Some standard content:
Standard SJ3251-89 of the Ministry of Machinery and Electronics Industry of the People's Republic of China
General Technical Conditions for Ground Gun Aiming Radar Antennas Issued on 1989-03-20
Implementation on 1989-03-25
Issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China Standard SJ3251-89 of the Ministry of Machinery and Electronics Industry of the People's Republic of China General Technical Conditions for Ground Gun Aiming Radar Antennas 1 Subject content and scope of application
SJ3251-89
This standard specifies the general technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of ground gun aiming radar antennas (hereinafter referred to as antennas), and is the basic basis for antenna design, manufacture and acceptance. This standard is applicable to the preparation of product standards (technical conditions). If necessary, the contents not included in this standard should be clearly specified in the product standards (technical conditions). 2 Reference standards
GB3784
GJB74.1~14
SJ2534.1~18
SJ2267
3 Terminology
Terminology
General technical conditions for military ground radar Common terminology Ground gun aiming radar reliability test method
General technical conditions for military ground radar
Antenna test method
General technical conditions for military electronic equipment and mechanical electrical assembly Any terminology not defined in this standard shall be based on the national standard GB3784 "Radar Terminology" and GJB74.2.
3.1 Damage
Damage includes the following: external and internal structural rupture or cracks, irreversible structural strain or deformation, screw damage, fiberglass antenna or radome peeling, epoxy resin bonding points or metal welding points cracking, and changes in tolerance limits.
3.2 Deterioration
Deterioration includes the following: fading, corrosion, scratches, plating or paint blistering, pitting or peeling, component distortion or bending, excessive wear, mildew and internal moisture caused by improper surface treatment. 3.3 Performance degradation
Performance degradation means any reduction in mechanical and electrical performance that does not meet the specified values. 3.4 Three-channel single pulse requirement
A typical single pulse requirement has three intermediate frequency channels, one sum signal channel, one azimuth error signal channel and one pitch error signal channel. The three channels use the sum signal as a reference signal to determine the polarity of the angle error detector error signal.
Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on March 20, 1989 and implemented on March 25, 1989
3.5 Single-channel pulse radar
SJ3251-89
refers to a single pulse radar receiver with only one intermediate frequency channel: it can combine the sum and difference signals in some way and restore them separately at the output end.
3.6 Dual-channel single pulse radar
refers to a single pulse radar receiver with two intermediate frequency channels. It has two forms, one is sum plus difference and sum minus difference, and the other is sum and difference separately.
4 Technical requirements
4.1 General requirements
4.1.1 The antenna and its components, parts and parts shall comply with the drawings and documents designed by the contractor. 4.1.2 The antenna and its components and parts shall be stamped with the inspection pass stamp at the appropriate position. If there are special requirements, the printing position shall be specified on the design drawings.
4.1.3 Materials
Materials that meet the antenna performance and environmental requirements should be used. 4.1.4 Surface treatment
Surface treatment should comply with the provisions of Article 4.11 of GJB74.5 "General Technical Conditions, Design and Manufacturing Requirements for Military Ground Radars", and the color should comply with the requirements of 4.11.3 of GJB74.5. 4.1.5 Electrical and mechanical assembly requirements
The antenna should be assembled according to the design drawings. Unless otherwise specified in the product standard (technical conditions), the electrical and mechanical assembly requirements of the antenna should be implemented in accordance with SJ2267.
4.1.6 Electrical and structural design and manufacturing requirements
Unless otherwise specified in the product standard (technical conditions), the design and manufacturing requirements of the antenna's high-frequency connectors, waveguides, coaxial lines and feeding components, and antenna reflectors should be implemented in accordance with Articles 4.4, 4.5 and 4.6 of GJB74.5. 4.2 Performance requirements
4.2.1 Three-channel single-pulse gun-aiming lyuda antenna 4.2.1.1 Antenna operating bandwidth
The antenna's operating bandwidth shall be specified in the product standard (technical conditions). Within the specified bandwidth, the antenna's plane pattern, electric axis drift, voltage standing wave ratio and power capacity shall meet the corresponding requirements. 4.2.1.2 Antenna plane pattern
4.2.1.2.1 and branch beam width
The antenna and branch beam width shall meet the specified requirements (see product standards or technical conditions. Same below) 4.2.1.2.2 and branch sidelobe level
The antenna and branch sidelobe level shall meet the specified requirements, 4.2.1.2.3 and branch gain
The antenna and branch gain shall meet the specified requirements. 4.2.1.2.4 Differential branch sidelobe level
SJ3251--89
The sidelobe level of the antenna differential branch should meet the specified requirements. 4.2.1.2.3 Differential branch gain
The gain of the antenna azimuth difference branch and the high and low difference branch should meet the specified requirements. 4.2.1.2.6 Differential branch amplitude imbalance
The amplitude imbalance of the antenna azimuth difference branch and the high and low difference branch should meet the specified requirements. 4.2.1.2.7 Zero-value depth of difference branch
The zero-value depth of the azimuth difference branch and elevation difference branch of the antenna shall meet the specified requirements. 4.2.1.3 Electric axis drift
Within the specified bandwidth, the relative change of the position of the antenna electric axis in the azimuth plane and elevation plane with frequency shall meet the specified requirements.
4.2.1.4 Voltage standing wave ratio
The voltage standing wave ratio of the antenna shall meet the specified requirements. 4.2.1.5 Power capacity
The power capacity of the antenna shall meet the specified requirements. 4.2.2 Single-channel and dual-channel monopulse radar antennas For single-channel and dual-channel monopulse radar antennas, all the contents of 4.2.1 are applicable, and the following contents shall also be included.
4.2.2.1 Cross-level of synthetic beams
The cross-level of the synthetic beams of the antenna shall meet the specified requirements. 4.2.2.2 Synthetic beam and side lobe level
The side lobe type of the antenna synthetic beam shall meet the specified requirements. 4.2.3 Conical scanning radar antenna
4.2.3.1 Antenna operating frequency bandwidth
Same as 4.2.1.1,
4.2.3.2 Antenna plane pattern
4.2.3.2.1 Antenna beam width
The antenna beam width shall meet the specified requirements, 4.2.3.2.2 Antenna side lobe level
The antenna side lobe level shall meet the specified requirements.
4.2.3.2.3 Antenna gain
The antenna gain shall meet the specified requirements,
4.2.3.2.4 Conical scanning beam cross level
The antenna conical scanning beam cross level shall meet the specified requirements. 4.2.3.3 Electric axis drift
Same as 4.2.1.3.
4.2.3.4 Voltage standing wave ratio
Same as 4.2.1.4.
4.2.3.5 Power capacity
Same as 4.2.1.5,
4.3 Environmental condition requirements
SJ3251—89
This standard only includes the overall environmental condition requirements for antennas. Product standards (technical conditions) should also list some other environments or comprehensive environmental tests as needed, and specify the items and sequence of environmental tests. Unless otherwise specified in the product standard, the general requirements for environmental testing shall be implemented in accordance with Chapter 3 "General Requirements" of GJB74.6 "General Technical Conditions, Environmental Technical Requirements and Test Methods for Military Ground Radars". The environmental test of the antenna can be carried out together with the gun aiming station, or separately if necessary. 4.3.1 Temperature
4.3.1.1 Working temperature
When the antenna is thermally stable at any temperature between -45℃ and +55℃, the antenna should not have structural looseness, damage, deterioration or performance degradation.
4.3.1.2 Storage temperaturebZxz.net
After the antenna has been stored at each extreme temperature of -50℃ to +65℃ for not less than 4 hours, the antenna should not have structural looseness, damage, deterioration or performance degradation.
4.3.2 Steady Humidity
The gun-aiming radar antenna should not become loose, damaged, deteriorate or have performance degradation after being exposed to an ambient humidity of +35°C and an atmospheric pressure of 95% to 98% relative humidity for at least 48 hours. 4.3.3 Impact
After the antenna is impacted three times in the positive and negative directions along each of the three mutually perpendicular axes (i.e. 18 impacts in total), the antenna should not have loose structure, damage or performance degradation. 4.3.4 Vibration
The antenna should be installed on the vibration table in the normal working position. The vibration test should be carried out under normal test atmospheric conditions and cyclically swept along the three mutually perpendicular axes. After the swept frequency vibration, the antenna should not have loose structure, damage or performance degradation. 4.3.5 Rain
After the antenna is exposed to rain with an intensity of 5mm/min for 1 hour, the antenna should not have damage or deterioration and should meet the requirements of 4.2.
4.4 Reliability requirements
The reliability requirements of the antenna should meet the reliability requirements of the antenna subsystem of the whole machine: the MTBF value is specified in the product standard (technical conditions).
4.5 Maintainability requirements
If the requirements for antenna maintainability are not specified in the product standard (technical conditions), then 4.5.1 shall apply. If the requirements for maintainability are specified, it is recommended to apply 4.5.2. 4.5.1 Non-repairable
Antenna that is not specified as a repairable product (see product standard) shall be considered non-repairable and shall be replaced once damaged.
4.5.2 Maintainability
SJ3251-89
When the maintainability of antennas and their components is specified, the following general maintainability principles shall be met: a. Adopt the safest design for the equipment and personnel involved in maintenance. b. When designing, it is required to minimize the maintenance skills and training required to achieve an appropriate level of familiarity with maintenance technology.
c. When designing, minimize the types of tools and test equipment required to complete maintenance tasks. d. Adopt the design that is most convenient for access to all components that need to be repaired, inspected, disassembled or replaced. e. To reduce the complexity of maintenance work, simple designs should be used to the maximum extent possible, including the use of standardized components for optimal interchangeability.
f. When designing, the average time to complete the scheduled maintenance and replacement of components should be short enough to ensure that the antenna has the required working efficiency.
g. Adopt a design that can enhance and facilitate field-level maintenance operations at the base. 5 Test methods
5.1 Test methods for general requirements
The antenna should be inspected visually and mechanically, and the design drawings and product standards should be compared to verify whether the antenna meets the requirements of 4.1.
5.2 Test methods for technical requirements
5.2.1 Design requirements for antenna test field
Unless otherwise specified, the requirements for test equipment in the antenna test field shall be implemented in accordance with SJ2534.1 "Antenna test methods - Test equipment in antenna test field".
Unless otherwise specified in the product standard, the distance between the auxiliary antenna in the test field and the antenna under test shall ensure that the maximum phase error of the radiated wave at the aperture of the antenna under test does not exceed 22.5°; at the same time, the distance between the two antennas shall not be less than 10 wavelengths; the directivity of the auxiliary antenna shall be selected to provide a radiated wavefront with an amplitude taper of less than 0.5dB at the aperture of the antenna under test, and the maximum level of irrelevant signals from reflections and other sources shall not exceed -40dB from the auxiliary antenna to the antenna under test via a direct path, which shall be verified by detecting the field strength of the aperture of the antenna under test. 5.2.2 Three-channel single-pulse gun-aiming radar antenna 5.2.2.1 The test method for the antenna operating frequency bandwidth is shown in 5.2.2.2, 5.2.2.3, 5.2.2.4 and 5.2.2.5 5.2.2.2 Test method for antenna plane radiation pattern Unless otherwise specified in the product standard (technical conditions), for gun-aiming radars operating at non-point frequency, several frequency points should be selected within the specified operating frequency range to measure the antenna's plane radiation pattern. The frequency interval between adjacent frequency points shall be selected according to the following principles:
The frequency interval shall not be greater than 250 MHz when the center frequency is between 2000 MHz and 5000 MHz. a.
b. When the center frequency is higher than 5000MHz, the frequency interval should not be greater than 500MHz5.2.2.2.1 and branch beam width test method a. The block diagram of a typical antenna test system is shown in Figure 1. The receiving system is connected to the output port of the antenna and branch, 5
SJ3251--89
b. Adjust the polarization states of the auxiliary antenna and the antenna under test to match, adjust the frequency of the signal source to the control device of the tuning book test field, so that the maximum values of the main lobes of the auxiliary antenna and the antenna under test are aligned on the upper surface of the azimuth plane. c. Adjust the variable attenuator to AdB (the A value can be arbitrarily set from a section of the attenuator linear wheel), and adjust the receiving system to make the recording device reach a certain reference level. d. Adjust the variable attenuator to (A~3)dB, rotate the antenna under test clockwise on the azimuth plane until the indication of the recording device is lower than the original reference level, and then rotate it counterclockwise until the indication reaches the original reference level, and record the azimuth scale of the antenna support under test at this time (, and continue to rotate the antenna under test counterclockwise: so that the level of the recording device returns to the reference level after the maximum value, and record the azimuth of the antenna support at this time. Scale 02. 3 dB beam width of the antenna under test. 5. Calculate according to the following formula 005=|0,--021()-
Adjust the signal source frequency to other frequency points in turn, repeat steps c to d, and get the beam width values of other frequency points,
f. Adjust the control equipment of the antenna test field, rotate the polarization position of the antenna under test and the auxiliary antenna by 90. Repeat steps 5.2.2.2.1.b to c to get the beam width value of the antenna under test in another main plane Polarization locator
Antenna under test
Test locator
Receiver
Auxiliary
Determination of life test
Indicator
Side window
Female table equipment||tt ||Source tower control input
Figure 1 Typical antenna test system block diagram
?Signal source
Source control
SJ3231-89
5.2.2.2.2 and branch sidelobe level test method. Same as 5.2.2.2.1a.
b.Same as 5.2.2.2.1b
c. Assume that the clipping level limit value specified in the product standard (technical conditions) is AdB, adjust the attenuator to AdB, adjust the receiving system, and make the recording equipment indicate a certain reference level. d. Rotate the antenna under test to each sidelobe position in the azimuth plane and gradually restore the attenuator to zero during the rotation process. The indicated level of the antenna under test at each sidelobe position should not exceed the reference level. e. Adjust the signal source frequency to other frequency points in turn, and repeat steps c and d. f. Rotate the polarization positions of the antenna under test and the auxiliary antenna by 90", and repeat steps c, d, and e. Test the sidelobe level value of the other main plane.
5.2.1.2.3 and branch gain test method 8. Same as 5.2.2.2.1.a;
b. Same as 5.2.2.2.1.b;
c. Adjust the attenuator to A, dB (A, value is selected by the test personnel according to the situation), adjust the receiving system, so that the indication of the recording equipment is a certain reference level:
d. Receive all receiving and recording equipment except the antenna under test to the standard gain antenna, and adjust the elevation and azimuth of the standard gain antenna at the same position to maximize the signal level. Adjust the attenuator to A, dB so that the indication of the recording equipment is still the reference level;
e. The antenna under test is at f. The gain is calculated as follows: G = Go + A, - A2
Where G is the gain of the standard gain antenna at f, which should be calibrated in advance. (dB)
f. Adjust the signal source frequency to other frequency points in turn, and repeat steps c to c to obtain the antenna gain at other frequency points.
5.2.2.2.4 Test method for differential branch sidelobe level Connect the receiving system to the high and low difference branch output ports of the azimuth difference branch output port in turn, and repeat all steps of 5.2.2.2.2.
5.2.2.2.5 Test method for differential branch gain Connect the receiving system to the azimuth difference branch output port and the high and low difference branch output port in turn, and repeat all steps of 5.2.2.2.3. It should be noted that the gains of the two differential lobes should be tested and both should meet the requirements. 5.2.2.2.6 Test method a for differential branch amplitude imbalance. Connect the receiving system to the antenna azimuth difference branch output port, and adjust the signal source frequency to fob. Same as 5.2.2.2.1.b. At this time, the main lobe of the antenna under test can be any one of the difference beams; c. Adjust the variable attenuator to AdB (the A value can be arbitrarily selected from a section of the attenuator with better linearity), adjust the receiving system, so that the indication of the recording device is a certain reference level, rotate the antenna under test on the azimuth plane, so that the recording level drops to the zero position and then rises to another maximum value; 7
SJ3251—89
d. Adjust the variable attenuator to BdB, so that the indication of the recording device is still the reference level; e.The corresponding difference branch amplitude imbalance is calculated as follows: imbalance = A - B (dB)..
f. Adjust the signal source frequency to other frequency points and repeat steps b to e; (3)
g. Rotate the polarization positions of the auxiliary antenna and the antenna under test by 90°, and connect the receiving system to the output port of the high and low difference branches and repeat steps b to f.
5.2.2.2.7 The test method for the zero-value depth of the difference branch is the same as 5.2.2.2.6a
b. The same as 5.2.2.2.6b;
c. Rotate the antenna under test to the zero point of the differential branch in the azimuth plane, adjust the receiving system so that the indication of the recording device is the first reference level;
d, rotate the antenna under test to the maximum value position of the differential beam, adjust the attenuator to A, dB, so that the recording indication is still the reference level;
e, rotate the antenna under test to another maximum value of the differential beam, adjust the attenuator to AzdB, so that the recording indication is still the reference level;
f. The zero value depth of the differential branch corresponding to the antenna under test is calculated as follows: Zero value depth = max-A-A2
g, adjust the signal source frequency to other frequency points, and repeat steps c to "; h. Rotate the polarization positions of the auxiliary antenna and the antenna under test by 90°, and connect the receiving system and the recording device to the height and depth of the antenna. Output port of the differential branch, repeat steps b to g, 5.2.2.3 Test method for electric axis source shift
Unless otherwise specified in the product standard (technical conditions), for antennas that do not work at a point frequency, several frequency points should be selected within the specified frequency range to measure the change (drift) of the electric axis position of the disk. The interval between adjacent test frequency points should be selected according to the following principles;
When the center frequency is between 2000MHz and 5000MHz, the frequency interval should not be greater than 25MHz; a.
When the center frequency is higher than 5000MHz, the frequency interval should not be greater than 50MHz b.
5.2.2.3.1 Azimuth
Same as 5.2.2.2.1a, the receiving and recording equipment is connected to the output port of the azimuth difference branch b.| |tt||Same as 5.2.2.2.1b;
Rotate the antenna under test on the azimuth plane to the zero point of the difference beam, and record the azimuth position of the electric axis at this time c.
d. Adjust the signal source to other frequency points in turn, and repeat step c. At the measured frequency point, the relative change in the azimuth position of the electric axis should not be greater than the specified value. 5.2.2.3.2 Elevation plane
SJ3251--89
Connect the receiving system and recording equipment to the output port of the height difference branch, and adjust the signal source to fo; a.
b.Same as 5.2.2.2.1h;
c.Rotate the antenna under test on the elevation plane to the zero point of the height difference beam, and record the elevation position of the electric axis at this time. The relative change is not greater than Specified value. 5.2.2.4 Test method for voltage standing wave ratio
The voltage standing wave ratio shall be measured in accordance with 5.2.2.4.1, 5.2.2.4.2 or any other method with the same level of accuracy. Unless otherwise specified, the antenna shall be installed in the center of a flat site. Precautions must be taken to ensure that the reflected signal from nearby objects (ground buildings, metal bodies, etc.) is at a negligible level. 5.2.2.4.1 Measuring line test
Unless otherwise specified, when testing the voltage standing wave ratio of an antenna using a measuring line, several frequency points shall be selected within the specified frequency range for measurement. The frequency interval selection principle for adjacent test frequency points is the same as that of Article 5.2.2.3. The measurement data shall be recorded in the acceptance test record or drawn on a drawing paper. The steps of measuring VSWR with measuring line are as follows: a. Arrange the connecting equipment and instruments according to Figure 2; Indicator flip
Signal source
Wavelength meter
Attenuator
Figure 2 Block diagram of measuring VSWR with measuring line
Measuring line
Test antenna
b. Adjust the signal to fo, adjust the attenuator level and the probe of the measuring line, so that all measurements are carried out in the square law area of the measuring detector;
C. Move the measuring line probe to obtain the maximum level Imax and the minimum level Imin. The VSWR S is calculated as follows:
d. Adjust the signal source frequency to other frequency points and repeat steps b and c. Note: The square law area of the crystal of the measuring line detector should be calibrated in advance 5.2.2.4.2 Ratio method
8. Arrange the connecting equipment and instruments according to Figure 3, and adjust the sweep signal to the steady amplitude state, which can be judged by observing the detection output waveform with an oscilloscope. At the same time, adjust the ratiometer to work normally;—9
Sweep frequency meter
SJ3251-69
Ratiometer
Ou Xiangchun
Oscilloscope
Incident radiation
Detector
Emission certificate
Figure 3 Ratio method for measuring reflection coefficient signal insertion system
Lantianyuan
b. The measured value is open circuit c. Use the mismatch device attached to the reflectometer as a standard reference element to verify the reliability of the test system. For example: if the voltage standing wave ratio of the mismatch device is 1.50±0.08, connect the mismatch device to the test port to check whether the voltage standing wave ratio is around 1.50; d. Connect the antenna to the measuring end of the reflectometer and observe the regularity on the oscilloscope. The reflection coefficient within a certain frequency band. It can also be connected to a recorder to draw a reflection coefficient curve; e Assuming that the maximum reflection coefficient observed within the specified frequency band is Tmax, the maximum value Smax of the voltage standing wave ratio within the specified frequency range is calculated as follows: 1+Imax
1-Imax
5.2.2.4.3 Reflection loss method
The reflection loss measurement disk uses the DC substitution method, and the steps are as follows: (6)
8. As shown in Figure 4, the connection equipment and instruments are set, and the sweep signal source is adjusted to a steady amplitude state. The power fluctuation of the full frequency band can be measured at the output end of the reflectometer with a power meter. It is not greater than ±0.5dB to judge: b. According to the size of the voltage standing wave ratio of the antenna under test, select the corresponding reflectometer scale plate and install it on the screen of the display. Use the corresponding mismatch as a standard reference element to verify the reliability of the test system, which is the same as step c of the "ratio method" measurement.
Scanner
Circulator
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Amplitude stabilization and shooting
Breaker
Modified shooting meter
Test antenna
Medical adapter
Figure 4 Reflection consumption method to measure reflection coefficient amplitude system c. Connect the antenna to be tested to the output end of the reflectometer and read the value directly on the oscilloscope. 5.2.2.5 Test method of power capacity
Antenna power capacity test can be carried out on the gun aiming radar station or on a special high-power test bench.
The environmental conditions (such as temperature, altitude, etc.) for high-power test should be specified in the product standard (technical conditions). After the working frequency is stabilized, there should be no sparking or breakdown inside and at the connection of the antenna. After the test is completed, the antenna should not be damaged or deteriorated.
The sparking sound can be used to determine whether there is sparking or breakdown. It can also be judged by observing whether there are sparks or breakdown marks on the outside or inside of the antenna.
Damage and deterioration are inspected by appearance.
Note: If there is a brief spark or breakdown phenomenon at a certain frequency, it is recommended to extend the test time at this frequency for judgment. The antenna should not have sparks or breakdown during the extended test time. The extended test time is specified by the product standard (technical conditions). 5.2.3 Single-channel and dual-channel monopulse radar antennas 5.2.3.1 Test method for cross-level of synthetic beams Unless otherwise specified in the product standard (technical conditions), for single-channel and dual-channel gun-aiming radar antennas operating at non-point frequencies, several frequency points should be selected within the specified working frequency band to measure the cross-level of the synthetic beam. The frequency interval between adjacent frequency points should be selected in the same principle as Article 5.2.2.3. 3. Connect the receiving system and recording equipment of the antenna test site to the output port of the synthetic beam. The device for sampling the sequential beam (usually called "quick turn joint" or "scanning component") should be clearly marked with the position marks representing the azimuth (for example, "2", "4\ position) and the height (for example, "1\, "3\ position) position. Adjust the signal source frequency to fo.b. Adjust the control device of the antenna test field so that the maximum value of the auxiliary antenna main lobe points to the antenna under test. c. Set the sampling position to "2", "4", "1", "3", and fine-tune the azimuth and elevation of the antenna under test in turn, until the recorder's indication level is the same regardless of the sampling position "1\ or "3\", "2" or "4", and record the azimuth and elevation positions of the electric axis at this time.
d. Set the sampling position to "2\, adjust the receiving system so that the recorder's indication is a certain reference level, rotate the antenna under test in the azimuth plane to the beam maximum value, adjust the variable attenuator to AdB, and make the indication still be the reference level.
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