TDM-MIMO (Time Division Multiplexing-Multiple Input Multiple Output) radar signal processing method based on improved sparse array and related equipment

Abstract

The invention relates to the technical field of radar three-dimensional imaging, in particular to a TDM-MIMO radar signal processing method based on an improved sparse array and related equipment. The TDM-MIMO radar signal processing method based on the improved sparse array comprises the following steps: acquiring first echo data of a moving target based on a first MIMO array; exchanging the positions of a transmitting channel and a receiving channel in the first MIMO array to obtain a second MIMO array, and determining an equivalent reference channel from the second MIMO array; determining a delay increase rate based on the equivalent reference channel; wherein the time delay increase rate represents the increase rate of the echo time delay generated by the moving target due to displacement in the process of switching the adjacent communication channels; and correcting the first echo data based on the delay increase rate.

Description

Technical Field

[0001] This application relates to the field of radar three-dimensional imaging technology, and in particular to a TDM-MIMO radar signal processing method and related equipment based on an improved sparse array. Background Technology

[0002] When using through-wall radar to detect targets through walls, multiple-input multiple-output (MIMO) technology is usually used. MIMO technology increases the azimuth resolution by increasing the array aperture. In order to ensure channel consistency while reducing system complexity, time-division multiplexing (TDM) is often used in engineering to implement MIMO radar. That is, the transmit and receive channels are activated alternately by switching microwave switches to form a TDM-MIMO radar system.

[0003] However, microwave switches introduce time delays during switching. During the single-frame echo acquisition time, the continuous movement of the imaging target will cause its echo signal to shift in the distance direction, resulting in sidelobe elevation and target position deviation in the imaging of moving targets, i.e., "distance migration", which makes it impossible to achieve accurate imaging results. Summary of the Invention

[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a TDM-MIMO radar signal processing method based on an improved sparse array, which can effectively solve the problems of high sidelobes and positional offsets that occur when TDM-MIMO radar performs three-dimensional imaging of moving targets.

[0005] In a first aspect, embodiments of this application provide a TDM-MIMO radar signal processing method based on an improved sparse array, comprising: acquiring first echo data of a moving target based on a first MIMO array; swapping the positions of the transmit and receive channels in the first MIMO array to obtain a second MIMO array, and determining an equivalent reference channel from the second MIMO array; determining a delay increase rate based on the equivalent reference channel; wherein the delay increase rate characterizes the rate of increase of the echo delay caused by the displacement of the moving target during the switching of adjacent communication channels; and correcting the first echo data based on the delay increase rate.

[0006] In some embodiments, the method further includes: acquiring multiple transmit channels and receive channels of the target MIMO radar; arranging the multiple transmit channels equidistantly on the circumference of a first circular trajectory to obtain a first MIMO transmit array; dividing the multiple receive channels into two parts to obtain a first receive channel set and a second receive channel set; arranging each receive channel in the first receive channel set equidistantly on the circumference of a second circular trajectory to obtain a first MIMO receive array; arranging each receive channel in the second receive channel set equidistantly on the circumference of a third circular trajectory to obtain a second MIMO receive array; and combining the first MIMO transmit array, the first MIMO receive array, and the second MIMO receive array to obtain a first MIMO array; wherein the first circular trajectory, the second circular trajectory, and the third circular trajectory are concentric circles, the radius of the first circular trajectory is greater than the radius of the second circular trajectory, and the radius of the second circular trajectory is greater than the radius of the third circular trajectory.

[0007] In some embodiments, acquiring first echo data of a moving target based on a first MIMO array includes: determining the channel echo delay of the moving target in each communication channel of the first MIMO array within a unit frame data acquisition time; determining the migration echo delay of the moving target due to displacement during the switching of communication channels via a microwave switch within a unit frame data acquisition time; determining the target echo delay of the moving target based on the channel echo delay and the migration echo delay; and determining the first echo data based on the target echo delay.

[0008] In some embodiments, swapping the positions of the transmit channels and receive channels in the first MIMO array to obtain a second MIMO array includes: selecting two adjacent transmit channels from the first MIMO transmit array as a first switching channel and a second switching channel, respectively; swapping the positions of the first switching channel and the receive channel on the first MIMO receive array that is closest to the first switching channel; and swapping the positions of the second switching channel and the receive channel on the first MIMO receive array that is closest to the second switching channel, to obtain the second MIMO array.

[0009] In some embodiments, determining an equivalent reference channel from a second MIMO array includes: obtaining an equivalent array of the second MIMO array; determining equivalent array elements that overlap in position in the equivalent array, and using the equivalent array elements as equivalent reference channels.

[0010] In some embodiments, the equivalent reference channel includes multiple equivalent reference channels; determining the delay increase rate based on the equivalent reference channel includes: for two adjacent equivalent reference channels, determining the time difference between two echo data obtained based on the two adjacent equivalent reference channels; and determining the delay increase rate of all communication channels between the two adjacent equivalent reference channels based on the time difference and the number of channels between the two adjacent equivalent reference channels.

[0011] In some embodiments, correcting the first echo data based on the delay increase rate includes: characterizing the migrating echo delay by the channel echo delay of the equivalent reference channel and the delay increase rate to correct the first echo data.

[0012] Secondly, embodiments of this application provide a TDM-MIMO radar signal processing device based on an improved sparse array, comprising: an acquisition module configured to acquire first echo data of a moving target based on a first MIMO array; an optimization module configured to swap the positions of the transmit and receive channels in the first MIMO array to obtain a second MIMO array, and determine an equivalent reference channel from the second MIMO array; a calculation module configured to determine a delay increase rate based on the equivalent reference channel; wherein the delay increase rate characterizes the increase rate of echo delay caused by displacement of the moving target during the switching of adjacent communication channels; and a correction module configured to correct the first echo data based on the delay increase rate.

[0013] Thirdly, embodiments of this application provide an electronic device, including: a processor and a memory, wherein the memory stores a program or instructions that can run on the processor, and when the program or instructions are executed by the processor, they implement the steps of the TDM-MIMO radar signal processing method based on the improved sparse array of the first aspect.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium, including: storing a program or instructions on the readable storage medium, wherein when the program or instructions are executed by a processor, they implement the steps of the TDM-MIMO radar signal processing method based on the improved sparse array of the first aspect.

[0015] The technical solution provided in this application, by swapping the transmit and receive channels of the MIMO array, further obtains the equivalent reference channel for wall penetration, and determines the delay increase rate based on the equivalent reference channel, thereby further compensating for the range migration of TDM-MIMO radar and repairing the echo data. This can effectively avoid the problems of high sidelobes and position shifts in TDM-MIMO through-wall radar imaging.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 A flowchart for setting up the first MIMO array provided in an embodiment of this application; Figure 2 A schematic diagram of a first MIMO array provided in an embodiment of this application; Figure 3 A schematic diagram of an equivalent array of a first MIMO array provided in an embodiment of this application; Figure 4 A flowchart of a TDM-MIMO radar signal processing method based on an improved sparse array provided in the embodiments of this application; Figure 5 This application provides a 3D imaging scene diagram of a moving target using MIMO through-wall radar; Figure 6 A flowchart for obtaining first echo data of a moving target based on a first MIMO array, provided in an embodiment of this application; Figure 7 This is a schematic diagram of a second MIMO array according to an embodiment of this application; Figure 8 This is a schematic diagram of an equivalent array of a second MIMO array according to an embodiment of this application; Figure 9 A schematic diagram showing the results of three-dimensional imaging through the wall before and after motion compensation, azimuth-range two-dimensional projection, and azimuth-height two-dimensional projection before and after motion compensation, provided in an embodiment of this application. Figure 10 A schematic diagram of a TDM-MIMO radar signal processing device based on an improved sparse array provided in an embodiment of this application; Figure 11 This is a schematic diagram of a more specific electronic device hardware structure provided for an embodiment of this application.

[0018] Reference numerals: 1010 - Acquisition module; 1020 - Optimization module; 1030 - Calculation module; 1040 - Correction module; 1110 - Processor; 1120 - Memory; 1130 - Input / output interface; 1140 - Communication interface; 1150 - Bus. Detailed Implementation

[0019] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0020] It should be understood that the steps described in the method embodiments of this application may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this application is not limited in this respect.

[0021] As described in the background section, MIMO (Multi-Input Multiple-Output) through-wall radar is a key technology in through-wall detection. MIMO radar can form a virtual array through multiple transmit and receive channel units, significantly improving the system's angular resolution and target recognition performance. To maintain channel consistency and system performance while reducing system complexity and cost, TDM (Transmit-Device Modeling) is often used in engineering to construct MIMO radar systems. This involves using microwave switches to cyclically switch a few physical channels to operate in a time-division multiplexing manner, simulating the effect of multi-channel transmission and reception. However, the switching delay introduced by TDM causes the echo acquisition to be discontinuous in time. When TDM-MIMO radar images moving targets, the target's position changes within a single frame of data acquisition, leading to high sidelobes and positional shifts in the echo signal, i.e., "range migration," which severely affects imaging accuracy and detection reliability.

[0022] To address the aforementioned issues, this application proposes a TDM-MIMO radar signal processing method based on an improved sparse array. The following description of the TDM-MIMO radar signal processing method based on an improved sparse array, with reference to the accompanying drawings, illustrates an embodiment of this application.

[0023] refer to Figure 1 This is a flowchart of a method for setting up a first MIMO array provided in an embodiment of this application.

[0024] Step S101: Obtain multiple transmit channels and receive channels of the target MIMO radar; Step S102: Arrange multiple transmission channels at equal intervals on the circumference of the first circular trajectory to obtain the first MIMO transmission array; Step S103: Divide the multiple receiving channels into two parts to obtain a first receiving channel set and a second receiving channel set. Arrange each receiving channel in the first receiving channel set at equal intervals on the circumference of the second circular track to obtain a first MIMO receiving array. Arrange each receiving channel in the second receiving channel set at equal intervals on the circumference of the third circular track to obtain a second MIMO receiving array. Step S104: Combine the first MIMO transmit array, the first MIMO receive array, and the second MIMO receive array to obtain the first MIMO array; wherein the first circular trajectory, the second circular trajectory, and the third circular trajectory are concentric circles, the radius of the first circular trajectory is greater than the radius of the second circular trajectory, and the radius of the second circular trajectory is greater than the radius of the third circular trajectory.

[0025] Specifically, this application takes 4 transmit channels and 8 receive channels as an example, with 32 data channels. Since the imaging resolution of MIMO radar depends on the size of the virtual aperture, which is determined by the distribution of the positions of all transmit and receive channels in pairs, the MIMO array is designed using a concentric circle rotating array optimization method, which can obtain a large and sparse virtual aperture, thereby improving the radar's azimuth and elevation resolution.

[0026] Four transmit channels are equidistantly arranged on the circumference of a first circular trajectory to obtain a first MIMO transmit array. Further, eight receive channels are divided into two groups, namely a first receive channel set and a second receive channel set. Further, the first receive channel set is equidistantly arranged on the circumference of a second circular trajectory to obtain a first MIMO receive array. The second receive channel set is equidistantly arranged on the circumference of a third circular trajectory to obtain a second MIMO receive array.

[0027] Combining the first MIMO transmit array, the first MIMO receive array, and the second MIMO receive array yields the following: Figure 2 The first MIMO array is shown. The first, second, and third circular trajectories are concentric circles, with the radius of the first circular trajectory being larger than that of the second, and the radius of the second circular trajectory being larger than that of the third. In this case, the projections of the concentric circles are consistent in all electromagnetic wave propagation and signal processing azimuth directions. This is achieved by rotating the first and second MIMO receiving arrays as shown. Figure 3 The equivalent array of the first MIMO array shown enables the projection redundancy of the first MIMO array to be minimized in each dimension. At this time, the equivalent array of the first MIMO array has the longest effective aperture and the most uniform element distribution in all azimuth angles, which enables imaging to have high resolution and low sidelobes in all dimensions.

[0028] refer to Figure 4 The flowchart below shows a TDM-MIMO radar signal processing method based on an improved sparse array provided in an embodiment of this application.

[0029] Step S401: Acquire the first echo data of the moving target based on the first MIMO array.

[0030] Specifically, Figure 5 This application provides a 3D imaging scene diagram of a moving target using a MIMO through-wall radar. If the radar includes M transmit channels and N receive channels, then the radar has a total of M×N channel data, where T1 represents the first transmit channel, R1 represents the first receive channel, and T... M R represents the Mth transmission channel. N This represents the Nth receiving channel, for example... Figure 5 It includes 4 transmit channels and 8 receive channels, giving the radar a total of 32 data channels.

[0031] refer to Figure 6 This is a flowchart of obtaining first echo data of a moving target based on a first MIMO array, provided in an embodiment of this application.

[0032] Step S601: Determine the channel echo delay of the moving target in each communication channel of the first MIMO array within the unit frame data acquisition time.

[0033] Specifically, when the radar detects a moving target, the unit frame data contains data from the aforementioned M×N channels. During the acquisition time, it is necessary to obtain the channel echo delay of the M×N communication channels in the first MIMO array. Since the electromagnetic wave is emitted from any transmitting channel to the moving target and returns to any receiving channel, there is a certain physical length in the two-way propagation path. The propagation of the electromagnetic wave in the propagation path takes a certain amount of time, which is the channel echo delay.

[0034] Step S602: Determine the migration echo delay caused by the displacement of the moving target during the switching of the communication channel via microwave switch within the unit frame data acquisition time.

[0035] Specifically, the radar's transmit and receive channels share resources through time-division multiplexing (TDM), and the alternating operation of the channels is controlled by a microwave switch. This switching generates a migration echo delay. When the radar detects a moving target, the target's position changes within a unit frame of data acquisition time, moving from P1 to P... M×N At this time, the unit frame data collected by the radar is not a snapshot of the same moment, but a mixture of a series of "continuous images" left by the target along its movement trajectory.

[0036] Step S603: Determine the target echo delay of the moving target based on the channel echo delay and the migration echo delay.

[0037] Specifically, for any one of the M×N channel data... ,aisle The formula for calculating the target echo delay is:

[0038] in, For channel Target echo delay, For channel The measured echo delay of the moving target at the starting position P1 is... To switch from the previous channel to the current channel The resulting migration echo delay.

[0039] Step S604: Determine the first echo data based on the target echo delay.

[0040] Specifically, when detecting a moving target, the first echo data of the moving target can be represented as:

[0041] in, The first echo data for the moving target; This is the data from the launch.

[0042] Step S402: Swap the positions of the transmit channel and the receive channel in the first MIMO array to obtain the second MIMO array, and determine the equivalent reference channel from the second MIMO array.

[0043] Specifically, in order to obtain an equivalent reference channel that can be used for motion compensation, this application swaps the positions of the transmit and receive channels in the first MIMO array to obtain a second MIMO array, and determines an equivalent reference channel from the second MIMO array. The equivalent reference channel is a specific pair of transmit and receive channels, the phase center of which is fixed in space, and the target echo signal of the equivalent reference channel can be a benchmark for measuring the target echo signals of other channels.

[0044] As an optional embodiment, the positions of the transmit channels and receive channels in the first MIMO array are interchanged to obtain the second MIMO array, including: selecting two adjacent transmit channels from the first MIMO transmit array as the first switching channel and the second switching channel, respectively; interchange the positions of the first switching channel and the receive channel on the first MIMO receive array that is closest to the first switching channel; and interchange the positions of the second switching channel and the receive channel on the first MIMO receive array that is closest to the second switching channel, to obtain the second MIMO array.

[0045] Specifically, two adjacent transmit channels, such as transmit channel 1 and transmit channel 2, are selected from the first MIMO transmit array as the first switching channel and the second switching channel. Further, the positions of the first switching channel and the second switching channel are swapped with their nearest adjacent receive channel on the first MIMO receive array, such as swapping transmit channel 1 with receive channel 3 and transmit channel 2 with receive channel 4, resulting in the following... Figure 7 The second MIMO array is shown.

[0046] As an optional embodiment, determining the equivalent reference channel from the second MIMO array includes: obtaining the equivalent array of the second MIMO array; determining the equivalent array elements that coincide in position in the equivalent array, and using the equivalent array elements as the equivalent reference channel.

[0047] Specifically, with Figure 7 Taking the provided second MIMO array as an example, the second MIMO array is rotated concentrically, and data is collected at each rotation angle to obtain the equivalent array of the second MIMO array, as shown below. Figure 8 As shown, at this point, we can obtain that channels 1, 10, 19 and 28 are overlapping equivalent array elements. Furthermore, the overlapping equivalent array elements are used as equivalent reference channels. At this point, the physical positions of multiple channels included in the equivalent reference channels are absolutely stationary in the global coordinate system, and the time delay of the remaining channels can be further determined based on the time delay of the equivalent reference channels.

[0048] It should be noted that the equivalent array of the second MIMO array has basically the same resolution as the equivalent array of the first MIMO array, but the sidelobes are improved. The improvement in sidelobes is less than -14dB, so it will not affect the quality of subsequent through-wall imaging.

[0049] Step S403: Determine the delay increase rate based on the equivalent reference channel; wherein, the delay increase rate characterizes the increase rate of echo delay caused by displacement of the moving target during the switching of adjacent communication channels.

[0050] Specifically, the echo delay variation observed by the equivalent reference channel is caused solely by the target's motion. Therefore, the delay increase rate can be determined based on the equivalent reference channel. The delay increase rate is the rate at which the echo delay caused by the moving target's displacement increases during the time interval between switching adjacent communication channels. By determining the delay increase rate based on the equivalent reference channel, the complex motion estimation problem coupled with the array geometry can be transformed into a simple problem of measuring the delay variation of a single fixed channel.

[0051] As an optional embodiment, determining the delay increase rate based on the equivalent reference channel includes: for two adjacent equivalent reference channels, determining the time difference between two echo data obtained based on the two adjacent equivalent reference channels; and determining the delay increase rate of all communication channels between the two adjacent equivalent reference channels based on the time difference and the number of channels between the two adjacent equivalent reference channels.

[0052] Specifically, refer to Figure 8 The equivalent array of the second MIMO array has channels 1, 10, 19 and 28 as overlapping equivalent reference channels. In the interval between channels 1 and 10, since channels 1 and 10 are overlapping, the time delay difference between them is only caused by the time difference between two adjacent echo data of the moving target, and is not affected by the change of channel position.

[0053] The time difference between the echo data from channels 1 to 10 It can be obtained by convolution, and the calculation formula is:

[0054] Similarly, the time difference between channel 10 and channel 19 can be calculated. Time difference between channel 19 and channel 28 Time difference between channel 28 and channel 32 They are respectively:

[0055] It should be noted that since channel 28 is the last coincidence point in the current frame, and channel 32 is the last channel in the current frame, but channel 32 is not a coincidence point, the next coincidence point is needed as a reference endpoint to calculate the time delay change between channels 28 and 32. Due to the periodicity of the system, the first channel 33 in the next frame is functionally equivalent to channel 1, and channel 33 is also a coincidence point, meaning that channel 33 and channel 1 have the same physical configuration and virtual phase center. Therefore, it is necessary to introduce the time difference between channel 33 and channels 28 and 32 in the next frame. Perform the calculation.

[0056] Furthermore, based on the time difference and the number of channels between two adjacent equivalent reference channels, the delay increase rate of all communication channels between two adjacent equivalent reference channels is determined. Specifically, there are 9 channels between channels 1 to 10, 9 channels between channels 10 to 19, 9 channels between channels 19 to 28, and 5 channels between channels 28 to 33. Therefore, the delay increase rate of all communication channels between channels 1 to 10 is calculated separately. for:

[0057] Similarly, the rate of increase in latency for all communication channels between channel 10 and channel 19 can be obtained. The rate of increase in latency for all communication channels between channel 19 and channel 28 The rate of increase in latency for all communication channels between channel 28 and channel 33 They are respectively:

[0058] Step S404: Correct the first echo data based on the delay increase rate.

[0059] Specifically, the delay increase rate can be used to compensate for the delay of the first echo data measured by each channel, and the compensated first echo data can be used for through-wall imaging, so that the imaging position shift of the moving target is eliminated and the imaging accuracy is greatly improved.

[0060] As an optional embodiment, the first echo data is corrected based on the delay increase rate, including: characterizing the migrating echo delay by the channel echo delay of the equivalent reference channel and the delay increase rate to correct the first echo data.

[0061] Specifically, the migration echo delay is characterized by the channel echo delay of the equivalent reference channel and the rate of delay increase, and the moving target echo delay measured in any channel of a unit frame of data is... Specifically, it can be expressed as:

[0062] in, Indicates the target echo delay for channel 1, others Similarly, channels The target echo delay.

[0063] Furthermore, depending on the channel, the compensated first echo data can be expressed as:

[0064] in, Indicates channel The first echo data after compensation; , and These are the time delay differences between overlapping channels 10, 19, and 28 and channel 1, respectively, which can be obtained using the convolution formula; n1, n2, n3, and n4 are... For example, if the first echo data of channel 3 is calculated at this time, then at this time... Substituting the data into the piecewise function of the first echo data, we can obtain the first echo data of channel 3; This represents a displacement function that can shift the original signal according to the corresponding time delay. Specifically, it can be expanded as follows:

[0065] refer to Figure 9 The schematic diagrams provided in this application show the results of three-dimensional through-wall imaging, azimuth-range two-dimensional projection, and azimuth-elevation two-dimensional projection before and after motion compensation in the embodiments of this application. It can be seen that the side lobes of the moving target are high before compensation, and the imaging position of the moving target is significantly shifted. After compensation, the side lobes of the moving target are suppressed, and the imaging position is corrected.

[0066] According to the TDM-MIMO radar signal processing method based on the improved sparse array provided in this application, by swapping the transmit and receive channels of the MIMO array, an equivalent reference channel for through-wall imaging is further obtained, and the delay increase rate is determined based on the equivalent reference channel. This further compensates for the range migration of the TDM-MIMO radar and repairs the echo data, effectively avoiding the problems of high sidelobes and position shifts in TDM-MIMO through-wall radar imaging.

[0067] refer to Figure 10 This is a schematic diagram of a TDM-MIMO radar signal processing device based on an improved sparse array provided in an embodiment of this application.

[0068] Based on the same concept, corresponding to the TDM-MIMO radar signal processing method based on improved sparse array provided in any of the above embodiments, this application also provides a TDM-MIMO radar signal processing device based on improved sparse array.

[0069] The TDM-MIMO radar signal processing device based on the improved sparse array includes: an acquisition module 1010, an optimization module 1020, a calculation module 1030, and a correction module 1040.

[0070] The acquisition module 1010 is configured to acquire first echo data of a moving target based on a first MIMO array; the optimization module 1020 is configured to swap the positions of the transmit and receive channels in the first MIMO array to obtain a second MIMO array, and determine an equivalent reference channel from the second MIMO array; the calculation module 1030 is configured to determine the delay increase rate based on the equivalent reference channel; wherein, the delay increase rate characterizes the increase rate of echo delay caused by displacement of the moving target during the switching of adjacent communication channels; the correction module 1040 is configured to correct the first echo data based on the delay increase rate.

[0071] In some embodiments, the acquisition module 1010 is further configured to: acquire multiple transmit channels and receive channels of the target MIMO radar; arrange the multiple transmit channels equidistantly on the circumference of a first circular trajectory to obtain a first MIMO transmit array; divide the multiple receive channels into two parts to obtain a first receive channel set and a second receive channel set; arrange each receive channel in the first receive channel set equidistantly on the circumference of a second circular trajectory to obtain a first MIMO receive array; arrange each receive channel in the second receive channel set equidistantly on the circumference of a third circular trajectory to obtain a second MIMO receive array; combine the first MIMO transmit array, the first MIMO receive array, and the second MIMO receive array to obtain a first MIMO array; wherein the first circular trajectory, the second circular trajectory, and the third circular trajectory are concentric circles, the radius of the first circular trajectory is greater than the radius of the second circular trajectory, and the radius of the second circular trajectory is greater than the radius of the third circular trajectory.

[0072] In some embodiments, the acquisition module 1010 is further configured to: determine the channel echo delay of the moving target in each communication channel of the first MIMO array within a unit frame data acquisition time; determine the migration echo delay of the moving target due to displacement during the switching of communication channels by a microwave switch within a unit frame data acquisition time; determine the target echo delay of the moving target based on the channel callback delay and the migration echo delay; and determine the first echo data based on the target echo delay.

[0073] In some embodiments, the optimization module 1020 is further configured to: select two adjacent transmission channels from the first MIMO transmit array as a first switching channel and a second switching channel, respectively; swap the positions of the first switching channel and the receiving channel on the first MIMO receive array that is closest to the first switching channel; and swap the positions of the second switching channel and the receiving channel on the first MIMO receive array that is closest to the second switching channel, to obtain a second MIMO array.

[0074] In some embodiments, the optimization module 1020 is further configured to: obtain the equivalent array of the second MIMO array; determine the equivalent array elements that coincide in position in the equivalent array, and use the equivalent array elements as equivalent reference channels.

[0075] In some embodiments, the equivalent reference channels include multiple channels; the calculation module 1030 is further configured to: for two adjacent equivalent reference channels, determine the time difference between two echo data obtained based on the two adjacent equivalent reference channels; and determine the delay increase rate of all communication channels between the two adjacent equivalent reference channels based on the time difference and the number of channels between the two adjacent equivalent reference channels.

[0076] In some embodiments, the correction module 1040 is further configured to: characterize the migrating echo delay by the channel echo delay of the equivalent reference channel and the delay increase rate, so as to correct the first echo data.

[0077] According to the TDM-MIMO radar signal processing device based on the improved sparse array provided in this application, by swapping the transmit and receive channels of the MIMO array, an equivalent reference channel for through-wall imaging is further obtained, and the delay increase rate is determined based on the equivalent reference channel, thereby further compensating for the range migration of the TDM-MIMO radar and repairing the echo data. This can effectively avoid the problems of high sidelobes and position shifts in TDM-MIMO through-wall radar imaging.

[0078] Based on the same concept, corresponding to the TDM-MIMO radar signal processing method based on improved sparse array provided in any of the above embodiments, this application also provides an electronic device, including a processor and a memory, wherein the memory stores a program or instructions that can run on the processor, and when the program or instructions are executed by the processor, the steps of the TDM-MIMO radar signal processing method based on improved sparse array as in the first aspect are implemented.

[0079] Figure 11 This illustration shows a more specific hardware structure diagram of an electronic device according to an embodiment of this application. The device may include: a processor 1110, a memory 1120, an input / output interface 1130, a communication interface 1140, and a bus 1150. The processor 1110, memory 1120, input / output interface 1130, and communication interface 1140 are interconnected internally via the bus 1150.

[0080] The processor 1110 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0081] The memory 1120 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1120 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1120 and is called and executed by the processor 1110.

[0082] Input / output interface 1130 is used to connect input / output modules to realize information input and output. Input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touch screens, microphones, various sensors, etc., and output devices may include displays, speakers, vibrators, indicator lights, etc.

[0083] The communication interface 1140 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0084] Bus 1150 includes a pathway for transmitting information between various components of the device, such as processor 1110, memory 1120, input / output interface 1130, and communication interface 1140.

[0085] It should be noted that although the above-described device only shows the processor 1110, memory 1120, input / output interface 1130, communication interface 1140, and bus 1150, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0086] The electronic devices described above are used to implement the corresponding TDM-MIMO radar signal processing method based on the improved sparse array in any of the foregoing embodiments, and have the beneficial effects of the corresponding TDM-MIMO radar signal processing method embodiments based on the improved sparse array, which will not be repeated here.

[0087] Based on the same concept, corresponding to the TDM-MIMO radar signal processing method based on improved sparse array provided in any of the above embodiments, this application also provides a computer-readable storage medium storing a program or instructions, which, when executed by a processor, implement the steps of the TDM-MIMO radar signal processing method based on improved sparse array as described in the first aspect.

[0088] The aforementioned computer-readable storage medium can be any available medium or data storage device that a computer can access, including but not limited to magnetic storage (e.g., floppy disks, hard disks, magnetic tapes, magneto-optical disks (MOs), etc.), optical storage (e.g., CDs, DVDs, BDs, HVDs, etc.), and semiconductor storage (e.g., ROMs, EPROMs, EEPROMs, non-volatile memory (NAND flash), solid-state drives (SSDs)).

[0089] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the corresponding TDM-MIMO radar signal processing method based on the improved sparse array in any of the foregoing embodiments, and have the beneficial effects of the corresponding TDM-MIMO radar signal processing method embodiments based on the improved sparse array, which will not be repeated here.

[0090] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0091] From the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of computer software products plus necessary general-purpose hardware platforms, and of course, they can also be implemented by hardware. The computer software product is stored in a storage medium (such as ROM, RAM, magnetic disk, optical disk, etc.) and includes several instructions to cause the terminal or network-side device to execute the methods described in the various embodiments of this application.

[0092] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other implementations under the guidance of this application without departing from the spirit and scope of the claims. All of these implementations are within the protection scope of this application.

Claims

1. A TDM-MIMO radar signal processing method based on an improved sparse array, characterized in that, include: Acquire first echo data of a moving target based on the first MIMO array; The positions of the transmit and receive channels in the first MIMO array are swapped to obtain the second MIMO array, and the equivalent reference channel is determined from the second MIMO array. The delay increase rate is determined based on the equivalent reference channel; wherein, the delay increase rate characterizes the rate of increase in echo delay caused by displacement of the moving target during the switching of adjacent communication channels; The first echo data is corrected based on the aforementioned delay increase rate.

2. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 1, characterized in that, The method further includes: Acquire multiple transmit and receive channels of the target MIMO radar; The multiple transmission channels are arranged equidistantly on the circumference of the first circular trajectory to obtain the first MIMO transmission array; The plurality of receiving channels are divided into two parts to obtain a first receiving channel set and a second receiving channel set. Each receiving channel in the first receiving channel set is placed at equal intervals on the circumference of the second circular trajectory to obtain a first MIMO receiving array. Each receiving channel in the second receiving channel set is placed at equal intervals on the circumference of the third circular trajectory to obtain a second MIMO receiving array. The first MIMO transmit array, the first MIMO receive array, and the second MIMO receive array are combined to obtain the first MIMO array; wherein the first circular trajectory, the second circular trajectory, and the third circular trajectory are concentric circles, the radius of the first circular trajectory is greater than the radius of the second circular trajectory, and the radius of the second circular trajectory is greater than the radius of the third circular trajectory.

3. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 2, characterized in that, The acquisition of the first echo data of the moving target based on the first MIMO array includes: Determine the channel echo delay of the moving target in each communication channel of the first MIMO array within a unit frame data acquisition time; Determine the migration echo delay of the moving target due to displacement during the switching of the communication channel via a microwave switch within a unit frame data acquisition time; The target echo delay of the moving target is determined based on the channel echo delay and the migration echo delay. The first echo data is determined based on the target echo delay.

4. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 3, characterized in that, The step of swapping the positions of the transmit and receive channels in the first MIMO array to obtain the second MIMO array includes: Two adjacent transmission channels are selected from the first MIMO transmitter array and used as the first switching channel and the second switching channel, respectively. The positions of the first switching channel and the receiving channel on the first MIMO receiving array that is closest to the first switching channel are swapped, and the positions of the second switching channel and the receiving channel on the first MIMO receiving array that is closest to the second switching channel are swapped, to obtain the second MIMO array.

5. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 4, characterized in that, Determining the equivalent reference channel from the second MIMO array includes: Obtain the equivalent array of the second MIMO array; Identify the equivalent array elements that coincide in position in the equivalent array, and use the equivalent array elements as the equivalent reference channels.

6. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 5, characterized in that, The equivalent reference channel includes multiple channels; The determination of the delay increase rate based on the equivalent reference channel includes: For two adjacent equivalent reference channels, determine the time difference between two echo data obtained based on the two adjacent equivalent reference channels; The delay increase rate of all communication channels between the two adjacent equivalent reference channels is determined based on the time difference and the number of channels between the two adjacent equivalent reference channels.

7. The TDM-MIMO radar signal processing method based on an improved sparse array according to claim 6, characterized in that, The correction of the first echo data based on the delay increase rate includes: The migrating echo delay is characterized by the channel echo delay of the equivalent reference channel and the rate of increase of the delay, in order to correct the first echo data.

8. A TDM-MIMO radar signal processing device based on an improved sparse array, characterized in that, include: The acquisition module is configured to acquire first echo data of a moving target based on a first MIMO array; The optimization module is configured to swap the positions of the transmit and receive channels in the first MIMO array to obtain a second MIMO array, and determine an equivalent reference channel from the second MIMO array; The calculation module is configured to determine the delay increase rate based on the equivalent reference channel; wherein the delay increase rate characterizes the increase rate of echo delay caused by displacement of the moving target during the switching of adjacent communication channels; The correction module is configured to correct the first echo data based on the delay increase rate.

9. An electronic device, characterized in that, include: A processor and a memory, the memory storing a program or instructions executable on the processor, the program or instructions, when executed by the processor, implementing the steps of the TDM-MIMO radar signal processing method based on an improved sparse array as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the TDM-MIMO radar signal processing method based on an improved sparse array as described in any one of claims 1 to 7.

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