阅读说明：本技术 一种基于动态范围拆分的二次雷达全动态接收系统 (Secondary radar full-dynamic receiving system based on dynamic range splitting ) 是由 杨志强 李君惠 李武旭 于 2020-12-29 设计创作，主要内容包括：本发明公开了一种基于动态范围拆分的二次雷达全动态接收系统,其包括两个ADC模块、混频模块、信号选择模块和幅度修正模块,两个ADC模块用于对第一射频通道和第二射频通道的信号进行采样得到第一采样信号和第二采样信号,并发送至混频模块；混频模块用于分别得到第一基带IQ信号和第二基带IQ信号；信号选择模块用于检测第一基带IQ信号以及第二基带IQ信号的幅度,在第一基带IQ信号的幅度大于或等于第一门限幅度且第二基带IQ信号的幅度小于第二门限幅度时,选择第一基带IQ信号输出,在第二基带IQ信号的幅度大于或等于第二门限幅度时,选择第二基带IQ信号输出。本发明能够实现实时全动态接收,并且无失真的恢复信号相位。(The invention discloses a full-dynamic secondary radar receiving system based on dynamic range splitting, which comprises two ADC modules, a frequency mixing module, a signal selection module and an amplitude correction module, wherein the two ADC modules are used for sampling signals of a first radio frequency channel and a second radio frequency channel to obtain a first sampling signal and a second sampling signal and sending the first sampling signal and the second sampling signal to the frequency mixing module; the frequency mixing module is used for respectively obtaining a first baseband IQ signal and a second baseband IQ signal; the signal selection module is used for detecting the amplitudes of the first baseband IQ signal and the second baseband IQ signal, selecting the first baseband IQ signal to output when the amplitude of the first baseband IQ signal is greater than or equal to a first threshold amplitude and the amplitude of the second baseband IQ signal is less than a second threshold amplitude, and selecting the second baseband IQ signal to output when the amplitude of the second baseband IQ signal is greater than or equal to the second threshold amplitude. The invention can realize real-time full dynamic receiving and recover the signal phase without distortion.)

1. A full dynamic receiving system of secondary radar based on dynamic range splitting is characterized by comprising a first ADC module, a second ADC module, a frequency mixing module, a signal selection module and an amplitude correction module, wherein the first ADC module is connected with an antenna of the secondary radar through a first radio frequency channel, the second ADC module is connected with the antenna of the secondary radar through a second radio frequency channel, the gain of the first radio frequency channel is a first numerical value, the gain of the second radio frequency channel is a second numerical value, the receiving power range of the first ADC module is between the lower limit value and the third numerical value of the dynamic range of a receiver, the receiving power range of the second ADC module is between the third numerical value and the upper limit value of the dynamic range of the receiver, the first numerical value is larger than the second numerical value, the third numerical value is a negative number, and the absolute value of the third numerical value is smaller than the first numerical value by 1;

the first ADC module is used for sampling a signal of a first radio frequency channel to obtain a first sampling signal and sending the first sampling signal to the frequency mixing module; the second ADC module is used for sampling a signal of a second radio frequency channel to obtain a second sampling signal and sending the second sampling signal to the frequency mixing module;

the frequency mixing module is used for carrying out down-conversion and AM demodulation processing on the first sampling signal and the second sampling signal to respectively obtain a first baseband IQ signal and a second baseband IQ signal, and sending the first baseband IQ signal and the second baseband IQ signal to the signal selection module;

the signal selection module is used for detecting whether the amplitude of the first baseband IQ signal is greater than a first threshold amplitude and whether the amplitude of the second baseband IQ signal is greater than a second threshold amplitude, selecting the first baseband IQ signal to output to the amplitude correction module when the amplitude of the first baseband IQ signal is greater than or equal to the first threshold amplitude and the amplitude of the second baseband IQ signal is less than a second threshold amplitude, and selecting the second baseband IQ signal to output to the amplitude correction module when the amplitude of the second baseband IQ signal is greater than or equal to the second threshold amplitude;

the amplitude correction module is used for multiplying a preset correction coefficient by the first baseband IQ signal and then outputting the result, or multiplying the preset correction coefficient by a correction multiple by the second baseband IQ signal and then outputting the result, wherein the correction multiple is the amplitude corresponding to the difference value of the first numerical value and the second numerical value.

2. The secondary radar full-dynamic receiving system based on dynamic range splitting according to claim 1, wherein the signal selecting module is further configured to select the first baseband IQ signal to output to the amplitude modifying module when the amplitude of the first baseband IQ signal is greater than or equal to a first threshold amplitude and the amplitude of the second baseband IQ signal is greater than or equal to a second threshold amplitude.

3. The secondary radar full-dynamic receiving system based on dynamic range splitting according to claim 1 or 2, further comprising a first FIFO buffer module, a second FIFO buffer module and a delay control module;

the first ADC module is used for sending the first sampling signal to the first FIFO cache module; the second ADC module is used for sending a second sampling signal to the second FIFO cache module;

the first FIFO cache module is used for delaying the first sampling signal by a first amount of clocks and sending the delayed first sampling signal to the frequency mixing module;

the second FIFO cache module is used for delaying a second sampling signal by a second number of clocks and sending the delayed second sampling signal to the frequency mixing module;

the frequency mixing module is used for sending the first baseband IQ signal and the second baseband IQ signal to the delay control module;

the delay control module is used for comparing the rising edges of the first baseband IQ signal and the second baseband IQ signal, calculating a relative delay difference, calculating a first quantity and a second quantity according to a system clock and the relative delay difference when the relative delay difference is not 0 so as to respectively control the first FIFO buffer module and the second FIFO buffer module to delay, and sending the first baseband IQ signal and the second baseband IQ signal to the signal selection module when the relative delay difference is 0.

4. The secondary radar full-dynamic receiving system based on dynamic range splitting as claimed in claim 3, wherein the receiver dynamic range is-85 dBm-15 dBm.

5. The full dynamic range splitting secondary radar receiving system according to claim 4, wherein the first value is 46, the second value is 10, and the third value is-45.

6. The secondary radar full-dynamic receiving system based on dynamic range splitting according to claim 5, wherein the first threshold amplitude is an amplitude corresponding to-39 dBm, and the second threshold amplitude is an amplitude corresponding to-35 dBm.

Technical Field

The invention relates to the technical field of secondary radars, in particular to a full-dynamic receiving system of a secondary radar based on dynamic range splitting.

Background

The minimum signal receiving power of a receiver of the traditional secondary radar is-85 dBm, and the dynamic range of the receiver is known to be-15 dBm to-85 dBm because the receiving power span of the receiver is usually 70 dB. The receiving power range of the existing ADC device is +1dBm to-50 dBm, the receiving power span is about 50dB, and dynamic receiving is not satisfied.

At present, the secondary radar mainly realizes full dynamic reception through AGC (automatic gain control) or an intermediate frequency logarithmic amplifier. However, the AGC performs positive feedback control according to the received signal strength, and the radar receives signals of a short-distance target and a long-distance target in a time-sharing manner under the action of the AGC, so that the signal of the long-distance target is lost when the signal of the short-distance target is received. The intermediate frequency logarithmic amplifier has the disadvantages of high cost, signal phase damage and the like.

Disclosure of Invention

The invention aims to provide a secondary radar full-dynamic receiving system based on dynamic range splitting, which can realize real-time full-dynamic receiving and recover signal phase without distortion.

In order to solve the technical problems, the invention adopts a technical scheme that: the full-dynamic receiving system comprises a first ADC module, a second ADC module, a frequency mixing module, a signal selection module and an amplitude correction module, wherein the first ADC module is connected with an antenna of a secondary radar through a first radio frequency channel, the second ADC module is connected with the antenna of the secondary radar through a second radio frequency channel, the gain of the first radio frequency channel is a first numerical value, the gain of the second radio frequency channel is a second numerical value, the receiving power range of the first ADC module is between the lower limit value and the third numerical value of the dynamic range of a receiver, the receiving power range of the second ADC module is between the third numerical value and the upper limit value of the dynamic range of the receiver, the first numerical value is larger than the second numerical value, the third numerical value is a negative number, and the absolute value of the third numerical value is smaller than the first numerical value by 1;

the first ADC module is used for sampling a signal of a first radio frequency channel to obtain a first sampling signal and sending the first sampling signal to the frequency mixing module; the second ADC module is used for sampling a signal of a second radio frequency channel to obtain a second sampling signal and sending the second sampling signal to the frequency mixing module;

the frequency mixing module is used for carrying out down-conversion and AM demodulation processing on the first sampling signal and the second sampling signal to respectively obtain a first baseband IQ signal and a second baseband IQ signal, and sending the first baseband IQ signal and the second baseband IQ signal to the signal selection module;

the signal selection module is used for detecting whether the amplitude of the first baseband IQ signal is greater than a first threshold amplitude and whether the amplitude of the second baseband IQ signal is greater than a second threshold amplitude, selecting the first baseband IQ signal to output to the amplitude correction module when the amplitude of the first baseband IQ signal is greater than or equal to the first threshold amplitude and the amplitude of the second baseband IQ signal is less than a second threshold amplitude, and selecting the second baseband IQ signal to output to the amplitude correction module when the amplitude of the second baseband IQ signal is greater than or equal to the second threshold amplitude;

the amplitude correction module is used for multiplying a preset correction coefficient by the first baseband IQ signal and then outputting the result, or multiplying the preset correction coefficient by a correction multiple by the second baseband IQ signal and then outputting the result, wherein the correction multiple is the amplitude corresponding to the difference value of the first numerical value and the second numerical value.

Preferably, the signal selection module is further configured to select the first baseband IQ signal to output to the amplitude modification module when the amplitude of the first baseband IQ signal is greater than or equal to a first threshold amplitude and the amplitude of the second baseband IQ signal is greater than or equal to a second threshold amplitude.

Preferably, the system also comprises a first FIFO buffer module, a second FIFO buffer module and a delay control module;

the first ADC module is used for sending the first sampling signal to the first FIFO cache module; the second ADC module is used for sending a second sampling signal to the second FIFO cache module;

the first FIFO cache module is used for delaying the first sampling signal by a first amount of clocks and sending the delayed first sampling signal to the frequency mixing module;

the second FIFO cache module is used for delaying a second sampling signal by a second number of clocks and sending the delayed second sampling signal to the frequency mixing module;

the frequency mixing module is used for sending the first baseband IQ signal and the second baseband IQ signal to the delay control module;

the delay control module is used for comparing the rising edges of the first baseband IQ signal and the second baseband IQ signal, calculating a relative delay difference, calculating a first quantity and a second quantity according to a system clock and the relative delay difference when the relative delay difference is not 0 so as to respectively control the first FIFO buffer module and the second FIFO buffer module to delay, and sending the first baseband IQ signal and the second baseband IQ signal to the signal selection module when the relative delay difference is 0.

Preferably, the dynamic range of the receiver is-85 dBm to-15 dBm.

Preferably, the first value is 46, the second value is 10, and the third value is-45.

Preferably, the first threshold amplitude is an amplitude corresponding to-39 dBm, and the second threshold amplitude is an amplitude corresponding to-35 dBm.

Different from the prior art, the invention has the beneficial effects that:

1. the method completely overcomes the defect that the signals of the short-distance target and the long-distance target are received in a time-sharing way by adopting AGC, and can simultaneously receive the signals of the long-distance target and the short-distance target;

2. compared with the mode of adopting an intermediate frequency logarithmic amplifier, the full-dynamic receiving can be realized at lower cost, the signal phase can be recovered without distortion, and the problem of damaging the signal phase does not exist.

Drawings

Fig. 1 is a schematic block diagram of a full dynamic receiving system of a secondary radar based on dynamic range splitting according to an embodiment of the present invention.

Fig. 2 is a schematic block diagram of a secondary radar full-dynamic receiving system based on dynamic range splitting according to another embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the full dynamic receiving system of a secondary radar based on dynamic range splitting according to the embodiment of the present invention includes a first ADC module 1, a second ADC module 2, a frequency mixing module 3, a signal selection module 4, and an amplitude correction module 5, where the first ADC module 1 is connected to an antenna of the secondary radar through a first radio frequency channel, the second ADC module 2 is connected to an antenna of the secondary radar through a second radio frequency channel, a gain of the first radio frequency channel is a first value, a gain of the second radio frequency channel is a second value, a receiving power range of the first ADC module 1 is between a lower limit value and a third value of a dynamic range of a receiver, a receiving power range of the second ADC module 2 is between the third value and an upper limit value of the dynamic range of the receiver, the first value is greater than the second value, the third value is a negative number, and an absolute value of the third value is smaller than the first value by 1.

The first ADC module 1 is used for sampling a signal of a first radio frequency channel to obtain a first sampling signal and sending the first sampling signal to the frequency mixing module 3; the second ADC module 2 is configured to sample a signal of the second radio frequency channel to obtain a second sampling signal, and send the second sampling signal to the frequency mixing module 3. The signals received by the antenna of the secondary radar are divided into two paths to enter the first radio frequency channel and the second radio frequency channel respectively, a large signal can be formed due to the large gain of the first radio frequency channel, and a small signal can be formed due to the small gain of the second radio frequency channel. The large and small signals of the two radio frequency channels are respectively sent to the first ADC module 1 and the second ADC module 2 for sampling. It should be noted that the sizes are relative to each other for the first rf channel and the second rf channel.

The frequency mixing module 3 is configured to perform down-conversion and AM demodulation processing on the first sampling signal and the second sampling signal to obtain a first baseband IQ signal and a second baseband IQ signal, respectively, and send the first baseband IQ signal and the second baseband IQ signal to the signal selection module 4. The mixing module 3 performs AM demodulation by summing up the squares of the down-converted baseband IQ.

The signal selection module 4 is configured to detect whether the amplitude of the first baseband IQ signal is greater than a first threshold amplitude and whether the amplitude of the second baseband IQ signal is greater than a second threshold amplitude, select the first baseband IQ signal to output to the amplitude correction module 5 when the amplitude of the first baseband IQ signal is greater than or equal to the first threshold amplitude and the amplitude of the second baseband IQ signal is less than the second threshold amplitude, and select the second baseband IQ signal to output to the amplitude correction module 5 when the amplitude of the second baseband IQ signal is greater than or equal to the second threshold amplitude.

In one practical application, the dynamic range of the receiver is-85 dBm to-15 dBm, the first value is 46, the second value is 10, the third value is-45, the first threshold amplitude is an amplitude corresponding to-39 dBm, and the second threshold amplitude is an amplitude corresponding to-35 dBm. That is, the gain of the first rf channel is 46dB, the gain of the second rf channel is 10dB, the received power range of the first ADC block 1 is (-85 to-45) dBm, and the received power range of the second ADC block 2 is (-45 to-15) dBm.

If the amplitude of the first baseband IQ signal is greater than or equal to the first threshold amplitude and the amplitude of the second baseband IQ signal is less than the second threshold amplitude, indicating that the dynamic range of the receiver is (-85 to-45) dBm, the amplitude of the first baseband IQ signal is relatively proper, and the amplitude of the second baseband IQ signal is too small to meet the sensitivity requirement, so the signal selection module 3 selects the first baseband IQ signal to output.

If the amplitude of the second baseband IQ signal is greater than or equal to the second threshold amplitude, which indicates that the dynamic range of the receiver is (-45 to-15) dBm, the amplitude of the first baseband IQ signal is too large and is saturated and overflowed, and the amplitude of the second baseband IQ signal is proper, so the signal selection module 3 selects the second baseband IQ signal to output.

The amplitude correction module 5 is configured to multiply the preset correction coefficient and the first baseband IQ signal and output the result, or multiply the preset correction coefficient and a correction multiple by the second baseband IQ signal and output the result, where the correction multiple is an amplitude corresponding to a difference between the first value and the second value. The difference between the first value and the second value is 36dB, and the correction factor is the amplitude corresponding to 36 dB.

The preset correction coefficient is a preset fixed value and can be flexibly set according to the data transmission bit width of the secondary radar. When the dynamic range of the receiver is (-85 to-45) dBm, the amplitude correction module 4 outputs a first baseband IQ value multiplied by a preset correction coefficient. When the dynamic range of the receiver is (-45- — 15) dBm, since the gain difference between the first rf channel and the second rf channel is 36dB, and the corresponding amplitude of 36dB is 63.1, the output of the amplitude correction module 4 is the second baseband IQ value × the preset correction coefficient × 63.1.

In this embodiment, the signal selection module 3 is further configured to select the first baseband IQ signal to output to the amplitude modification module 4 when the amplitude of the first baseband IQ signal is greater than or equal to a first threshold amplitude and the amplitude of the second baseband IQ signal is greater than or equal to a second threshold amplitude.

The received power range of the first ADC module 1 and the received power range of the second ADC module 2 do not overlap, that is, the received power ranges do not include the third value, and if the receiver dynamic range is just-45 dBm, the amplitude of the first baseband IQ signal is 1dBm, which is greater than-39 dBm, and the amplitude of the second baseband IQ signal is-35 dBm, which is equal to-35 dBm, but the larger the signal amplitude is, the better the signal-to-noise ratio is, so the signal selection module 3 still selects the first baseband IQ signal to output.

Referring to fig. 2, it is a schematic block diagram of a full dynamic receiving system of a secondary radar based on dynamic range splitting according to another embodiment of the present invention, and the full dynamic receiving system of the secondary radar of this embodiment has the same technical features as the previous embodiments, except that the full dynamic receiving system of the secondary radar of this embodiment further includes a first FIFO buffer module 6, a second FIFO buffer module 7, and a delay control module 8.

The first ADC module 1 is configured to send the first sampling signal to the first FIFO buffer module 5; the second ADC module 2 is configured to send the second sampling signal to the second FIFO buffer module 6;

the first FIFO buffer module 6 is configured to delay the first sampling signal by a first number of clocks, and send the delayed first sampling signal to the frequency mixing module 3;

the second FIFO buffer module 7 is configured to delay the second sampling signal by a second number of clocks, and send the delayed second sampling signal to the frequency mixing module 3;

the frequency mixing module 3 is configured to send the first baseband IQ signal and the second baseband IQ signal to the delay control module 8;

the delay control module 8 is configured to compare rising edges of the first baseband IQ signal and the second baseband IQ signal, calculate a relative delay difference, calculate a first quantity and a second quantity according to a system clock and the relative delay difference when the relative delay difference is not 0, respectively control the first FIFO buffer module 6 and the second FIFO buffer module 7 to perform delay, and send the first baseband IQ signal and the second baseband IQ signal to the signal selection module 4 when the relative delay difference is 0.

Through the manner, the dynamic range splitting-based secondary radar full-dynamic receiving system provided by the embodiment of the invention has the advantages that the dynamic range of the receiver is split into two sections which are respectively used as the receiving power ranges of the two ADC sampling modules, and the signal amplitude sampled by the two ADC sampling modules is compared to select one signal for output, so that the real-time full-dynamic receiving can be realized, and the signal phase can be recovered without distortion.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.