1. Aerial target detection device based on DVB-S forward scattering characteristic, characterized by comprising: the receiving antenna and the target detection module are connected in sequence; the receiving antenna is used for acquiring satellite signals in real time, and the target detection module is used for judging whether a target at the current moment appears according to the power of the satellite signals at the current moment and the power of the satellite signals at the previous moment.

2. The apparatus for detecting an airborne object based on DVB-S forward scattering characteristics according to claim 1, further comprising: and the low-noise amplification module is respectively connected with the receiving antenna and the target detection module.

3. The apparatus for detecting an airborne object based on DVB-S forward scattering characteristics according to claim 2, further comprising: and the band-pass filtering module is respectively connected with the low-noise amplification module and the target detection module.

4. The apparatus for detecting an airborne object based on DVB-S forward scattering characteristics according to claim 3, further comprising: and the down-conversion module is respectively connected with the band-pass filtering module and the target detection module.

5. The apparatus for detecting an airborne object based on DVB-S forward scattering characteristics according to claim 4, further comprising: and the A/D conversion module is respectively connected with the down-conversion module and the target detection module.

6. The DVB-S forward scattering properties based airborne object detection device according to claim 1, wherein the object detection module comprises:

the data processing submodule is used for sequentially carrying out coherent integration and noncoherent accumulation on the satellite signals at the current moment to obtain the power of the satellite signals at the current moment;

and the target judgment submodule is used for judging whether a target appears according to the power of the satellite signal at the current moment, the power of the satellite signal at the previous moment and a set attenuation threshold.

7. The apparatus according to claim 6, wherein the object determination sub-module comprises:

the power change unit is used for obtaining a power change value of the satellite signal at the current moment according to the power of the satellite signal at the current moment and the power of the satellite signal at the previous moment;

and the threshold comparison unit is used for determining whether the target appears at the current moment according to the power change value of the satellite signal at the current moment and the set attenuation threshold.

8. The apparatus according to claim 7, wherein the threshold comparing unit comprises:

the judging subunit is used for judging whether the power change value of the satellite signal at the current moment exceeds a set attenuation threshold to obtain a first judgment result;

and the first result subunit is used for determining that the target appears at the current moment if the first judgment result is yes.

Background

With the development of electronic information technology, the defects of electronic interference, low altitude/ultra-low altitude penetration, high-speed anti-radiation missile, high-power microwave weapon, stealth airplane and the like of the traditional radar system are reflected. The passive radar as a new system radar has the comprehensive four-resistance capabilities of resisting interference, resisting low-altitude penetration, resisting anti-radiation missile and resisting stealth, and has relatively simple structure, low cost, high concealment and battlefield survivability due to the fact that the passive radar does not actively radiate any signal, so that the passive radar becomes one of hot spots of domestic and foreign research.

The existing DVB-S external radiation source radar receives a direct satellite signal by arranging a reference channel antenna, receives a target reflection signal by a monitoring channel antenna, detects a target by adopting a backscattering mode, realizes target detection by utilizing the result of relevant processing of two paths of signals, and detects by using backscattering signals, so that the detection range and the detection probability are smaller, and the accuracy of target detection is reduced.

Disclosure of Invention

The invention aims to provide an aerial target detection device based on DVB-S forward scattering characteristics, which improves the detection precision of the occurrence of a target and realizes the purpose of more accurately detecting the occurrence of the target.

In order to achieve the purpose, the invention provides the following scheme:

an aerial target detection device based on DVB-S forward scattering characteristics comprises: the receiving antenna and the target detection module are connected in sequence; the receiving antenna is used for acquiring satellite signals in real time, and the target detection module is used for judging whether a target at the current moment appears according to the power of the satellite signals at the current moment and the power of the satellite signals at the previous moment.

Optionally, the apparatus for detecting an airborne object based on DVB-S forward scattering characteristics further includes: and the low-noise amplification module is respectively connected with the receiving antenna and the target detection module.

Optionally, the apparatus for detecting an airborne object based on DVB-S forward scattering characteristics further includes: and the band-pass filtering module is respectively connected with the low-noise amplification module and the target detection module.

Optionally, the apparatus for detecting an airborne object based on DVB-S forward scattering characteristics further includes: and the down-conversion module is respectively connected with the band-pass filtering module and the target detection module.

Optionally, the apparatus for detecting an airborne object based on DVB-S forward scattering characteristics further includes: and the A/D conversion module is respectively connected with the down-conversion module and the target detection module.

Optionally, the target detection module includes:

the data processing submodule is used for sequentially carrying out coherent integration and noncoherent accumulation on the satellite signals at the current moment to obtain the power of the satellite signals at the current moment;

and the target judgment submodule is used for judging whether a target appears according to the power of the satellite signal at the current moment, the power of the satellite signal at the previous moment and a set attenuation threshold.

Optionally, the target judgment sub-module includes:

the power change unit is used for obtaining a power change value of the satellite signal at the current moment according to the power of the satellite signal at the current moment and the power of the satellite signal at the previous moment;

and the threshold comparison unit is used for determining whether the target appears at the current moment according to the power change value of the satellite signal at the current moment and the set attenuation threshold.

Optionally, the threshold comparing unit includes:

the judging subunit is used for judging whether the power change value of the satellite signal at the current moment exceeds a set attenuation threshold to obtain a first judgment result;

and the first result subunit is used for determining that the target appears at the current moment if the first judgment result is yes.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: according to the invention, the target detection module is arranged, whether a target at the current moment appears is judged according to the power of the satellite signal at the current moment and the power of the satellite signal at the previous moment, the power of the direct satellite signal is adopted when the target does not appear, the power of the target scattered signal is adopted when the target appears, the radar scattering sectional area of the detected target is effectively increased by utilizing the forward scattering effect, the detection range and the detection probability of the detection device are improved, and the target detection module can more accurately detect the appearance of the target.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of an aerial target detection device based on DVB-S forward scattering characteristics according to an embodiment of the present invention;

fig. 2 is a schematic view of a detection scene of an aerial target detection device based on DVB-S forward scattering characteristics according to an 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.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The embodiment provides an airborne target detection device based on DVB-S forward scattering characteristics, as shown in fig. 1, the device includes: the receiving antenna and the target detection module are connected in sequence; the receiving antenna is used for acquiring satellite signals in real time, and the target detection module is used for judging whether a target at the current moment appears according to the power of the satellite signals at the current moment and the power of the satellite signals at the previous moment. The receiving antenna converts the received satellite signals (the direct satellite signals when the target does not appear and the scattered target signals when the target appears) from electromagnetic signals into voltage signals for processing by a subsequent module.

In practical application, the receiving antenna is a receiving antenna with a certain polarization direction, and is oriented to a selected digital video broadcasting satellite to receive a DVB-S direct signal and a forward scattering signal, and convert the DVB-S direct signal and the forward scattering signal into a voltage signal, the DVB-S signal is modulated by a Quadrature Phase Shift Keying (QPSK) method, and a signal structure of the DVB-S signal is as follows:

wherein S (t) is a DVB-S direct signal, and g (t-nT) is a pulse signal; t is the duration, which is the inverse of the symbol rate of the QPSK signal; omega₀Is the carrier angular frequency;taking the phase of the nth symbol as the value { pi/4, 3 pi/4, 5 pi/4, 7 pi/4 }; n is the number of the symbols,is a signal carrier.

The DVB-S complex signal u (t) can be expressed as:

where t is the receiving time and j is the imaginary symbol.

The received satellite signal r (t) can be represented as:

r (t) ═ u (t) + n (t), where n (t) is a noise signal.

In practical application, the aerial target detection device based on the DVB-S forward scattering characteristics further includes: and the low-noise amplification module is respectively connected with the receiving antenna and the target detection module. The low noise amplifier module is used for amplifying the power of the received voltage signal.

In practical application, the aerial target detection device based on the DVB-S forward scattering characteristics further includes: and the band-pass filtering module is respectively connected with the low-noise amplification module and the target detection module. The band-pass filtering module is used for filtering noise parts in the voltage signals after power amplification.

In practical application, the aerial target detection device based on the DVB-S forward scattering characteristics further includes: and the down-conversion module is respectively connected with the band-pass filtering module and the target detection module. The down-conversion module is used for converting the denoised DVB-S signal into an intermediate frequency signal.

In practical application, the aerial target detection device based on the DVB-S forward scattering characteristics further includes: and the A/D conversion module is respectively connected with the down-conversion module and the target detection module. The A/D conversion module is used for carrying out A/D sampling on the intermediate frequency signal and converting the intermediate frequency signal into a digital signal for the target detection module to process.

In practical applications, the object detection module includes:

the data processing submodule is used for sequentially carrying out coherent integration and noncoherent accumulation on the satellite signals at the current moment to obtain the power of the satellite signals at the current moment; because the satellite signals can be considered coherent in a short time, the target detection module performs coherent integration on the satellite signals, and then performs incoherent accumulation to further improve the power of the satellite signals, so that the change condition of the power amplitude can be observed more obviously.

And the target judgment submodule is used for judging whether a target appears according to the power of the satellite signal at the current moment, the power of the satellite signal at the previous moment and a set attenuation threshold.

In practical application, the target judgment sub-module includes:

and the power change unit is used for obtaining a power change value of the satellite signal at the current moment according to the power of the satellite signal at the current moment and the power of the satellite signal at the previous moment.

And the threshold comparison unit is used for determining whether the target appears at the current moment according to the power change value of the satellite signal at the current moment and the set attenuation threshold.

In practical applications, the threshold comparing unit includes:

and the judging subunit is used for judging whether the power change value of the satellite signal at the current moment exceeds a set attenuation threshold to obtain a first judgment result.

And the first result subunit is used for determining that the target appears at the current moment if the first judgment result is yes.

The specific expression form of the judging subunit is as follows:

where Δ p (t) is the degree of power change at adjacent times when the target is not present, and ε (t) is the change in power attenuation caused by the presence of the target. As shown in fig. 2, when the target appears on the connection between the satellite and the receiver, the power of the received signal is significantly attenuated, the attenuation threshold is set to η, and when the power attenuation condition Δ p (t) exceeds the attenuation threshold, that is, Δ p (t) > η, it is determined that the moving target appears.

The technology selects a DVB-S satellite as an external radiation source of a passive radar, receives and processes DVB-S forward scattering signals through a shore-based special device, judges the occurrence of an aerial target by utilizing a forward scattering effect generated when the target passes through a base line, and realizes the detection of the aerial moving target.

The specific working process of the device provided by the embodiment is as follows:

the ground base station device receives signals transmitted by a digital video broadcasting satellite through a receiving antenna, when a target passes through a connecting line between the satellite and the receiving antenna, a shadow effect is generated, so that the amplitude of the signals received by the receiving antenna changes, and after the signals are amplified, filtered, frequency-converted and A/D-converted, the signals are subjected to data processing and analysis through a target detection module to judge the appearance of the target. Due to the forward scattering effect, when the target appears near the baseline, the received signal power is obviously attenuated, and the target detection module is provided with an attenuation threshold to carry out constant false alarm rate detection, so that the detection of the aerial moving target is realized.

The invention has the advantages that:

1. the device utilizes DVB-S satellite signals as signal sources, and can implement all-weather uninterrupted observation all the day.

2. The device utilizes the forward scattering characteristic of DVB-S signal to carry out target detection, can effectively improve the radar scattering sectional area of target, compares with traditional backscatter detection mode, has increased detection distance and detection probability, compensaties the not enough of backscatter detection mode.

3. The device only needs to be provided with one receiving antenna, has simple structure and low cost, and simultaneously has strong anti-radiation missile, electronic interference resistance, low altitude penetration resistance and stealth resistance as a passive radar.

4. The DVB-S satellite signal has higher transmitting power and longer maximum target detection distance.

5. Compared with a backscattering detection method, the method is simpler and has lower complexity.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.