Radar monitoring method based on broadband real-time spectrum analysisTechnical Field
The invention relates to a radar monitoring method based on broadband real-time spectrum analysis, and relates to the field of radar monitoring.
Background
With the expansion of the task area of the modern battlefield, the increase of the training force and the development of the wireless communication technology, the number of the frequency-using equipment is greatly increased, the electromagnetic signal systems are various, and the electromagnetic environment of the task area is more complex and variable. In the complex electromagnetic signal environment facing dense signal interleaving aliasing, extremely high concealment, large bandwidth and high dynamics, the radar monitoring equipment needs to rapidly capture signals, analyze in real time and present signal characteristics.
In principle, the traditional spectrum analysis generally adopts a frequency scanning mode of a superheterodyne receiver, the local oscillation frequency of the receiver scans in a frequency band, narrowband signal analysis is sequentially carried out, the wider the monitoring bandwidth is, the longer the scanning time is, and the monitoring loss of transient signals and burst signals is caused. At present, in principle, a digital technology is adopted to collect, capture and measure a broadband signal frequently, and in-band collected signals are analyzed in multiple domains such as frequency, power, time and the like by digital signal processing methods such as FFT and the like, so that the timely triggering and capturing of transient signals can be realized. The current radar monitoring equipment has great difficulty in monitoring the continuous frequency spectrums of burst signals, complex radar signals, interference signals and other signals.
Disclosure of Invention
The invention aims to: a radar monitoring method based on broadband real-time spectrum analysis is provided to solve the above problems.
The technical scheme is as follows: a radar monitoring method based on broadband real-time spectrum analysis comprises the following steps:
a signal preprocessing module is constructed to convert a received radio frequency signal RF into an intermediate frequency analog signal IF, comprising: the device comprises a limiter module, an amplifier module, a first filter module, a first mixer module, a second filter module, a second mixer module and a third filter module;
the amplitude limiter module is connected with the receiving antenna module and used for limiting the amplitude of the received radio frequency signal; the output sequentially passes through an amplifier module, a first filter module, a first mixer module, a second filter module, a second mixer module and a third filter module;
as a further improvement of the present invention, the amplifier module is configured to power amplify the limited rf signal;
the first filter module is used for filtering interference signals in radio frequency signals;
the first mixer module is configured to provide a local oscillation signal LO1, and shift a radio frequency signal to an intermediate frequency to obtain an intermediate frequency analog signal if1=rf-LO 1;
the second filter module is used for filtering local oscillation interference signals in the intermediate frequency analog signal IF 1;
the second mixer module is configured to provide a local oscillation signal LO2, and mix to obtain an intermediate frequency analog signal if2=rf-LO 2;
the third filter module is used for filtering local oscillation interference signals in the intermediate frequency analog signals IF2 and sending the local oscillation interference signals to the high-speed ADC analog-to-digital conversion module;
the signal processing module is configured to convert the intermediate frequency analog signal IF into a radio frequency spectrum, and includes: the device comprises a high-speed ADC analog-to-digital conversion module, a time slice control module, a fast Fourier transform FFT module, an amplitude conversion module, a medium frequency spectrum statistics module, a radio frequency spectrum statistics module and a logic control module;
wherein the high-speed ADC analog-to-digital conversion module receives the intermediate frequency analog signal IF2 and converts the intermediate frequency analog signal IF2 into an intermediate frequency digital signalThe method comprises the steps of carrying out a first treatment on the surface of the The output sequentially passes through a time slice control module, a fast Fourier transform FFT module and an amplitude conversion moduleThe device comprises a block, a medium frequency spectrum statistics module, a radio frequency spectrum statistics module and a logic control module;
as a further improvement of the present invention, the time slice control module is configured to divide the monitoring time T into 8 time slices uniformly in the time domain, and the time slices are denoted as T0 (i), T1 (i), T2 (i), …, and T7 (i), where i=0, 1, …, N, and t=t0×n;
the fast Fourier transform FFT module correspondingly sends the intermediate frequency digital signals IF in the time slices T0 (i) to T7 (i) into fast Fourier transform FFT0 to FFT7 cores to obtain FFT results FFT_T1 (i), … and FFT_T7 (i);
the amplitude conversion module is used for carrying out amplitude adjustment on the FFT_T1 (i), … and FFT_T7 (i) obtained by the FFT module, converting an amplitude unit from a code value into a power unit dBm, and obtaining amplitude adjustment results P_T0 (i), … and P_T7 (i);
the intermediate frequency spectrum statistics module is used for counting P_T0 (i), … and P_T7 (i) in the monitoring time T, and the power P (power P: Pmin ～Pmax Power resolution Δpmax ) The different intermediate frequency Freq (frequency Freq: freqmin ～Freqmax ) The number of occurrences at the time gives the intermediate frequency spectrum statistics sum_if (i, j), i=0, …, ((P)min ～Pmax )/ ΔPmax ) The method comprises the steps of carrying out a first treatment on the surface of the j=0, …, (FFT point number M-1);
the radio frequency spectrum statistics module is configured to convert the intermediate frequency spectrum statistics sum_if (i, j) into radio frequency spectrum statistics sum_rf (i, j) according to a microwave frequency conversion formula rf=if+lo, and send the radio frequency spectrum statistics result to the user terminal.
The logic control module is used for monitoring whether the time T is finished or not and judging that a new working frequency band monitoring task exists in the monitoring time T. And if a new work frequency band monitoring task is received, carrying out real-time frequency spectrum statistics again. And (5) not receiving a new work frequency band monitoring task and ending the task.
The beneficial effects are that: according to the scheme, the function expansion is performed on the basis of the original monitoring equipment hardware, the radar monitoring method based on broadband real-time spectrum analysis is used, burst signals can be effectively captured, pulse radar signals and continuous wave radar signals are obviously distinguished in a spectrum analysis domain, meanwhile, various complex electromagnetic environment signals can be effectively distinguished in frequency, energy and other details, and the monitoring capability of the radar monitoring equipment is greatly enhanced.
Drawings
Fig. 1 is a schematic block diagram of a real-time spectrum analysis system of the present invention.
Fig. 2 is a flow chart of the broadband real-time spectrum analysis of the present invention.
FIG. 3 is a timing diagram of the broadband real-time spectrum analysis of the present invention.
Fig. 4 is a diagram of a spectrometer analyzing a noise fm signal.
Fig. 5 is a diagram of the wideband real-time spectrum versus noise fm signal analysis of the present invention.
Description of the embodiments
The technical scheme of the invention is further specifically described below through examples and with reference to the accompanying drawings.
As shown in fig. 1, in a radar monitoring method based on broadband real-time spectrum analysis, a receiving antenna receives an electromagnetic signal, converts the electromagnetic signal into a radio frequency signal, and sends the radio frequency signal to a signal preprocessing module for converting the received radio frequency signal RF into an intermediate frequency analog signal IF; and then the intermediate frequency analog signal IF is converted into a radio frequency spectrum through a signal processing module and is sent to a user side.
Wherein, the signal preprocessing module includes: the device comprises a limiter module, an amplifier module, a first filter module, a first mixer module, a second filter module, a second mixer module and a third filter module;
the amplitude limiter module is connected with the receiving antenna module and used for limiting the amplitude of the received radio frequency signal; the output sequentially passes through an amplifier module, a first filter module, a first mixer module, a second filter module, a second mixer module and a third filter module;
in this embodiment, the limiter module limits the amplitude of the received radio frequency signal to between-40 dBm and 15dBm.
The amplifier module is used for amplifying the power of the radio frequency signal after amplitude limiting;
the first filter module is used for filtering interference signals in the radio frequency signals;
the first mixer module is used for providing a local oscillation signal LO1, moving the radio frequency signal to an intermediate frequency to obtain an intermediate frequency analog signal IF1=RF-LO1;
the second filter module is used for filtering local oscillation interference signals in the intermediate frequency analog signals IF 1;
the second mixer module is used for providing a local oscillation signal LO2 and mixing to obtain an intermediate frequency analog signal IF2=RF-LO2;
the third filter module is used for filtering local oscillation interference signals in the intermediate frequency analog signals IF2 and sending the local oscillation interference signals to the high-speed ADC analog-to-digital conversion module;
as shown in fig. 2, the signal processing module includes: the device comprises a high-speed ADC analog-to-digital conversion module, a time slice control module, a fast Fourier transform FFT module, an amplitude conversion module, a medium frequency spectrum statistics module, a radio frequency spectrum statistics module and a logic control module;
the high-speed ADC analog-to-digital conversion module receives the intermediate frequency analog signal IF2 and converts the intermediate frequency analog signal IF2 into an intermediate frequency digital signalThe method comprises the steps of carrying out a first treatment on the surface of the The output sequentially passes through a time slice control module, a fast Fourier transform FFT module, an amplitude conversion module, an intermediate frequency spectrum statistics module, a radio frequency spectrum statistics module and a logic control module;
the time slice control module is configured to divide the monitoring time T into 8 time slices in the time domain, and record the time slices as T0 (i), T1 (i), T2 (i), …, and T7 (i), where i=0, 1, …, N, and t=t0×n;
the fast Fourier transform FFT module correspondingly sends the intermediate frequency digital signals IF in the time slices T0 (i) to T7 (i) into fast Fourier transform FFT0 to FFT7 cores to obtain FFT results FFT_T1 (i), … and FFT_T7 (i);
the amplitude conversion module is used for carrying out amplitude adjustment on the FFT_T1 (i), … and FFT_T7 (i) obtained by the FFT module, converting an amplitude unit from a code value into a power unit dBm, and obtaining amplitude adjustment results P_T0 (i), … and P_T7 (i);
an intermediate frequency spectrum statistics module for counting P_T0 (i), …, P_T7 (i) at different powers P (power P: P) within a monitoring time Tmin ～Pmax Power resolution Δpmax ) The different intermediate frequency Freq (frequency Freq: freqmin ～Freqmax ) The number of occurrences at the time gives the intermediate frequency spectrum statistics sum_if (i, j), i=0, …, ((P)min ～Pmax )/ ΔPmax ) The method comprises the steps of carrying out a first treatment on the surface of the j=0, …, (FFT point number M-1);
the radio frequency spectrum statistics module is used for converting the intermediate frequency spectrum statistics sum_if (i, j) into radio frequency spectrum statistics sum_rf (i, j) according to a microwave frequency conversion formula rf=if+lo, and transmitting the radio frequency spectrum statistics result to the user terminal.
The logic control module is used for monitoring whether the time T is finished or not and judging that a new working frequency band monitoring task exists in the monitoring time T. If a new working frequency band monitoring task is received, carrying out real-time frequency spectrum statistics again, and ending the task if the new working frequency band monitoring task is not received.
In addition, the embodiment takes the noise spectrum signal and the burst signal as input, and the scheme of the invention is simulated and analyzed.
As shown in fig. 4, a spectrum analysis result diagram is shown, and it can be found that: conventional spectrometers can analyze noisy fm signals but fail to find burst signals in the simulation results.
As shown in fig. 5, for the analysis chart of the broadband real-time spectrum of the present invention for noise fm signals, it can be found that: the scheme of the invention can carry out limited analysis on noise frequency modulation signals and burst signals, which shows that the scheme of the invention can effectively capture burst signals, can obviously distinguish pulse radar signals and continuous wave radar signals in a frequency spectrum analysis domain, can effectively distinguish various complex electromagnetic environment signals in details such as frequency, energy and the like, and greatly enhances the monitoring capability of radar monitoring equipment.
As described above, although the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.