A 2GHz Instantaneous Bandwidth Radar Target Echo Simulation System

Abstract

A 2GHz instantaneous bandwidth radar target echo simulation system, relating to the technical field of radar target echo simulation systems, comprises a radio frequency downconversion module, an analog-to-digital converter, a field programmable gate array, a digital-to-analog converter, and a radio frequency upconversion module. Utilizing a high sampling frequency AD and 16-channel multiphase operation, the FPGA sampling frequency is 375MHz. Combining 16 channels of signals yields a total sampling rate of 6GHz, increasing the instantaneous bandwidth to 2GHz. This system combines high instantaneous bandwidth, high resolution, multiple scattering points, and integration.

Description

Technical Field

[0001] The present invention relates to the technical field of radar target echo simulation systems, in particular to a 2GHz instantaneous bandwidth radar target echo simulation system. Background Art

[0002] Radar target echo simulation is a technology that stores radar signals, adds appropriate delays, modifies Doppler frequency and amplitude, and then forwards them. This technology arose from the needs of radar debugging and testing and has advanced significantly with the emergence of technologies such as field-programmable gate arrays (FPGAs), digital radio frequency memory (DRFM), and direct frequency generation (DDS).

[0003] The instantaneous bandwidth of a radar target echo simulation system determines the bandwidth of the radar transmit signal it can simulate. A larger instantaneous bandwidth increases the range of radar signal types that can be simulated and improves the resolution of the radar target echo simulation system. The instantaneous bandwidth of a device is limited by the sampling frequency of hardware devices such as the analog-to-digital converter (ADC) and FPGA. To increase the instantaneous bandwidth, hardware with a higher sampling frequency can be used, or multiphase operation can be employed. Multiphase operation processes multiple channels of signals at the expense of FPGA computing power, then combines them into one channel through the ADC, thereby increasing the instantaneous bandwidth. Summary of the Invention

[0004] The significance of this invention lies in providing an implementation of a 2GHz instantaneous bandwidth radar target echo simulation system. This system utilizes a high-sampling-frequency analog-to-digital conversion module and 16-channel multiphase operation, combining the analog-to-digital converter into one channel to improve the instantaneous bandwidth. This system combines high instantaneous bandwidth with high resolution, multiple scattering points, and integration.

[0005] A 2GHz instantaneous bandwidth radar target echo simulation system includes a radio frequency down-conversion module, an analog-to-digital converter, a field programmable gate array, a digital-to-analog converter, and a radio frequency up-conversion module. The radio frequency down-conversion module converts an input radio frequency analog signal into an intermediate frequency signal that can be processed by the digital-to-analog converter. The analog-to-digital converter uses 16 outputs to convert the analog intermediate frequency signal into a digital intermediate frequency signal. The field programmable gate array stores the signal, changes the delay, power, and Doppler frequency, and sends the signal. The digital-to-analog converter uses 16 inputs to convert the intermediate frequency digital signal into an intermediate frequency analog signal. The radio frequency up-conversion module converts the intermediate frequency analog signal into an radio frequency analog signal to be output.

[0006] Preferably, the field programmable gate array includes a digital down-conversion module, a modulation module and a digital up-conversion module. The digital down-conversion module converts the intermediate frequency signal into a baseband signal. The modulation module stores the baseband signal, changes the amplitude, phase and Doppler frequency of the signal and sends it out after a delay. The digital up-conversion module converts the modulated baseband signal into an intermediate frequency signal.

[0007] Preferably, the digital down-conversion module includes a down-conversion DDS module, a down-conversion 16-phase multiplication module, and a down-conversion low-pass filter. The down-conversion DDS module generates 16 mixed signals. The down-conversion 16-phase multiplication module multiplies the 16 mixed signals with 16 digital intermediate frequency signals respectively to obtain 16 mixed signals. The down-conversion low-pass filter filters out high-frequency non-target signals to obtain a baseband target signal.

[0008] Preferably, the modulation module includes a large delay control module, a modulation DDS module, a multi-scattering point control module, and a modulation low-pass filter module. The large delay control module stores the baseband target signal in RAM, and then delays the output of the 16-phase target signal according to the large delay control word. The modulation DDS module generates a Doppler frequency point frequency signal according to the Doppler frequency control word. The multi-scattering point control module multiplies the 16 signals from the modulation DDS module and the large delay control module respectively, and changes the amplitude and phase. The modulation low-pass filter module filters out non-target components.

[0009] Preferably, the digital up-conversion module includes an up-conversion DDS module, an up-conversion 16-phase multiplier module, and an up-conversion low-pass filter. The up-conversion DDS module generates 16 mixed signals. The up-conversion 16-phase multiplier module multiplies the 16 mixed signals with the 16 baseband signals respectively to obtain 16 mixed signals. The up-conversion low-pass filter filters out high-frequency non-target signals to obtain an intermediate frequency target signal.

[0010] The beneficial effects of the present invention are as follows: Based on the basic radar target echo simulation equipment, the present invention utilizes a 16-channel multiphase operation method to increase the instantaneous bandwidth to 2 GHz, taking into account the characteristics of high instantaneous bandwidth, high resolution, multiple scattering points and integration. It can be applied to target echo simulation projects with high instantaneous bandwidth requirements such as SAR radar and ultra-wideband signals, thereby improving the signal resolution. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 2GHz instantaneous bandwidth radar target echo simulation device principle block diagram;

[0012] Figure 2 2GHz instantaneous bandwidth radar target echo simulation device field programmable gate array principle block diagram;

[0013] Figure 3 2GHz instantaneous bandwidth radar target echo simulation device digital down-conversion module principle block diagram;

[0014] Figure 4 2GHz instantaneous bandwidth radar target echo simulation device modulation module principle block diagram;

[0015] Figure 5 2GHz instantaneous bandwidth radar target echo simulation device digital up-conversion module principle block diagram;

[0016] In the figure, 1-RF down-conversion module, 2-analog-to-digital converter, 3-field programmable gate array, 4-digital-analog converter, 5-RF up-conversion module, 6-digital down-conversion module, 7-modulation module, 8-digital up-conversion module, 9-down-conversion-DDS module, 10-down-conversion 16-phase multiplier module, 11-down-conversion low-pass filter module, 12-large delay control module, 13-multi-scattering point control module, 14-modulation low-pass filter module, 15-modulation DDS module, 16-up-conversion 16-phase multiplier module, 17-up-conversion low-pass filter module, and 18-up-conversion DDS module. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, a 2 GHz instantaneous bandwidth radar target echo simulation system includes an RF downconversion module, an analog-to-digital converter (ADC), a field programmable gate array (FPGA), a digital-to-analog converter (DAC), and an RF upconversion module. The RF downconversion module converts the input RF analog signal into an intermediate frequency (IF) signal that can be processed by the ADC. The ADC converts the analog IF signal into a digital IF signal. The FPGA stores the signal, modifies the delay, power, and Doppler frequency, and transmits the signal. The DAC converts the IF digital signal into an IF analog signal. The RF upconversion module converts the IF analog signal into an RF analog signal to be output. It is worth noting that the ADC uses 16 outputs and the DAC uses 16 inputs to ensure the FPGA's 16-channel multiphase operation.

[0019] like Figure 2 As shown, the field programmable gate array (FPGA) preferably includes a digital down-conversion module, a modulation module, and a digital up-conversion module. The digital down-conversion module converts the intermediate frequency (IF) signal into a baseband signal. The modulation module stores the baseband signal, modifies the signal's amplitude, phase, and Doppler frequency, and then transmits it after a delay. The digital up-conversion module converts the modulated baseband signal into an IF signal. In this embodiment, the FPGA sampling frequency is 375 MHz. Combining 16 signals yields a total sampling rate of 6 GHz, and the instantaneous bandwidth can be increased to 2 GHz.

[0020] like Figure 3As shown, the digital down-conversion module includes a down-conversion DDS module, a down-conversion 16-phase multiplication module, and a down-conversion low-pass filter. The down-conversion DDS module generates 16 center frequency mixed signals (the center frequency here is 1.5GHz, and each signal has two components, I and Q). The down-conversion 16-phase multiplication module multiplies the 16 mixed signals with 16 digital intermediate frequency signals to obtain 16 mixed signals. The frequency range of each mixed signal is -1GHz. - +2GHz. The cutoff frequency of the down-conversion low-pass filter is 1GHz, and the IQ components are extracted to filter out high-frequency non-target signals and obtain 16 baseband target signals, each with a frequency of -1GHz. - +1GHz.

[0021] like Figure 4 As shown, the modulation module includes a large delay control module, a modulation DDS module, a multi-scattering point control module, and a modulation low-pass filter module. The large delay control module stores the baseband target signal in RAM, and then delays the output of the 16-phase target signal according to the large delay control word. The modulation DDS module generates a Doppler frequency point signal according to the Doppler frequency control word. The multi-scattering point control module multiplies the 16 signals from the DDS module and the large delay control module respectively, controls the number of output signals and the corresponding delay according to the number of multi-scattering points and the small delay control word, controls the amplitude of the output signal by the amplitude control word, and controls the phase change of the output signal by the phase control word. The modulation low-pass filter module filters out non-target components.

[0022] like Figure 5 As shown, the digital upconversion module includes an upconversion DDS module, an upconversion 16-phase multiplier module, and an upconversion low-pass filter. The upconversion DDS module generates 16 mixed signals that can be combined to form a center frequency (the center frequency here is 1.5 GHz, and each signal has two components, I and Q). The upconversion 16-phase multiplier module first interpolates the 16 baseband signals and then multiplies the result with each of the 16 mixed signals to produce 16 mixed signals. The upconversion low-pass filter has a cutoff frequency of 2.5 GHz to filter out high-frequency non-target signals and obtain the intermediate frequency target signal.

Claims

1. A 2GHz instantaneous bandwidth radar target echo simulation system, characterized in that: It includes an RF down-conversion module, an analog-to-digital converter, a field programmable gate array, a digital-to-analog converter, and an RF up-conversion module. The RF down-conversion module converts the input RF analog signal into an intermediate frequency signal that can be processed by the digital-to-analog converter. The analog-to-digital converter uses 16 outputs to convert the analog intermediate frequency signal into a digital intermediate frequency signal. The field programmable gate array stores the signal, changes the delay, power, and Doppler frequency, and sends the signal. The digital-to-analog converter uses 16 inputs to convert the intermediate frequency digital signal into an intermediate frequency analog signal. The RF up-conversion module converts the intermediate frequency analog signal into an RF analog signal to be output. The field programmable gate array includes a digital down-conversion module, a modulation module and a digital up-conversion module. The digital down-conversion module converts the intermediate frequency signal into a baseband signal. The modulation module stores the baseband signal, modifies the amplitude, phase and Doppler frequency of the signal and sends it out after delay. The digital up-conversion module converts the modulated baseband signal into an intermediate frequency signal. The digital down-conversion module includes a down-conversion DDS module, a down-conversion 16-phase multiplication module, and a down-conversion low-pass filter. The down-conversion DDS module generates 16 mixed signals. The down-conversion 16-phase multiplication module multiplies the 16 mixed signals with 16 digital intermediate frequency signals to obtain 16 mixed signals. The down-conversion low-pass filter filters out high-frequency non-target signals to obtain a baseband target signal. The modulation module includes a large delay control module, a modulation DDS module, a multi-scattering point control module, and a modulation low-pass filter module. The large delay control module stores the baseband target signal in RAM, and then delays the output of the 16-phase target signal according to the large delay control word. The modulation DDS module generates a Doppler frequency point frequency signal according to the Doppler frequency control word. The multi-scattering point control module multiplies the 16 signals from the modulation DDS module and the large delay control module respectively to change the amplitude and phase. The modulation low-pass filter module filters out non-target components. The digital up-conversion module includes an up-conversion DDS module, an up-conversion 16-phase multiplier module, and an up-conversion low-pass filter. The up-conversion DDS module generates 16 mixed signals. The up-conversion 16-phase multiplier module multiplies the 16 mixed signals with 16 baseband signals respectively to obtain 16 mixed signals. The up-conversion low-pass filter filters out high-frequency non-target signals to obtain an intermediate frequency target signal.

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