Method and device for judging direction of secondary radar receiving signal

Abstract

In order to solve the problem that the indicator F in the traditional method for judging the direction of the secondary radar received signal relative to the beam normal line may be affected by the performance of the device and deteriorate, the embodiment of the present invention provides a method and device for judging the direction of the secondary radar received signal, including: sampling the intermediate frequency signals of the Σ channel and the Δ channel, and converting each intermediate frequency signal from an analog signal to a discrete digital signal; orthogonally decomposing the intermediate frequency signal of the Σ channel and the intermediate frequency signal of the Δ channel by using a local oscillator signal with the same frequency as the intermediate frequency signal, and generating a zero intermediate frequency I signal sequence S of the Σ channel ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ; Calculate the signal sequence S ΣI With S ΔQ The product of ΣQ With S ΔI The product of ΣI With S ΔQ The product of ΣQ With S ΔI The embodiment of the present invention realizes the determination of the direction of the secondary radar receiving signal.

Description

Technical Field

[0001] The invention relates to a method and a device for judging the direction of a secondary radar receiving signal. Background Art

[0002] The secondary surveillance radar (SSR) locates the target by processing the reply signal of the flying target in the air, and provides the air traffic situation information to the controller.

[0003] The single pulse secondary radar antenna has three signal channels, namely Σ, Δ and Ω channels. The secondary radar receives the secondary radar echo signal of the aircraft in the air through its antenna. The signal is filtered, amplified and detected to form three video signals of Σ, Δ and Ω respectively. The secondary radar receiving signal processing is as follows: Figure 1 The secondary radar uses a Σ / Δ antenna to measure angles. The Σ / Δ antenna receives the signal vector synthesis as shown in Figure 2 As shown, when the signal comes from the left side of the normal line, the phase difference between the Σ channel and the Δ channel signals is π / 2, and when the signal comes from the right side of the normal line, the phase difference between the Σ channel and the Δ channel signals is -π / 2.

[0004] The signal processing module calculates the off-boresight angle (OBA) based on the amplitude difference between the Σ channel and the Δ channel signals: First, the phase detector gives the left and right indication F(- / +) of the direction of the signal relative to the beam normal based on the phase difference of the Σ / Δ signal; then, the difference between the amplitudes of the corresponding Σ signal and Δ signal in the time domain is calculated. The relationship between the Σ / Δ signal and the OBA is as follows: Figure 3 , the target deviation angle θ is obtained based on the difference OBA Finally, add or subtract θ from the beam normal angle θ0 according to the direction indication. OBA Get the real angle θ of the signal, θ=θ0±θ OBA .

[0005] In the prior art, the method for determining the direction of the secondary radar received signal relative to the beam normal is implemented using a dedicated hardware circuit. First, the phase detector generates a phase detection voltage V according to the Σ / Δ channel signal difference. P , then: The circuit compares V P With the preset voltage V S The relative value between them is used to give the left and right indication index F of the signal direction. The disadvantages of the existing technology are as follows: 1. The analog circuit is easily affected by the change of ambient temperature and the attenuation of device performance. The index F will change and needs to be calibrated regularly; 2. The analog device attenuates and ages, and there is a life problem; 3. When the signal is weak, the performance of the analog device is greatly affected by noise, resulting in a large fuzzy area for direction judgment, which affects the system performance. Summary of the invention

[0006] In order to solve the problem that the indicator F in the traditional method for determining the direction of a secondary radar received signal relative to the beam normal may be affected by the performance of the device and deteriorate, the embodiments of the present invention provide a method and device for determining the direction of a secondary radar received signal.

[0007] The embodiment of the present invention is achieved through the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a method for determining the direction of a secondary radar received signal, comprising:

[0009] The intermediate frequency signals of the Σ channel and the Δ channel are sampled, and each intermediate frequency signal is converted from an analog signal to a discrete digital signal;

[0010] The Σ channel intermediate frequency signal and the Δ channel intermediate frequency signal are orthogonally decomposed using a local oscillator signal with the same frequency as the intermediate frequency signal to generate a zero intermediate frequency I signal sequence S of the Σ channel. ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ;

[0011] Calculate the signal sequence S ΣI With S ΔQ The product of ΣQ With S ΔI The product of

[0012] According to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point.

[0013] Furthermore, according to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point; including:

[0014] Determine the S of the current point ΣI With S ΔQ Is the absolute value of the product greater than S? ΣQ With S ΔI The absolute value of the product of ΣI With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ΣQ With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

[0015] Furthermore, each intermediate frequency signal converted into a discrete digital signal is expressed by the following formula:

[0016] Σ channel signal: S Σ (t) = cos(ωt) (1)

[0017] Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2)

[0018] Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3)

[0019] Where ω is the carrier frequency and t is the time.

[0020] Furthermore, the zero intermediate frequency I signal sequence S of the Σ channel ΣI and the zero intermediate frequency Q signal sequence S ΣQ It is expressed by the following formula:

[0021] ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4)

[0022] Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2) (5)

[0023] The zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ It is expressed by the following formula:

[0024] Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6)

[0025] Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7)

[0026] Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8)

[0027] Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9)

[0028] Where ω is the carrier frequency and t is the time.

[0029] Furthermore, SΣI With S ΔQ The product of S ΣI (t)×S ΔQ (t); S ΣQ With S ΔI The product of S ΣQ (t)×S ΔI (t).

[0030] In a second aspect, an embodiment of the present invention provides a device for determining a direction of a secondary radar received signal, comprising:

[0031] The analog-to-digital conversion unit is used to sample the intermediate frequency signals of the Σ channel and the Δ channel, and convert each intermediate frequency signal from an analog signal to a discrete digital signal;

[0032] The signal decomposition unit is used to perform orthogonal decomposition of the intermediate frequency signal of the Σ channel and the intermediate frequency signal of the Δ channel using a local oscillator signal with the same frequency as the intermediate frequency signal to generate a zero intermediate frequency I signal sequence S of the Σ channel. ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ;

[0033] The calculation unit is used to calculate the S ΣI With S ΔQ The product of ΣQ With S ΔI The product of

[0034] The judging unit is used to judge the ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point.

[0035] Furthermore, the judgment unit is used to judge the S of the current point ΣI With S ΔQ Is the absolute value of the product greater than S? ΣQ With S ΔI The absolute value of the product of ΣI With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ΣQ With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

[0036] Furthermore, the analog-to-digital conversion unit is used to convert each intermediate frequency signal into a discrete digital signal represented by the following formula:

[0037] Σ channel signal: SΣ (t) = cos(ωt) (1)

[0038] Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2)

[0039] Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3)

[0040] Where ω is the carrier frequency and t is the time.

[0041] Furthermore, the signal decomposition unit is used to orthogonally decompose the Σ channel intermediate frequency signal and the Δ channel intermediate frequency signal into:

[0042] The zero intermediate frequency I signal sequence S of the Σ channel is expressed by the following formula: ΣI and the zero intermediate frequency Q signal sequence S ΣQ :

[0043] ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4)

[0044] Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2) (5)

[0045] The zero intermediate frequency I signal sequence S of the ΣΔ channel is expressed by the following formula: ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ :

[0046] Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6)

[0047] Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7)

[0048] Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8)

[0049] Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9)

[0050] Where ω is the carrier frequency and t is the time.

[0051] Furthermore, the signal decomposition unit is a DDC controller.

[0052] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects:

[0053] A method and device for determining the direction of a secondary radar received signal according to an embodiment of the present invention is based on a method program or a hardware system that can implement the corresponding method program, and determines the direction of a secondary radar received signal through signal sampling analog-to-digital conversion, signal decomposition processing, and signal direction determination, thereby avoiding the defect that the prior art uses analog circuits to determine the direction of a secondary radar received signal, which is easily affected by ambient temperature changes and device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 This is the block diagram of the existing secondary radar receiving signal processing.

[0056] Figure 2 This is the vector relationship diagram between Σ antenna signal and Δ antenna signal.

[0057] Figure 3 This is the relationship diagram between Σ signal, Δ signal and OBA.

[0058] Figure 4 The figure is a flow chart of a method for determining the direction of a secondary radar receiving signal.

[0059] Figure 5 It is a schematic diagram of the signal processing flow.

[0060] Figure 6 This is a schematic diagram of the principle of a device for determining the direction of a secondary radar receiving signal based on component cross-equalization.

[0061] Figure 7 This is a schematic diagram of the structure of a device for determining the direction of secondary radar receiving signals. DETAILED DESCRIPTION

[0062] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0063] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to one of ordinary skill in the art that these specific details are not necessarily employed to practice the present invention. In other embodiments, in order to avoid obscuring the present invention, well-known structures, circuits, materials, or methods are not specifically described.

[0064] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment," "an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. In addition, it will be appreciated by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] In the description of the present invention, the directions or positional relationships indicated by terms such as “front”, “rear”, “left”, “right”, “up”, “down”, “vertical”, “horizontal”, “high”, “low”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0066] Example

[0067] In order to solve the problem that the indicator F in the traditional method for judging the direction of the secondary radar received signal relative to the beam normal line may be affected by the performance of the device and deteriorate, in the first aspect, an embodiment of the present invention provides a method for judging the direction of the secondary radar received signal, referring to Figure 4-5 As shown, including:

[0068] S1. Sampling the intermediate frequency signals of the Σ channel and the Δ channel, and converting each intermediate frequency signal from an analog signal to a discrete digital signal;

[0069] S2. Use the local oscillator signal with the same frequency as the intermediate frequency signal to perform orthogonal decomposition on the intermediate frequency signal of the Σ channel and the intermediate frequency signal of the Δ channel to generate a zero intermediate frequency I signal sequence S of the Σ channel. ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ;

[0070] S3. Calculate S in the signal sequence ΣI With S ΔQ The product of ΣQ With S ΔI The product of

[0071] S4. According to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point.

[0072] Therefore, the embodiment of the present invention realizes the determination of the direction of the secondary radar receiving signal through signal sampling analog-to-digital conversion, signal decomposition processing and signal direction determination based on the method program, avoiding the defect that the prior art uses analog circuits to determine the direction of the secondary radar receiving signal, which is easily affected by ambient temperature changes and device performance.

[0073] The method for determining the direction of a secondary radar received signal in an embodiment of the present invention is a method for determining the direction of a secondary radar received signal based on component cross-equalization, so as to solve the problem that the signal direction identification circuit in the secondary radar is easily affected by the ambient temperature and device performance attenuation and the life problem of the phase detection function component.

[0074] Furthermore, according to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point; including:

[0075] Determine the S of the current point ΣI With S ΔQ Is the absolute value of the product greater than S? ΣQ With S ΔI The absolute value of the product of ΣI With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ΣQ With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

[0076] Select the cross product of the signal components in the sampling sequence (ie: S ΣI (t)×S ΔQ (t), S ΣQ (t)×S ΔI The sign of the term with the larger absolute value of (t)) is used to determine the signal direction F of the current point. This is equivalent to selecting a signal pair with more balanced I and Q components, avoiding signal pairs with low single-path components, thereby preventing the judgment of signal direction F from being affected by noise.

[0077] Furthermore, each intermediate frequency signal converted into a discrete digital signal is expressed by the following formula:

[0078] Σ channel signal: S Σ (t) = cos(ωt) (1)

[0079] Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2)

[0080] Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3)

[0081] Where ω is the carrier frequency and t is the time.

[0082] Furthermore, the zero intermediate frequency I signal sequence S of the Σ channel ΣI and the zero intermediate frequency Q signal sequence S ΣQ It is expressed by the following formula:

[0083] ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4)

[0084] Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2) (5)

[0085] The zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ It is expressed by the following formula:

[0086] Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6)

[0087] Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7)

[0088] Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8)

[0089] Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9)

[0090] Where ω is the carrier frequency and t is the time.

[0091] Furthermore, SΣI With S ΔQ The product of S ΣI (t)×S ΔQ (t); S ΣQ With S ΔI The product of S ΣQ (t)×S ΔI (t).

[0092] Signal processing flow reference Figure 5 Specifically, it includes:

[0093] Signal sampling: From the intermediate frequency output point of the secondary radar receiver, the intermediate frequency signals of the Σ and Δ channels are sampled respectively, and converted from analog signals to discrete digital signals. The signal expression is shown in Formula 1-3, where is the carrier frequency and t is the time.

[0094] Σ channel signal: S Σ (t) = cos(ωt) (1)

[0095] Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2)

[0096] Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3)

[0097] Orthogonal decomposition down-conversion: Use a local oscillator signal with the same frequency as the intermediate frequency signal to perform orthogonal decomposition on the intermediate frequency signals of the Σ and Δ channels to generate zero intermediate frequency I and Q signals for the Σ and Δ channels respectively. The signal expression is shown in Formula 4-9.

[0098] ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4)

[0099] Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2) (5)

[0100] Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6)

[0101] Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7)

[0102] Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8)

[0103] Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9)

[0104] Direction determination: By analyzing formula 4-9, we can obtain the positive and negative rules of the sampling values ​​of each signal when the phase changes from 0-2π, as shown in Table 1.

[0105] Table 1 The positive and negative rules of signal sampling values

[0106]

[0107] The following rules can be summarized from Table 1:

[0108] S ΣI (t)×S ΔQ (t)<0 and S ΣQ (t)×S ΔI (t)<0, the signal is on the left side of the normal line, and F(t) is “-”;

[0109] S ΣI (t)×S ΔQ (t)>0 and S ΣQ (t)×S ΔI (t)>0, the signal is on the right side of the normal line and F(t) is “+”.

[0110] Signal optimization: Due to the different initial phases, the corresponding phases of each IQ signal component have different amplitude distributions. In the actual operating system, the channel has noise. When the amplitude of a signal component is close to the noise amplitude, it is superimposed with the noise, and the positive or negative value of the signal component will be affected.

[0111] In this case, the cross product of the signal components in the sampling sequence (ie: S ΣI (t)×S ΔQ (t), S ΣQ (t)×S ΔI The sign of the term with the larger absolute value of (t)) is used to determine the signal direction F of the current point. This is equivalent to selecting a signal pair with more balanced I and Q components, avoiding signal pairs with low single-path components, thereby preventing the direction F judgment from being affected by noise.

[0112] The secondary radar receiving signal direction judgment module based on component cross-equalization replaces the original system analog channel phase identification circuit. The module processing logic is as follows: Figure 5 As shown, the specific application implementation method is as follows:

[0113] 1) Signal connection: connect Σ and Δ channel signals from the intermediate frequency point of the secondary radar receiver;

[0114] 2) Signal sampling: Through the analog-to-digital conversion circuit, the intermediate frequency signals of the Σ and Δ channels are sampled respectively and converted from analog signals to digital signals;

[0115] 3) Signal processing: Down-convert and orthogonally decompose the digital signal sampled in 2) to generate I / Q signal sequences (S ΣI , S ΣQ , S ΔI , S ΔQ );

[0116] 4) Signal optimization direction determination: Select S in the signal sequence ΣI (t)×S ΔQ (t), S ΣQ (t)×S ΔI (t) The signal direction F(t) of the current point is determined by the term with the larger absolute value of the product.

[0117] The method for determining the direction of a secondary radar received signal in an embodiment of the present invention is based on digital software processing. The processing module itself does not have the problem of component attenuation affecting performance, does not require regular calibration, and has a longer service life. The direction is determined based on signal optimization, and the direction determination is more accurate in weak signal conditions.

[0118] In a second aspect, an embodiment of the present invention provides a device for determining the direction of a secondary radar receiving signal, referring to Figure 6-7 As shown, including:

[0119] The analog-to-digital conversion unit is used to sample the intermediate frequency signals of the Σ channel and the Δ channel, and convert each intermediate frequency signal from an analog signal to a discrete digital signal;

[0120] The signal decomposition unit is used to perform orthogonal decomposition of the intermediate frequency signal of the Σ channel and the intermediate frequency signal of the Δ channel using a local oscillator signal with the same frequency as the intermediate frequency signal to generate a zero intermediate frequency I signal sequence S of the Σ channel. ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ;

[0121] The calculation unit is used to calculate the S ΣI With S ΔQ The product of ΣQ With S ΔI The product of

[0122] The judging unit is used to judge the ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point.

[0123] Therefore, the embodiment of the present invention realizes the determination of the direction of the secondary radar receiving signal through signal sampling analog-to-digital conversion, signal decomposition processing and signal direction determination based on the hardware system that can realize the corresponding method program, thereby avoiding the defect that the prior art uses analog circuits to determine the direction of the secondary radar receiving signal, which is easily affected by environmental temperature changes and device performance.

[0124] Furthermore, the judgment unit is used to judge the S of the current point ΣI With S ΔQ Is the absolute value of the product greater than S? ΣQ With S ΔI The absolute value of the product of ΣI With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ΣQ With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

[0125] Furthermore, the analog-to-digital conversion unit is used to convert each intermediate frequency signal into a discrete digital signal represented by the following formula:

[0126] Σ channel signal: S Σ (t) = cos(ωt) (1)

[0127] Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2)

[0128] Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3)

[0129] Where ω is the carrier frequency and t is the time.

[0130] Furthermore, the signal decomposition unit is used to orthogonally decompose the Σ channel intermediate frequency signal and the Δ channel intermediate frequency signal into:

[0131] The zero intermediate frequency I signal sequence S of the Σ channel is expressed by the following formula: ΣI and the zero intermediate frequency Q signal sequence S of the Σ channel ΣQ :

[0132] ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4)

[0133] Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2) (5)

[0134] The zero intermediate frequency I signal sequence S of the Δ channel is expressed by the following formula: ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ :

[0135] Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6)

[0136] Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7)

[0137] Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8)

[0138] Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9)

[0139] Where ω is the carrier frequency and t is the time.

[0140] Furthermore, the signal decomposition unit is a DDC controller.

[0141] The implementation principle of the secondary radar receiving signal direction judgment device refers to the above method and will not be repeated here.

[0142] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for determining the direction of a secondary radar received signal, characterized in that: include: The intermediate frequency signals of the Σ channel and the Δ channel are sampled, and each intermediate frequency signal is converted from an analog signal to a discrete digital signal; The Σ channel intermediate frequency signal and the Δ channel intermediate frequency signal are orthogonally decomposed using a local oscillator signal with the same frequency as the intermediate frequency signal to generate a zero intermediate frequency I signal sequence S of the Σ channel. ΣI and the zero intermediate frequency Q signal sequence S ΣQ And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ; Calculate the signal sequence S ΣI With S ΔQ The product of ΣQ With S ΔI The product of According to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point; According to S ΣI With S ΔQ The product of ΣQ With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point; include: Determine the S of the current point ΣI With S ΔQ Is the absolute value of the product greater than S? ΣQ With S ΔI The absolute value of the product of ΣI With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ΣQ With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

2. The method for determining the direction of a secondary radar receiving signal as claimed in claim 1, characterized in that: Each intermediate frequency signal converted into a discrete digital signal is expressed by the following formula: Σ channel signal: S Σ (t) = cos(ωt)(1) Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2)(2) Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2)(3) Where ω is the carrier frequency and t is the time.

3. The method for determining the direction of a secondary radar receiving signal as claimed in claim 2, characterized in that: The zero intermediate frequency I signal sequence S of the Σ channel ΣI and the zero intermediate frequency Q signal sequence S ΣQ It is expressed by the following formula: ΣChannel I signal: S ΣI (t) = cos(ωt) × cos(ωt) (4) Σ channel Q signal: S ΣQ (t)=cos(ωt)×cos(ωt+π / 2)(5) The zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ It is expressed by the following formula: Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt)(6) Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2)(7) Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt)(8) Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2)(9) Where ω is the carrier frequency and t is the time.

4. The method for determining the direction of a secondary radar receiving signal as claimed in claim 3, characterized in that: S ΣI With S ΔQ The product of S ∑I (t)×S ΔQ (t); S ∑Q With S ΔI The product of S ∑Q (t)×S ΔI (t).

5. A device for determining the direction of a secondary radar receiving signal, characterized in that: include: The analog-to-digital conversion unit is used to sample the intermediate frequency signals of the ∑ channel and the Δ channel, and convert each intermediate frequency signal from an analog signal to a discrete digital signal; The signal decomposition unit is used to perform orthogonal decomposition of the intermediate frequency signal of the ∑ channel and the intermediate frequency signal of the Δ channel using a local oscillator signal with the same frequency as the intermediate frequency signal to generate a zero intermediate frequency I signal sequence S of the ∑ channel. ∑I and the zero intermediate frequency Q signal sequence S ∑Q And generate the zero intermediate frequency I signal sequence S of the Δ channel ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ ; The calculation unit is used to calculate the S ∑I With S ΔQ The product of ∑Q With S ΔI The product of The judging unit is used to judge the ∑I With S ΔQ The product of ∑Q With S ΔI The product of determines the direction of the secondary radar receiving signal at the current point; Judgment unit, used to judge the S of the current point ∑I With S ΔQ Is the absolute value of the product greater than S? ∑Q With S ΔI The absolute value of the product of ∑I With S ΔQ The sign of the product of determines the direction of the secondary radar receiving signal at the current point; if not, use S ∑Q With S ΔI The sign of the product determines the direction of the secondary radar receiving signal at the current point.

6. The device for determining the direction of a secondary radar receiving signal as claimed in claim 5, characterized in that: The analog-to-digital conversion unit is used to convert each intermediate frequency signal into a discrete digital signal represented by the following formula: ∑ channel signal: S ∑ (t) = cos(ωt) (1) Δ channel signal on the left side of the beam normal: S ΔL (t) = cos(ωt-π / 2) (2) Δ channel signal on the right side of the beam normal: S ΔR (t) = cos(ωt+π / 2) (3) Where ω is the carrier frequency and t is the time.

7. The device for determining the direction of a secondary radar receiving signal as claimed in claim 6, characterized in that: The signal decomposition unit is used to orthogonally decompose the intermediate frequency signal of the ∑ channel and the intermediate frequency signal of the Δ channel into: The zero intermediate frequency I signal sequence S of the ∑ channel is expressed by the following formula: ∑I and the zero intermediate frequency Q signal sequence S ∑Q : ∑ Channel I signal: S ∑I (t) = cos(ωt) × cos(ωt) (4) ∑ channel Q signal: S ∑Q (t)=cos(ωt)×cos(ωt+π / 2) (5) The zero intermediate frequency I signal sequence S of the ∑Δ channel is expressed by the following formula: ΔI and the zero intermediate frequency Q signal sequence S of the Δ channel ΔQ : Channel I signal on the left side of the beam normal: S ΔLI (t)=cos(ωt-π / 2)×cos(ωt) (6) Q signal of the Δ channel on the left side of the beam normal: S ΔLQ (t)=cos(ωt-π / 2)×cos(ωt+π / 2) (7) Channel I signal on the right side of the beam normal: S ΔRI (t)=cos(ωt+π / 2)×cos(ωt) (8) Q signal of the Δ channel on the right side of the beam normal: S ΔRQ (t)=cos(ωt+π / 2)×cos(ωt+π / 2) (9) Where ω is the carrier frequency and t is the time.

8. The device for determining the direction of a secondary radar receiving signal as claimed in claim 7, characterized in that: The signal decomposition unit is a DDC controller.

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