CN115131460A - Weather radar coverage area calculation method and radar equal-beam height map making algorithm - Google Patents
Weather radar coverage area calculation method and radar equal-beam height map making algorithm Download PDFInfo
- Publication number
- CN115131460A CN115131460A CN202210757134.2A CN202210757134A CN115131460A CN 115131460 A CN115131460 A CN 115131460A CN 202210757134 A CN202210757134 A CN 202210757134A CN 115131460 A CN115131460 A CN 115131460A
- Authority
- CN
- China
- Prior art keywords
- radar
- angle
- degree
- degrees
- azimuth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T11/00—2D [Two Dimensional] image generation
- G06T11/20—Drawing from basic elements, e.g. lines or circles
- G06T11/203—Drawing of straight lines or curves
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T11/00—2D [Two Dimensional] image generation
- G06T11/60—Editing figures and text; Combining figures or text
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
The invention discloses a weather radar coverage area calculation method and a radar equal-beam height map making algorithm, S1: calculating an azimuth angle; s2: calculating the slope distance; s3: calculating the shielding elevation angle; s4: detecting the spherical distance corresponding to the slant distance, wherein in the azimuth calculation: assuming that the earth is a standard sphere, O is the geocentric, N is the geographic north pole, the weather radar station is located at the point A, and the longitude and latitude are (lambda) 0 ，h 0 ) The obstacle is located at the point B, the longitude and latitude are (lambda, h), the geocentric angle of the obstacle relative to the radar station is n, and the inferior arc length corresponding to the maximum circle is L AB And the included angles between the connecting line of the radar station, the obstacle and the center of the earth and the connecting line of the north pole and the center of the earth are b and a respectively. The invention deduces the manufacturing theory of the weather radar shielding angle diagram and the equal beam height diagram and points out the deviation of the prior theoretical calculation in the aspects of azimuth angle, elevation angle, slope distance and the like.
Description
Technical Field
The invention relates to the technical field of radar algorithms, in particular to a weather radar coverage area calculation method and a radar equal-beam height map making algorithm.
Background
The weather radar plays an important role in monitoring and early warning of disastrous weather. At present, 273 parts of new-generation weather radars are built in the whole country, and weather radar observation station networks are encrypted in observation blind areas and key areas according to needs in all places in the future. In the radar construction planning stage, the detection coverage rate of the established radar is calculated, and the improvement effect of the newly-established radar on the detection coverage rate is evaluated, which is the problem to be solved firstly.
In addition, when using radar data, service personnel should know the detection coverage rate of the radar in each direction at first, avoid because the radar can't cover and think that there is not the weather process in this direction by mistake. The detection coverage rate of the weather radar is not only influenced by radar parameters and various factors such as attenuation, refraction and precipitation cloud properties, but also influenced by tall buildings and terrains around the radar. In order to correctly evaluate the radar detection coverage, a requirement for drawing a distribution diagram of the shielding angle around the radar and an equal beam height diagram is provided [1 ].
Deng Shi et al [2] proposed a method for making an equal-beam height map in 1999, and assumed that the distance between the slope distance and the geography is approximately equal and a large error exists when calculating the slope distance;
wanyufa et al [3] proposed a set of radar site apparent distance analysis technology in 2000, and the method has certain errors in the calculation of azimuth, elevation and slant distance between a shelter and a radar station;
wan Shudong et al [4] uses the principle of Wanyufa et al in 2011 to summarize a set of radar coverage rate statistical indexes, and uses SRTM data to evaluate the coverage and shielding of the weather radar of the new generation in China;
liu Jiang Shun et al [5] proposed a method for calculating radar detection coverage rate in 2019 by using basic reflectivity factors of historical base data, and the method can well evaluate the coverage rate of the established radar, cannot evaluate the contribution of the proposed radar to the coverage rate, and cannot meet the requirement of radar site selection.
Therefore, a weather radar coverage area calculation method and a radar equal beam height map making calculation method are proposed to solve the problems.
Disclosure of Invention
In order to overcome the above defects in the prior art, embodiments of the present invention provide a weather radar coverage calculation method and a radar beam height map making algorithm, so as to solve the above problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme: a radar equal beam height map making algorithm;
s1: calculating an azimuth angle;
s2: calculating the slope distance;
s3: calculating the shielding elevation angle;
s4: and detecting the spherical distance corresponding to the slant distance.
In a preferred embodiment, in the azimuth calculation: assuming that the earth is a standard sphere, O is the geocentric, N is the geographic north pole, the weather radar station is located at the point A, and the longitude and latitude are (lambda) 0 ，h 0 ) The barrier is positioned at the point B, the longitude and the latitude are (lambda, h), the geocentric angle of the barrier relative to the radar station is n, and the inferior arc length corresponding to the maximum circle is L AB And the included angles between the connecting line of the radar station, the obstacle and the center of the earth and the connecting line of the north pole and the center of the earth are b and a respectively.
In a preferred embodiment, in the slope distance calculation: h is the radar feed source altitude, H is the barrier altitude, R is the earth radius with a value of 6371km, n is the geocentric angle, L AB Is the propagation path of the radar rays in the actual atmosphere, H m Equivalent barrier altitude, R m The value under the standard atmospheric condition is 8500km, n for equivalent earth radius m Is the equivalent center of earth angle, L A'B' Is the equivalent straight-line propagation distance.
In a preferred embodiment, in the occlusion elevation calculation: l is the equivalent slant range, H is the radar feed elevation, and H is the shelter elevation.
The method for calculating the coverage area of the weather radar comprises the steps of firstly calculating from 0 degree of an azimuth angle, wherein the azimuth resolution is a degree;
the method comprises the following steps: calculating the altitude of the maximum elevation angle of 20 degrees of the radar ray corresponding to each sampling point above the space between 0-a degrees of the azimuth angle within the detection radius range of the radar;
step two: calculating the altitude of the lowest elevation angle 0 degree of the radar ray corresponding to the upper space of each sampling point between the azimuth angle 0 degree and a degree within the range of the detection radius of the radar;
step three: in the range of radar detection radius, inquiring a sampling point A which is closest to a radar and has an elevation angle larger than the lowest ray elevation angle relative to a radar feed source within an azimuth angle of 0-a degrees;
step four: calculating the altitude of each sampling point and the height of the coverage rate to be calculated by taking the distance of the position of the point A relative to the radar station as a radius and the azimuth angle of the azimuth angle between 0 degree and a degree, wherein if the distance is between the heights calculated in the first step and the second step, the sampling point can be covered, otherwise, the sampling point cannot be covered;
step five: stepping by taking the elevation resolution as b degrees, and repeating the steps from the first step to the fourth step until all points which can be covered by radar rays are found within the range of the detection radius of the radar and between the azimuth angle of 0 degree and a degree;
step six: and stepping the azimuth angle according to a degree of resolution, and repeating the steps from the first step to the fifth step until all points which can be covered by the radar in the azimuth angle from 0 degree to 360 degrees are found.
The invention has the technical effects and advantages that:
1. the invention deduces the manufacturing theory of a weather radar shielding angle diagram and an equal beam height diagram, and points out the deviation of the past theoretical calculation in the aspects of azimuth angle, elevation angle, slope distance and the like.
2. According to the method, geographic information data are adopted to make a shielding angle map and an equal-beam height map of the new generation of weather radar of Shangluo, and the shielding angle map and the equal-beam height map are compared with actual measurement data of the new generation of weather radar of Shanluo for 5 months. The comparison result shows that the consistency of the theoretical calculation graph and the radar actual measurement echo graph is better except that the deviation exists in individual directions caused by the geographic information resolution problem.
3. Compared with the traditional mode of acquiring data by referring to a map, the method has unique advantages of manufacturing the shielding angle map and the equal beam height map by adopting the geographic information data.
Drawings
FIG. 1 is a block angle azimuth view of the present invention;
FIG. 2 is a schematic diagram of an equivalent earth radius according to the present invention;
FIG. 3 is a schematic diagram of the maximum detection range in the present invention;
FIG. 4 is a graph of commercial Rockwell radar shielding angle in accordance with the present invention;
FIG. 5 is a plot of the heights of the equal beams of the Mercury radar of the present invention;
FIG. 6 is a schematic diagram of a Mercury radar echo superposition diagram according to the present invention;
FIG. 7 is a simulation diagram of the ground object occlusion in the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1-6, a radar isopeam height mapping algorithm,
s1: calculating an azimuth angle;
as shown in FIG. 1, assume that the earth is a standard sphere, O is the geocentric, N is the geographic north pole, the weather radar station is located at point A, and the longitude and latitude are (λ) 0 ，h 0 ) The obstacle is positioned at the point B, the longitude and latitude are (lambda, h), the geocentric angle of the obstacle relative to the radar station is n, and the inferior arc length corresponding to the maximum circle is L AB . The included angles between the connecting line of the radar station, the barrier and the center of the earth and the connecting line of the north pole and the center of the earth are b and a respectively.
From the spherical cosine function [5 ]:
cos(n)＝cos(a)cos(b)+sin(a)sin(b)cos(N) (1)
cos(a)＝cos(b)cos(n)+sin(b)sin(n)cos(A) (2)
wherein & lt N is the dihedral angle of the plane AON and the plane BON, and & lt A is the dihedral angle of the plane AON and the plane AOB. Angle a is also the azimuth angle of the obstruction relative to the radar station. And (2) calculating the geocentric angle n corresponding to the radar station and the sheltering object according to the formula (1).
And substituting the longitude and latitude of the radar station and the shelter into a spherical sine function [6 ]:
the following can be obtained:
and (2) substituting the longitude and latitude of the radar station and the shelter into the formula (1) to obtain:
cos(n)＝sin(h)sin(h 0 )+cos(h)cos(h 0 )cos(λ-λ 0 ) (5)
theoretically, the azimuth angle of the obstacle with respect to the radar station can be obtained from the expressions (4) and (5).
When the azimuth angle & lt A is solved by the formula (4), firstly, which quadrant the & lt A is in is judged. Literature [3] distinguishes quadrants where & lt A is located according to the radar station and the longitude and latitude of a shelter, namely, when lambda is larger than or equal to lambda 0 And h is more than or equal to h 0 When the azimuth angle is in the first quadrant, when lambda is more than or equal to lambda 0 And h is more than or equal to h 0 The azimuth angle is located in the second quadrant when lambda<λ 0 And h is<h 0 When the azimuth is in the third quadrant, when lambda<λ 0 And h is<h 0 If the latitude of the shelter is the same as the latitude of the radar station and the longitude of the shelter is greater than the latitude of the radar station, the azimuth of the shelter relative to the radar station should be 90 degrees, which is not the case according to the method of reference 3 set forth in the background. The details are shown in Table 1.
TABLE 1 azimuth angle of shelter at the same latitude as radar station
| Radar station latitude and longitude | Longitude +1 degree | Longitude +2 degree | Longitude +3 degree | Longitude +4 degree | Longitude +5 degrees |
| (109,15) | 89.8706 | 89.7412 | 89.6117 | 89.4822 | 89.3526 |
| (109,20) | 89.8290 | 89.6578 | 89.4868 | 89.3157 | 89.1445 |
| (109,30) | 89.7500 | 89.5000 | 89.2499 | 88.9997 | 88.7494 |
| (109,40) | 89.6786 | 89.3572 | 89.0357 | 88.7141 | 88.3924 |
| (109,50) | 89.6170 | 89.2339 | 88.8508 | 88.4677 | 88.0844 |
In table 1, assuming that the shade is the same as the radar station latitude, the shade longitude is incremented by 1o, and the azimuth angles calculated according to the expressions (4) and (5) are shown as numerical values in the table. As can be seen from table 1, when the shelter is the same as the radar station latitude and the shelter longitude is greater than the radar station longitude, the azimuth is not 90 ° but smaller than 90 °, and the larger the difference between the longitudes is, the smaller the azimuth is, and the larger the latitude is, the smaller the azimuth is at the same longitude. Assuming that the radar station longitude and latitude are (109,30), when the obstruction longitude and latitude are (111,30), the azimuth angle is 89.5 °. When the shade latitude slightly exceeds 30 °, the azimuth will fall into the second quadrant, according to the algorithm of document 3, and the calculated azimuth will be around 90.5 °, with an error of about 1 °. Through the analysis, when the latitude of the shelter is close to that of the radar station, the quadrant of the azimuth angle cannot be judged according to the latitude and the longitude of the radar station and the shelter.
When the latitude of the radar station is close to that of the shelter, and the azimuth angle of the shelter relative to the radar station is calculated, a criterion of a quadrant where the azimuth angle is located needs to be found. Assuming that the longitude and latitude of the obstruction is (λ ', h'), and the azimuth angle thereof with respect to the radar station is 90 °, equation (2) is substituted into equation (1):
(1-sin 2 (h 0 ))sin(h')＝sin(h 0 )cos(h 0 )cos(h')cos(λ'-λ 0 ) (6)
is provided with
Then there is
tg(h')＝mcos(λ'-λ 0 ) (7)
After the longitude and the latitude of an obstruction are determined, the longitude value is utilized, and the corresponding latitude value when the azimuth angle relative to the radar station on the longitude is 90 degrees can be calculated through the formula (7). The azimuth angle of the shelter smaller than the latitude value and the radar station is the result calculated by the formula (4), and the azimuth angle of the shelter larger than the latitude value is 180 degrees minus the calculated value by the formula (4). Table 2 shows latitude values for shades located at different longitudes when the radar station latitude and longitude is (109,38), which correspond to radar station azimuth angles of 90. As can be seen from table 2, when the shelter is located in the northern hemisphere and has a longitude greater than the longitude of the radar station, and has an azimuth angle of 90 ° with the radar station, its latitude values are all smaller than those of the radar station, and as the longitude increases, the latitude values gradually decrease.
TABLE 2 latitude value corresponding to a shield having an azimuth angle of 90 DEG with respect to the radar station
| Radar station latitude and longitude | Longitude +1 degree | Longitude +2 degree | Longitude +3 degree | Longitude +4 degree | Longitude +5 degrees |
| (109,38) | 37.9957 | 37.9830 | 37.9619 | 37.9322 | 37.8940 |
Is provided with
t is a latitude value corresponding to the longitude of each shelter and the azimuth angle of the radar station forming 90 degrees (each shelter corresponds to a t value), and is obtained by the formula (4):
the azimuth angle of each shade with respect to the radar station can be obtained by the formula (8).
S2: calculating the slope distance;
due to the influence of the atmosphere, the propagation path of the radar electromagnetic wave is bent. Typically, the ray propagates with a slight downward curvature. The curve propagation of the ray brings about a lot of inconvenience to the analysis and calculation. To solve this difficulty, the concept of equivalent earth radius is proposed. That is, under certain conditions, the actual earth radius is replaced by some equivalent earth radius, so that the atmosphere is equivalent to be uniform, and the propagation path of the radar is also a straight line. In the case of standard atmospheric refraction, the equivalent earth radius is 4/3 times the earth radius. For many years, radar shielding angles and equal-beam height maps are all calculated by using equivalent earth radii, but the corresponding relation between the equivalent earth and the real earth is unclear, and partial algorithms have deviation.
As shown in the attached figure 2 of the specification, H is the radar feed source altitude, H is the obstacle altitude, R is the earth radius and has the value of 6371km, n is the geocentric angle, and L is AB Is the propagation path of the radar ray in the actual atmosphere (A, B arc between two points). H M Equivalent barrier altitude, R M Equivalent earth radius, a value of 8500km, n under standard atmospheric conditions m Is the equivalent center of earth angle, L A'B' Is the equivalent straight-line propagation distance. Document [8]It is pointed out that the method of correcting atmospheric refraction using equivalent earth radius is suitable for arbitrary (but not necessarily for) starting elevation angles at low ray heights (less than 3km)
) The situation of (1) proves the equivalent linear propagation and the point pairs on the actual curve propagation pathThe height, the elevation angle and the ray length are all the same, and when the elevation angle is not high, the equivalent geocentric angle is about 3/4 times of the actual geocentric angle, namely
L A'B' ＝L AB (9)
H m ＝H (10)
δ'＝δ (11)
In Δ OA 'B' of fig. 2, it is obtained by the cosine theorem of the triangle:
l can be obtained by using the equations (1), (9), (10) and (12) A'B' The value of which is also the true real slant distance L of the radar ray AB . It should be noted that the equivalent ray length is equal to the length of the curve actually propagated by the ray, and is not the geometric straight-line distance between the radar station and the target (the dotted line l between two points A, B in fig. 2) AB ) And the equivalent geocentric angle is not equal to the actual geocentric angle.
According to the latest weather radar observation specifications, the radar with the conditions should carry out negative elevation observation. As shown in fig. 3 of the accompanying drawings of the specification, for a target with a height H, when a radar beam is tangent to the ground, the corresponding detection distance is maximum, and the maximum detection distance can be calculated by a trigonometric function as follows:
s3: calculating the shielding elevation angle;
radar height finding formula:
obtaining:
wherein L is equivalent slant distance, H is the elevation of the radar feed source, and H is the elevation of the shelter.
Substituting the maximum detection slope distance to obtain the lowest negative elevation angle delta min The lowest negative elevation angle is the elevation angle when the radar beam is tangent to the ground, and if the service needs and the conditions allow, lower elevation angle observation can be carried out around the radar.
S4: and detecting the spherical distance corresponding to the slant distance.
As shown in the attached figure 2 of the specification, the arc length is calculated according to the formula and the equivalent radius of the standard atmosphere and the formula (12):
where n is expressed in radian, the value can be obtained by the formula (1). As can be seen from equation (17), the arc length is substantially equal to the arc length of the real earth after the equivalent earth radius is adopted.
In order to verify the correctness of the theory, the application document uses geographic information data with the resolution of 0.01 degrees to make a new generation weather radar shielding angle map and equal beam height maps with the height of 1km above a radar station and the height of 3km and 6km above the radar station, as shown in the attached figure 4 of the specification and the attached figure 5 of the specification. The Shandong Luo is located in the Danjiang canyon of the northwest-southeast trend, the Shandong Luo new generation weather radar is located at the top of the Jinfeng mountain in the northwest of the city (the position indicated by an arrow in the figure), the altitude of a radar feed source is 987.65 meters, only terrain shielding exists around the Shandong Luo radar, no building shielding exists, and the attached figure 6 in the specification is a 0.5-degree elevation angle basic reflection rate factor data superposition graph of the Shandong Luo radar in the month of 2017 and 5-9 (only counting whether echoes exist or not, and not calculating the echo intensity). As can be seen from the attached figure 6 in the specification, the Shangluo radar has better coverage rate in the trend of the Danjiang canyons and the north canyons, and has poorer coverage rate in other directions due to terrain shielding.
The wave beam width of the weather radar of the new generation is 1 degree, the upper edge of the elevation angle wave beam of 0.5 degree is 1 degree, and theoretically, the radar wave beam can cover as long as the shielding angle is less than 1 degree. Comparing fig. 4 and fig. 6, it can be seen that at the azimuth of 90 ° -150 °, the theoretically calculated shielding angle is greater than 1 °, and the radar measurement result shows that there is no shielding at the azimuth.
In the azimuth of 220 degrees to 330 degrees, the theoretically calculated shielding angle is basically larger than 1 degree, the individual azimuth is smaller than 1 degree, the radar actual measurement result is displayed in the azimuth interval, the overall coverage is better, shielding exists near the azimuths of 210 degrees, 250 degrees, 280 degrees, 305 degrees, 325 degrees and the like, and the theoretically calculated result shows that the shielding angle is also smaller than 1 degree near the azimuths.
In the vicinity of 0 degrees, the shield angle is calculated by theory and has a small angle, and the shield angle is smaller than 0 degrees, and the actual measurement result shows that narrow coverage exists in the vicinity of the azimuth. In the azimuth angle of 5 degrees to 45 degrees, theoretical calculation shows that shielding angles of nearly 3 degrees exist near only 28 degrees, shielding angles of other azimuths are all larger than 1 degree, the actual measurement result of the radar shows that serious shielding exists near the radar within 70km, and after the used geographic information data are checked, the altitude values in the azimuths are found to be small except that a maximum value exists near 28 degrees.
The analysis considers that the reason for this phenomenon is that the resolution of the geographic information data is low, and the position is just the mountainous section which is upright in the east of the Qin mountain.
In azimuth angles of 45-85 degrees and 155-220 degrees, theoretically calculating the jump of a shielding angle between 3.5-0 degrees, wherein the fluctuation is large, the actual measurement result shows that the radar in the azimuth has serious shielding, and the map is checked to find the fluctuation of mountains and mountains in the azimuth, the vertical and horizontal gullies and the high and large mountains. In conclusion, as long as the adopted geographic information data has high enough resolution, the consistency between the theoretically-calculated shielding angle and the actually-measured radar result is good.
Since the shading angle calculation formula (16) is calculated by the slope distance calculation formulas (13) and (14), the slope distance calculation theory of the radar is indirectly proved to be correct. The comparison shows that the overall shape of the beam height map of the radar and the like in the figure 5 of the specification and the figure 6 of the specification is basically consistent with the echo superposition map of the radar in the figure 6 of the specification except for the azimuth of 5-45 degrees, and for some special terrains, if the resolution ratio of the adopted geographic information is not high, the calculated result has certain deviation, in addition, the theoretical calculation is based on standard atmosphere, the actual atmospheric condition is much more complicated, therefore, even if the geographic information with high enough resolution ratio is adopted, the theoretically calculated result cannot be completely consistent with the actual condition, but for the early evaluation of radar construction, the theoretically calculated result can meet the business requirement.
The embodiment also comprises a calculation method of the coverage area of the weather radar:
coverage is an important parameter in weather radar site selection and data applications. When the radar is built, firstly, the station to be selected is evaluated, and parameters such as a shielding angle, an equal beam height diagram, a coverage range and the like of the newly built radar are calculated. After the good station radar is built, the surrounding shielding is small, the radar coverage rate is high, and the weather change in a wider range can be monitored. Poor station location, large shielding around the built radar, small radar coverage and insufficient radar function. In addition, when radar observation data is applied, the coverage area of the radar is firstly known, and particularly, the central number of the areas, which are shaded by terrains and buildings, in the detection radius of the radar is required. After the weather condition radar is shielded by the terrain or the building, the weather condition radar in the shielded area cannot be detected, or the detected echo is weak, so that the missed judgment or the wrong judgment of heavy weather is easily caused.
In a traditional radar coverage rate calculation method, the coverage rate of a radar to a spherical surface of a certain height relative to the space above a radar station or the coverage rate of the radar to a certain altitude is calculated. In the meteorological service, the coverage rate of the radar with the height of 1 kilometer and the coverage rate of 2 kilometers are frequently used, wherein the coverage rate refers to the coverage rate of the radar to a continuous curved surface with a fixed height above each point on the ground. The traditional calculation method is an approximate calculation of radar coverage.
The specific method comprises the following steps:
the method utilizes a precipitation observation mode VCP21 commonly used by a new-generation weather radar to carry out calculation, the VCP21 mode has 9 observation elevation angles (0.5 degrees, 1.5 degrees, 2.4 degrees, 3.4 degrees, 4.3 degrees, 6.0 degrees, 9.9 degrees, 14.6 degrees and 19.5 degrees), and the radar beam width is about 1.0 degree. Theoretically, within the detection radius of the radar, all points in the space between the radar observation elevation angle of 0-4.8 degrees, 5.5-6.5 degrees, 9.4-10.4 degrees, 14.1-15.1 degrees and 19.0-20.0 degrees can be detected under the condition of no shielding. A
As shown in the attached figure 7 of the specification, O is the equivalent earth center, R is the radar feed source position, A, B, C, D, E is five points in the coverage range of the radar detection radius, the length of the line segment above the point represents the radar coverage height over the ground surface to be calculated,
for ease of discussion, assume 1 km. RL is 0.5 DEG elevation angle beam lower edge, angle LRM is 0.5 DEG radar lowest detection elevation angle, RN is 19.5 DEG elevation angle beam upper edge, and angle LRN is 20.0 deg.
Calculating from 0.0 degrees of the lower edge of an elevation wave beam with the azimuth angle of 0.0 degree and the radar angle of 0.5 degree, for a radar ray with the 0.0 degree, the radar ray is influenced by a point A of an obstruction nearest to the radar, points outside the point A cannot be detected by the radar ray with the 0.0 degree, the elevation of each point inside the point A is added by 1km, if the radar ray with the azimuth angle of 0.0 degree and the maximum observation elevation angle of the radar are positioned, the radar ray can be detected, and otherwise, the radar ray cannot be detected.
For example, point a, whose altitude plus 1km, is beyond the 20.0 deg. ray on the radar's maximum elevation beam and therefore cannot be detected. And because the ray height of 20.0 degrees is low, the points which are close to the radar cannot be detected by 1km above a plurality of points, and a top dead zone of the radar is formed. And increasing the elevation angle of the radar ray, and when the elevation angle of the point A relative to the radar feed source is exceeded (the elevation angle at the moment is assumed to be alpha), all points between the point A and the shield Q which is next to the radar and is closest to the radar are added with 1km of the elevation height, and if the radar ray with the elevation angle of alpha and the radar ray with the maximum elevation angle are located, the radar ray can be detected, otherwise, the radar ray cannot be detected. In this way, the elevation angle is increased stepwise until it approaches 20.0 °. During the period, points B and D can be detected, and points C and E cannot be detected due to the influence of the front shelter. And then calculating the next azimuth angle until all points 1km above the earth surface which can be covered in the radar detection radius range are found.
N 1 ＝COUNTIF(N,h 1 ＜H+h＜h 2 ) (3)
Mu is radar coverage, S is total area of area to be evaluated, S 1 The area covered by radar at a specific height of the area to be evaluated, N is the total number of points of the area to be evaluated in the used elevation data, N 1 The number of points covered by the radar at a specific height, H is the altitude of the position of a certain point, H is the height to be evaluated, H 1 、h 2 The height of the lower edge and the upper edge of the radar wave beam above the position of a certain point.
Elevation data of any resolution can be calculated by the method. Firstly, the azimuth resolution is a degrees from the azimuth angle of 0 degrees;
the method comprises the following steps: calculating the altitude of the maximum elevation angle of 20 degrees of the radar ray corresponding to each sampling point above the azimuth angle between 0 degree and a degree within the range of the detection radius of the radar;
step two: calculating the altitude of the lowest elevation angle of 0 degree of the radar ray corresponding to the space above each sampling point between the azimuth angle of 0 degree and a degree within the detection radius range of the radar;
step three: in the range of radar detection radius, inquiring a sampling point A which is closest to a radar and has an elevation angle larger than the lowest ray elevation angle relative to a radar feed source within an azimuth angle of 0-a degrees;
step four: calculating the altitude of each sampling point and the height of the coverage rate to be calculated by taking the distance of the position of the point A relative to the radar station as a radius and the azimuth angle of the azimuth angle between 0 degree and a degree, wherein if the distance is between the heights calculated in the first step and the second step, the sampling point can be covered, otherwise, the sampling point cannot be covered;
step five: stepping by taking the elevation resolution as b degrees, and repeating the steps from the first step to the fourth step until all points which can be covered by radar rays are found within the range of the detection radius of the radar and between the azimuth angle of 0 degree and a degree;
step six: and stepping the azimuth angle according to a degree of resolution, and repeating the steps from the first step to the fifth step until all points which can be covered by the radar in the azimuth angle of 0-360 degrees are found.
In the drawings of the disclosed embodiments of the invention, only the structures related to the disclosed embodiments are referred to, and other structures can refer to common designs, and under the condition of no conflict, the same embodiment and different embodiments of the invention can be combined with each other;
and finally: the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (5)
1. The radar equal beam height map making algorithm is characterized by comprising the following steps of (1) making a radar equal beam height map;
s1: calculating an azimuth angle;
s2: calculating the slope distance;
s3: calculating the shielding elevation angle;
s4: and detecting the spherical distance corresponding to the slant distance.
2. The radar isopipe height mapping algorithm of claim 1, wherein: in the azimuth calculation: assuming that the earth is a standard sphere, O is the geocentric, N is the geographic north pole, the weather radar station is located at the point A, and the longitude and latitude are (lambda) 0 ，h 0 ) The obstacle is located at point B, the longitude and latitude are (lambda, h), the geocentric angle of the obstacle relative to the radar station is n, and the inferior arc length corresponding to the maximum circle is L AB And the included angles between the connecting line of the radar station, the obstacle and the center of the earth and the connecting line of the north pole and the center of the earth are b and a respectively.
3. Radar isobeam according to claim 1The height map making algorithm is characterized in that: in the slope distance calculation: h is the radar feed source altitude, H is the obstacle altitude, R is the earth radius with a value of 6371km, n is the geocentric angle, L AB For the propagation path of radar rays in the actual atmosphere, H m Equivalent barrier altitude, R m The value under standard atmospheric conditions is 8500km, n for equivalent earth radius m Is the equivalent center of earth angle, L A'B' Is the equivalent straight-line propagation distance.
4. The radar isopipe height mapping algorithm of claim 1, wherein: in the calculation of the shielding elevation angle: l is the equivalent slant distance, H is the radar feed source altitude, and H is the shelter altitude.
5. The calculation method of the coverage area of the weather radar is characterized by comprising the following steps: firstly, the azimuth resolution is a degrees from the azimuth angle of 0 degrees;
the method comprises the following steps: calculating the altitude of the maximum elevation angle of 20 degrees of the radar ray above each sampling point within the range of the radar detection radius and between the azimuth angle 0 degree and a degree;
step two: calculating the altitude of the lowest elevation angle 0 degree of the radar ray corresponding to the upper space of each sampling point between the azimuth angle 0 degree and a degree within the range of the detection radius of the radar;
step three: the elevation angle calculation resolution is b degrees within the range of radar detection radius, the azimuth angle is between 0 degree and a degrees, the sampling point A which is closest to the radar and has the elevation angle larger than b degrees relative to the radar feed source is inquired;
step four: calculating the altitude of each sampling point and the height of the coverage rate to be calculated by taking the distance of the position of the point A relative to the radar station as a radius and the azimuth angle of the azimuth angle between 0 degree and a degree, wherein if the distance is between the heights calculated in the first step and the second step, the sampling point can be covered, otherwise, the sampling point cannot be covered;
step five: stepping by taking the elevation resolution as b degrees, and repeating the steps from the first step to the fourth step until all points which can be covered by radar rays are found within the range of the detection radius of the radar, between 0 degree and a degree of the azimuth angle and between 0 degree and 20 degrees of the elevation angle;
step six: and stepping the azimuth angle according to a degree of resolution, and repeating the steps from the first step to the fifth step until all points which can be covered by the radar in the azimuth angle from 0 degree to 360 degrees are found.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210757134.2A CN115131460A (en) | 2022-06-30 | 2022-06-30 | Weather radar coverage area calculation method and radar equal-beam height map making algorithm |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210757134.2A CN115131460A (en) | 2022-06-30 | 2022-06-30 | Weather radar coverage area calculation method and radar equal-beam height map making algorithm |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115131460A true CN115131460A (en) | 2022-09-30 |
Family
ID=83382541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210757134.2A Pending CN115131460A (en) | 2022-06-30 | 2022-06-30 | Weather radar coverage area calculation method and radar equal-beam height map making algorithm |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115131460A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115617820A (en) * | 2022-12-19 | 2023-01-17 | 广东省气象公共服务中心(广东气象影视宣传中心) | Method for making deep learning data set for position-dependent radar quantitative precipitation estimation |
| CN117214846A (en) * | 2023-11-09 | 2023-12-12 | 成都远望科技有限责任公司 | Detection method for near-ground detection blind area range of weather radar |
-
2022
- 2022-06-30 CN CN202210757134.2A patent/CN115131460A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115617820A (en) * | 2022-12-19 | 2023-01-17 | 广东省气象公共服务中心(广东气象影视宣传中心) | Method for making deep learning data set for position-dependent radar quantitative precipitation estimation |
| CN115617820B (en) * | 2022-12-19 | 2023-04-28 | 广东省气象公共服务中心(广东气象影视宣传中心) | Deep learning data set manufacturing method for quantitative precipitation estimation of position-related radar |
| CN117214846A (en) * | 2023-11-09 | 2023-12-12 | 成都远望科技有限责任公司 | Detection method for near-ground detection blind area range of weather radar |
| CN117214846B (en) * | 2023-11-09 | 2024-01-30 | 成都远望科技有限责任公司 | Detection method for near-ground detection blind area range of weather radar |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115131460A (en) | Weather radar coverage area calculation method and radar equal-beam height map making algorithm | |
| CN103217177B (en) | A kind of radio wave refractive correction method, Apparatus and system | |
| CN112558076B (en) | Volume scanning mode calculation method based on networking weather radar coverage area and application | |
| CN107218923A (en) | Surrounding enviroment history settles methods of risk assessment along subway based on PS InSAR technologies | |
| CN110044327B (en) | Infrastructure settlement monitoring method and system based on SAR data and GNSS data | |
| CN107843895B (en) | A kind of Dual-Doppler weather radar dimensional wind inversion method | |
| CN110879428B (en) | Method for measuring rain through networking in overlapped area between radars in same wave band under complex terrain condition | |
| CN112284332B (en) | High-rise building settlement monitoring result three-dimensional positioning method based on high-resolution INSAR | |
| CN105044669A (en) | Three-station time-difference-measuring stereoscopic positioning method | |
| CN112346086B (en) | Efficient and rapid star-masking forecasting method based on near space floating platform | |
| CN102707284A (en) | Ground control and measurement stationing method based on onboard interferometric synthetic aperture radar (InSAR) | |
| CN115436906B (en) | Method for improving accuracy of radar detection target position and wind field inversion information | |
| CN109141427A (en) | EKF localization method under nlos environment based on distance and angle probabilistic model | |
| CN115047463B (en) | Collaborative scanning scheduling method considering radar echo attenuation in rainfall area | |
| CN110673181A (en) | GNSS interference source positioning method based on grid energy traversal search | |
| CN107817489A (en) | mapping method | |
| CN107404349B (en) | Signal coverage analysis method for integrating ADS-B actual measurement signal and line-of-sight transmission analysis | |
| CN112556636B (en) | Method for calibrating receiving antenna by using GPS data provided by satellite | |
| CN113253276A (en) | Intelligent evaluation method and device for weather radar site selection | |
| CN112867052B (en) | Method and system for determining coverage range blind area of communication equipment in plateau area | |
| JP5429493B2 (en) | Investment plan evaluation method for rainfall observation facilities | |
| CN110850382A (en) | Method and system for evaluating measurement accuracy of interferometric radar altimeter | |
| CN114812520B (en) | Method and system for testing high-speed magnetic levitation track installation measurement and control three-dimensional control network | |
| CN113156441B (en) | Effective three-dimensional airspace subdivision approximation calculation method for meteorological radar detection | |
| CN109164439A (en) | Air index calculation method on a kind of electric wave ray |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |