CN103675772B - A multifunctional SAR complex electromagnetic environment simulator - Google Patents

Abstract

A kind of Multifunctional SAR complex electromagnetic environment simulator, comprises antenna and microwave subsystem, base band interfere information produces and modulating unit, control display and model unit.Antenna and microwave subsystem obtain SAR radar emission signal, export to base band interfere information after carrying out power adjustment and multiple stage downconversion to produce and modulating unit, base band interfere information is produced and frequency interference signal in modulating unit output simultaneously, after carrying out multistage up-conversion and power control, export to SAR radar.The generation of base band interfere information and modulating unit, according to the control command received and parameter, calculate the baseband modulation information producing multiple interference type in real time, baseband modulation information and if radar signal are produced required undesired signal after ovennodulation.Control display and model unit to call interference model and produce interference parameter according to simulating requirement and deliver to base band interfere information and produce and modulating unit, the running status of whole analogue means is monitored and reference record simultaneously.

Description

A multifunctional SAR complex electromagnetic environment simulator

technical field

The invention belongs to the communication field and relates to a SAR electromagnetic environment simulation device.

Background technique

Synthetic Aperture Radar (abbreviated as SAR) has the characteristics of all-day, all-weather detection and imaging, strong perspective, high resolution, and good anti-interference ability. These characteristics make SAR widely used in the aerospace field. In actual use, SAR may face interference from the complex electromagnetic environment in the space environment, so it is necessary to test and assess its electromagnetic environment adaptability before the technical status of SAR products is finalized.

At present, for the assessment of the adaptability of SAR to complex electromagnetic environments, it is mainly through the modes of flying in the field of aircraft and actual flight of aerospace vehicles, and the test cost is high and expensive. There is no relevant report on the research on the indoor equivalent alternative method of SAR electromagnetic environment adaptability assessment in the technical literature published abroad. In the domestic technical literature, "Design and Research of Radar Jamming Simulator" published in "Basics of National Defense Technology" in November 2010 explained the composition and basic working principle of a radar jamming simulator from the basic principle, but its description is relatively It is simple, and does not fully cover the complex electromagnetic environment for the working mode and characteristics of SAR.

Therefore, for the specific application of SAR in the indoor equivalent assessment of complex electromagnetic environment adaptability, it is necessary to research and develop an equivalent simulation device, by applying different types of electromagnetic environment interference, to assess the SAR in the specified interference type or the superposition of multiple interference types The ability to adapt to the environment.

Contents of the invention

The technical solution of the present invention is to overcome the deficiencies of the prior art and provide a multi-functional SAR complex electromagnetic environment simulation device, which can receive radar transmission signals in real time according to the SAR working mode and scene parameters, and transmit them through space radiation or direct feed The cable coupling method simulates space electromagnetic interference signals from different directions and various types of superimposition, which is used for the anti-interference performance test of SAR.

The technical solution of the present invention is: a multi-functional SAR complex electromagnetic environment simulation device, including antenna and microwave subsystem, baseband interference information generation and modulation unit, SAR real-time image acquisition unit, control display and model unit, wherein:

Antenna and microwave subsystem: including horn antenna, radio frequency cable, AGC unit, multi-level down-conversion unit, frequency synthesis unit, multi-level up-conversion unit, power adjustment unit; SAR radar transmit signal is received through horn antenna space or sent through radio frequency cable To the AGC unit, the AGC unit adjusts the power of the SAR radar transmission signal and sends it to the multi-stage down-conversion unit. The multi-stage down-conversion unit performs two-stage down-conversion on the power-adjusted SAR radar transmission signal to obtain an intermediate frequency radar signal and outputs it to the baseband Interference information generation and modulation unit; the multi-stage up-conversion unit performs two-stage up-conversion on the baseband interference information generation and the intermediate frequency interference signal generated by the modulation unit, and then sends it to the power adjustment unit, and the power adjustment unit performs power on the up-converted intermediate frequency interference signal After adjustment, the radio frequency interference signal is obtained. The radio frequency interference signal is radiated through the horn antenna space or sent to the SAR radar through the radio frequency cable; The information generation and modulation unit provides a working clock;

Baseband interference information generation and modulation unit: including instantaneous frequency measurement unit, interference information real-time calculation unit, and interference information real-time modulation unit; the interference information real-time calculation unit generates baseband modulation of the corresponding interference type according to the interference parameters transmitted from the control display and model unit Information; the instantaneous frequency measurement unit obtains the frequency of the intermediate frequency radar signal through the method of digital frequency measurement; the interference information real-time modulation unit generates the required intermediate frequency interference signal after modulation according to the frequency of the intermediate frequency radar signal and the intermediate frequency radar signal. Baseband interference information generation and modulation unit;

SAR real-time image acquisition unit: receive SAR real-time image through LVDS interface and send it to the control display and model unit;

Control display and model unit: including interface control and display unit, interference model unit; interference model unit stores suppression interference model, deception interference model, related interference model, chaff interference model, clutter interference model, according to the interference conditions input from the outside Call the corresponding interference model to generate corresponding interference parameters and send them to the real-time calculation unit of interference information; control the power of the power adjustment unit according to the external input interference conditions; compare the image generated by the SAR radar under interference conditions with the actual image , to obtain the SAR interference effect; to monitor and record the operating status of the entire simulation device.

The multi-stage down-conversion unit includes two mixers, an automatic gain regulator, and a low-pass filter; the 12-18GHz radio frequency signal emitted by the SAR radar passes through the local oscillator signal of the frequency range 12-16GHz provided by the frequency synthesis unit The first mixer performs the first-stage down-conversion to obtain the first intermediate frequency signal of 2GHz; after the first intermediate frequency signal undergoes automatic gain control by the automatic gain regulator, the 2.5GHz local signal provided by the second mixer and the frequency synthesis unit The vibrating signal is mixed for the second-stage down-conversion, and the signal after the second-stage down-conversion is passed through a low-pass filter to obtain an intermediate frequency radar signal of 500±250MHz.

The multi-stage up-conversion unit includes two mixers, a bandpass filter, a switch filter bank, two amplifiers and an attenuator; the intermediate frequency interference signal and the 2.5GHz local oscillator signal provided by the frequency synthesis unit are in the third mixer The signal of 2GHz frequency is obtained by mixing in the frequency converter; the signal of 2GHz frequency is sent to the fourth mixer after being filtered by a bandpass filter and amplified by the first amplifier, and the signal of 2GHz center frequency is synthesized with the frequency in the fourth mixer The 12-16GHz local oscillator signal provided by the unit is mixed to obtain a signal with a center frequency of 12-18GHz and an intermediate signal with a signal bandwidth of 500MHz. After the intermediate signal is filtered by a switch filter bank to filter out the corresponding frequency band, the 12-18GHz that meets the purity requirements is obtained. Signals, 12-18GHz signals that meet the purity requirements are attenuated by the program-controlled attenuator and amplified by the second amplifier to obtain the required radio frequency interference signal.

The advantage of the present invention compared with prior art is:

(1) The device of the present invention separates the interference model from the generation of baseband interference information and the modulation unit. The interference model can be configured independently. The simulation of combined interference signals of five types of interference, wave interference and chaff interference, constitutes a complex electromagnetic environment, while effectively reducing the size and cost of hardware equipment;

(2) The interference signal simulated by the device of the present invention can be received by the radar through radio frequency injection or space radiation, and the use method is flexible. The power of the interference signal can be flexibly configured according to actual needs, effectively simulating the effects of various interference radiation sources at various operating distances Effect;

(3) The device of the present invention has the function of SAR real-time image acquisition, which provides conditions for evaluating and comparing SAR image output results in various electromagnetic environments;

(4) According to the characteristics of ultra-wide working bandwidth of SAR, the present invention performs multi-level down-conversion control and multi-level up-conversion processing on the radio frequency signal based on the two-level local oscillator signal output by the broadband frequency synthesis, so that the equipment can adapt to a wider frequency range , while ensuring that the system provides a high level of spurious suppression in the ultra-wideband frequency range.

Description of drawings

Fig. 1 is the block diagram of composition principle of device of the present invention;

Fig. 2 is the block diagram of the composition principle of the multistage down-conversion unit of the present invention;

Fig. 3 is a block diagram of the composition principle of the multi-stage up-conversion unit of the present invention;

Fig. 4 is the composition principle block diagram of frequency synthesis unit of the present invention;

Fig. 5 is a composition principle diagram of the SAR real-time image acquisition unit of the present invention.

Detailed ways

As shown in Figure 1, the multifunctional SAR complex electromagnetic environment simulator of the present invention is composed of the following subsystems: antenna and microwave subsystem, baseband interference information generation and modulation unit, SAR real-time image acquisition unit, control display and model unit.

The antenna and microwave subsystem is mainly composed of horn antenna, radio frequency cable, multi-stage down-conversion, AGC, multi-stage up-conversion, power adjustment, power splitter, frequency synthesis and other modules. The main function of this subsystem has two parts. The first part is to obtain the SAR radar transmission signal through space reception or line feed, and perform power adjustment and multi-stage down-conversion on the signal, and then output the intermediate frequency radar signal to the baseband interference information. Generation and modulation unit. The second part is to perform multi-level up-conversion and power control on the baseband interference information generation and the intermediate frequency interference signal output by the modulation unit, and then output it to the SAR radar under test through antenna radiation or line feed.

The baseband interference information generation and modulation unit includes several components such as instantaneous frequency measurement, real-time calculation of interference information, and real-time modulation of interference information. According to the received control commands and parameters, the interference information real-time calculation module can generate baseband modulation information of various types of interference, including suppression interference, deception interference, correlation interference, clutter interference and chaff interference; The frequency algorithm provides the frequency of the intermediate frequency radar signal. For the digital frequency measurement algorithm, refer to "Wideband Single Bit Instantaneous Frequency Measurement Reception Technology Based on Real-time Digital Signal Processing" published in "Ship Electronic Countermeasures" in March 2012; the interference information real-time modulation module is used The real-time calculated interference information and the intermediate frequency radar signal frequency information obtained by instantaneous frequency measurement are modulated to generate the required interference signal, which includes broadband signal AD acquisition, digital down-conversion, baseband interference information modulation, digital up-conversion and broadband DA And so on.

The SAR real-time image acquisition unit receives the SAR real-time image through the LVDS interface, can compare the image generated by the radar under interference conditions with the actual image, and evaluate the SAR interference effect through the interference evaluation software.

The control display and model unit is mainly composed of two main parts: interface control and display and interference model. The interference model calculates the parameters of various types of interference information required according to the interface setting parameters, and sends the parameters to the baseband interference information generation and modulation unit; according to the set interference power, interference signal frequency and other parameters, the antenna and microwave splitter The system is controlled; the operating status of the entire simulation device is monitored and the parameters are recorded.

The working principle of the system is: before the simulation starts, the operator completes the interference decision-making and the setting of interference parameters by controlling the display and the interference model unit. The interference model generates control commands and outputs them to the baseband interference information according to the set parameters and corresponding models. and modulation unit. The antenna and microwave subsystems receive radar radio frequency signals in the form of air feed or line feed. After power adjustment, the low power radar radio frequency signals are down-converted to obtain radar intermediate frequency signals for signal collection. The baseband interference information generation and modulation unit uses A/D to collect radar signals, and after instantaneous frequency measurement and digital down-conversion, it is used to convolve with interference parameters. The interference parameters are mainly calculated by the interference information real-time calculation module according to the control command (suppression Interference, etc. are generated directly according to the model without convolution). The interference signal generated after convolution is output to the antenna and microwave subsystem after D/A conversion. The antenna and microwave subsystem complete frequency up-conversion and filtering, power amplification and power control, and finally output to the antenna through line feed or space radiation. Radar under test. The SAR real-time image acquisition unit receives the SAR real-time image through the LVDS interface, and evaluates the SAR interference effect.

As shown in Figure 2, it is a block diagram of the composition of the multi-stage down-conversion unit in the antenna and microwave subsystem. The 12-18GHz radio frequency signal transmitted by the SAR and the local oscillator signal with a frequency range of 12-16GHz are down-converted in the first stage to obtain the first intermediate frequency signal of 2GHz; after the first intermediate frequency signal is controlled by automatic gain control, the second-stage down-conversion is performed, and the The 2.5GHz local oscillator signal is mixed and low-pass filtered to obtain a 500±250MHz second intermediate frequency signal (IF radar signal), which is provided to the baseband interference information generation and modulation unit.

As shown in Figure 3, the multi-stage up-conversion unit is used to convert the baseband interference information generation and the intermediate frequency interference signal of the modulation unit into radio frequency interference signals, and control the power of the interference signals. In the first stage of frequency conversion, the intermediate frequency interference signal is mixed with the 2.5GHz local oscillator signal to obtain a 2GHz frequency signal; in the second stage of frequency conversion, the 2GHz center frequency signal is filtered and amplified and then mixed with the 12-16GHz local oscillator signal from the frequency synthesizer The signal with a center frequency of 12-18GHz can be obtained at a frequency of 12-18GHz, and the signal bandwidth is 500MHz, and then the corresponding frequency band can be filtered out by a switch filter bank, and the signal of 12-18GHz with the required spectral purity can be obtained, and finally, it can be controlled by program-controlled attenuation and power amplification. , the desired radio frequency interference signal can be obtained.

As shown in Figure 4, the broadband frequency synthesis utilizes the SAR synchronization signal to provide the baseband interference information generation and the synchronization clock required by the modulation unit and the broadband variable local oscillator and intermediate frequency required by the frequency conversion link; the built-in crystal oscillator can also be used as a The reference provides a synchronous clock and local oscillator and intermediate frequencies. Broadband frequency synthesis adopts frequency mixing and phase-locking technology, in which the reference phase-locked loop generates a small step signal, and the signal is processed and then input to the main phase-locked loop; The output signal is mixed and input to the main loop; the main loop controls the phase-locked polarity to select the locked frequency range, and generates a voltage signal Vt to control the RF voltage-controlled oscillator; the output signal of the voltage-controlled oscillator is equalized by the amplifier after frequency multiplication and frequency band selection output. The amplifier is used to amplify the signal and provide a certain power, and the equalizer ensures the flatness of the signal within the bandwidth.

The ultra-wideband double-ridge horn antenna selected by the antenna has an extremely wide frequency bandwidth and high gain. Frequency coverage is greater than one octave.

The baseband interference information generation and modulation unit collects the low-intermediate frequency radar emission broadband signal output by the multi-stage down-conversion unit, performs instantaneous frequency measurement, digital down-conversion, and convolves with the interference information, digital up-conversion, and DA outputs low-interference frequency interference signals; Suppress jamming signals, including aiming noise jamming, blocking noise jamming, sweeping noise jamming, covering pulse jamming, such signals have nothing to do with radar transmission signals; generate related jamming signals, including convolution noise, Doppler noise and dense Duplication, such signals are related to radar emission signals; generate deceptive jamming signals, including point targets and surface targets, such signals are related to radar emission signals; generate chaff and ground clutter interference signals, such signals are coherent with radar emission signals .

The baseband interference information generation and modulation unit controls the reception of intermediate frequency radar signals, which are transformed into baseband signals containing SAR signal characteristics through analog-to-digital conversion and digital down-conversion; the interference information real-time calculation module receives interference signal parameters, and generates corresponding suppression interference, correlation, Deception interference model; under the control of the synchronous clock, the interference information real-time calculation module uses the generated interference model to modulate the baseband signal containing the characteristics of the SAR signal to obtain the baseband interference signal that can interfere with the SAR; the baseband interference signal is passed After digital up-conversion and digital-to-analog conversion, an intermediate frequency interference signal is obtained and sent to subsequent multi-stage up-converters.

As shown in Figure 5, the SAR real-time image acquisition unit uses the LVDS interface to output high-speed and large-capacity real-time image data from the SAR. The chip clock frequency of the LVDS interface is 12MHz, and the bus transmission code rate is 144Mbps.

The role of the control display and model unit is to control the simulated interference signal type, interference signal frequency and power, etc., and to monitor the operating status of the entire device and record parameters; and the interference model will calculate the work of the baseband unit according to the parameters set on the interface. Various types of interference information calculation parameters required.

Various interference models are introduced in detail below.

1. Suppress interference

Suppression jamming includes aiming noise jamming, blocking noise jamming, sweeping noise jamming, covering pulse jamming and comb spectrum jamming. The sparse spectrum interference model is realized by referring to "Simulation Research on Comb Spectrum Interference of No Carrier Frequency Ultra-Wideband Radar" published in "Computer Simulation" in June 2008. Blocking noise jamming, aiming noise jamming, sweeping noise jamming, Covering pulse interference and other suppression interference models refer to the 2010 University of Electronic Science and Technology of China master's degree thesis "Research on Radar Active Jamming Generation Technology Based on FPGA".

2. Related interference

Related jammers include convolution noise, Doppler noise, and dense copy jammers.

The convolution noise interference model is realized by referring to "Convolution Interference Technology for Chirp Radar" published in "Journal of Electronics and Information Technology" in June 2007. Due to the mismatch between the traditional noise interference signal and the radar signal processor, most of the interference energy is filtered out by the matched filter, which reduces the interference effect. The convolution noise is to convolve the baseband noise and the baseband radar signal to obtain the convolution noise signal, and then up-convert the output. The main purpose of this is to reduce the energy loss of the noise interference signal after passing through the matched filter, and then cover the echo signal after pulse compression, affecting subsequent detection. Convolution noise can make full use of interference energy, and can produce better interference effect on chirp compression radar under lower power input.

The Doppler noise interference model is realized by referring to the "Interference Analysis of Doppler Noise to PD Radar Based on Narrowband Noise Phase Modulation" published in "Electronic Information Countermeasure Technology" in April 2010. During implementation, the maximum bandwidth of the Doppler noise signal is 5MHz, which is relatively small compared to the platform system clock of 250MHz. After generating Gaussian white noise with a specific bandwidth, in order to achieve a sampling rate of 250MHz, it is necessary to perform band-limited white noise Interpolation filtering processing. Since the interpolation multiple is high, in order to save hardware logic resources, a cascaded integral comb filter is used here to realize it.

The Doppler noise interference model is realized by referring to the 2010 master's degree thesis of the University of Electronic Science and Technology of China "Research on Radar Active Interference Generation Technology Based on FPGA". False target dense copy jamming adopts the method of delay superposition to cover the target echo in the distance upward, and the interference signal can obtain processing gain in the distance upward, cover the real target, and achieve the effect of linear interference. It is realized in the way of dense replication, using the delay module to read the data after a period of delay, and the copied target is only different from the original target in distance. The number of densely replicated pulses in a single RRI is 100, and the pulses are evenly distributed in distance, with the same Doppler and the same amplitude.

3. Deceptive Interference

The deceptive jamming model is realized by referring to "Research on SAR Active Deceptive Jamming Model" published in "Modern Defense Technology" in August 2009. Deceptive interference is mainly based on the generation method of the SAR target echo to generate a false target echo. After receiving the SAR radar transmission signal, the false target response is directly transmitted to the radar, so that the SAR radar received signal is mixed with certain false target information. After general SAR imaging processing, a SAR false target or image is formed.

For point target interference, in the implementation process, each target in the lattice can be regarded as an independent SAR point target, and each target is subjected to independent phase modulation, and the target motion is processed according to uniformly accelerated linear motion, through the FPGA Complete the interpolation operation of the target trajectory, and finally weight the output of multiple independent point targets to obtain the dot matrix target echo signal simulation.

For surface target interference, considering the large number of SAR surface target simulation scattering points, it is unrealistic for FPGA to realize the usual point target realization method, so the realization of the surface target requires the current PRI (pulse repetition interval) to be set in advance And the PRI remains unchanged, the echo transfer function of the current simulation system is obtained, the system replays and updates the echo transfer function in real time, and then the baseband target echo signal is obtained by convolution with the radar baseband signal. The radar baseband signal required for real-time convolution is obtained by collecting the radar intermediate frequency signal, and then performing digital down-conversion and FFT (fast Fourier transform) processing.

4. Ground clutter interference

The ground clutter interference model is realized by referring to the "Clutter Simulation Model in Radar Signal Simulator" published in "Aerospace Electronic Countermeasures" in June 2003. Clutter in radar refers to the echo component contained in the received signal due to body scattering or surface scattering. For the simulation of clutter interference, it is usually generated by real-time convolution between the baseband echo signal and the clutter model data. According to the model, the baseband clutter data is generated, which is convoluted with the received transmission signal under the trigger of the detection pulse. For the simulation modeling of clutter, it can be described by the radar cross-sectional area of clutter and the probability density function of the change of scattering rate. According to the amplitude statistical model, clutter can be divided into: Rayleigh, Weibull, log-normal, K, according to the power spectrum can be divided into: Gaussian spectrum, Cauchy spectrum, cubic spectrum.

5. Chaff interference

The chaff interference model is realized by referring to "A Modeling and Simulation Method for Chaff Cloud Echo" published in "Modern Radar" in August 2006. In order to generate chaff interference signals more conveniently, it is necessary to further simplify the echo model of chaff signals, and use simple means to reproduce various characteristics of chaff echo signals, including distance delay, distance spread, and echo power. Fluctuation, Doppler frequency shift, Doppler spread, transmitted signal form, etc. In this implementation, the chaff cloud is considered to be composed of multiple small cubes, and the movement speed of each small cube is not consistent, there will be a fluctuation of speed, which is considered to obey the normal distribution, so that we can get The Doppler frequency shift caused by the velocity fluctuation of each small cube can then generate the echo of this small cube, and finally add the echoes of all the small cubes to obtain the overall echo signal of the chaff cloud.

In actual use, multiple simulation devices proposed by the present invention can be used to simulate space electromagnetic interference signals superimposed in different directions and in various types through networking.

The content that is not described in detail in the description of the present invention belongs to the well-known technology of those skilled in the art.

Claims (3)

1. A multifunctional SAR complex electromagnetic environment simulator, characterized in that: comprising antenna and microwave subsystem, baseband interference information generation and modulation unit, SAR real-time image acquisition unit, control display and model unit, wherein: Antenna and microwave subsystem: including horn antenna, radio frequency cable, AGC unit, multi-level down-conversion unit, frequency synthesis unit, multi-level up-conversion unit, power adjustment unit; SAR radar transmit signal is received through horn antenna space or sent through radio frequency cable To the AGC unit, the AGC unit adjusts the power of the SAR radar transmission signal and sends it to the multi-stage down-conversion unit. The multi-stage down-conversion unit performs two-stage down-conversion on the power-adjusted SAR radar transmission signal to obtain an intermediate frequency radar signal and outputs it to the baseband Interference information generation and modulation unit; the multi-stage up-conversion unit performs two-stage up-conversion on the baseband interference information generation and the intermediate frequency interference signal generated by the modulation unit, and then sends it to the power adjustment unit, and the power adjustment unit performs power on the up-converted intermediate frequency interference signal After adjustment, the radio frequency interference signal is obtained. The radio frequency interference signal is radiated through the horn antenna space or sent to the SAR radar through the radio frequency cable; The information generation and modulation unit provides a working clock; Baseband interference information generation and modulation unit: including instantaneous frequency measurement unit, interference information real-time calculation unit, and interference information real-time modulation unit; the interference information real-time calculation unit generates baseband modulation of the corresponding interference type according to the interference parameters transmitted from the control display and model unit Information; the instantaneous frequency measurement unit obtains the frequency of the intermediate frequency radar signal through the method of digital frequency measurement; the interference information real-time modulation unit generates the required intermediate frequency interference signal after modulation according to the frequency of the intermediate frequency radar signal and the intermediate frequency radar signal. Baseband interference information generation and modulation unit; SAR real-time image acquisition unit: receive SAR real-time image through LVDS interface and send it to the control display and model unit; Control display and model unit: including interface control and display unit, interference model unit; interference model unit stores suppression interference model, deception interference model, related interference model, chaff interference model, clutter interference model, according to the interference conditions input from the outside Call the corresponding interference model to generate corresponding interference parameters and send them to the real-time calculation unit of interference information; control the power of the power adjustment unit according to the external input interference conditions; compare the image generated by the SAR radar under interference conditions with the actual image , to obtain the SAR interference effect; to monitor and record the operating status of the entire simulation device. 2. A kind of multifunctional SAR complex electromagnetic environment simulation device according to claim 1, is characterized in that: described multi-stage down-conversion unit comprises two frequency mixers, automatic gain regulator, low-pass filter; SAR The 12-18GHz radio frequency signal emitted by the radar and the local oscillator signal with a frequency range of 12-16GHz provided by the frequency synthesis unit are first down-converted through the first mixer to obtain the first intermediate frequency signal of 0-2GHz; the first intermediate frequency signal passes through After the automatic gain regulator performs automatic gain control, the second mixer is mixed with the 2.5GHz local oscillator signal provided by the frequency synthesis unit to perform the second-stage down-conversion, and the signal after the second-stage down-conversion passes through the low-pass filter Finally, a 500±250MHz intermediate frequency radar signal is obtained. 3. A kind of multifunctional SAR complex electromagnetic environment simulation device according to claim 1, characterized in that: said multi-stage up-conversion unit comprises two mixers, a bandpass filter, a switching filter bank, two An amplifier and an attenuator; the intermediate frequency interference signal and the 2.5GHz local oscillator signal provided by the frequency synthesis unit are mixed in the third mixer to obtain a 2GHz frequency signal; the 2GHz frequency signal is filtered by a bandpass filter and amplified by the first amplifier It is then sent to the fourth mixer, where the 2GHz center frequency signal is mixed with the 12-16GHz local oscillator signal provided by the frequency synthesis unit in the fourth mixer to obtain a signal with a center frequency of 14-18GHz and a signal bandwidth of 500MHz The intermediate signal, the intermediate signal passes through the switch filter bank to filter out the corresponding frequency band to obtain the 14-18GHz signal that meets the purity requirement, and the 14-18GHz signal that meets the purity requirement is attenuated by the program-controlled attenuator and amplified by the second amplifier in turn to obtain Desired RFI signal.