Airborne PD radar small Doppler blind area false alarm and ground moving target suppression method

Abstract

The invention belongs to the technical field of airborne PD radar detection, and particularly relates to an airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, which adopts a small Doppler blind area to carry out target detection, identifies target attributes according to multi-dimensional information such as carrier height, ground speed, target speed, height, scattering characteristics and number of occupied range gates, and carries out target detection on the target according to multi-dimensional information such as carrier height, ground speed, target speed, height and scattering characteristics. According to the method, clutters and ground moving targets are identified, clutter false alarms and the ground moving targets are suppressed, tracks of needed targets are output, the discovery probability of slow moving targets in the air and targets near notches can be increased, and the air-to-air detection performance of airborne PD radar is ensured.

Description

Technical Field

[0001] The present application belongs to the technical field of airborne PD radar detection, and in particular relates to a method for suppressing false alarms in small Doppler blind areas of airborne PD radar and ground moving targets. Background Art

[0002] Compared with single-pulse radar, airborne PD radar has good downward-looking strong clutter detection target capability, but it will also form many tracks of slow-moving ground targets. In order to perform main clutter blanking and suppress slow-moving ground targets, it is usually necessary to specify a main clutter suppression zone of a certain width, namely the Doppler blind zone.

[0003] At present, in order to suppress more ground moving targets, the Doppler blind zone is usually larger. Due to the development of high-speed rail technology, the speed of ground high-speed rail is close to the speed of some aerial targets. The method of suppressing ground targets by using a large Doppler blind zone will inevitably limit the detection of many aerial targets. In addition, since it is difficult to obtain the field height of the target location, it is impossible to distinguish between aerial targets and ground targets based on height alone.

[0004] In addition, with the continuous advancement of aircraft research and development technology, more and more slow-moving aerial aircraft are being used, such as airships, floating balloons, and high-altitude air control drones. These slow-moving aerial targets are likely to enter the Doppler blind zone due to their low speed and cannot be detected. In addition, aerial targets entering near the notch will also fall into the Doppler blind zone due to their low radial speed and are difficult to be stably tracked.

[0005] Therefore, reducing the Doppler blind spot, making the aerial targets fall outside the Doppler blind spot, and improving the detection range have become urgent needs for air-to-air detection tasks. However, reducing the Doppler blind spot will cause more clutter to be detected, resulting in false alarms, and more ground moving targets to be detected, interfering with air-to-air detection tasks. In view of this, the present application is proposed. Summary of the invention

[0006] The invention provides a method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar. The method adopts small Doppler blind areas for target detection, identifies target attributes according to multi-dimensional information such as carrier field altitude, ground speed, target speed, altitude, scattering characteristics and the number of occupied range gates, outputs the track of the required target, suppresses false alarms of clutter and ground moving targets, and ensures the detection performance of aerial targets.

[0007] The technical solution of this application is:

[0008] A method for suppressing false alarms in small Doppler blind areas of airborne PD radar and ground moving targets, comprising:

[0009] Step 1: Initialize parameters, including setting the Doppler blind zone velocity detection threshold V p, air-ground target height separation threshold H lim , air-ground target speed separation threshold V0;

[0010] Step 2: Use the Doppler blind zone velocity detection threshold V p Screening out target detection information and establishing internal tracks for the remaining target detection information;

[0011] Step 3: Calculate the carrier altitude H0 and the target altitude H based on the target detection information T and its three-way velocity V N 、V E 、V U ;

[0012] Step 4: Identify the type of target:

[0013] Based on the carrier field height H0 and the target height H T and its three-way velocity V N 、V E 、V U , combined with the air-ground target height separation threshold H lim , the air-ground target speed separation threshold is V0, and the target types are identified, including targets near the notch, high-altitude slow targets, high-altitude high-speed targets, clutter targets, low-altitude high-speed targets, ground fast-moving targets, and ground slow-moving targets;

[0014] Step 5: Mark the internal tracks that need to be displayed and delete the internal tracks that do not need to be displayed:

[0015] Mark the internal tracks corresponding to the targets near the notch, high-altitude slow-moving targets, high-altitude high-speed targets, and low-altitude high-speed targets as the internal tracks that need to be displayed, and delete the internal track marks corresponding to the clutter targets, ground fast-moving targets, and ground slow-moving targets;

[0016] Step 6: Output and display the internal track that needs to be displayed.

[0017] According to at least one embodiment of the present application, in the above-mentioned airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, in step 3, the carrier field height H0 is calculated, specifically:

[0018] H0=H a -H r ;

[0019] in,

[0020] H a is the altitude;

[0021] H r is the aircraft radio altitude.

[0022] According to at least one embodiment of the present application, in the above-mentioned airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, in step 3, the target height H is calculated according to the target detection information. T , specifically:

[0023]

[0024] in,

[0025] H p is the pressure altitude of the carrier aircraft;

[0026] R e is the radius of curvature of the earth;

[0027] R T is the distance from the target to the carrier aircraft;

[0028] θ is the pitch angle of the target in the geographic frame.

[0029] According to at least one embodiment of the present application, in the above-mentioned airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, in step 4, identifying the type of target is specifically:

[0030] If H T >H lim +H0 and The target radial velocity V is calculated based on the target detection information. r , if V r <V g +V p , the target is identified as a target near the notch, and the notch detection waveform is scheduled to continuously track the target. If not, the target is identified as a high-altitude slow target, where V g is the ground speed of the carrier aircraft;

[0031] If H T >H lim +H0 and The target is identified as a high-altitude, high-speed target;

[0032] If H T <H lim +H0 and The target scattering cross-sectional area RCS is calculated based on the target detection information. If the target scattering cross-sectional area RCS exceeds the preset normal range, the target is identified as a clutter target. If not, the target is identified as a low-altitude high-speed target.

[0033] If H T <H lim +H0 and Then calculate the number of range gates occupied by the target according to the target detection information N r , if N r>FS*PW, the target is identified as a fast-moving ground target; otherwise, the target is identified as a slow-moving ground target, where FS is the echo sampling rate and PW is the pulse width of the signal.

[0034] According to at least one embodiment of the present application, in the above-mentioned airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, in step 4, the target scattering cross-sectional area RCS is calculated according to the target detection information, specifically:

[0035]

[0036] in,

[0037] K is the Boltzmann constant;

[0038] T is standard room temperature;

[0039] Bd is the receiver bandwidth;

[0040] Fn is the receiver noise factor;

[0041] L is the radar system loss;

[0042] SNR is the target signal-to-noise ratio;

[0043] R is the target distance;

[0044] Pt is the radar transmission power;

[0045] Gt is the radar system transmission gain;

[0046] Gr is the radar system receiving gain;

[0047] λ is the radar wavelength.

[0048] According to at least one embodiment of the present application, in the above-mentioned airborne PD radar small Doppler blind area false alarm and ground moving target suppression method, in step 6, before the internal track output to be displayed is displayed, the target healthy time T is calculated according to the target detection information i , if T i >T0, the corresponding internal track will be deleted and will no longer be output and displayed.

[0049] This application has at least the following beneficial technical effects:

[0050] The invention provides a method for suppressing false alarms and ground moving targets in a small Doppler blind area of ​​an airborne PD radar. The method adopts a small Doppler blind area to detect targets, identifies target attributes according to multi-dimensional information such as the carrier's field altitude, ground speed, target speed, altitude, scattering characteristics, and the number of occupied range gates, identifies clutter and ground moving targets, suppresses clutter false alarms and ground moving targets, outputs the track of the required target, and can increase the probability of finding slow-moving targets in the air and targets near notches, thereby ensuring the air-to-air detection performance of the airborne PD radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram of the airborne PD radar small Doppler blind area false alarm and ground moving target suppression method provided in this application.

[0052] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0053] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0054] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0055] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0056] Aiming at the contradiction between clutter false alarm, ground moving target suppression and air slow-moving target detection when the airborne PD radar performs air-to-air target detection mission, a method for suppressing clutter and ground false alarm in small Doppler blind area of ​​PD radar is provided. Figure 1 As shown, a small Doppler blind area is used for target detection, clutter and ground moving targets are identified, false alarms of clutter and ground moving targets are suppressed, and the probability of detecting slow-moving targets in the air and targets near the notch can be increased.

[0057] Step 1: Initialize parameters, including setting the Doppler blind zone velocity detection threshold V p , air-ground target height separation threshold H lim , the air-ground target speed separation threshold is V0.

[0058] Doppler blind zone velocity detection threshold V p It can be set according to the specific needs of the air-to-air target detection mission. The smaller the value, the smaller the Doppler blind area and the larger the target detection range.

[0059] Air-ground target height separation threshold H lim It can be set according to the height of common open-air targets.

[0060] The air-to-ground target speed separation threshold is V0 and can be set according to the altitude of common air-to-ground targets.

[0061] Step 2: Use the Doppler blind zone velocity detection threshold V p The target detection information is filtered out and the internal track of the remaining target detection information is established.

[0062] The Doppler blind zone velocity detection threshold V p By filtering out the target detection information, low-speed targets near the main clutter can be suppressed.

[0063] Step 3: Calculate the carrier altitude H0 and the target altitude H based on the target detection information T and its three-way velocity V N 、V E 、V U .

[0064] H0=H a -H r ;

[0065] in,

[0066] H a is the altitude;

[0067] H r is the aircraft radio altitude.

[0068]

[0069] in,

[0070] H p is the pressure altitude of the carrier aircraft;

[0071] R e is the radius of curvature of the earth;

[0072] R T is the distance from the target to the carrier aircraft;

[0073] θ is the pitch angle of the target in the geographic frame.

[0074] Step 4: Identify the type of target.

[0075] Based on the carrier field height H0 and the target height H T and its three-way velocity V N 、V E 、V U , combined with the air-ground target height separation threshold H lim , the air-ground target speed separation threshold is V0, and the types of identified targets may specifically include targets near the notch, high-altitude slow targets, high-altitude high-speed targets, clutter targets, low-altitude high-speed targets, ground fast-moving targets, and ground slow-moving targets. Among them, targets near the notch, high-altitude slow targets, high-altitude high-speed targets, and low-altitude high-speed targets are targets that are expected to be detected and need to be displayed, while clutter targets, ground fast-moving targets, and ground slow-moving targets are interference targets and do not need to be displayed.

[0076] If H T >H lim +H0 and The target radial velocity V is calculated based on the target detection information. r , if V r <V g +V p , the target is identified as a target near the notch, and the notch detection waveform is scheduled to continuously track the target. If not, the target is identified as a high-altitude slow target, where V g is the ground speed of the carrier aircraft;

[0077] If H T >H lim +H0 and The target is identified as a high-altitude, high-speed target;

[0078] If H T <H lim +H0 and The target scattering cross-sectional area RCS is calculated based on the target detection information. If the target scattering cross-sectional area RCS exceeds the preset normal range, the target is identified as a clutter target. If not, the target is identified as a low-altitude high-speed target.

[0079] If H T <H lim +H0 and Then calculate the number of range gates occupied by the target according to the target detection information N r , if N r >FS*PW, the target is identified as a fast-moving ground target; otherwise, the target is identified as a slow-moving ground target, where FS is the echo sampling rate and PW is the pulse width of the signal.

[0080]

[0081] in,

[0082] K is the Boltzmann constant;

[0083] T is standard room temperature;

[0084] Bd is the receiver bandwidth;

[0085] Fn is the receiver noise factor;

[0086] L is the radar system loss;

[0087] SNR is the target signal-to-noise ratio;

[0088] R is the target distance;

[0089] Pt is the radar transmission power;

[0090] Gt is the radar system transmission gain;

[0091] Gr is the radar system receiving gain;

[0092] λ is the radar wavelength.

[0093] Step 5: Mark the internal tracks that need to be displayed and delete the internal tracks that do not need to be displayed.

[0094] The internal tracks corresponding to the targets near the notch, high-altitude slow targets, high-altitude high-speed targets, and low-altitude high-speed targets are marked as internal tracks that need to be displayed, and the internal track marks corresponding to the clutter targets, ground fast-moving targets, and ground slow-moving targets are deleted.

[0095] Step 6: Output and display the internal track that needs to be displayed.

[0096] Before the internal track to be displayed is output, the target health time T can be calculated based on the target detection information. i , evaluate the health of the corresponding internal track, if T i>T0, the corresponding internal track will be deleted and no longer output and displayed, where T0 is the extrapolated time to measure whether the target track is healthy, which can be set according to the specific needs of the air-to-air target detection mission.

[0097] In a specific embodiment, V g =200m / s, H a =5700m, H r =5600m, radar waveform PRI=10us, PW=0.75us, FS=4M, V0=95m / s, V p =20m / s, the normal range of RCS preset is (0.01,100), H lim =300m, based on the Doppler blind zone velocity detection threshold V p The target detection information is filtered out, and the internal tracks of the remaining target detection information are established, including track 1, track 2, and track 3.

[0098] Track 1: Radial velocity V r =260m / s, distance R T =71km;

[0099] Track 2: Radial velocity V r =390m / s, distance R T =80km;

[0100] Track 3: Radial velocity V r =350m / s, distance R T =78km.

[0101] Calculate the carrier airport altitude H0 = 5700m-4900m = 100m.

[0102] Calculate the target height:

[0103] Track 1: H T1 =24m;

[0104] Track 2: H T2 =4700m;

[0105] Track 3: H T3 =2200m.

[0106] Calculate the target's three-dimensional velocity:

[0107] Track 1: V N1 =-35.51m / s,V E1 =-52.51m / s,V U1 =-0.02m / s;

[0108] Track 2: V N2=-201.14m / s,V E2 =14.86m / s,V U2 =-0.15m / s;

[0109] Track 3: V N3 =15.7m / s,V E3 =36.3m / s,V U3 =-0.03m / s.

[0110] in:

[0111] Track 1: H T1 <400m and Calculate the number of range gates N occupied by the target r =7, there are N r >4*0.75, the target is identified as a fast-moving ground target and the corresponding internal track mark is deleted.

[0112] Track 2: H T2 >400m and The target is identified as a high-altitude, high-speed target, and the corresponding internal track is marked as the internal track that needs to be displayed, and then output for display.

[0113] Track 3: H T3 >400m and Not V r <V g +V p , identify the target as a high-altitude slow target, mark the corresponding internal track as the internal track that needs to be displayed, and output it for display.

[0114] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for suppressing false alarms in small Doppler blind areas of airborne PD radar and ground moving targets, characterized in that: include: Step 1: Initialize parameters, including setting the Doppler blind zone velocity detection threshold V p , air-ground target height separation threshold H lim , air-ground target speed separation threshold V0; Step 2: Use the Doppler blind zone velocity detection threshold V p Screening out target detection information and establishing internal tracks for the remaining target detection information; Step 3: Calculate the carrier altitude H0 and the target altitude H based on the target detection information T and its three-way velocity V N 、V E 、V U ; Step 4: Identify the type of target: Based on the carrier field height H0 and the target height H T and its three-way velocity V N 、V E 、V U , combined with the air-ground target height separation threshold H lim , the air-ground target speed separation threshold is V0, and the target types are identified, including targets near the notch, high-altitude slow targets, high-altitude high-speed targets, clutter targets, low-altitude high-speed targets, ground fast-moving targets, and ground slow-moving targets; Step 5: Mark the internal tracks that need to be displayed and delete the internal tracks that do not need to be displayed: Mark the internal tracks corresponding to the targets near the notch, high-altitude slow-moving targets, high-altitude high-speed targets, and low-altitude high-speed targets as the internal tracks that need to be displayed, and delete the internal track marks corresponding to the clutter targets, ground fast-moving targets, and ground slow-moving targets; Step 6: Output and display the internal track that needs to be displayed.

2. The method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar according to claim 1, characterized in that: In step 3, the carrier field height H0 is calculated as follows: H0=H a -H r ; in, H a is the altitude; H r is the aircraft radio altitude.

3. The method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar according to claim 1, characterized in that: In step 3, the target height H is calculated based on the target detection information. T , specifically: in, H p is the pressure altitude of the carrier aircraft; R e is the radius of curvature of the earth; R T is the distance from the target to the carrier aircraft; θ is the pitch angle of the target in the geographic frame.

4. The method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar according to claim 1, characterized in that: In step 4, identify the type of target, specifically: If H T >H lim +H0 and The target radial velocity V is calculated based on the target detection information. r , if V r <V g +V p , the target is identified as a target near the notch, and the notch detection waveform is scheduled to continuously track the target. If not, the target is identified as a high-altitude slow target, where V g is the ground speed of the carrier aircraft; If H T >H lim +H0 and The target is identified as a high-altitude, high-speed target; If H T <H lim +H0 and The target scattering cross-sectional area RCS is calculated based on the target detection information. If the target scattering cross-sectional area RCS exceeds the preset normal range, the target is identified as a clutter target. If not, the target is identified as a low-altitude high-speed target. If H T <H lim +H0 and Then calculate the number of range gates occupied by the target according to the target detection information N r , if N r >FS*PW, the target is identified as a fast-moving ground target; otherwise, the target is identified as a slow-moving ground target, where FS is the echo sampling rate and PW is the pulse width of the signal.

5. The method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar according to claim 4, characterized in that: In step 4, the target scattering cross-sectional area RCS is calculated based on the target detection information, specifically: in, K is the Boltzmann constant; T is standard room temperature; Bd is the receiver bandwidth; Fn is the receiver noise factor; L is the radar system loss; SNR is the target signal-to-noise ratio; R is the target distance; Pt is the radar transmission power; Gt is the radar system transmission gain; Gr is the radar system receiving gain; λ is the radar wavelength.

6. The method for suppressing false alarms and ground moving targets in small Doppler blind areas of airborne PD radar according to claim 1, characterized in that: In step 6, before the internal track to be displayed is output, the target health time T is calculated based on the target detection information. i , if T i >T0, the corresponding internal track will be deleted and will no longer be output and displayed.

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