阅读说明：本技术 一种生成正交波形的方法及雷达系统 (Method for generating orthogonal waveform and radar system ) 是由 练小庆 于 2020-12-25 设计创作，主要内容包括：本发明实施例公开了一种生成正交波形的方法及雷达系统,涉及MIMO雷达技术领域,码长长度不受限制而且易于产生。本发明包括：控制台(1)根据所需码长l产生16组正交波形基带数据并发送至FPGA(2),并存储在FPGA(2)上；FPGA(2)用16组正交波形基带数据对数字载波信号进行调制,得到数字调制信号；将所得到的数字调制信号,分别发送至16组D/A转换器(3),每个D/A转换器(3)将接收到的数字调制信号转换成模拟调制信号；16组模拟调制信号再经各自的变频处理模块(4)处理后,得到对应的射频信号,并将所得到的射频信号输入滤波放大器(5)进行滤波放大,之后各个滤波放大器(5)通过各自所连接的天线(6)发射。本发明适用于MIMO雷达。(The embodiment of the invention discloses a method for generating orthogonal waveforms and a radar system, which relate to the technical field of MIMO radar, and have the advantages of unlimited code length and easiness in generation. The invention comprises the following steps: the console (1) generates 16 groups of orthogonal waveform baseband data according to the required code length l, sends the orthogonal waveform baseband data to the FPGA (2) and stores the orthogonal waveform baseband data on the FPGA (2); the FPGA (2) modulates the digital carrier signal by 16 groups of orthogonal waveform baseband data to obtain a digital modulation signal; sending the obtained digital modulation signals to 16 sets of D/A converters (3), wherein each D/A converter (3) converts the received digital modulation signals into analog modulation signals; the 16 groups of analog modulation signals are processed by respective frequency conversion processing modules (4) to obtain corresponding radio frequency signals, the obtained radio frequency signals are input into a filter amplifier (5) for filtering and amplification, and then the filter amplifiers (5) transmit through respective connected antennas (6). The invention is suitable for MIMO radar.)

1. A method of generating orthogonal waveforms, comprising:

s1, the console (1) generates 16 groups of orthogonal waveform baseband data according to the required code length l;

s2, sending the generated orthogonal waveform baseband data to the FPGA (2) and storing the orthogonal waveform baseband data on the FPGA (2);

s3, the console (1) sends a trigger signal to the FPGA (2), the FPGA (2) starts to work, and the FPGA (2) modulates a digital carrier signal by adopting 16 groups of orthogonal waveform baseband data to obtain a digital modulation signal;

s4, sending the obtained digital modulation signals to 16 sets of D/A converters (3), wherein each D/A converter (3) converts the received digital modulation signal into an analog modulation signal, and each orthogonal waveform baseband data corresponds to one analog modulation signal;

and S5 and 16 groups of analog modulation signals are processed by respective frequency conversion processing modules (4) to obtain corresponding radio frequency signals, the obtained radio frequency signals are input into filter amplifiers (5) for filtering and amplification, and then the filter amplifiers (5) transmit through antennas (6) connected with the filter amplifiers respectively.

2. The method according to claim 1, wherein step S1 includes:

s11, for MAC sequence with code length l, confirming a prime number p, wherein p is nearest to code length

S12, calculating the value of p, extracting the required prime number p value from the calculated value, and obtaining the orthogonal waveform data according to the required prime number p value, wherein, if (x)²)_pIf i has a solution, the integer i is the quadratic residue of modulo p, p is 4t-1, and t is a positive integer.

3. The method according to claim 2, wherein step S12 includes:

s121, calculatingA value of (d);

s122, detecting whether the value i is 1, 2, …, p appears in the calculation result of S121, and if so, making a_i-11, otherwise a_i-11, and obtaining a core sequence L ═ { a ═ a₀，a₁，…，a_p-1}；

S123. starting from the core sequence L ═ { a ═ a₀，a₁，…，a_p-1Truncating the last u elements, and truncating the kernel sequence L ═ a₀，a₁，…，a_p-1V elements at the front end, and then writing the u elements and v elements intercepted into the front end and the tail end of the core respectively to obtain a MAC sequence with the length of l ═ p + u + v: and a_p-u，a_p-u-1…a_p-1，a₀，a₁，…，a_p-1，a₀，a₁，…，a_vDenotes that the adjacent p is reselected andand then u ', v', u ', v' are simultaneously selected to represent the new number of elements, and the above steps S121-123 are repeated until 16 sets of signals are reached.

4. The method of claim 1, wherein the code length l is greater than or equal to 1000.

5. The method of claim 4, wherein the code length l is 3000.

6. The method according to any one of claims 1-5, wherein the method is used in a radar system comprising: the console (1) is connected with the FPGA (2) through optical fibers, and the FPGA (2) is connected with 16 groups of radio frequency components.

7. The method of claim 6, wherein each set of radio frequency components comprises: the device comprises a D/A converter (3) and a frequency conversion processing module (4) connected with the D/A converter (3), wherein the frequency conversion processing module (4) is connected with a filter amplifier (5), and the filter amplifier (5) is connected with an antenna (6).

Technical Field

The invention relates to the technical field of MIMO radar, in particular to a method for generating orthogonal waveforms and a radar system.

Background

In order to avoid mutual interference among channels of the MIMO radar and obtain high resolution for multi-target detection, the waveform design is very important. Among them, especially the cross-correlated orthogonal waveform with low autocorrelation side lobe peak is important for MIMO radar.

For MIMO radars, generating multiple sets of orthogonal waveforms is commonTwo-phase coding sequence is used, and commonly used two-phase coding sequence comprises Barker code and M sequence. Barker codes have large time-bandwidth products and good autocorrelation performance, but the best two-phase codes are only found out 7 types at present, the longest one is 13 bits, and the ratio of main side lobes after pulse compression is lower; the M sequence has better autocorrelation, the code length is not limited, more code sequences can be provided, but the code length can only be 2^n-1-1。

When the MIMO radar needs to generate long code data, the pulse width time is 100 us-3 ms, the time precision is 0.1us, namely the phase coding length is 1000-30000. The common two-phase coding sequence Barker code is adopted, the longest code is 13 bits, and the length is insufficient. The length of M sequence code can only be 2^n-11, e.g. M sequences can only produce 2^n-11, i.e. 2^11-1-1 ═ 1023, or 2^12-1The length of the intermediate code between 1023 and 2047 cannot be generated when the code is 2047, so that the current two-phase coding sequence is not easy to realize.

Disclosure of Invention

The embodiment of the invention provides a method for generating orthogonal waveforms and a radar system, wherein the length of a code length is not limited and is easy to generate, the autocorrelation and cross-correlation characteristics are good, the interception probability characteristic is low, and the method is suitable for an MIMO radar.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

the method is particularly applicable to a radar system, comprising: the console (1) is connected with the FPGA (2) through optical fibers, and the FPGA (2) is connected with 16 groups of radio frequency components. Wherein each set of radio frequency components comprises: the D/A converter (3) and the frequency conversion processing module (4) connected with the D/A converter (3), the frequency conversion processing module (4) is connected with the filter amplifier (5), and the filter amplifier (5) is connected with the antenna (6);

the method comprises the following steps: s1, the console (1) generates 16 groups of orthogonal waveform data according to the required code length l;

s2, sending the generated orthogonal waveform data to the FPGA (2) and storing the orthogonal waveform data on the FPGA (2);

s3, the console (1) sends a trigger signal to the FPGA (2), the FPGA (2) starts to work, and the FPGA (2) modulates 16 groups of orthogonal waveform data to obtain a digital sine signal;

s4, sending the obtained digital sinusoidal signals to 16 sets of D/A converters (3), wherein each D/A converter (3) converts the received digital sinusoidal signals into analog baseband signals, and each piece of orthogonal waveform data corresponds to one digital sinusoidal signal;

and S5 and 16 groups of analog baseband signals are processed by respective frequency conversion processing modules (4) to obtain corresponding radio frequency signals, the obtained radio frequency signals are input into filter amplifiers (5) for filtering and amplification, and then the filter amplifiers (5) transmit through antennas (6) connected with the filter amplifiers respectively.

Specifically, in step S1: for a MAC sequence with code length l, a prime number p is identified, wherein p is nearest to the code length, andcalculating the value of p, extracting the required prime number p from the calculated value, and obtaining orthogonal waveform data according to the required prime number p, wherein if (x)²)_pIf i has a solution, the integer i is the quadratic residue of modulo p, p is 4t-1, and t is a positive integer. Wherein, calculatingA value of (d); detecting whether the value of p is 1, 2, …, if so, making a_i-11, otherwise a_i-11, and obtaining a core sequence L ═ { a ═ a₀，a₁，…，a_p-1Represents; from the core sequence L ═ { a ═ a₀，a₁，…，a_p-1Truncating the last u elements, and truncating the kernel sequence L ═ a₀，a₁，…，a_p-1V elements at the front end, and then writing the u elements and v elements intercepted into the front end and the tail end of the core respectively to obtain a MAC sequence with the length of l ═ p + u + v. Then the neighboring p can be reselectedP ' and then u ' and v ' are simultaneously selected, the above steps S121-123 are repeated,until 16 sets of signals are reached, i.e. the requirements are met.

In the embodiment, 16 groups of orthogonal waveforms are generated by adopting the MAC sequence, compared with the commonly used biphase coding sequence Barker code in the prior art, the longest code is 13 bits, and the length of the M sequence code can only be 2^n-1The above technique is not easy to implement when long code data is needed and the length is arbitrary, and the length of the code length in the scheme is not limited when the long code data is implemented. And the orthogonal waveform only needs to modify the required code length in the console, the console directly generates 16 groups of orthogonal waveform data according to the written algorithm, and transmits the data to the FPGA, and the data is transmitted after modulation, digital-to-analog conversion and frequency conversion, so that the generation is easy, and the longer the code length is, the better the cross correlation and autocorrelation are. Because the orthogonal waveform data disperses the power in an arbitrarily large bandwidth range, an interception receiver without knowing the code may find that the spectral density of a signal is lower than that of thermal noise, but does not notice the existence of the signal, has the characteristic of low interception probability, and can identify a related signal only if a signal peak appears at the origin of an autocorrelation function after a system of our party performs autocorrelation processing on the received signal. Is suitable for MIMO radar.

Drawings

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

Fig. 1 is a flow chart of generating 16 orthogonal waveforms according to an embodiment of the present invention.

Fig. 2 is a diagram of a hardware architecture according to an embodiment of the present invention.

Fig. 3 is a cross-correlation function of two of the 16 orthogonal waveforms provided by the embodiment of the present invention, wherein the code length is 1000.

Fig. 4 is an autocorrelation function of one of the 16 orthogonal waveforms provided by the embodiment of the present invention, wherein the code length is 1000.

Fig. 5 is a fuzzy graph of one of the 16 sets of orthogonal waveforms according to the embodiment of the present invention, wherein the code length is 1000.

Fig. 6 is a cross-correlation function of two of the 16 orthogonal waveforms provided by the embodiment of the present invention, wherein the code length is 3000.

Fig. 7 is an autocorrelation function of one of the 16 orthogonal waveforms provided by the embodiment of the present invention, wherein the code length is 3000.

Fig. 8 is a fuzzy graph of one of the 16 orthogonal waveforms provided by the embodiment of the present invention, wherein the code length is 3000.

Wherein each reference numeral represents: 1. the system comprises a console, 2, an FPGA, 3, a DAC (digital-to-analog converter), 4, a frequency conversion processing module, 5, a filter amplifier, 6 and an antenna.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

When the MIMO radar needs to generate long code data, the pulse width time is 100 us-3 ms, the time precision is 0.1us, namely the phase coding length is 1000-30000, so the existing two-phase coding sequence is not easy to realize, therefore, a two-phase coding which can be randomly adjusted within the code length of 1000-30000, is easy to realize engineering and has the autocorrelation and cross-correlation functions less than 0.2 is needed to generate a plurality of groups of orthogonal waveform data

An embodiment of the present invention provides a method for generating orthogonal waveforms, where the method is used in a radar system as shown in fig. 2, and the radar system includes: the console (1) is connected with the FPGA (2) through optical fibers, and the FPGA (2) is connected with 16 groups of radio frequency components. Wherein each set of radio frequency components comprises: a D/A converter (3) (D/A converter), a frequency conversion processing module (4) connected with the D/A converter (3), the frequency conversion processing module (4) is connected with a filter amplifier (5), and the filter amplifier (5) is connected with an antenna (6). Specifically, the method in this embodiment may be implemented by a program (e.g., Matalab) running on the console (1), and as long as the size of the code length l is adjusted, 16 sets of orthogonal waveform data with a required length may be obtained.

The method specifically comprises the following steps:

s1, the console (1) generates 16 sets of orthogonal waveform baseband data according to the required code length l.

And S2, sending the generated orthogonal waveform baseband data to the FPGA (2) and storing the orthogonal waveform baseband data on the FPGA (2).

S3, the console (1) sends a trigger signal to the FPGA (2), the FPGA (2) starts to work, and the FPGA (2) modulates the digital carrier signal by adopting 16 groups of orthogonal waveform baseband data to obtain a digital modulation signal.

And S4, respectively sending the obtained digital modulation signals to 16 groups of D/A converters (3), wherein each D/A converter (3) converts the received digital modulation signal into an analog modulation signal, and each piece of orthogonal waveform baseband data corresponds to one analog modulation signal.

And S5 and 16 groups of analog modulation signals are processed by respective frequency conversion processing modules (4) to obtain corresponding radio frequency signals, the obtained radio frequency signals are input into filter amplifiers (5) for filtering and amplification, and then the filter amplifiers (5) transmit through antennas (6) connected with the filter amplifiers respectively.

Specifically, in this embodiment, 16 sets of orthogonal waveforms may be generated by using MAC sequence bi-phase coding, as shown in fig. 1, step S1 includes:

s11, for MAC sequence with code length l, confirming a prime number p, wherein p is nearest to code length

S12, calculating the value of p, extracting the required prime number p value from the calculated value, and obtaining the orthogonal waveform data according to the required prime number p value, wherein, if (x)²)_pIf i has a solution, the integer i is the quadratic residue of modulo p, p is 4t-1, and t is a positive integer.

Further, step S12 includes:

s121, calculatingThe value of (c).

S122, detecting whether the value i is 1, 2, …, p appears in the calculation result of S121, and if so, making a_i-11, otherwise a_i-11, and obtaining a core sequence L ═ { a ═ a₀，a₁，…，a_p-1}. S123. starting from the core sequence L ═ { a ═ a₀，a₁，…，a_p-1Truncating the last u elements, and truncating the kernel sequence L ═ a₀，a₁，…，a_p-1V elements at the front end, and then writing the u and v elements into the front end and the core, respectivelyAt the end, a MAC sequence of length l ═ p + u + v is obtained: { a_p-u，a_p-u-1…a_p-1，a₀，a₁，…，a_p-1，a₀，a₁，…，a_vReselect neighboring p andand then u ', v', u ', v' are simultaneously selected to represent a new number of elements, and the above steps S121-123 are repeated until 16 sets of signals are reached in order to meet the requirements.

In this embodiment, the code length l is equal to or greater than 1000. As shown in fig. 3-5, when l is 1000, the generated 16 sets of orthogonal waveform autocorrelation and cross-correlation functions are less than 0.2, and the cross-correlation and autocorrelation are better as the code length is longer, which may be less than 0.1. In a preferred embodiment, the code length l is set to 3000 as shown in FIGS. 6-8.

In this embodiment, 16 sets of orthogonal waveforms are generated by using the MAC sequence, and the code length in this scheme is not limited compared to the prior art. Orthogonal waveforms are easy to generate, the longer the code length is, the better the cross correlation and autocorrelation performance is, the low interception probability characteristic is also realized, and the method is suitable for the MIMO radar.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points. The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.