Phased array rain measurement radar observation method based on terrain matching

Abstract

The invention discloses a phased array rain measuring radar observation method based on terrain matching, which comprises the steps of matching radial terrain, designing a low-layer vertical coverage elevation angle, designing pulses and designing thunder control synchronization, and specifically comprises the following steps: S1, collecting terrain elevation data in a region according to a deployment position of a phased array rain measuring radar; interpolation is carried out according to the azimuth angle and the radial resolution of phased array rain measurement radar scanning, and the terrain height D is obtained; s2, calculating a lowest elevation angle which is not influenced by terrain; s3, considering the non-uniformity of the terrain in the azimuth dimension, and designing a low-layer coverage elevation angle sequence; s4, during beam blocking and high-elevation detection, a double-pulse probe is adopted; when no wave beam blocking or half wave beam blocking exists, a three-pulse probe is adopted; and S5, acquiring surrounding environment situation information of a radar position, and establishing a synchronous scheduling scanning library. The terrain influence can be reduced; the dual-polarization observation data quality is improved; and volume scanning data volume is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radar, in particular to a phased array rain measuring radar observation method based on terrain matching. BACKGROUND

[0002] Under the background of global warming, the extreme nature of rainstorm in China is becoming more and more prominent, and disasters such as floods of small and medium rivers and mountain torrents occur frequently, which brings serious threat to people's life and property. Therefore, the water conservancy and other relevant departments urgently need to improve the fine monitoring, accurate forecasting and early warning capability of disaster-causing rainstorm. The rain measuring radar system is an important part of the sky-ground integrated sensing system in the construction of digital twin river basin, which has the ability of all-weather, large-scale, fine grid rainfall active monitoring and near rainfall forecasting, and is increasingly becoming an important technical means for disaster-causing rainstorm monitoring, forecasting and early warning.

[0003] In recent years, the water conservancy department actively carries out the construction and application of water conservancy rain measuring radar system. The Ministry of Water Resources has carried out real-time radar short-term rainstorm early warning during flood season for four consecutive years and directly reached the defense front line, and has achieved good results in improving rainstorm monitoring and early warning. At the same time, in the past two years, the latest generation of phased array rain measuring radar pilot application work has been carried out in Xiangjiang River in Hunan and Xiong'an New Area in Hebei River Basin of Yangtze River Basin, and beneficial exploration and practice have been carried out in water conservancy rain measuring radar equipment technical indicators, data format, quality control, safety management and data sharing, and good experience has been accumulated, laying a solid foundation for guiding the construction and application of water conservancy rain measuring radar system nationwide.

[0004] In view of the strong professionalism and high technical threshold of rain measuring radar system, in order to orderly promote business application, strengthen co-construction and sharing, and improve the rainstorm monitoring and early warning capability of flood and drought disaster prevention, in accordance with the requirements of smart water conservancy construction such as "demand traction, application first, digital empowerment and capability improvement", and the "Digital Twin River Basin Co-construction and Sharing Management Measures (Trial)", the Ministry of Water Resources Information Center organizes various manufacturers to carry out the construction of rain measuring radar system of the Ministry of Water Resources in accordance with the "Water Conservancy Rain Measuring Radar System Construction and Application Technical Requirements (Trial)", and the radar core indicators such as Figure 1 As shown in the figure, the phased array system radar has the advantage of flexible electronic scanning, and its observation mode has an important influence on rain measuring effect. In the "Water Conservancy Rain Measuring Radar System Construction and Application Technical Requirements (Trial)", it is stipulated that the body scanning period T of phased array rain measuring radar ≤1min (azimuth angle 0-360°, azimuth scanning step ≤1°, elevation scanning step ≤0.5° below the vertical height of 2km above the ground, elevation scanning step ≤2.0° above the vertical height of 2km above the ground, and the number of elevation layers ≥35).

[0005] The estimation principle of the phased array rain measuring radar for precipitation is to use the radar to observe the precipitation echo or the dual polarization information, to invert the precipitation based on the empirical formula, to construct a certain fixed height puzzle or a lowest elevation angle puzzle, and to realize the precipitation inversion in the observation range. Since the precipitation is unevenly distributed in the vertical height, the rain measuring radar mainly focuses on the ground precipitation, so theoretically the lower the puzzle height is, the better the effect is. However, in the actual operation process, there are often mountainous terrains and other terrains on the ground, which will pollute the radar observation of the precipitation echo and the dual polarization information, thereby affecting the precipitation inversion effect. In mountainous areas, it is difficult to deploy and observe conventional rain gauge sites, and the time of the mountain flood caused by precipitation is short, so it is particularly necessary to use the rain measuring radar to realize the monitoring and estimation of the precipitation. Therefore, for the rain measuring radar, it is necessary to remove the terrain influence as much as possible, and the terrain influence can be effectively reduced by effectively setting the observation mode.

[0006] In addition, the phased array rain measuring radar adopts a wide-emission narrow-reception multi-beam scanning mode, which can improve the scanning speed, but will cause the sidelobe to deteriorate, thereby affecting the quality of the dual polarization parameter data.

[0007] In addition, the existing rain measuring radar adopts a multi-layer observation mode with a fixed elevation angle, which will cause the volume scanning file to be large, thereby causing the demand for network bandwidth to be high, which is not conducive to the implementation of engineering construction and later maintenance.

[0008] The technical problems solved by the present application mainly include three points:

[0009] (1) Reduce the terrain influence: the existing phased array rain measuring radar observation mode does not consider the terrain, so that terrain clutter is easily introduced in low layer observation, thereby interfering with the observation data quality and causing a large precipitation inversion error.

[0010] (2) Improve the quality of the dual polarization observation data: the phased array rain measuring radar needs to adopt a wide-emission narrow-reception multi-beam scanning mode to realize more than 35 layers of observation elevation angle in a short time (within 1 minute), which will cause the quality of the dual polarization observation data to decrease. The dual polarization observation parameter is of great significance to the estimation of precipitation, especially the estimation of heavy precipitation, so the scanning mode needs to be improved through the optimization of the observation mode, thereby improving the effect of the dual polarization observation data.

[0011] (3) Reduce the volume scanning data amount: the current phased array rain measuring radar has a large volume scanning observation data amount, and when there is a precipitation process, a single volume scanning file occupies a storage amount of more than 100 MB, which has a great pressure on the network bandwidth under the condition of ensuring low delay of data transmission. In fact, a large amount of observation data above 2km has little effect on the estimation of ground precipitation, so the volume scanning data needs to be simplified through the improvement of the observation mode, thereby saving the network bandwidth resources. SUMMARY

[0012] In view of the problems in the prior art, the application provides a phased array rain measuring radar observation method based on terrain matching, which can reduce terrain influence, improve double-polarization observation data quality and reduce the amount of volume scanning data.

[0013] The application achieves the purpose by the following technical solutions.

[0014] The application provides a phased array rain measuring radar observation method based on terrain matching, which comprises matching radial terrain, designing a low-layer vertical coverage elevation angle, designing a pulse and designing radar control synchronization, and the specific steps comprise:

[0015] Step S1: according to the deployment position of the phased array rain measuring radar, collecting terrain elevation data in the region, interpolating according to the azimuth angle and radial resolution of the phased array rain measuring radar scanning to obtain terrain height D;

[0016] Step S2: calculating the lowest elevation angle not affected by terrain;

[0017] Step S3: designing a low-layer coverage elevation angle sequence;

[0018] Step S4: when beam blocking and high-elevation detection, a double-pulse detection needle is used; when there is no beam blocking or half-beam blocking, a three-pulse detection needle is used;

[0019] Step S5: obtaining environmental situation information around the radar site, establishing a synchronous scheduling scanning library to synchronously adjust radar scanning waveform parameters according to the optimal scanning elevation angle combination matched with terrain in different azimuths.

[0020] Further, the step S1 specifically comprises:

[0021] According to the longitude and latitude and height information of the deployment of the phased array rain measuring radar, terrain elevation data in the region is collected at a distance of a standard scanning radius of 45km.

[0022] Further, the calculation method of the step S2 is:

[0023] According to the radar height measurement formula:

[0024] ;

[0025] h is the antenna height (km), δ is the beam center elevation angle (°), R is the distance of the target from the antenna (km), Rm is the equivalent earth radius (km), H is the height of the beam center axis from the ground at the slant distance R (km), and in the standard atmosphere, the equivalent earth radius (Rm) is 4 / 3 times the true earth radius (about 8500km).

[0026] The phased array rain measuring radar scans frame by frame according to a certain azimuth angle accuracy, assuming that a certain frame (azimuth angle a) and a certain elevation angle δ, the actual height reached by the lower edge of the beam With the highest terrain height within this radial range If they are equal, meaning the main beam is unaffected by terrain at that radial and elevation angles, then:

[0027] ;

[0028] Beam lower edge elevation angle Elevation angle with beam center The difference is half the elevation beamwidth. Assuming the elevation beamwidth of the phased array rain-measuring radar is... ,but:

[0029] ;

[0030] The lowest elevation angle at which the main beam is unaffected by terrain at a specific frame (azimuth angle α) is the optimal elevation angle for precipitation measurement. Beams below this elevation angle will be blocked and affected by terrain in that radial direction, while beams above this elevation angle will scan for high-altitude precipitation echoes, resulting in additional errors compared to ground precipitation estimation.

[0031] Calculate according to different azimuth angles. This forms the optimal beam center elevation angle sequence for radial terrain matching.

[0032] Furthermore, step S3 specifically includes: during the scanning process, expanding the elevation angle upwards by 1 angle, and setting the vertical elevation angle step to... Then, at a certain azimuth angle 'a', the maximum scanning elevation angle does not exceed... ;

[0033] When the radar station is located at an altitude slightly higher than the surrounding environment, the minimum elevation angle is set to half the beamwidth, i.e. When the radar station is located at a significantly higher altitude than the surrounding environment, a negative elevation angle scan is used; specifically, when the difference in altitude between the radar station and the average terrain elevation over a 10km radius is within 500m, the minimum elevation angle is set to half the beamwidth, i.e. When the radar station is located at an altitude that is more than 500m higher than the average terrain altitude within 10km of the surrounding area, a negative elevation angle scan should be set.

[0034] The low-rise vertical coverage elevation angle is designed to be the lowest elevation angle. According to the steps Lift, with the highest elevation angle not exceeding .

[0035] Further, the dual-pulse detection needle has a detection range of 30km, adopts two frequency diversities, f1 and f2, the f2 pulse is a blind-filling pulse, adopts single carrier frequency, the pulse width is designed to match the detection distance resolution, is 0.2us, the blind area of the f1 pulse is detected, the f1 pulse adopts a linear frequency modulation pulse, the pulse width is designed to be 10us, 15us or 20us, and the specific value is determined according to the detection distance; considering the influence of the detection data of the low-elevation clutter, the pulse accumulation point number is designed to be 64 points;

[0036] Further, the three-pulse detection needle has a detection range of 45km, adopts three frequency diversities, f1, f2 and f3, the f2 and f3 pulses are blind-filling pulses, the f3 pulse adopts single carrier frequency, the pulse width is designed to match the detection distance resolution, is 0.2us, the blind area of the f2 pulse is detected, the f2 pulse adopts a linear frequency modulation pulse, the width is designed to be 10us, the blind area of the f1 pulse is detected, the f1 pulse adopts a linear frequency modulation pulse, the pulse width is designed to be 40us, and the detection distance covers 45km; the pulse accumulation point number of the three-pulse detection can be designed to be 64 points or 32 points according to the influence of the clutter.

[0037] Further, the synchronous scheduling scanning library mainly includes azimuth angle, low-layer vertical coverage elevation angle, waveform parameter, step And the maximum scanning elevation angle, the storage of these contents is indexed by the azimuth angle, and the synchronous scheduling parameters of each azimuth are established.

[0038] Further, the step S5 specifically includes: in the normal working process of the radar, the radar control obtains the pitch scanning parameters on the azimuth according to the azimuth angle code information provided by the servo, starts from the lowest vertical coverage elevation angle, schedules the waveform parameters of each elevation angle according to the step , completes the detection task of the vertical coverage elevation angle one by one, and stores the detection data of each elevation angle according to the azimuth angle.

[0039] Compared with the existing fixed elevation angle working mode, the rain measuring radar working mode based on terrain matching can effectively play the advantages of phased array radar beam flexibility and agility, and matches the optimal scanning elevation angle combination according to the terrain in different scanning frames, which can ensure that the selected elevation angle is low enough when providing mixed puzzles, ensure that the detected echo is consistent with the ground precipitation as much as possible, and at the same time, reduce the influence of terrain clutter as much as possible; on the other hand, the number of scanning layers can be effectively reduced, so as to reduce the data volume, reduce the network bandwidth required for data transmission, and thus reduce the construction and operation cost. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 It is a core index diagram of the rain measuring radar.

[0041] Figure 2Flow chart of the method of phased array rain radar observation based on terrain matching.

[0042] Figure 3 Design diagram for double-pulse detection.

[0043] Figure 4 Design for three-pulse detection.

[0044] Figure 5 Matching terrain scanning elevation Distribution diagram.

[0045] Figure 6 Schematic diagram of vertical elevation sequence for volume scanning observation.

[0046] Figure 7 Observation effect diagram of precipitation (a. Low-level fixed elevation observation b. Terrain matching elevation observation). DETAILED DESCRIPTION

[0047] As Figure 2 shown, the present application provides a method of phased array rain radar observation based on terrain matching, which comprises matching radial terrain, designing low-level vertical coverage elevation, designing pulse and designing radar control synchronization, and the specific steps comprise:

[0048] 1. Radial terrain matching:

[0049] According to the deployment position (longitude and latitude and height information) of the phased array rain radar, the terrain elevation data in the region is collected at a distance of 45 km standard scanning radius, and is interpolated according to the azimuth angle and radial resolution of the phased array rain radar scanning to obtain the terrain height D.

[0050] According to the radar height measurement formula:

[0051] ;

[0052] h is the antenna height (km), δ is the beam center elevation (°), R is the distance of the target from the antenna (km), R m is the equivalent earth radius (km), H is the height of the beam center axis from the ground at the slant distance R (km), and in the standard atmosphere, the equivalent earth radius (R m ) is 4 / 3 times the true earth radius (about 8500 km).

[0053] The phased array rain radar scans frame by frame according to a certain azimuth angle accuracy, assuming a certain frame (azimuth angle a) and a certain elevation δ, the actual height reached by the beam lower edge is equal to the highest terrain height in the radial range, that is, the main beam is not affected by the terrain at the radial and the elevation, then:

[0054] ;

[0055] Beam lower edge elevation with beam center elevation with half of the beam width in pitch, assuming the phased array weather radar has a pitch beam width of , then:

[0056] ;

[0057] The lowest elevation angle of the main beam that is not affected by the terrain at a certain frame (azimuth a), that is, the optimal elevation angle of the rain measurement. The beam below this elevation angle will be blocked and affected by the terrain in that radial direction, and the beam above this elevation angle will scan the precipitation echo in the upper air, causing additional errors in the estimation of surface precipitation.

[0058] According to different azimuth angles, respectively calculate , forming the optimal beam center elevation sequence matched with the terrain in the radial direction.

[0059] 2. Low-level vertical coverage elevation angle design:

[0060] The optimal beam center elevation sequence matched with the terrain in the radial direction only considers the terrain elevation D and does not consider other factors such as buildings on the terrain. At the same time, due to the certain width of the radar beam in the azimuth direction, the above calculation ignores the unevenness of the terrain in the azimuth dimension.

[0061] Therefore, in the actual scanning process, the elevation angle can be expanded by 1, and the vertical direction elevation angle step is set to , then the maximum scanning elevation angle at a certain azimuth angle a does not exceed .

[0062] At elevation below will be blocked by the terrain, but since the terrain is a certain distance away from the radar, within this distance, observation below elevation still has some significance, so when the radar station is slightly higher than the surrounding environment, the lowest elevation is set to half the beam width, that is, When the height of the radar station is significantly higher than the surrounding environment, negative elevation scanning can be appropriately considered. Specifically, when the height of the radar station and the average terrain height within 10 km around the station differ by 500 m or less, the lowest elevation is set to half the beam width, that is, When the height of the radar station is higher than the average terrain height within 10 km around the station by 500 m or more, negative elevation scanning is set.

[0063] Therefore, the low-level vertical coverage elevation angle is designed to be the lowest elevation , which is lifted by a step of , and the highest elevation does not exceed .

[0064] 3. Waveform design

[0065] For the rain measurement phased array weather radar, after using the precipitation observation method based on terrain matching, the single-beam scanning operation mode can also meet the resolution requirements of minute-level observation. Single-beam waveform design involves pulse repetition period (PRT), pulse waveform, and pulse accumulation point number. Based on radial terrain matching and vertical coverage angle detection requirements, two waveform designs, double-pulse detection and triple-pulse detection, are proposed in this patent as follows:

[0066] As shown in Figure 3 , the double-pulse detection is designed for beam blocking and high-angle detection, suitable for precipitation echo detection within 30 km, using two frequency diversity (f1 and f2), f2 pulse is a blind pulse, using single carrier frequency, pulse width design matches the distance resolution of detection, which is 0.2us, to detect the blind area of f1 pulse, f1 pulse uses linear frequency modulation pulse, pulse width design is 10us, 15us or 20us, specific to the detection distance; considering the influence of low-angle clutter detection data, the pulse accumulation point number is designed as 64 points.

[0067] As shown in Figure 4 , the triple-pulse detection is designed for no beam blocking or half-beam blocking, with a detection range of 45 km, using three frequency diversity (f1, f2 and f3), f2 and f3 pulses are blind pulses, f3 pulse uses single carrier frequency, pulse width design matches the distance resolution of detection, which is 0.2us, to detect the blind area of f2 pulse, f2 pulse uses linear frequency modulation pulse, width design is 10us, to detect the blind area of f1 pulse, f1 pulse uses linear frequency modulation pulse, pulse width design is 40us, covering a detection distance of 45km; the pulse accumulation point number of triple-pulse detection can be designed as 64 points or 32 points according to the clutter influence.

[0068] 4. Radar control synchronization design

[0069] From the above pulse design, it can be seen that the radar is required to detect at different angles using different waveform parameters, and as the azimuth changes, the elevation waveform parameters also change, which requires the radar control to have synchronization control function, and can seamlessly switch different azimuth and elevation scanning parameters.

[0070] Because the rain measurement radar installation environment is relatively complex, there are different shielding angles in different directions, therefore after the completion of the radar construction, the radar site surrounding environment situation information needs to be obtained, and a synchronous scheduling scanning library needs to be established, so that the radar control can adjust the radar scanning waveform parameters according to the optimal scanning elevation combination in different directions, and improve the quality of precipitation data detection in complex site environment.

[0071] The main parameters of the synchronous scheduling scan library include azimuth angle, lower-level vertical coverage elevation angle, waveform parameters, and step size. The radar stores information such as the maximum scanning elevation angle, indexed by azimuth angle, establishing synchronization scheduling parameters for each azimuth. During normal operation, the radar controller obtains the elevation scanning parameters for that azimuth based on the azimuth code information provided by the servo, starting from the lowest vertical coverage elevation angle and proceeding in steps. By scheduling waveform parameters at each elevation angle, the system completes the vertical coverage elevation angle detection task one by one, and stores the detection data for each elevation angle according to azimuth. This not only achieves optimal detection of meteorological data under complex arrays but also solves the problem of excessively large base data under existing storage methods. This is beneficial for the large-scale deployment of rain-measuring radar networks and reduces subsequent maintenance and usage costs. According to statistics, the amount of precipitation observation data obtained by the terrain-matching precipitation observation model is less than 10% of that obtained by the original volume scan, which can greatly reduce the amount of data to be stored.

[0072] Example

[0073] Step 1: Based on the radar latitude and longitude coordinates, collect terrain elevation data D within a radius of 45km of the observation range, and interpolate it around the radar position coordinates according to the azimuth angle of 1° and the radial resolution of 30m to form a terrain elevation polar coordinate dataset within the radar observation range, frame by frame and database by database.

[0074] like Figure 5 As shown, step 2: Based on the radar altimeter formula, calculate the lowest elevation angle of the lower edge of the beam that is unaffected by terrain, according to the radial direction.

[0075] (1)

[0076] in, This is the highest radial terrain elevation. The altitude of the radar antenna is given by R, which is the Earth's radius, taken as 6370 km. The equivalent Earth radius is approximately 4 / 3 times the actual Earth radius R, and is typically taken as 8500 km under standard atmospheric refractive index conditions. The vertical beamwidth of the rain-measuring radar is taken as 1.8°. The minimum observation elevation angle of each radial beam, unaffected by terrain, can be calculated according to formula (1).

[0077] Step 3: Without considering negative elevation angle scanning, follow the lowest... The elevation angle is 0.9°, with increments of 0.5°, and the maximum cannot exceed [a certain value]. +0.5°, construct a radial observation elevation angle sequence. For example... Figure 6 As shown, a1, a2, and a3 are the appropriate observation elevation angles for this azimuth.

[0078] Step 4: Pulse Design

[0079] There are five elevation angles a1, a2, a3, a4, a5 in the orientation shown in the above figure. At the a1 elevation angle, the ground object is blocked, but in order to effectively observe the precipitation between the ground object and the radar, the elevation angle frame PRT is designed as R / 150+20us (R is the distance between the ground object and the radar, and 10us is the long transmission pulse time), double pulse detection is used, and the pulse accumulation point number is designed as 64 points to better suppress the clutter interference introduced from the side lobe.

[0080] After the a1 elevation angle frame detection is completed, the radar changes the detection parameters to detect the a2 elevation angle precipitation echo under the radar control synchronous trigger. At the a2 elevation angle, the beam is not completely blocked, and the half-beam can be used to detect the precipitation echo in the space above the ground object and the far zone. At this time, the effective detection distance of the PRT is set as 45km, three pulses are used for detection, and the pulse accumulation point number is also designed as 64 points to better suppress the clutter.

[0081] The elevation angle a3 frame has a good observed area environment, and the effective beam is below 2km, so the PRT and pulse are the same as the elevation angle a2, but the pulse accumulation point number is reduced to 32 points to reduce the system detection time overhead.

[0082] Step 5: Input the radar control software

[0083] The above scanning parameters are input into the radar control software, and the radar real-time scanning can be carried out.

[0084] As shown in Figure 7 It can be seen that the low-layer fixed elevation angle observation is affected by a large number of ground objects, and the terrain matching elevation angle observation can obtain better continuous precipitation observation.

Claims

1. A method of observing a phased array rain radar based on terrain matching, characterized by, The steps include matching radial terrain, designing low-layer vertical coverage elevation angle, designing pulse and designing radar control synchronization, and the specific steps include: Step S1: collecting terrain elevation data in the region according to the deployment position of the phased array rain measuring radar, interpolating according to the azimuth angle and radial resolution of the phased array rain measuring radar scanning, and obtaining terrain height D; Step S2: calculating the lowest elevation angle not affected by terrain; Step S3: designing a low-layer coverage elevation angle sequence; Step S4: using a double-pulse detection needle when there is beam blocking and high-elevation detection, and using a three-pulse detection needle when there is no beam blocking or half-beam blocking; Step S5: obtaining environmental situation information around the radar site, establishing a synchronous scheduling scan library, and synchronously adjusting radar scan waveform parameters according to the optimal scan elevation angle combination in different directions according to terrain matching.

2. The method of claim 1, wherein, The step S1 specifically includes: According to the latitude and longitude and height information of the deployment of the phased array rain measuring radar, terrain elevation data in the region is collected at a distance of a standard scanning radius of 45 km.

3. The method of claim 1, wherein, The calculation method of the step S2 is: According to the radar height measurement formula: ； h is the antenna height, δ is the beam center elevation angle, R is the distance of the target from the antenna, Rm is the equivalent earth radius, H is the height of the beam center axis from the ground at the slant distance R, and in the standard atmosphere, the equivalent earth radius is 4 / 3 times the true earth radius; The phased array rain radar scans frame by frame according to azimuth accuracy. Assuming a certain frame, set as azimuth a and certain elevation angle δ, the height actually reached by the lower edge of the beam is equal to the highest terrain height within the radial range , i.e. the main beam is not affected by the terrain at this radial and this elevation angle, then: ； Beam lower edge elevation is half the elevation beamwidth, assuming a phased array weather radar elevation beamwidth of is half the elevation beamwidth, assuming a phased array weather radar elevation beamwidth of then: ； The minimum elevation angle of the main beam not affected by the terrain at a certain frame is the optimal elevation angle for rain measurement. The beam below this elevation angle will be blocked and affected by the terrain in this radial direction. The beam above this elevation angle will scan the precipitation echo in the upper air, which will cause additional errors in the estimation of ground precipitation. According to different azimuth angles, the following is calculated , forming a sequence of optimal beam center elevation angles that match the radial terrain.

4. The method of claim 1, wherein, The step S3 specifically comprises: during the scanning, extending 1 elevation angle upward, setting the vertical direction elevation angle step as , then the maximum scanning elevation angle at a certain azimuth angle a is not more than ; When the height of the radar station is within 500m of the average height of the surrounding terrain within 10km, the minimum elevation angle is set to half the beam width, i.e. When the height of the radar station is more than 500m higher than the average height of the surrounding terrain within 10km, a negative elevation angle is set. Low tier vertical coverage elevation designed for lowest elevation , according to step up, highest elevation not exceeding .

5. The method of claim 1, wherein, The double-pulse detection needle has a detection range of 30 km, uses two frequency diversities, f1 and f2, f2 pulse is a blind filling pulse, uses single carrier frequency, pulse width design is matched with detection distance resolution, which is 0.2us, and f1 pulse is used to detect the blind area of f1 pulse, f1 pulse uses linear frequency modulation pulse, pulse width design is 10us, 15us or 20us, which is determined according to the detection distance; considering the influence of low-elevation clutter detection data, the pulse accumulation point number is designed to be 64 points.

6. The method of claim 1, wherein, The three-pulse detection needle has a detection range of 45 km, uses three frequency diversities, f1, f2 and f3, f2 and f3 pulses are blind filling pulses, f3 pulse uses single carrier frequency, pulse width design is matched with detection distance resolution, which is 0.2us, and f2 pulse is used to detect the blind area of f2 pulse, f2 pulse uses linear frequency modulation pulse, width design is 10us, f1 pulse is used to detect the blind area of f1 pulse, f1 pulse uses linear frequency modulation pulse, pulse width design is 40us, and the detection distance covers 45km; the pulse accumulation point number of the three-pulse detection can be designed to be 64 points or 32 points according to the clutter influence.

7. The method of claim 1, wherein the method is based on a terrain matching phased array rain radar observation. The synchronized schedule scan library includes azimuth, low level vertical coverage elevation, waveform parameters, step and maximum scan elevation, the contents of which are indexed by azimuth to establish synchronized schedule parameters for each azimuth.

8. The method of claim 7, wherein the method is based on a terrain matching phased array rain radar observation. The step S5 specifically comprises: in a normal working process of the radar, the radar control acquires the elevation scanning parameters in the azimuth according to the azimuth code information provided by the servo, starts from the lowest vertical coverage elevation angle, and schedules the waveform parameters of each elevation angle to complete the detection task of the vertical coverage elevation angle one by one, and stores the detection data of each elevation angle according to the azimuth. , schedules the waveform parameters of each elevation angle to complete the detection task of the vertical coverage elevation angle one by one, and stores the detection data of each elevation angle according to the azimuth.

Images