Satellite-borne receiving multichannel amplitude-phase error calibration method

Abstract

The invention relates to a satellite-borne receiving multichannel amplitude-phase error calibration method, which integrally combines a calibration signal and an interference detection result, and can change the frequency of the calibration signal, the spread spectrum code length and the accumulation time according to the interference condition so as to achieve the purpose of accurately calibrating a system. Meanwhile, due to the fact that the working temperature of the satellite-borne multi-feed-source antenna changes greatly, a temperature sensor is used for collecting the temperature value of the down-conversion receiving assembly, calibration compensation is carried out at different temperatures, and the amplitude-phase error calibration precision of the system is improved; the problem of amplitude-phase error calibration under the condition of unknown interference is solved, and the calibration compensation precision of the channel at different temperatures is improved by using the temperature value.

Description

Technical Field

[0001] The invention belongs to the technical field of array signal processing, and in particular relates to a method for calibrating amplitude and phase errors of satellite-borne receiving multi-channels. Background Art

[0002] For traditional satellite-borne multi-channel amplitude and phase calibration technology, two methods are used: external calibration and internal calibration. The external calibration technology requires the installation of an additional transmitting antenna outside the receiving antenna to transmit the calibration signal. The internal calibration technology designs a switch at the input end and switches the switch to perform calibration processing during calibration. At the same time, the operating temperature of satellite-borne products is relatively wide. When the temperature changes, the channel amplitude and phase errors will produce large changes, affecting the calibration accuracy of the system. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a method for calibrating multi-channel amplitude and phase errors of satellite-borne reception, so as to solve the problem of multi-channel amplitude and phase error calibration under unknown interference and a wide operating temperature range.

[0004] To achieve the above object, the technical solution adopted by the present invention includes:

[0005] A method for calibrating multi-channel amplitude and phase errors of satellite-borne receivers comprises the following steps:

[0006] S1, multiple groups of RF signals are respectively passed through multiple groups of serially connected couplers and down-conversion receiving components to obtain multiple groups of first intermediate frequency signals, and the multiple groups of first intermediate frequency signals are collected by multiple ADCs to obtain multiple first digital signals, and interference detection and SNR estimation are performed on all the first digital signals to obtain calibration signal frequency f0 and calibration signal code length N;

[0007] Obtain the temperature value of the down-conversion receiving component, and obtain the temperature signal through ADC acquisition;

[0008] S2, generates a spread spectrum modulated signal S(t) according to the calibration signal frequency f0 and the calibration signal code length N obtained in S1, the spread spectrum modulated signal is converted into an analog intermediate frequency signal through a DAC, the analog intermediate frequency signal is converted into a radio frequency signal through an up-conversion transmitting component, and the radio frequency signal is converted through a power division network to obtain a multi-channel calibration radio frequency signal;

[0009] S3, the output multi-channel calibration radio frequency signals obtained by S2 are respectively circulated through multiple couplers to obtain multiple groups of calibration signals and uplink signals, and the multiple groups of calibration signals and uplink signals are respectively passed through multiple groups of down-conversion components to obtain multiple groups of second intermediate frequency signals, and the multiple groups of second intermediate frequency signals are collected by multiple ADCs to obtain multiple second digital signals;

[0010] S4, respectively perform despreading and demodulation, cumulative integration and signal-to-noise ratio estimation on the multiple second digital signals obtained in S3. When the estimated signal-to-noise ratio is lower than the required signal-to-noise ratio, double the cumulative integration time; after reaching the required signal-to-noise ratio, calculate the amplitude and phase errors of the multiple second digital signals and the temperature signal obtained in S1 to obtain the calibration weights at the storage temperature And when the direction finding channel is working, the calibration weights at the storage temperature are Perform error compensation.

[0011] Preferably, the spread spectrum modulated signal S(t) is calculated by formula (1) in S2:

[0012] S(t)=Ac(t)cos2πf0t (1)

[0013] Wherein, A represents the amplitude of the calibration signal, c represents the code sequence of the calibration signal, c is obtained according to the code length N of the calibration signal, and t represents time.

[0014] Preferably, S4 stores the calibration weights at temperature The calculation process is as follows:

[0015] S41, measuring the amplitude and phase errors between the direction finding channels of the multiple second digital signals, and forming the initial calibration weights of the direction finding channels after the measurements

[0016] S42, processing the multiple second digital signals to obtain the amplitude and phase errors between the calibration channels, and forming the calibration weights of the calibration channels

[0017] S43, measure the amplitude and phase error of the calibration channel when calculating the amplitude and phase error And the calibration weight at storage temperature is obtained by formula (2):

[0018]

[0019] Preferably, the cumulative integration time in S4 is 1 ms, and the maximum integration time after doubling the cumulative integration time is 100 ms.

[0020] Preferably, the temperature value is incremented by 5°C. If the current temperature value is equal to the calibration weight at the stored temperature If the temperature reaches above 5°C, it is necessary to execute S1-S4 again to obtain the calibration weight under the new storage temperature.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] The present application discloses a method for calibrating the amplitude and phase errors of multi-channel satellite receivers, which combines the calibration signal and the interference detection result as a whole. The frequency, spread spectrum code length and accumulation time of the calibration signal can be changed according to the interference situation to achieve the purpose of accurately calibrating the system. At the same time, since the operating temperature of the satellite-borne multi-feed antenna varies greatly, a temperature sensor is used to collect the temperature value of the down-conversion receiving component, and calibration compensation is performed at different temperatures to improve the amplitude and phase error calibration accuracy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a flow chart of the multi-channel amplitude and phase error calibration method for satellite-borne reception in this application. DETAILED DESCRIPTION

[0024] The invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention. All components and devices in the present invention, unless otherwise specified, are all components and devices known in the prior art.

[0025] Example

[0026] A method for calibrating multi-channel amplitude and phase errors of satellite-borne receivers comprises the following steps:

[0027] S1, multiple groups of RF signals are respectively passed through multiple groups of serially connected couplers and down-conversion receiving components to obtain multiple groups of first intermediate frequency signals, the multiple groups of first intermediate frequency signals are collected through multiple ADCs to obtain multiple first digital signals, interference detection and SNR estimation are performed on all the first digital signals to obtain calibration signal frequency f0 and calibration signal code length N; the temperature value of the down-conversion receiving component is obtained, and the temperature value is collected through the ADC to obtain a temperature signal;

[0028] S2, generating a spread spectrum modulated signal S(t) according to the calibration signal frequency f0 and the calibration signal code length N obtained in S1, the spread spectrum modulated signal is converted into an analog intermediate frequency signal through a DAC, the analog intermediate frequency signal is converted into a radio frequency signal through an up-conversion transmitting component, and the radio frequency signal is converted through a power division network to obtain a multi-channel calibration radio frequency signal;

[0029] S3, the output multi-channel calibration radio frequency signals obtained in S2 are respectively circulated through multiple couplers to obtain multiple groups of calibration signals and uplink signals, and the multiple groups of calibration signals and uplink signals are respectively passed through multiple groups of down-conversion components to obtain multiple groups of second intermediate frequency signals, and the multiple groups of second intermediate frequency signals are collected by multiple ADCs to obtain multiple second digital signals;

[0030] S4, respectively perform despreading and demodulation, cumulative integration and signal-to-noise ratio estimation on the multiple second digital signals obtained in S3. When the estimated signal-to-noise ratio is lower than the required signal-to-noise ratio, double the cumulative integration time; after reaching the required signal-to-noise ratio, calculate the amplitude and phase errors of the multiple second digital signals and the temperature signal obtained in S1 to obtain the calibration weights at the storage temperature And when the direction finding channel is working, the calibration weights at the storage temperature are Perform error compensation.

[0031] The calibration signal and interference detection results are combined as a whole. The frequency, spread spectrum code length and accumulation time of the calibration signal can be changed according to the interference situation to achieve the purpose of accurately calibrating the system. At the same time, since the operating temperature of the onboard multi-feed antenna varies greatly, a temperature sensor is used to collect the temperature value of the down-conversion receiving component, and calibration compensation is performed at different temperatures to improve the system's amplitude and phase error calibration accuracy.

[0032] In this embodiment, if the working bandwidth of the receiving channel is B1, the frequency of the RF signal is f1, the interference frequency and power in the working frequency band are detected. If there is no interference in the band, the calibration signal frequency f0 selects the default frequency f1, and the calibration signal code length N selects the default code length 2 10 ; If there is interference, and the interference frequency is f2, then select the frequency f3 as far away from f2 as possible in the band as the calibration signal frequency f0; If the interference power is less than 15dB higher than the calibration signal power, the calibration signal code length selects the default code length 2 10 If the interference power is more than 15dB higher than the calibration signal power, the calibration signal code length will be doubled for every 3dB increase in interference power, with a maximum code length of 2. 14 .

[0033] In this embodiment S2, the spread spectrum modulated signal S(t) is calculated by formula (1):

[0034] s(t)=Ac(t)cos2πf0t (1)

[0035] The calibration weights at the storage temperature in S4 of this embodiment The calculation process is as follows:

[0036] S41, measuring the amplitude and phase errors between the direction finding channels of the multiple second digital signals, and forming the initial calibration weights of the direction finding channels after the measurements Among them, the first channel is used as the reference channel, and the remaining channels calculate the amplitude and phase errors between the first channel signal to form calibration weights, which are multiplied by the signals to compensate for the amplitude and phase errors between channels. To obtain the initial calibration weights, an external input signal is used as the calibration signal, and the signals with consistent amplitude and phase are input into multiple receiving channels, and the calibration weights are calculated directly after ADC sampling.

[0037] S42, processing the multiple second digital signals to obtain the amplitude and phase errors between the calibration channels, and forming the calibration weights of the calibration channels

[0038] The initial calibration weights obtained in S41 are The calibration weights of the calibration channels obtained by S42 Store it in the storage space to get the basic weight;

[0039] S43, measure the amplitude and phase error of the calibration channel when calculating the amplitude and phase error And the calibration weight at storage temperature is obtained by formula (2): and store it in the storage space;

[0040]

[0041] The intermediate frequency sampled signal is first down-converted using a signal according to the RF signal sent in S1 to obtain a first intermediate frequency signal, and the code phase of all first intermediate frequency signals is calculated according to The code phase is searched step by step, and the code phase with the largest correlation value is selected. Code phase according to Perform precise search to obtain the final code phase. Then all channels start despreading correlation integration according to the final code phase, and the cumulative integration time is 1ms. After doubling the cumulative integration time, the maximum integration time is 100ms.

[0042] According to the integration results of each channel, the first signal is used as the reference signal I1+j*Q1, and the second signal to the subsequent multi-channel signal Q is inverted I n -j*Q n Then, the subsequent signals are correlated with the first signal to obtain the amplitude and phase differences between the subsequent signals and the first signal. The calibration weights at the storage temperature are finally obtained based on the amplitude and phase differences.

[0043] The value of the temperature sensor in this embodiment is sampled by ADC to obtain the current temperature value. In order to obtain the accurate amplitude phase error when the channel temperature changes, the temperature value is stepped by 5°C. If the current temperature value and the temperature of the stored calibration value are more than 5°C, the S1-S4 calibration is re-executed to obtain the calibration weight under the new temperature value, and the storage space is re-opened for storage. In this way, each set of calibration weights will be related to a set of temperature values. In order to achieve the purpose of accurate calibration under temperature changes.

[0044] The above embodiments are only specific application examples of the present invention. In actual operation, corresponding adjustments can be made according to the on-site geological conditions, detection requirements and specific conditions of technical equipment to achieve the best detection effect.

[0045] Through the above steps, a new satellite-borne receiving multi-channel amplitude and phase error calibration method is realized, which effectively solves the problems existing in the prior art and plays a positive role in promoting coal mine safety production and industry development.

[0046] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0047] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations. In addition, the various different embodiments disclosed in this solution can also be combined arbitrarily, as long as they do not violate the ideas of this disclosure, they should also be regarded as the contents invented by this disclosure.

Claims

1. A method for calibrating multi-channel amplitude and phase errors of satellite-borne receivers, characterized in that: The steps include: S1, multiple groups of RF signals are respectively passed through multiple groups of serially connected couplers and down-conversion receiving components to obtain multiple groups of first intermediate frequency signals, and the multiple groups of first intermediate frequency signals are collected by multiple ADCs to obtain multiple first digital signals, and interference detection and SNR estimation are performed on all the first digital signals to obtain calibration signal frequency f0 and calibration signal code length N; Acquire the temperature value of the down-conversion receiving component, wherein the temperature value is collected by ADC to obtain a temperature signal; S2, generating a spread spectrum modulated signal S(t) according to the calibration signal frequency f0 and the calibration signal code length N obtained in S1, the spread spectrum modulated signal is converted into an analog intermediate frequency signal through a DAC, the analog intermediate frequency signal is converted into a radio frequency signal through an up-conversion transmitting component, and the radio frequency signal is converted through a power division network to obtain a multi-channel calibration radio frequency signal; S3, the output multi-channel calibration radio frequency signals obtained in S2 are respectively circulated through multiple couplers to obtain multiple groups of calibration signals and uplink signals, and the multiple groups of calibration signals and uplink signals are respectively passed through multiple groups of down-conversion components to obtain multiple groups of second intermediate frequency signals, and the multiple groups of second intermediate frequency signals are collected by multiple ADCs to obtain multiple second digital signals; S4, respectively perform despreading and demodulation, cumulative integration and signal-to-noise ratio estimation on the multiple second digital signals obtained in S3. When the estimated signal-to-noise ratio is lower than the required signal-to-noise ratio, double the cumulative integration time; after reaching the required signal-to-noise ratio, calculate the amplitude and phase errors of the multiple second digital signals and the temperature signal obtained in S1 to obtain the calibration weight A0e at the storage temperature jφ0 , and when the direction finding channel is working, the calibration weight A0e at the storage temperature is jφ0 Perform error compensation.

2. The method for calibrating multi-channel amplitude and phase errors of satellite-borne reception according to claim 1, characterized in that: The spread spectrum modulated signal S(t) is calculated by equation (1) in S2: S(t)=Ac(t)cos2πf0t (1) Wherein, A represents the amplitude of the calibration signal, c represents the code sequence of the calibration signal, the code sequence c of the calibration signal is obtained according to the code length N of the calibration signal, and t represents time.

3. The method for calibrating multi-channel amplitude and phase errors of satellite-borne reception according to claim 1, characterized in that: The S4 stores the calibration weights at the temperature The calculation process is as follows: S41, measuring the amplitude and phase errors between the direction finding channels of the multiple second digital signals, and forming the initial calibration weights of the direction finding channels after the measurements S42, processing the multiple second digital signals to obtain the amplitude and phase errors between the calibration channels, and forming the calibration weights of the calibration channels S43, measure the amplitude and phase error of the calibration channel when performing amplitude and phase error calculation And the calibration weight at storage temperature is obtained by formula (2):

4. The method for calibrating multi-channel amplitude and phase errors of satellite-borne reception according to claim 1, characterized in that: The cumulative integration time in S4 is 1 ms, and the maximum integration time after doubling the cumulative integration time is 100 ms.

5. The method for calibrating amplitude and phase errors of multi-channel satellite receiving according to any one of claims 1 to 4, characterized in that: The temperature value step is 5°C. If the current temperature value and the calibration weight at the stored temperature If the temperature reaches above 5°C, it is necessary to execute S1-S4 again to obtain the calibration weight under the new storage temperature.

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