a decision on the set of height candidate values and outputting a final height discrimination result includes: According to the spectral data of the beat frequency signal in the current frame and the historical height value, through algorithm and logical judgment, determining the working area where the radar altimeter is located, and calculating the credibility of the current height value.

3. The height calculation method for improving the stability of blind areas and over-limit areas according to claim 2, characterized in that, The making a decision on the set of height candidate values and outputting a final height discrimination result further includes: If a spectral peak with a credibility greater than the credibility threshold is detected in the normal working area, the radar altimeter is located in the normal working area, and the height corresponding to the spectral peak is used as the current height value; If no spectral peak with a credibility greater than the credibility threshold is detected in the normal working area, the radar altimeter is not in the normal working area.

4. The height calculation method for improving the stability of blind areas and over-limit areas according to claim 3, characterized in that, The making a decision on the set of height candidate values and outputting a final height discrimination result further includes: When the radar altimeter is not in the normal working area, If there is a spectral peak with non-zero Doppler in the blind area, it is determined that the radar altimeter is located in the blind area, and the minimum range value of the radar altimeter is used as the current height value; If there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the threshold data obtained by pre-training.

5. The height calculation method for improving the stability of blind areas and over-limit areas according to claim 4, characterized in that, The if there is no spectral peak with non-zero Doppler in the blind area, threshold detection is performed on the blind area amplitude according to the threshold data obtained by pre-training, includes: If there is a spectral peak in the blind area with an amplitude greater than the threshold data obtained by pre-training, it is determined that the radar altimeter is located in the blind area, and the minimum range value of the radar altimeter is used as the current height value; If there is no spectral peak in the blind area with an amplitude greater than the threshold data obtained by pre-training, it is determined that the radar altimeter is located in the over-range area, and the maximum range value of the radar altimeter is used as the current height value.

6. The height calculation method for improving the stability of blind areas and over-limit areas according to claim 1, wherein Also including: When there is no surface with a sudden change in height in the working scenario, using tracking logic to determine whether the radar altimeter is located in the blind area or the over-range area through the historical height value.

7. The height calculation method for improving the stability of blind areas and over-limit areas according to claim 1, characterized in that The obtaining the spectral data of the beat frequency signal includes: Performing one-dimensional Fourier transform on each chirp of the digital signal of the beat frequency signal to obtain the range spectrum of each chirp; and Performing two-dimensional Fourier transform on each range bin of the range spectra of all the chirps in the current frame to obtain the range-velocity spectrum.

8. A height calculation system for improving the stability of blind areas and over-limit areas, characterized in that, Including: A radio frequency front-end module for obtaining a beat frequency signal by using a chirp sequence waveform; A signal processing module for obtaining the spectral data of the beat frequency signal, and performing constant false alarm detection according to the spectral data to obtain a set of height candidate values; A decision-making module makes a decision on the set of candidate height values and outputs a final height discrimination result, where the height discrimination result includes the working area where the radar altimeter is located, the current height value, and the confidence level of the current height value.

9. A computer-readable storage medium stores computer instructions, where the computer instructions are operated to execute the height calculation method for improving the stability of the blind area and the overrun area according to any one of claims 1-7.

10. A computer device includes a processor and a memory, the memory stores computer instructions, where the processor operates the computer instructions to execute the height calculation method for improving the stability of the blind area and the overrun area according to any one of claims 1-7.

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