GB 31223-2014Specifications for observing environs protection of weather radar station (English PDF)

Foreword

All technical content of this standard is mandatory. This standard was drafted in accordance with rules GB/T 1.1-2009 given. The standard proposed by the China Meteorological Administration. This standard by the national meteorological Standardization Technical Committee (SAC/TC507) instruments and methods of observation. Drafted by: China Meteorological Administration meteorological centers, Fujian Meteorological Bureau, Guizhou Provincial Meteorological Bureau, the Liaoning Provincial Meteorological Bureau. The main drafters of this standard. Daren Chen, high Yuchun, Li Lin, Zhang Hu students, Wu Taiwang, Chai Xiumei, Cheng Fei, Li Zhe, Guo Rui, Chen Bao.

Weather radar is to monitor the typhoon, heavy rain, hail, tornadoes, downburst and other disastrous weather system for disaster prevention and mitigation, to protect people's life and property Important remote sensing equipment production safety, short-term nowcasting warning to provide a scientific basis for decisions. To protect the environment, weather radar detection, charge Minutes played using weather radar performance, formulated standards. Meteorological environmental protection norms Weather Radar

1 Scope

GB 31223-2014 is the Chinese national standard on specifications for observing environs protection of weather radar station, in the field of natural and applied sciences. It carries no /T suffix, which in the Chinese system means compliance is mandatory: a product or a practice within its scope has to meet it to be lawfully made, sold or carried out in China. It was issued on 30 September 2014 by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of China, and has been in force since 1 January 2015. Classification: ICS 07.060, CCS A47. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This standard specifies the scope and requirements of the weather radar to detect environmental protection. This standard applies to weather radar to detect environmental protection activities.

2 Normative references

The following documents for the application of this document is essential. For dated references, only applies to the version dated paper Pieces. For undated references, the latest edition (including any amendments) applies to this document.

GB 4824-2004 industrial, scientific and medical (ISM) radio disturbance characteristics Limits apparatus and methods of measurement (CISPR11. 2003, IDT) GB air intelligence radar station on the electromagnetic environment protection requirements 13618-1992

3 Terms and Definitions

The following terms and definitions apply to this document.

3.1 Weather radar weatherradarstation Weather radar by the operating environment and equipment to meet the requirements of the facility and its spatial composition.

Note. weather radar is based on scattering clouds, fog, rain, snow and other particles and electromagnetic wave generation principle Doppler effect and the like, and detect the Doppler velocity echo intensity rainfall And the evolution of the spatial distribution, and thus precipitation weather surveillance radar tracking system.

3.2 Beamwidth beamwidth Antenna pattern angle between the direction of maximum radiation two half-power points.

3.3 Obstacle obstacle Generating object and the shielding effect on high frequency electromagnetic waves emitted and received by the radar.

3.4 Isolated obstacles isolatedobstacle Obstacle adjacent lateral spacing is greater than 2 azimuth beamwidth and not greater than the tolerance value shielding obstacle.

3.5 Blocking elevation blockelevationangle Start from the radar minimum operational elevation angle of the lifting beam away from the obstacle until its lower edge, i.e. from the occlusion to occlusion on the presence of The beam angle of the edge lifting disappears.

3.6 Occlusion azimuth blockazimuthangle Blocking obstacle beamforming radar, which radar beam edge orientation (-3dB) into the barrier region, and the edge of the radar beam (-3dB) when the angle between the orientation in which the exit obstacle region.

3.7 Total occlusion azimuth totalblockangleinazimuth All occlusion sum azimuth angle.

3.8 Obstacle limitation altitude restrictedaltitudeforobstacle The maximum allowed blocking obstacle elevation of the highest point is located calculated altitude.

3.9 Obstacle limitation azimuth width restrictedazimuthwidthforobstacle The width of the obstacle obtained by calculating the maximum allowable occlusion azimuth.

3.10 Headroom clearance Weather radar based business work at the lowest elevation, antenna main beam is not obstructed detection environment.

4 Scope of protection

4.1 General Weather radar detection range of environmental protection and the protection zone consists of a two protected areas, the scope of illustration and description in Appendix A. In the days There should be no other air Zhou Bian the radar station interference affecting the normal operation of the radar. For electromagnetic interference protection scope is not limited to one, two Level protected areas.

4.2 a protected area The near-field region of radiation above and below the weather radar radar antenna port 10 along the vertical parallel lines radar wavelength transition region "side Edge "area thereof.

4.3 two protected areas In weather radar as the center from the outer edge of a protected area to the distance from the radar 20km annular region.

Appendix A

(Normative) Weather radar antenna electromagnetic radiation field region Calculation A.1 electromagnetic radiation field around the weather radar antenna area into the radiation near field and far field radiation, shown in Figure A.1, A.2 is a plan FIG. Schematic view. Description. 1

--- shaded protected area, 0 \u003cd2<=2D2/lambda; Parallel beam region, 0 \u003cd1<=D2/2lambda; h = 10lambda; Above and below the upper and lower radar antenna port 10 along an extension line of the wavelength of the radar parallel lines, D2/2lambda \u003cd4<=D2/2lambda 10lambda/tan(180lambda/piD); 2

--- to 20km outside the shadow of the two protected areas, 2D2/lambda \u003cd3<=20km; 3

--- beam "edge" (corresponding to the "edge" of the transition zone). A.1 schematic view field region of electromagnetic radiation and protected areas Description. 1

--- a protected area, 0 \u003cd1<=2D2/lambda; 2

--- two protected areas, 2D2/lambda \u003cd2<=20km. Figure A.2 electromagnetic radiation field region and a schematic plan view of protected areas A.2 respect to the aperture of the antenna, the radiation near field range calculated according to formula (A.1). 0 \u003cd<=2D2/lambda (A.1) Where. D

--- point viewing distance to the antenna in meters (m); D

--- radar antenna diameter, in meters (m);

--- radar wavelength [lambda], in meters (m). Where 0 \u003cd<=D2/2lambda,D2/2lambda\u003cd<=2D2/lambda. A.3 for the range of the antenna aperture, radiation in the far field region according to equation (A.2) is calculated. d > 2D2/lambda (A.2) Where. D

--- point viewing distance to the antenna in meters (m); D

--- radar antenna diameter, in meters (m);

--- radar wavelength [lambda], in meters (m).

Appendix B

(Normative) Weather radar protection clearance calculation method B.1 radar antenna radiation environmental clearance calculated near-field region B.1.1 collimated beam region and the extension region obstacle height limit calculated altitude Parallel beam region, radiated from the antenna the radar energy is concentrated in the cylindrical space having a diameter D propagation, consider engineering practice Experience, to near-field region above and below the radar antenna port 10 and down along the parallel lines of the radar wavelength radar headroom baseline environmental protection, Be the corresponding extension (extension configuration) protected from. Limit altitude corresponding to the formula in Figure B.1 (B.1) is calculated. h2 = h1-10lambda, 0 \u003cd<=D2/2lambda 10lambda/tan(180lambda/piD) (B.1) Where. H2

--- radar antenna to limit the horizontal scanning altitudes of the highest point of the object, in meters (m); Point along the altitude h1 of the radar antenna port

--- in meters (m);

--- radar wavelength [lambda], in meters (m); D

--- the radar antenna port object point to the highest point along the horizontal distance in meters (m). Description. 1

--- beam centerline, h = 10lambda; A

--- when the radar antenna is not just caused by the horizontal scanning an object altitude limit point of occlusion;

--- C under point along the radar antenna port; O

--- radar antenna center point (feed). FIG schematic elevation height B.1 parallel beam region and object region extending limit Limit height calculation method altitude B.1.2 transition zone Transition zone with its "edge" baseline environmental clearance for the radar. Limit altitude corresponding to the formula in Figure B.2 (B.2) is calculated. h2 = h1 D/2-d × tan (180lambda/piD), D2/2lambda 10lambda/tan (180lambda/piD) \u003cd<=2D2/lambda (B.2) Where. H2

--- radar antenna to limit the horizontal scanning altitudes of the highest point of the object, in meters (m); Point along the altitude h1 of the radar antenna port

--- in meters (m);

--- radar wavelength [lambda], in meters (m); D

--- radar antenna diameter, in meters (m); D

--- the radar antenna port object point to the highest point along the horizontal distance in meters (m). Description. 1

Appendix C

(Normative) Obstructions limit capacity calculation method of the angle C.1 calculate the radar echo power loss caused by obstructions In the case where the same radar range, the radar echo intensity when a loss when a group of formula (C.1). 10lg p '= a (C.1) Where. P

--- radar beam is not blocked when an obstacle echo reception power, in watts (W is); p '

--- beam is blocked by the obstacle received radar echo power in watts (W). Radar echo power loss rate (p-p ')/p. According to 5.1.1, the radar echo intensity loss takes a maximum value a = 1dB, calculated according to the formula (C.1) obtained radar echo power loss was 21%. Total power (before blocking) of the radar radiation is calculated C.2 In practical engineering, the power density within the weather radar antenna Mainlobe (3dB) approximates a Gaussian function curve, a Gaussian distribution Function is. Phi (x) = integral - JPY 2pi e- theta2 2dtheta Energy main lobe antenna pattern by integral theta1 -theta1 2pi e- theta2 2dtheta calculated, wherein (-theta1, theta1) of the antenna's main beam, the main beam deviates from the lower edge Angle axis. From the "standard normal distribution function value table", found -4 2pi e- x2 2dx =

1 The 3dB beamwidth is defined, when the power density is reduced to half the maximum value (half power point), 2pi e- x21 2 = 2 × 2pi e- x2 x = 0 2 × 2pi Solve for x1 = 1.18. Check the "standard normal distribution function table of values" was P (x<=1.18) =

0.881 Then P (x > 1.18) = 0.119. Total power radar radiation (before blocking) is. P (-1.18<=x<=1.18) = 1-2 × 0.119 =

0.762 C.3 isolated obstructions angle calculating tolerance value When obstructions caused radar radiation power loss was 21%, effective radiated power of 79% of the total radiated power; For simplicity, Consider only one way obstructions caused radar radiation power loss, the power loss of 0.762 × 21% = 0.16. P (x<=x2) = 0.881-0.762 × 21% =

0.721 Now "function of the standard normal distribution table of values" de x2 = 0.59. The antenna pattern and the density of the Gaussian probability function correspondence relationship may be of formula (C.2). theta2 theta1 = x2 x1 = 0.59 1.18 = (C.2) Where.

--- theta] 1 at the half power point of the edges from the main beam axis angle (equal to the half value width of the beam) in degrees ([deg.]); After blocking the beam edge theta] 2

--- main beam axis deviation angle, in degrees (°). Counting from the edge of the radar beam shielding angle tolerance value Deltatheta = theta1-theta2. By the formula (C.2) found Deltatheta = 0.5theta1, this formula applies to elevation and azimuth. C.4 under typical weather radar beamwidth isolated obstructions azimuth, elevation tolerance value When the antenna beamwidth of 0.5 °, theta1 = 0.25 °, Deltatheta = 0.125 °. When the antenna beamwidth of 1.0 °, theta1 = 0.5 °, Deltatheta = 0.25 °. When the antenna beamwidth of 1.5 °, theta1 = 0.75 °, Deltatheta = 0.375 °. Isolated obstructions typical weather radar azimuth beam width, the pitch angle margin value in Table C.1. Table C.1 isolated tolerance value obstructions angle in degrees Weather radar beam elevation width tolerance value obstructions isolated isolated obstructions azimuth tolerance value 0.5 0.125 0.125 1.0 0.25 0.25 1.5 0.375

0.375 twenty one

Appendix D

(Informative) Calculation example weather radar calculation methods of the various sources of interference tolerance value and the minimum interference voltage protection pitch D.1 interference voltage tolerance value calculation

5.1.2 The resulting loss of sensitivity, interference signal takes the maximum value 1dB, obtained by the radar weather equation 10lg P'r, min Pr, min = 1, I.e. of formula (D.1) P'r, min = Pr, min 0.26Pr, min (D.1) Where. When the radar receiver P'r, min

--- interference signal power of the input signal, in units of decibel milliwatts (dBm); Pr, radar receiver when the input signal power signals without interference

--- min (equal to the minimum detectable signal power N), in units of dBm (DBm). P'r, min should meet the minimum detectable signal to noise ratio requirements, i.e. P'r, min = IN, where I is the interference power, then I = 0.26N. The minimum interference power sources of interference caused by weather radar principles, a voltage corresponding to the interference tolerance value Ujf, max is Ujf, max = 0.51Unf Wherein, when no Unf interference signal equivalent to the system noise rms voltage receiver input, in units of microvolts (µV). By the noise power to noise temperature relationship Pn = U2n R = kTBn It can be derived Unf formula, see formula (D.2). Unf = kTBnR (D.2) Where. K

--- Boltzmann constant in Joules per Kelvin (J/K);

--- T system noise temperature, in Kelvin (K);

--- BN equivalent noise bandwidth of the receiver unit of megahertz (MHz);

--- R & lt receiver input impedance, ohms (Omega). Seen from the formula (D.2) is calculated, 5.3GHz ~ 5.7GHz, 9.3GHz ~ 9.7GHz input of the receiver and the equivalent noise voltage UCnf UXnf Respectively 0.86µV, 0.88µV. 13618-1992,2.7GHz ~ 3.0GHz by the receiver input noise voltage USnf equivalent to GB 0.85µV. The minimum pitch calculation example D.2 Protection To high voltage overhead transmission lines, substations, for example, by the GB 13618-1992 Annex B of formula (B.2) may be obtained of formula (D.3) and formula (D.4). ESjq, max = USjf, max 20lgfS-G-10lgZ DeltaEgp L-9.8 (D.3) ECjq, max = UCjf, max 20lgfC-G-10lgZ DeltaEgp L-9.8 (D.4) Where. ESjq, max

--- S-band quasi-peak field strength of interference tolerance value in decibels microvolts per meter (dB · µV/m); ECjq, max quasi-peak

--- C-band interference field strength tolerance value in decibels microvolts per meter (dB · µV/m); USjf, max

--- S-band interference voltage tolerance value, microvolt units of decibels (dB · µV); UCjf, max

--- C-band interference voltage tolerance value, microvolt units of decibels (dB · µV); fS

--- S-band weather radar typical operating frequency in megahertz (MHz); The typical operating frequency fC

--- C-band weather radar, in units of megahertz (MHz); G