CN107329127B - A kind of phase linearity analysis method and system for radar system DBF Function detection - Google Patents

Abstract

The present invention relates to a phase linear analysis method and system for radar system DBF function detection. The method and system divide each baseband digital signal of a radio frequency receiver into several data segments; convert the divided data segments into corresponding The phase sequence of the complex signal in each data segment is estimated; by comparing with the phase sequence in each data segment of the reference channel, the relative phase sequence in each data segment of each channel is obtained, and the phase sequence of each data segment is calculated. The average value of the relative phase sequence; estimate the linearity of the sequence composed of the relative phase average value of each data segment in each channel, obtain the slope of the curve of each sequence, and obtain the DBF function detection by comparing the slope of the curve of each channel result. The above-mentioned phase linearity analysis method and system eliminate the influence of the inherent phase of each channel by analyzing the relative phase linearity of each channel, improve the accuracy of DBF function detection, and simplify the circuit structure of the radar system.

Description

A phase linear analysis method and system for radar system DBF function detection

technical field

The invention relates to the technical field of radar remote sensing, in particular to a phase linear analysis method and system for DBF function detection of a radar system.

Background technique

DBF (Digital Beam Forming) is a digital beam forming technology. Its basic principle is to convert the radio frequency echo signal received by each antenna array unit into an intermediate frequency signal through a radio frequency receiver, and then convert it into a digital signal through high-speed digital acquisition, and then Amplitude and phase weighting processing is performed in the digital signal processing unit to form the required receiving beam. DBF technology has the advantages of fast and flexible scanning, high resolution, and excellent anti-interference and clutter performance. The DBF technology is applied to the satellite radar, and the space diversity effect of the array antenna can be used to realize multi-beam coverage on the surface of the earth. Compared with the active phased array implemented by traditional analog technology, DBF technology has obvious advantages in system accuracy, flexibility, stability, etc., and has received increasing attention in the application of satellite radar systems. The principle of DBF technology is shown in Figure 1.

The radar system antenna is composed of N antenna array elements. For an incident signal in a certain direction (α angle), the propagation path difference (n·Δd, n=1, 2...N ), and then superimpose the compensated complex signals in the same direction to realize beamforming in this direction, and finally obtain the maximum energy reception in this direction. The basic mathematical relationship between D B F is as follows:

In the formula (1), N is the number of receiving channels, C _n is the complex signal obtained by quadrature down-conversion and amplitude-phase correction of the real signal of the nth receiving channel; W _βn is the weighting coefficient in the β direction, which can be further written for:

(2) In the formula, d is the antenna array element spacing; λ is the signal wavelength; β is the synthetic beam pointing angle.

The complex signal C _n can be further written as:

(3) In the formula, A _n is the amplitude of the nth complex signal; f is the signal frequency; θ _n is the initial phase of the nth complex signal. θ _n can be further written as:

(4) where, is the inherent phase of the nth receiving channel, that is, the inherent delay of the received signal, depends on the hardware circuit characteristics of each receiving channel. Substituting equation (4) into equation (3), the expression of the complex signal C _n is further obtained:

It can be seen from the above relationship that the phase of the signal path introduced by the different positions of each array element It can be eliminated by multiplying with the weighting coefficient W _βn , and when β=α, the maximum signal energy can be synthesized in the direction of α.

According to the above relationship, in order to test the receiving DBF performance of a radar system, it is necessary to eliminate the inherent phase of each receiving channel due to the inconsistent characteristics of components Impact. In the prior art, calibration within the receiving channel or calibration outside the whole system is usually adopted.

The internal calibration method is to inject the internal calibration signal from the front end of each receiving channel of the radar, and obtain the inherent phase of each receiving channel after signal processing at the back end. The internal calibration method needs to increase the internal calibration signal source. On the one hand, it increases the complexity of the system. At the same time, because the internal calibration signal does not pass through the antenna unit, the obtained channel phase does not include the phase deviation introduced by the antenna unit, thereby reducing the calibration accuracy.

The external calibration method usually takes the radar system as a whole, and uses the rotating electric field vector method to correct the inherent phase of the receiving channel. This calibration method is complicated to operate, requires high precision of the measuring equipment, and needs to measure all array elements one by one, and the calibration time is long.

Contents of the invention

The purpose of the present invention is to provide a phase linear analysis method and system for radar system DBF function detection in order to solve the technical problems of low calibration accuracy and complex operation in the existing radar system DBF performance detection method; The system and method can accurately and quickly test the DBF function of the radar system without calibrating the influence of the inherent phase of the receiving channel, and are suitable for the function detection of the DBF of the radar system under far-field conditions.

In order to solve the above problems, a kind of phase linear analysis method for radar system DBF function detection provided by the invention, the method comprises:

Step 1) Sampling and quantizing the intermediate frequency signals output by each radio frequency receiver respectively, and digitally down-converting the quantized intermediate frequency signals to obtain the baseband digital signals of each road;

Step 2) Carry out inter-channel synchronous timing discrimination for each baseband digital signal, and divide the baseband digital signal of each channel satisfying the synchronous timing relationship into several data segments;

Step 3) converting the divided data segments into corresponding complex signals, and estimating the phase sequence of the complex signals in each data segment;

Step 4) setting any channel as a reference channel, comparing the phase sequence in each data segment of each channel with the phase sequence in each data segment of the reference channel, and obtaining the relative phase sequence in each data segment of each channel, And calculate the average value of the relative phase sequence of each data segment;

Step 5) Carry out linearity estimation to the sequence formed by the relative phase average value of each data segment in each channel, and obtain the curve slope of each sequence;

Step 6) Carry out the arithmetic series relationship comparison to the curve slopes of each channel except the reference channel, if the curve slope does not satisfy the arithmetic series relationship, then its corresponding channel is judged as not meeting the DBF functional requirements, otherwise, it is judged as meeting DBF functional requirements.

The present invention also provides a phase linear analysis system for radar system DBF function detection, the system includes: ADC conversion unit, digital down-conversion module, phase linear analysis module, clock synchronization unit, rotation angle synchronous recorder and DBF function detection module;

The ADC conversion unit is used to sample and quantize the intermediate frequency signals output by each radio frequency receiver;

The digital down-conversion module is used to digitally down-convert the intermediate frequency signal quantized by the ADC conversion unit to obtain each baseband digital signal, and output the baseband digital signal to the phase linear analysis module;

The phase linear analysis module is used to discriminate the synchronous timing between channels for each baseband digital signal, and divide the baseband digital signal of each channel satisfying the synchronous timing relationship into several data segments; convert the divided data segments into For the corresponding complex signal, estimate the phase sequence of the complex signal in each data segment; set any channel as the reference channel, compare the phase sequence in each data segment of each channel with the phase sequence in each data segment of the reference channel, Obtain the relative phase sequence in each data segment of each channel, and calculate the average value of the relative phase sequence of each data segment; estimate the linearity of the sequence composed of the relative phase average value of each data segment in each channel, and obtain The curve slope of each sequence; compare the arithmetic sequence relationship of the curve slope of each channel except the reference channel, and output the comparison result to the DBF function detection module;

The DBF function detection module analyzes the curve slope comparison result output by the phase linear analysis module, and detects the DBF function of the radar system in combination with the antenna array rotation angle output by the rotation angle synchronous recorder;

The clock synchronization unit is used to generate clock synchronization signals required by the ADC conversion unit, digital down-conversion module, phase linear analysis module and rotation angle synchronization recorder;

The rotation angle synchronous recorder is used for recording the rotation angle value of the antenna array in real time, and the time synchronization correspondence between the rotation angle value and the radar received data is maintained.

As a further improvement of the above technical solution, the ADC conversion unit includes: an amplifier, a filter and an ADC conversion module; the amplifier and the filter are respectively used to amplify and filter the intermediate frequency signal output by the radio frequency receiver; the The ADC conversion module described above is used for digital acquisition of the amplified and filtered intermediate frequency signal.

As a further improvement of the above technical solution, the digital down-conversion module includes: a numerically controlled oscillator, a frequency mixer, and a sampling filter; the digital oscillator is used to provide a local oscillator signal for the system; It is used to convert the digitally collected intermediate frequency signal into a low frequency signal; the sampling filter is used to reduce the sampling data rate of the low frequency signal.

The advantages of a phase linear analysis method and system for radar system DBF function detection of the present invention are:

⑴ Simplifies the complexity of the radar system receiving DBF function detection, reduces the test time, and improves the test efficiency. Existing DBF tests need to correct the influence of the inherent phase of each channel. For this purpose, high-precision measuring instruments and complex testing methods are required, resulting in complex operations, long test times, and large errors. A digital phase linear analyzer used for DBF function detection of a radar receiving system in the present invention does not need to use complicated special calibration instruments and equipment, and does not need complicated operation steps; the data processing process is simple, the calculation is fast, and the radar system can be detected in a short time The receiving DBF function.

(2) By analyzing the relative phase linearity of each channel, the influence of the inherent phase of each channel is eliminated, and the accuracy of DBF function detection is further improved. Moreover, since it is not affected by the inherent phase of each channel, the radar system does not need to set a special internal calibration circuit for correcting the inherent phase of the channel, thereby simplifying the circuit design of the radar system.

(3) The full digital processing method makes data segmentation, signal complex transformation, and linear analysis more flexible, and has a higher processing signal-to-noise ratio and calculation speed. The length of the data segment can be flexibly divided according to the rotation angle of the antenna array, different complex signal transformation methods are adopted according to the ADC sampling rate and quantization bits, and the reference channel is selected according to the relative position between the antenna array and the transmitting antenna, so the data processing method is very flexible . FPGA or FPGA+high-speed DSP can be used for data processing, which can obtain higher processing signal-to-noise ratio and calculation speed, and improve the timeliness and accuracy of radar system DBF function detection.

Description of drawings

Figure 1 is a schematic diagram of the principle of DBF technology;

Figure 2 is a schematic diagram of the radar system receiving DBF function test principle;

Fig. 3 is a schematic flow chart of a phase linear analysis method for radar system DBF function detection provided by the present invention;

Fig. 4 is a kind of digital phase linear analyzer structure schematic diagram that is used for radar system DBF function detection provided by the present invention;

Fig. 5 is a schematic structural diagram of a phase linear analysis module in the present invention;

Fig. 6 is to utilize the digital phase linear analyzer to divide the timing relationship diagram of each channel data segment;

Fig. 7 is a schematic diagram of an example of applying the digital phase linear analyzer to the DBF function detection of the radar system.

reference sign

1. ADC conversion unit 2. Digital down conversion module

3. Phase linear analysis module 4. Clock synchronization unit

5. Rotation angle synchronous recorder 6. DBF function detection module

31. Inter-channel timing synchronization discriminator 32. In-channel data segment divider

33. Complex signal converter 34. Intra-segment phase estimator

35. Inter-channel inter-segment phase comparator 36. In-channel inter-segment relative phase linearity estimator

37. Phase curve slope comparator between channels 41. Clock synchronization signal of ADC conversion unit

42. Clock synchronization signal of the digital down-conversion module

43. The clock synchronization signal of the inter-channel timing synchronization discriminator

44. The clock synchronization signal of the data segment divider in the channel

45. Clock synchronization signal of rotation angle synchronization recorder

51. First angle position signal

52. Second angle position signal

Detailed ways

A digital phase linear analyzer for radar system DBF function detection according to the present invention will be described in detail below in conjunction with the drawings and embodiments.

For the radar system adopting the DBF system, the radar equipment itself has a large number of receiving channels and a complex circuit structure. In order to verify the DBF function of the radar system, it is necessary to eliminate the inherent phase of the receiving channel Impact, The calibration method is complicated, requires high precision of the measuring equipment, and takes a long time to test. In order to solve this technical problem, the present invention designs a kind of digital phase linear analyzer for radar system receiving DBF function detection, and phase linear analysis method, can test the receiving DBF function of radar system accurately and quickly, and does not need to calibrate Intrinsic Phase of Receive Channel It is suitable for the functional detection of the radar system receiving DBF under far-field conditions.

The radar system receiving DBF function test is usually carried out under far-field conditions, and the test site is a microwave anechoic chamber or an open field. If the physical size of the antenna array is a×b, and the wavelength of the electromagnetic wave is λ, the test distance that satisfies the far-field condition is:

Set up the radio frequency signal source and transmitting antenna so that the distance from the antenna array Adjust the position and orientation of the RF signal source and the array antenna so that the antenna array is located within the main beam range of the RF transmitting antenna (3dB beam width) as much as possible to obtain a larger receiving signal-to-noise ratio. The positional relationship between the transmitting antenna and the antenna array as shown in picture 2.

The physical size of the antenna array is a×b.

The physical size of each array unit perpendicular to the direction of the incident wave is l, and there are N array units in total.

The distance from the radio frequency signal source and the transmitting antenna to the radar antenna array is R, And R>>1.

Each array unit is connected to a radio frequency receiver, and there are N radio frequency receivers in total. The phase of the intermediate frequency signal output by the receiver is expressed as i=1,2,...N, where is the intrinsic phase of the i-th receiving channel; is the relative phase introduced by the transmission path difference of the received signal. As shown in Figure 2, taking the first array unit whose distance from the transmitting antenna is R as a reference, the signal transmission path difference of adjacent array units is Δr ₁ , Δr ₂ ... Δr _i ..., i=1, 2, .. .N. Since R>>l and θ angle is small (θ≤±5°), Δr _i can be approximately expressed as Δr _i =(i-1)l·sinθ, then i=1, 2...N. Taking channel 1 as a reference, the relative phase of each receiving channel signal is expressed as follows:

Channel N:

In the range of small θ angle (θ≤±5°), sinθ≈θ, so that (constant), then formula (1) can be further expressed as:

Channel N:

According to formula (2), except for the reference channel, the relative phase of each channel signal has a linear relationship with the angle θ, and the slope of the relative phase curve of each channel has an arithmetic sequence relationship. Rotate the array antenna within a small angle (θ≤±5°) in the azimuth direction to obtain the phase value of each receiving channel at different θ angles; by digitally processing the received signals of each channel, analyze the relationship between its relative phase and angle θ The linear relationship can detect the receiving DBF function of the radar system.

The purpose of the present invention is to simplify the test complexity of the radar system receiving DBF function detection, reduce the test time, eliminate the influence of the inherent phase of the radar receiving channel on the test result, and improve the detection accuracy. In order to achieve the above object, the present invention provides a phase linear analysis method for radar system receiving DBF function detection; as shown in Figure 3, the method specifically includes the following steps:

Step 1) Sampling and quantizing the intermediate frequency signals output by each radio frequency receiver respectively, and digitally down-converting the quantized intermediate frequency signals to obtain the baseband digital signals of each road;

Step 2) Carry out inter-channel synchronous timing discrimination for each baseband digital signal, and divide the baseband digital signal of each channel satisfying the synchronous timing relationship into several data segments;

Step 3) converting the divided data segments into corresponding complex signals, and estimating the phase sequence of the complex signals in each data segment;

Step 4) setting any channel as a reference channel, comparing the phase sequence in each data segment of each channel with the phase sequence in each data segment of the reference channel, and obtaining the relative phase sequence in each data segment of each channel, And calculate the average value of the relative phase sequence of each data segment;

Step 5) Carry out linearity estimation to the sequence formed by the relative phase average value of each data segment in each channel, and obtain the curve slope of each sequence;

Step 6) Carry out arithmetic sequence relationship comparison to the curve slopes of each channel except the reference channel, if the curve slope does not satisfy the arithmetic sequence relationship, then its corresponding channel is determined as not meeting the DBF function detection requirements, otherwise, it is determined as Comply with DBF function testing requirements.

The invention also provides a digital phase linear analyzer used for the detection of the radar system receiving DBF function. The phase linear analyzer includes: an ADC conversion unit, a digital down-conversion module, a phase linear analysis module, a clock synchronization unit, a rotation angle synchronous recorder and a DBF function detection module.

The ADC conversion unit is connected with the radio frequency receiver of the front end, and is used for sampling and quantizing the intermediate frequency signals output by each radio frequency receiver, and each radio frequency receiver is connected with an ADC conversion module. If there are N radio frequency signals in the radar system The receiver has N ADC conversion modules. Each ADC conversion module has a strict synchronous clock signal to ensure the timing consistency of the sampling and quantization data of each channel. The ADC conversion unit is connected with the digital down-conversion module at the same time, and outputs the quantized digital signal to the digital down-conversion module.

The digital down-conversion module is connected with the ADC conversion unit and the phase linearity analysis module. The quantized intermediate frequency signal is digitally down-converted to the baseband, and the obtained baseband digital signal is output to the phase linear analysis module.

The phase linearity analysis module is connected with the digital down-conversion module and the DBF function detection module. Perform synchronous timing discrimination between channels for each input baseband digital signal, divide the baseband digital signal of each channel that satisfies the synchronous timing relationship into several data segments, convert the divided real signal data segments into corresponding complex signals, and then Estimate the phase sequence of the complex signal in each data segment; then set any channel as the reference channel, compare the phase sequence in each data segment of each channel with the phase sequence in each data segment of the reference channel, and obtain each The relative phase sequence in each data segment of the channel, and calculate the average value of the relative phase sequence of each data segment, and then perform linearity estimation on the sequence composed of the relative phase average value of each data segment of each channel, and obtain the primary value of each sequence Curve slope: analyze and compare the arithmetic sequence relationship of the curve slope of each channel except the reference channel, and output the comparison result to the DBF function detection module.

The DBF function detection module is connected with a phase linear analysis module and a rotation angle synchronous recorder. Analyze the curve slope comparison results input by the phase linear analysis module, and combine the antenna array rotation angle input by the rotation angle synchronization recorder to detect the receiving DBF function of the radar system.

In the DBF function detection module, according to the above relationship (2), the relative phase of each receiving channel signal is linearly fitted, the abscissa is the antenna array rotation angle θ, and the ordinate is the relative phase of each channel signal can be calculated The slope k _ch2 , k _ch3 ...k _chN between θ and θ, if k _ch2 , k _ch3 ...k _chN satisfy the arithmetic sequence relationship, it is judged that the radar system can realize the DBF function; if it does not satisfy the arithmetic sequence relationship, it is judged The radar system cannot realize the DBF function or the error of the DBF synthetic beam is relatively large.

The clock synchronization unit is connected with the ADC conversion unit, the digital down-conversion module, the phase linearity analysis module and the rotation angle synchronous recorder. The clock synchronization unit is used to generate the clock synchronization signal required by the ADC conversion unit, digital down conversion module, phase linear analysis module and rotation angle synchronous recorder, to ensure the synchronization of the ADC conversion unit, digital down conversion module, phase linear analysis module and rotation angle Strict time synchronization relationship between loggers.

The rotation angle synchronous recorder is connected with a phase linear analysis module and a DBF function detection module. The rotation angle synchronous recorder is used to record the azimuth angle value of the array antenna in real time, which maintains a strict time synchronization correspondence relationship with the radar received data. The rotation angle synchronous recorder outputs the recorded angle value to the phase linear analysis module and the DBF function detection module, which is used to assist in detecting the receiving DBF function of the radar system.

Based on the phase linear analysis module of the above functions, the phase linear analysis module may further include: an inter-channel timing synchronization discriminator, an intra-channel data segment divider, a complex signal converter, an intra-segment phase estimator, and an inter-channel intra-segment phase comparator , an inter-channel relative phase linearity estimator and an inter-channel relative phase slope comparator.

The inter-channel timing synchronization discriminator is used for discriminating the synchronous relationship of the digital baseband signals of each channel after demodulation, and performing further follow-up processing on the digital signals satisfying the synchronous relationship. Since the clocks of each ADC conversion module are kept synchronized, the discrimination of the synchronous relationship of the baseband digital signals of each channel can be transformed into the judgment of the consistency of the sampling data points of each channel. If the number of data points of channel 1 is P ₁ , and the number of data points of channel 2 is P ₂ ,...the number of data points in channel N is P _N , when P ₁ =P ₂ =...=P _N , it is determined that the data of each channel satisfies the synchronization relationship, and further subsequent processing can be done;

The data segment divider in the channel is used to divide the continuous sampling data of each channel into several data segments suitable for segmentation processing, and the number of data points in the corresponding data segment of each channel is the same. The description of the number of data points in each channel segment is shown in Table 1, satisfying SP ₁₁ =SP ₂₁ =...=SP _N1 , SP ₁₂ =SP ₂₂ =...=SP _N2 ,..., SP _1k =SP _2k =...=SP _Nk ;

Table 1 Representation list of data points in each channel segment

serial number Data segment 1 point Data segment 2 points ... Data segment k points channel one SP₁₁ SP₁₂ ... SP_1k channel two SP₂₁ SP₂₂ ... SP_2k ... ... ... ... Channel N SP_N1 SP_N2 ... SP_Nk

The complex signal converter is used to transform the divided real signals of each data segment into corresponding complex signals, and output the transformed complex signals to the intra-segment phase estimator;

The phase estimator in the segment is used to calculate the phase of the complex signal in each data segment, that is, calculate the phase angle value of each complex data sample point, and obtain the phase sequence of each data segment in each channel, as shown in Table 2;

Table 2 Phase sequence list in each channel segment

serial number Phase sequence of data segment 1 Phase sequence of data segment 2 ... Phase sequence of data segment k channel one θ₁₁[...], a total of SP₁₁ elements θ₁₂[...], a total of SP₁₂ elements ... θ_1k[...], a total of SP_1k elements channel two θ₂₁[...], a total of SP₂₁ elements θ₂₂[...], a total of SP₂₂ elements ... θ_1k[...], a total of SP_2k elements ... ... ... ... ... Channel N θ_n1[...], a total of SP_N1 elements θ_n2[...], a total of SP_N2 elements ... θ_Nk[...], a total of SP_Nk elements

The phase estimation method of the complex signal specifically includes: converting the real signal into a complex signal through the Hilbert transform method, the complex signal has a real component and an imaginary component, such as: s=a+j*b, according to this relational expression can be Compute the phase of the complex signal: The above calculation process needs to use the clock synchronization unit to maintain the synchronization relationship between the two, that is to say, it is necessary to determine the one-to-one correspondence between the signal phase angle value and the array antenna azimuth angle value.

The inter-channel inter-segment phase comparator is used to calculate the intra-segment relative phase of each channel relative to any channel (in this embodiment, channel 1 is used as a reference channel for description), obtain the intra-segment relative phase sequence, and calculate The mean value of the sequence, the relative phase sequence and the mean value of the sequence are shown in Table 3 and Table 4, respectively.

Table 3 Relative phase sequence in each channel segment

Table 4 Mean value of relative phase sequence in each channel segment

The inter-channel inter-segment relative phase linearity estimator is used for independent linear analysis of the relative phase average value sequence of each channel output by the inter-channel inter-segment phase comparator. That is, linear fitting is performed on k relative phase mean values of each channel, and the slope of each fitting curve is calculated, as shown in Table 5.

Table 5 The slope of the fitting curve of each channel

serial number The slope of the fitting curve of the relative phase mean of each channel channel one k_ch1=0 channel two k_ch2 channel three k_cha ... ... Channel N-1 k_chN-1 Channel N k_chN

The inter-channel phase curve slope comparator is used to compare the slope of each channel fitting curve output by the relative phase linearity estimator between the segments in the channel, and judge whether the slope values of each channel k _ch2 , k _ch3 , ..., k _chN satisfy Arithmetic sequence relationship, and output the discrimination result to the DBF function detection module. The comparison results of the slopes of the curves are the slopes k _ch2 , _{k ch3} . . .

If the arithmetic sequence relationship is satisfied, it is judged that the radar system can realize the receiving DBF function; if the arithmetic sequence relationship is not satisfied, it is judged that the radar system cannot realize the receiving DBF function or the error of the synthesized beam is large, so the DBF function can be further determined. The detection module performs hardware troubleshooting of the radar system or detects whether the system timing logic control signal is normal, whether the clock signal is synchronized, and other performances.

The above-mentioned digital phase linear analyzer and phase linear analysis method of the present invention have been well applied in the field test of radar system DBF performance detection. The actual test results show that the digital phase linear analyzer and phase linear analysis method work well in the field DBF performance test of the radar system, and can quickly and accurately detect the receiving DBF performance of the radar system. The operation steps are simple, and the data processing is fast and flexible. .

Embodiment one

As shown in Figure 4, a digital phase linear analyzer for radar system receiving DBF function detection is provided in this example, including: ADC conversion unit 1, digital down-conversion module 2, phase linear analysis module 3, clock Synchronization unit 4, rotation angle synchronization recorder 5 and DBF function detection module 6. The ADC conversion unit 1 is connected to the digital down-conversion module 2, quantifies the intermediate frequency analog signal output by the radio frequency receiver, and outputs the quantized digital intermediate frequency signal to the digital down-conversion module. The ADC conversion unit 1 is controlled by the clock synchronization unit, and maintains a strict time synchronization relationship with the digital down-conversion module 2 , the phase linearity analysis module 3 , and the rotation angle synchronous recorder 5 .

The digital down-conversion module 2 is connected with the ADC conversion unit 1 and the phase linear analysis module 3, and is used to convert the digital intermediate frequency signal input from the ADC conversion unit 1 to baseband, and output it to the phase linear analysis module 3 for digital signal processing .

The phase linear analysis module 3 is the core element of the digital phase linear analyzer of the present invention. Its input terminal is connected with the digital down-conversion module 2 to process the input digital baseband signal, including inter-channel timing discrimination, data segment segmentation, complex signal conversion, intra-segment phase estimation, inter-channel phase comparison, and inter-channel relative phase linearity Estimation analysis operation, its output terminal is connected with the DBF function detection module, and the analysis result is output to the DBF function detection module.

The clock synchronization unit 4 is connected with the ADC conversion unit 1, the digital down-conversion module 2, the phase linear analysis module 3, and the rotation angle synchronous recorder 5 to provide a synchronous clock signal for it. The clock synchronization unit 4 is simultaneously connected with other radar system The clock signal of the unit module maintains strict time synchronization.

The rotation angle synchronous recorder 5 is connected with the phase linear analysis module 3 and the DBF function detection module 6, and the antenna array rotation angle signal recorded in real time is output to the phase linear analysis module 3 and the DBF function detection module 6; the rotation angle is synchronized The recorder 5 is controlled by the clock synchronization unit 4, and the output rotation angle signal has a certain timing mark.

The DBF function detection module 6 is connected with the phase linear analysis module 3 and the rotation angle synchronous recorder 5, analyzes the DBF function of the radar system according to the relative phase linear relationship of each channel and the corresponding antenna array rotation angle, and gives the radar system Receive the DBF function detection result.

The ADC conversion unit 1 is an analog-to-digital conversion device of a digital phase linear analyzer, and the ADC conversion unit specifically includes: an amplifier, a filter and an ADC conversion module. The amplifier and the filter are respectively used to amplify and filter the intermediate frequency signal output by the radio frequency receiver; the ADC conversion module is used to digitally collect the amplified and filtered intermediate frequency signal. The input end of the ADC conversion unit 1 is connected to the intermediate frequency signal output end of the radar radio frequency receiver through a radio frequency cable; its output end is connected to the digital down-conversion module 2 through a low frequency cable; the ADC conversion unit 1 is connected to the clock synchronization unit 4 through a radio frequency cable. As shown in FIG. 5 , the clock synchronization unit 4 inputs the clock synchronization signal 41 of the ADC conversion unit to the ADC conversion unit 1 to complete the analog-to-digital conversion and establish a time synchronization relationship with other unit modules.

The digital down-conversion module 2 includes: a digitally controlled oscillator, a mixer and a sampling filter. The digital oscillator is used to provide a local oscillator signal for the system; the mixer is used to convert the digitally collected intermediate frequency signal into a low frequency signal; the sampling filter is used to reduce the sampling data rate of the low frequency signal. The input end of the digital down-conversion module 2 is connected to the ADC conversion unit 1; its output end is connected to the phase linearity analysis module 3 through a low-frequency cable; the digital down-conversion module 2 is connected to the clock synchronization unit 4 through a radio frequency cable at the same time; as shown in Figure 5 , the clock synchronization unit 4 outputs the clock synchronization signal 42 of the digital down-conversion module to the digital down-conversion module 2, so that it completes the conversion from the digital intermediate frequency to the digital baseband signal, and the digital down-conversion module 2 maintains a time synchronization relationship with other unit modules.

As shown in Figure 5, in this embodiment, the phase linear analysis module 3 includes: an inter-channel timing synchronization discriminator 31, an intra-channel data segment divider 32, a complex signal converter 33, and an intra-segment phase estimator 34 , an intra-channel inter-segment phase comparator 35 , an intra-channel inter-segment relative phase linearity estimator 36 , and an inter-channel phase curve slope comparator 37 . The inter-channel timing synchronization discriminator 31 is connected with the digital down-conversion module 2, carries out timing discrimination to the multi-channel digital baseband signal input by the digital down-conversion module 2, and judges whether each channel signal has a strict time synchronization relationship, which will have strict The digital signals of the time synchronization relationship are output to the in-channel data segment divider 32 . The inter-channel timing discriminator 31 is connected with the clock synchronization unit 4 through a radio frequency cable, and receives the clock synchronization signal 43 of the clock synchronization unit 4 input channel timing synchronization discriminator to ensure the accuracy and consistency of multi-channel data timing discrimination; The intra-channel data segment divider 32 receives the multi-channel digital signal input by the inter-channel timing discriminator 31, divides the data of each channel into several data segments, and maintains strict time synchronization between the corresponding data segments of each channel. The waveform is shown in Figure 6. The data segment divider 32 in the channel receives the clock synchronization signal 44 input by the clock synchronization unit 4 to the data segment divider in the channel, and generates a timing control signal for dividing the data of each channel, data segment 1, data segment 2, ... of each channel ...The data segment k maintains a strict synchronous time relationship to ensure that the number of data points in the same data segment of each channel is consistent. The data segment divider 32 in the channel is connected with the rotation angle synchronous recorder 5 at the same time, receives the first angle position signal 51 of the antenna array input by the rotation angle synchronous recorder 5, and determines the segmented data segment length according to the rotation angle, that is, determines the data segment division The control timing and logic of the timing control signal; the complex signal converter 33 is connected with the data segment divider 32 and the phase estimator 34 in the channel, receives the real signal input by the data segment divider 32 in the channel, and converts it into a corresponding complex signal, and output to the phase estimator 34 in the segment; the phase estimator 34 in the segment is connected with the complex signal converter 33 and the phase comparator 35 in the segment between the channels, and is used to calculate each data of each channel The phases of all complex signals in the segment are obtained to obtain the phase sequence corresponding to the data segment, and output to the phase comparator 35 in the segment between the channels; the phase comparator 35 in the segment between the channels and the phase estimator 34 and the channel Inter-section relative phase linearity estimator 36 is connected to calculate the relative phase within each channel relative to the reference channel, obtain the relative phase sequence within the segment, and calculate the average value of the relative phase sequence within the segment, and output the calculation result to the channel Inter-segment relative phase linearity estimator 36; the relative phase linearity estimator 36 between the segments in the passage is connected with the phase comparator 35 and the inter-passage phase curve slope comparator 37 in the passage, for each passage The phase mean value of all data segments in the interior is carried out linear fitting, calculates the slope value of each channel fitting curve, and the calculation result is output to the inter-channel phase curve slope comparator 37; Described inter-channel phase curve slope comparator 37 and channel The inter-internal relative phase linearity estimator 36 is connected to the DBF function detection module 6 for comparing the numerical relationship between the slopes of the curves of each channel, judging whether the slopes of the curves of each channel satisfy the arithmetic sequence, and output the comparison results to the DBF function detection Module 6.

The clock synchronization unit 4 is used to generate all the clock signals required by the digital phase linear analyzer, and the generated clock signals are in a synchronous relationship with the clock signals of other unit modules of the radar system. The clock synchronization unit 4 is connected with the ADC conversion unit 1, the digital down-conversion module 2, the inter-channel timing synchronization discriminator 31, and the data segment divider 32 in the channel, and outputs a synchronous clock signal. The signal output by the clock synchronization unit has high frequency accuracy and high Characteristics of frequency stability.

The rotation angle synchronous recorder 5 is used to record the azimuth angle value of the radar antenna array in real time, and a strict time synchronization relationship is maintained between the angle value and the digital signal of each channel. The first angle position signal 51 of the antenna array output to the data segment divider in the channel is used to determine the segmentation mode of each channel data segment; the second angle position signal 52 of the antenna array output to the DBF function detection module is used for DBF function detection analysis data input.

The DBF function detection module 6 is connected with the phase linear analysis module 3 and the rotation angle synchronous recorder 5, analyzes the DBF function of the radar system according to the relative phase linear relationship of each channel and the corresponding antenna array rotation angle, and provides the radar system Receive the DBF function detection result.

As shown in FIG. 7 , it is a schematic block diagram of an application example of the digital phase linear analyzer of the present invention in a radar system. The digital linear phase analyzer is applied to the radar system receiving DBF function detection, which reduces the test complexity, improves the test efficiency and detection accuracy; at the same time, it does not need to perform special correction on the inherent delay of each channel, which simplifies the operation steps; adopts digital The method of signal calculation and processing greatly increases the flexibility of signal processing, can obtain higher processing signal-to-noise ratio and calculation speed, and improves the timeliness and accuracy of radar system DBF function detection.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit them. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent replacements to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all of them should be included in the scope of the present invention. within the scope of the claims.

Claims (4)

1. a kind of phase linearity analysis method for radar system DBF Function detection, which is characterized in that this method comprises:

The intermediate-freuqncy signal that step 1) exports each radio-frequency transmitter carries out sample quantization respectively, and the intermediate-freuqncy signal after quantization is carried out Digital Down Convert obtains each road baseband digital signal；

Step 2) carries out the differentiation of inter-channel synchronization timing to each road baseband digital signal, will meet each logical of synchronous sequence relationship The baseband digital signal in road is divided into several data segments；

Data segment after segmentation is converted to corresponding complex signal by step 3), estimates the phase sequence of complex signal in each data segment Column；

Step 4) sets any channel as reference channel, by each of phase sequence in each data segment in each channel and reference channel Phase sequence is compared in data segment, obtains relative phase sequence in each data segment in each channel, and calculate each data segment Relative phase sequence average value；

The sequence that step 5) forms the average value of the relative phase sequence of data segment each in each channel carries out linearity estimation, Acquire the slope of curve of each sequence；

Step 6) carries out arithmetic progression Relationship Comparison to the slope of curve in each channel in addition to reference channel, if the slope of curve is not Meet arithmetic progression relationship, then its corresponding channel is judged to not meeting DBF functional requirement, otherwise, it is determined that meet DBF function It can require.

2. a kind of phase linearity analysis system for radar system DBF Function detection, which is characterized in that the system includes: ADC Converting unit (1), Digital Down Converter Module (2), phase linearity analysis module (3), clock synchronization unit (4), rotation angle are same Walk logger (5) and DBF function detection module (6)；

The ADC converting unit (1), the intermediate-freuqncy signal for exporting each radio-frequency transmitter carry out sample quantization；

The Digital Down Converter Module (2), for carrying out the intermediate-freuqncy signal after ADC converting unit (1) quantization, number is lower to be become Frequently, each road baseband digital signal is obtained, and baseband digital signal is exported to phase linearity analysis module (3)；

The phase linearity analysis module (3) will for carrying out the differentiation of inter-channel synchronization timing to each road baseband digital signal The baseband digital signal for meeting each channel of synchronous sequence relationship is divided into several data segments；By the data segment conversion after segmentation For corresponding complex signal, the phase sequence of complex signal in each data segment is estimated；Any channel is set as reference channel, it will be each Phase sequence is compared with phase sequence in each data segment of reference channel in each data segment in channel, obtains each channel Relative phase sequence in each data segment, and calculate the average value of the relative phase sequence of each data segment；By number each in each channel Linearity estimation is carried out according to the sequence of the average value composition of the relative phase sequence of section, acquires the slope of curve of each sequence；To removing The slope of curve in each channel outside reference channel carries out arithmetic progression Relationship Comparison, and comparison result is exported to DBF Function detection Module (6)；

The DBF function detection module (6) carries out the slope of curve comparison result of phase linearity analysis module (3) output Analysis, and combine the DBF function of the aerial array rotation angle detection radar system of rotation angle synchronous recording device (5) output；

The clock synchronization unit (4), for generating ADC converting unit (1), Digital Down Converter Module (2), phase linearity point Clock sync signal needed for analysing module (3) and rotation angle synchronous recording device (5)；

The rotation angle synchronous recording device (5), for recording the rotation angle value of aerial array in real time, the rotation angle value Retention time synchronous corresponding relationship between data is received radar.

3. the phase linearity analysis system according to claim 2 for radar system DBF Function detection, feature exist In the ADC converting unit includes: amplifier, filter and ADC conversion module；The amplifier and filter difference For the intermediate-freuqncy signal that radio-frequency transmitter exports to be amplified and is filtered；The ADC conversion module is used for amplification Digital collection is carried out with the intermediate-freuqncy signal after filtering processing.

4. the phase linearity analysis system according to claim 3 for radar system DBF Function detection, feature exist In the Digital Down Converter Module includes: digital controlled oscillator, frequency mixer and sampling filter；The digital oscillator is used In providing local oscillation signal for system；The frequency mixer is used to the intermediate-freuqncy signal of digital collection being transformed into baseband digital signal； The sampling filter is used to lower the sampled data rate of baseband digital signal.