A power calibration method for an airborne receiver based on frequency and attenuation compensation

Abstract

The present invention discloses a power calibration method for an airborne receiver based on frequency and attenuation compensation, comprising the following steps: S1. Construct a power value calibration table and an attenuation code calibration table and initialize them, and then write the two initialized tables into the corresponding addresses of the RAM module of the receiver; S2. During the working process, process the PDW_Pre message uploaded by the receiver, and the specific steps are as follows: S21. Extract the local oscillator frequency, intermediate frequency, and voltage amplitude value in the PDW_Pre message, and calibrate through the power value calibration table to obtain the power value before power compensation; S22. Extract the local oscillator frequency and the current attenuation code of microwave control in the PDW_Pre message, and obtain the power compensation value through the attenuation code calibration table; S23. Add the power value obtained in S21 and the power compensation value obtained in S22 to obtain the final true power value. The present invention automatically compensates for the nonlinearity and frequency response differences of the internal link of the receiver, and even if the voltage amplitude value fluctuates, a stable power value can be obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic countermeasure and radar signal processing, and particularly relates to a power calibration method for an airborne receiver based on frequency and attenuation compensation. Background Art

[0002] In modern electronic countermeasure and radar systems, the receiver is an important component, and its performance directly affects the accuracy of signal reception and processing. Especially under complex battlefield environments and the action of various interference signals, accurate power measurement of the receiver is crucial. However, due to problems such as the amplitude-frequency characteristic differences and nonlinearity of the internal links of the receiver, there is a nonlinear relationship between the voltage amplitude and the input power in traditional receivers during actual operation. The volatility and instability of this relationship result in deviations in the measured voltage amplitude when the same power value is applied at the input end, making the power value in the power description word (PDW) output by the receiver inaccurate and unstable, bringing measurement errors to the system, and thus affecting the functions of other modules.

[0003] Currently, the methods to solve this problem mainly rely on single calibration of frequency points or manual correction. These methods often lack flexibility and precision and are difficult to meet the power measurement requirements in wide frequency bands and dynamic environments. Especially for airborne radar receiving and jamming systems in complex environments, the accuracy and stability of receiver power measurement are even more important. Summary of the Invention

[0004] Technical Objective: To solve the above technical problems, the present invention proposes a power calibration method for an airborne receiver based on frequency and attenuation compensation, providing accurate and stable power measurement results and enhancing the reliability and anti-interference ability of the system.

[0005] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solution: A power calibration method for an airborne receiver based on frequency and attenuation compensation, characterized by comprising the following steps:

[0006] S1. Construct a power value calibration table and an attenuation code calibration table and initialize them, and then write the two initialized tables into the corresponding addresses of the RAM module of the receiver;

[0007] The fields of the power value calibration table include: local oscillator number, intermediate frequency point number, power values corresponding to multiple groups of amplitude values; the fields of the attenuation code calibration table include: local oscillator number and attenuation values corresponding to multiple groups of attenuation codes;

[0008] S2. During the working process, the receiver processes the uploaded PDW_Pre message, and the specific steps are as follows:

[0009] S21. Extract the local oscillator frequency, intermediate frequency, and voltage amplitude value from the PDW_Pre message, and calibrate to obtain the power value before power compensation through the power value calibration table;

[0010] S22. Extract the local oscillator frequency and the current microwave control attenuation code from the PDW_Pre message, and obtain the power compensation value through the attenuation code calibration table;

[0011] S23. Add the power value obtained in S21 and the power compensation value obtained in S22 to obtain the final true power value.

[0012] A further limitation of the technical solution of the present invention is that the fields of the power value calibration table are specifically:

[0013] The value range of the local oscillator number is 0 to 36, and the corresponding relationship with the local oscillator frequency is: the frequency range of the local oscillator frequency is 0 to 18 GHz, with a step of 500 MHz;

[0014] The value range of the intermediate frequency point number is 0 to 10, and the corresponding relationship with the intermediate frequency point is: the intermediate frequency point takes a transient width of 1 GHz centered on the local oscillator frequency, with a step of 100 MHz.

[0015] Further, the initialization process of the power value calibration table is as follows:

[0016] 1.1. Switch the receiver status to the calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, set the signal source pulse width to 2 us, and set the repetition frequency to 4 us;

[0017] S1.2. Set the signal source frequency to the lower sideband of the current frequency band;

[0018] 1.3. Set the signal source power to -80 dBm;

[0019] 1.4. According to the PDW_Pre message uploaded by the receiver, the PDW_Pre message refers to the PDW message to be processed. Record the average value of the PA in 200 PDW_Pres, where PA is the voltage amplitude value, and at the same time record the power value corresponding to this amplitude value in the corresponding position of the power value calibration table;

[0020] 1.5. Determine whether the power value of the current signal source is less than or equal to 35 dBm. If the signal source power is less than or equal to 35 dBm, adjust the signal source power by 1 dBm and re-execute step 1.4; if the signal source power is greater than 35 dBm, then execute step 1.6;

[0021] 1.6. Determine whether the frequency value of the current signal source is less than the upper sideband of the current frequency band. If the signal source frequency is less than the upper sideband of the current frequency band, adjust the signal source frequency by adding 100 MHz and re - execute step 1.3; if the signal source frequency is not less than the upper sideband of the current frequency band, then execute step 1.7;

[0022] 1.7. If the current local oscillator is not the last local oscillator, then switch to the next local oscillator and execute step 1.2, otherwise end.

[0023] Further, the fields of the attenuation code calibration table are specifically:

[0024] The value range of the local oscillator number is 0 to 36, and its corresponding relationship with the local oscillator frequency is: the frequency range of the local oscillator frequency is 0 to 18 GHz, with a step of 500 MHz; the value range of the attenuation code is 0 to 127.

[0025] Further, the initialization process of the attenuation code calibration table is:

[0026] 2.1. Switch the receiver state to the calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, set the signal source pulse width to 2 us, and set the pulse repetition frequency to 4 us;

[0027] 2.2. Set the signal source frequency to the center frequency point of the current frequency band;

[0028] 2.3. Set the signal source power to - 35 dBm;

[0029] 2.4. Record the power attenuation value corresponding to the attenuation code at this time in the corresponding position of the mapping table. The attenuation code is sent from the receiver to the microwave, and the attenuation code corresponds to the actual attenuation value of the microwave. The corresponding relationship is provided by the microwave;

[0030] 2.5. If the actual attenuation value at this time is greater than 40 dBm, then execute step 2.6; otherwise, adjust the attenuation code to increase the attenuation value by 1 dBm and re - execute step 2.4;

[0031] 2.6. If the local oscillator is not the last local oscillator, then switch to the next local oscillator and execute step 2.1, otherwise end.

[0032] Further, the specific method of writing the two initialized tables into the corresponding addresses of the receiver's RAM module is:

[0033] The calculation logic of the power value calibration table address is: w_addr_1 = spi_data_addr0 * 256 + 37 * 256 * spi_data_addr1 + spi_data_cnt[8:0], where w_addr_1 represents the address for writing data into the power value calibration table in the RAM, spi_data_addr0 corresponds to the local oscillator number value in the mapping table, spi_data_addr1 corresponds to the intermediate frequency point number value in the mapping table, and spi_data_cnt represents the data count received by the receiver;

[0034] The calculation logic of the attenuation code calibration table address is: w_addr_2 = spi_data_addr0[6:0] * 128 + spi_data_cnt[8:0], where w_addr_2 represents the address for writing data into the attenuation code calibration table in the RAM, spi_data_addr0 corresponds to the local oscillator number value in the mapping table, and spi_data_cnt corresponds to the data count received by the SPI.

[0035] Further, in step S21, the specific method for calibrating the power value before power compensation through the power value calibration table is as follows: First, convert the local oscillator frequency and intermediate frequency corresponding to PDW_Pre before calibration into the corresponding local oscillator number and intermediate frequency point number, and then calculate the read data address of the corresponding power value in the RAM together with the measured voltage amplitude value in PDW_Pre. The calculation formula for this address is as follows:

[0036] r_addr = lo_num * 256 + if_num * 37 * 256 + PA[15:8],

[0037] where r_addr represents the address for reading data in the RAM, lo_num represents the local oscillator number corresponding to the current local oscillator frequency, if_num represents the intermediate frequency point number corresponding to the current intermediate frequency, obtained according to the previous calculation method of the local oscillator number and intermediate frequency point number, and PA represents the currently measured voltage amplitude value, directly read from PDW_Pre; the power value read from the read data address obtained in the above manner will be used as the power value before power compensation.

[0038] Further, in step S22, the specific method for obtaining the power compensation value through the attenuation code calibration table is as follows: When performing look-up table compensation, convert the current local oscillator frequency into the corresponding local oscillator number, and then calculate the read data address of the compensated power value in the RAM together with the current attenuation code of the microwave control given in the microwave control message. The calculation formula for this address is as follows:

[0039] r_addr = lo_num * 128 + front_atten,

[0040] In the formula, r_addr represents the address for reading data in the RAM, lo_num represents the local oscillator number corresponding to the current local oscillator frequency, which is obtained according to the calculation method of the previous local oscillator number, and front_atten represents the attenuation code word of the current microwave, which is read from the microwave message; the power compensation value is read out from the read data address obtained in the above manner.

[0041] Beneficial effects:

[0042] The method of the present invention realizes the technology of adaptive calibration. By automatically compensating for the nonlinearity and frequency response differences of the internal links of the receiver, even if the voltage amplitude value fluctuates, a stable power value can still be obtained through two look-up table calibration operations, and it is equal to the actually input power value, ensuring that the subsequent module will have a stable input, and the final frequency measurement result can be kept stable and accurate, and is more meaningful for reference. Description of the drawings

[0043] Figure 1 It is a flowchart of a power calibration method for an airborne receiver based on frequency and attenuation compensation proposed by the present invention;

[0044] Figure 2 It is a flowchart of the initialization process of the power value calibration table proposed by the present invention;

[0045] Figure 3 It is a flowchart of the initialization process of the attenuation code calibration table proposed by the present invention. Specific implementation manners

[0046] The following describes in detail the embodiments of the present invention with reference to the drawings.

[0047] Embodiment 1

[0048] Specifically, it relates to an adaptive calibration method and device for improving the power measurement accuracy and stability of an airborne receiver, which is applicable to radar signal receiving and interference systems in complex environments.

[0049] In this embodiment, by means of pre-making tables, the corresponding relationships between voltage amplitude values and power values under different local oscillator frequencies, intermediate frequency frequencies, and attenuation codes are measured in advance and recorded in two tables. Table 1 is the power value calibration table, and Table 2 is the attenuation code calibration table.

[0050] The content in the power value calibration table is the corresponding relationship between voltage amplitude values and power values under different local oscillator frequencies and intermediate frequency frequencies. Each intermediate frequency frequency under each local oscillator corresponds to an independent table, and each table records the power values corresponding to different amplitude values under the current local oscillator and intermediate frequency frequencies. Its mapping table structure is shown in Table 1:

[0051] Serial Number Field Name Range Description Unit Default Value Length (bit) Description 0 Start Frame / / 32 / 1 Message Type / / 32 / 2 Message Length / / 32 / 3 Local Oscillator Number 0～36 / / 32 / 4 Intermediate Frequency Point Number 0～10 / / 32 / 5 Power Value Corresponding to Amplitude Value 0 0.25 dBm / 32 6 Power Value Corresponding to Amplitude Value 1 / / 32 … … … / / /

[0052] Table 1

[0053] The power value calibration table realizes the conversion of voltage amplitude value to power value and performs amplitude calibration. The main information included in the power value calibration table message includes the local oscillator frequency, intermediate frequency, and the power value corresponding to the amplitude value.

[0054] In the message, the value range of the local oscillator number is 0 to 36, and the corresponding relationship with the local oscillator frequency is: the frequency range of the local oscillator frequency is 0 to 18 GHz, with a step of 500 MHz. In the message, the value range of the intermediate frequency point number is 0 to 10, and the corresponding relationship with the intermediate frequency point is: the intermediate frequency point takes a transient width of 1 GHz centered on the local oscillator frequency, with a step of 100 MHz. For example, when the local oscillator frequency is 2 GHz and the frequency is 2.3 GHz, the corresponding local oscillator number is 4, and the intermediate frequency point number is 8.

[0055] During the table generation process, each time the power is adjusted, a set of amplitude values and the corresponding power values are generated and then recorded in the table. To update the content in the table, the table generation process is executed again. The message also includes the power value information corresponding to two sets of amplitude values from 0 to 255. In the table, the amplitude values from 0 to 255 correspond to the data of the 8th to 15th bits of the voltage amplitude value in the PDW before calibration, and the amplitude values from 0 to 255 in the second part correspond to the data of the 4th to 11th bits of the voltage amplitude value in the PDW before calibration.

[0056] The generation process of the power value calibration table is as follows:

[0057] 1.1. Switch the receiver status to the calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, set the signal source pulse width to 2 us, and set the repetition frequency to 4 us;

[0058] 1.2. Set the signal source frequency to the lower sideband of the current frequency band;

[0059] 1.3. Set the signal source power to -80 dbm;

[0060] 1.4. According to the PDW_Pre message uploaded by the receiver, the PDW_Pre message refers to the PDW message to be processed. Record the average value of the PA in 200 PDW_Pres, where PA is the voltage amplitude value, and at the same time record the power value corresponding to this amplitude value in the corresponding position of the power value calibration table;

[0061] 1.5. Judge whether the power value of the current signal source is less than or equal to 35 dBm. If the signal source power is less than or equal to 35 dBm, adjust the signal source power by 1 dBm and re-execute step 1.4; if the signal source power is greater than 35 dBm, then execute step 1.6;

[0062] 1.6. Determine whether the frequency value of the current signal source is less than the upper sideband of the current frequency band. If the signal source frequency is less than the upper sideband of the current frequency band, adjust the signal source frequency by adding 100 MHz and re - execute step 1.3; if the signal source frequency is not less than the upper sideband of the current frequency band, then execute step 1.7;

[0063] 1.7. If the current local oscillator is not the last local oscillator, switch to the next local oscillator and execute step 1.2, otherwise end.

[0064] The content in the attenuation code calibration table is the corresponding relationship between the attenuation code and the power compensation value at different local oscillator frequencies. Each intermediate frequency at each local oscillator will correspond to an independent table, and each table will record the power values corresponding to different attenuations at the current local oscillator. To update the content in the table, re - execute the table - making process, which is similar to the power attenuation table logic. Its mapping table structure is shown in Table 2:

[0065] Serial Number Field Name Range Description Unit Default Value Length (bit) Description 0 Start Frame Flag / / 32 / 1 Message Type / / 32 / 2 Message Length / / 32 / 3 Local Oscillator Number 0～36 / / 32 / 4 Attenuation Value Corresponding to Attenuation Code 0 0.25 dBm / 32 / 5 Attenuation Value Corresponding to Attenuation Code 1 / / 32 … … … … … … …

[0066] Table 2

[0067] The attenuation code calibration table is used to compensate the power value after microwave attenuation to finally obtain the true power value. The main information included in the attenuation code calibration table message includes the local oscillator number and the power value corresponding to the attenuation code. The generation method of the local oscillator number is the same as that in the power value calibration table, and its value range is also 0 - 36, corresponding to 0 - 18 GHz. The message also includes the true power attenuation value corresponding to different attenuation codes. The value range of the attenuation code is 0 - 127.

[0068] The generation process of the attenuation code calibration table is as follows:

[0069] 2.1. Switch the receiver status to the calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, set the signal source pulse width to 2 us, and set the repetition frequency to 4 us;

[0070] 2.2. Set the signal source frequency to the center frequency point of the current frequency band;

[0071] 2.3. Set the signal source power to - 35 dBm;

[0072] 2.4. Record the power attenuation value corresponding to the attenuation code at this time in the corresponding position of the mapping table. The attenuation code is sent from the receiver to the microwave, and the attenuation code corresponds to the actual attenuation value of the microwave. The corresponding relationship is provided by the microwave;

[0073] 2.5. If the actual attenuation value at this time is greater than 40 dB, then execute step 2.6; otherwise, adjust the attenuation code to increase the attenuation value by 1 dB and re - execute step 2.4;

[0074] 2.6. If the local oscillator is not the last one, switch to the next local oscillator and execute step 2.1; otherwise, end.

[0075] The above two tables will be sent to the receiver in the form of a message, and the receiver will write the data into the corresponding address of the RAM module of the receiver according to the designed address calculation logic.

[0076] The address calculation logic for the power value calibration table is as follows: The message is transmitted to the receiver through SPI, and the data is stored in the RAM of the receiver that stores the power value calibration table. The address where the data is written is generated by three parameters: the local oscillator number, the intermediate frequency point number, and the data count. The formula is as follows:

[0077] w_addr_1 = spi_data_addr0 * 256 + 37 * 256 * spi_data_addr1 + spi_data_cnt[8:0]

[0078] In the formula, w_addr_1 represents the address where the data is written into the power value calibration table in the RAM. spi_data_addr0 corresponds to the local oscillator number value in the mapping table, spi_data_addr1 corresponds to the intermediate frequency point number value in the mapping table, and spi_data_cnt represents the data count received by SPI. These parameters will all be sent in the form of a message.

[0079] The address calculation logic for the attenuation code calibration table is as follows: The message is transmitted to the receiver through SPI, and the data is stored in the RAM of the receiver that stores the attenuation value calibration table. The address where the data is written is generated by two parameters: the local oscillator number and the data count. The formula is as follows:

[0080] w_addr_2 = spi_data_addr0[6:0] * 128 + spi_data_cnt[8:0];

[0081] In the formula, w_addr_2 represents the address where the data is written into the attenuation code calibration table in the RAM. spi_data_addr0 corresponds to the local oscillator number value in the mapping table, and spi_data_cnt corresponds to the data count received by SPI. These parameters will all be sent in the form of a message.

[0082] When the receiver is working, it will perform two look-up table operations based on information such as the local oscillator frequency, intermediate frequency, and attenuation code of the current signal, read the corresponding data from the correct address, and finally calculate the calibrated power value through arithmetic operations to ensure that the finally output is the true power value.

[0083] During the working process, the PDW_Pre message uploaded by the receiver is processed. The specific steps are as follows:

[0084] Step 1: Calibrate to obtain the power value before power compensation through the power value calibration table.

[0085] When performing table look-up calibration, first convert the local oscillator frequency and intermediate frequency corresponding to PDW_Pre before calibration into the corresponding local oscillator number and intermediate frequency point number, and then calculate the read data address of the corresponding power value in the RAM together with the voltage amplitude value measured in PDW_Pre. The calculation formula for this address is as follows:

[0086] r_addr = lo_num * 256 + if_num * 37 * 256 + PA[15:8],

[0087] In the formula, r_addr represents the read data address in the RAM, lo_num represents the local oscillator number corresponding to the current local oscillator frequency, if_num represents the intermediate frequency point number corresponding to the current intermediate frequency, obtained according to the calculation methods of the previous local oscillator number and intermediate frequency point number, and PA represents the currently measured voltage amplitude value, directly read from PDW_Pre.

[0088] The power value read out through the read data address obtained in the above manner will be used as the power value before power compensation. This power value needs to be compensated for the attenuation of the power value in the next step to obtain the true power value.

[0089] Step 2: Obtain the power compensation value through the attenuation code calibration table.

[0090] When performing table look-up compensation, convert the current local oscillator frequency into the corresponding local oscillator number, and then calculate the read data address of the compensated power value in the RAM together with the current attenuation code of the microwave control given in the microwave control message. The calculation formula for this address is as follows:

[0091] r_addr = lo_num * 128 + front_atten,

[0092] In the formula, r_addr represents the read data address in the RAM, lo_num represents the local oscillator number corresponding to the current local oscillator frequency, obtained according to the calculation methods of the previous local oscillator number, and front_atten represents the current attenuation code word of the microwave, read from the microwave message.

[0093] Read out the power compensation value through the read data address obtained in the above manner.

[0094] Step 3: Add the power value obtained in Step 1 and the power compensation value obtained in Step 2 to obtain the final true power value.

[0095] Through the above two lookups, a stable power value is obtained, which is equal to the actually input power value, ensuring a stable input for the subsequent stage module and enabling the final frequency measurement result to be stable and accurate.

[0096] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A power calibration method for an airborne receiver based on frequency and attenuation compensation, characterized in that: The following steps are involved: S1, construct a power value calibration table and an attenuation code calibration table and initialize them, and then write the two initialized tables into the corresponding addresses of the RAM module of the receiver; The fields of the power value calibration table include: local oscillator number, intermediate frequency point number, and power values ​​corresponding to multiple groups of amplitude values; the fields of the attenuation code calibration table include: local oscillator number and attenuation values ​​corresponding to multiple groups of attenuation codes; S2. During the working process, the receiver processes the uploaded PDW_Pre message. The specific steps are as follows: S21, extracting the local oscillator frequency, intermediate frequency and voltage amplitude value in the PDW_Pre message, and calibrating the power value before power compensation through the power value calibration table; In step S21, the specific method of calibrating the power value before power compensation through the power value calibration table is: first convert the local oscillator frequency and intermediate frequency frequency corresponding to the PDW_Pre before calibration into the corresponding local oscillator number and intermediate frequency point number, and then calculate the corresponding power value read data address in RAM together with the voltage amplitude value measured in PDW_Pre. The calculation formula of the address is as follows: r_addr = lo_num * 256 + if_num * 37 * 256 + PA[15:8], Where r_addr indicates the address of the data read in RAM, lo_num indicates the local oscillator number corresponding to the current local oscillator frequency, if_num indicates the intermediate frequency point number corresponding to the current intermediate frequency frequency, which is obtained according to the calculation method of the local oscillator number and the intermediate frequency point number mentioned above, and PA indicates the current measured voltage amplitude value, which is directly read from PDW_Pre; The power value read out from the read data address obtained in the above manner will be used as the power value before power compensation; S22, extracting the local oscillator frequency in the PDW_Pre message and the attenuation code of the current microwave control, and obtaining the power compensation value through the attenuation code calibration table; The specific method of obtaining the power compensation value through the attenuation code calibration table is as follows: when performing table lookup compensation, the current local oscillator frequency is converted into the corresponding local oscillator number and then the read data address of the compensated power value in the RAM is calculated together with the attenuation code of the current microwave control given in the microwave control message. The calculation formula of the address is as follows: r_addr = lo_num * 128 + front_atten, Where r_addr indicates the address of the data read in the RAM, lo_num indicates the local oscillator number corresponding to the current local oscillator frequency, which is obtained according to the calculation method of the previous local oscillator number, and front_atten indicates the attenuation codeword of the current microwave, which is read from the microwave message; The power compensation value is read out through the read data address obtained in the above manner; S23, adding the power value obtained in S21 and the power compensation value obtained in S22 to obtain a final real power value.

2. The power calibration method of an airborne receiver based on frequency and attenuation compensation according to claim 1, characterized in that: The fields of the power value calibration table are specifically: The value range of the local oscillator number is 0~36, and the corresponding relationship with the local oscillator frequency is: the frequency range of the local oscillator frequency is 0~18GHz, with a step of 500MHz; The intermediate frequency point number ranges from 0 to 10, and the corresponding relationship with the intermediate frequency point is: the intermediate frequency point takes the instantaneous width of 1 GHz with the local oscillator frequency as the center, with a step of 100 MHz.

3. The power calibration method of an airborne receiver based on frequency and attenuation compensation according to claim 2, characterized in that: The initialization process of the power value calibration table is: 1.

1. Switch the receiver state to calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, the signal source pulse width to 2us, and the repetition rate to 4us; S1.2, the signal source frequency is set to the lower sideband of the current frequency band; 1.

3. Set the signal source power to -80dBm; 1.

4. According to the PDW_Pre message uploaded by the receiver, the PDW_Pre message refers to the PDW message to be processed, record the average value of PA in 200 PDW_Pre, PA is the voltage amplitude value, and record the power value corresponding to the amplitude value in the corresponding position of the power value calibration table; 1.

5. Determine whether the power value of the current signal source is less than or equal to 35dBm. If the signal source power is less than or equal to 35dBm, adjust the signal source power by 1dBm and re-execute step 1.4; If the signal source power is greater than 35dBm, go to step 1.6; 1.

6. Determine whether the frequency value of the current signal source is less than the upper sideband of the current frequency band. If the signal source frequency is less than the upper sideband of the current frequency band, adjust the signal source frequency plus 100MHz and re-execute step 1.3; If the signal source frequency is not less than the upper sideband of the current frequency band, execute step 1.7; 1.

7. If the current local oscillator is not the last local oscillator, switch to the next local oscillator and execute step 1.2, otherwise end.

4. The power calibration method of an airborne receiver based on frequency and attenuation compensation according to claim 1, characterized in that: The fields of the attenuation code calibration table are specifically: The value range of the local oscillator number is 0~36, and the corresponding relationship with the local oscillator frequency is: the frequency range of the local oscillator frequency is 0~18GHz, with a step of 500MHz; the value range of the attenuation code is 0~127.

5. The power calibration method of an airborne receiver based on frequency and attenuation compensation according to claim 4, characterized in that: The initialization process of the attenuation code calibration table is: 2.1 Switch the receiver state to calibration mode, switch the local oscillator point to the first local oscillator point, set the attenuation code to 0, the signal source pulse width to 2us, and the repetition rate to 4us; 2.

2. The signal source frequency is set to the center frequency of the current frequency band; 2.

3. Set the signal source power to -35dBm; 2.

4. The power attenuation value corresponding to the attenuation code is recorded in the corresponding position of the mapping table. The attenuation code is sent to the microwave by the receiver. The attenuation code corresponds to the actual attenuation value of the microwave, and the corresponding relationship is provided by the microwave. 2.

5. If the actual attenuation value is greater than 40dBm, execute step 2.6; otherwise, adjust the attenuation code to increase the attenuation value by 1dBm and execute step 2.4 again; 2.

6. If the local oscillator is not the last local oscillator, switch to the next local oscillator and execute step 2.1, otherwise end.

6. The power calibration method of an airborne receiver based on frequency and attenuation compensation according to claim 1, characterized in that: The specific method of writing the two initialized tables into the addresses corresponding to the RAM module of the receiver is: The power value calibration table address calculation logic is: w_addr_1 = spi_data_addr0 * 256 + 37 * 256* spi_data_addr1 + spi_data_cnt[8:0], where w_addr_1 represents the address of the power value calibration table in the RAM where data is written, spi_data_addr0 corresponds to the local oscillator number value in the mapping table, spi_data_addr1 corresponds to the intermediate frequency point number value in the mapping table, and spi_data_cnt represents the data count received by the receiver; The calculation logic of the attenuation code calibration table address is: w_addr_2 =spi_data_addr0[6:0]*128 + spi_data_cnt[8:0], where w_addr_2 represents the address where the attenuation code calibration table writes data in RAM, spi_data_addr0 corresponds to the local oscillator number value in the mapping table, and spi_data_cnt is the data count received by the receiver.

Images