Anti-interference multi-beam phased-array antenna calibration method

Abstract

According to the anti-interference multi-beam phased-array antenna calibration method, a brand new spread spectrum signal system is adopted as a calibration source signal system for calibration and is different from a traditional single-carrier signal system, a spread spectrum calibration signal is generated by calibration processing equipment, then is transmitted through a beacon antenna located in a phased-array near field and is received by a certain TR channel of the phased-array antenna, and the calibration source signal system is used for calibration. And finally, the signal is looped back to a receiving channel of calibration processing equipment and is down-converted to intermediate frequency, amplitude and phase measurement is performed after AD sampling and capturing accumulation, the signal is transmitted to a wave control machine, and the wave control machine performs data processing on the measured signal amplitude and phase to complete amplitude and phase correction. The amplitude-phase correction method has the advantages that the whole amplitude-phase correction method has high self-coupling interference resistance and space environment interference resistance, the interference-to-signal ratio can be realized by adjusting incoherent accumulation times, the amplitude-phase correction of the multi-beam phased-array antenna is completed under strong interference, the implementation principle is simple, additional hardware resources are not needed, and the purposes of quickly capturing and converging signals and calculating an amplitude-phase correction result are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of antenna calibration, and in particular relates to an anti-interference multi-beam phased array antenna calibration method. Background Art

[0002] In the satellite communication link using multi-beam phased array, there are transmitting RF interface and receiving RF interface between the transceiver channel of calibration processing equipment and the switch network of phased array antenna. The radiating units, active channels, power division networks and other components that make up the phased array antenna, especially the active components, will cause the gain consistency and phase consistency between channels to change due to aging and temperature changes during on-orbit application, which will affect the performance of the phased array antenna's synthetic beam. Therefore, each channel must be accurately calibrated. When the phased array antenna is in calibration mode, the calibration processing equipment provides the phased array antenna with the signal source required for calibration within a given time, serially measures the amplitude, phase and other parameters of the return signal of the phased array antenna, and sends the measurement results to the phased array antenna's beam control machine.

[0003] Since amplitude and phase calibration requires simultaneous transmission and reception, the transmitted signal will be coupled to the receiving channel, causing interference to the normal reception of the signal. Furthermore, due to the multi-beam phased array antenna, there will be occasional strong interference between the channels and in the payload space environment. The traditional signal system calibration scheme cannot meet the calibration requirements. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an anti-interference multi-beam phased array antenna calibration method to solve the problem that the traditional amplitude and phase correction co-frequency transceiver system has large self-interference when adopting a single carrier system, and cannot meet the system amplitude and phase correction requirements when there is large interference in the space environment.

[0005] To achieve the above object, the technical solution adopted by the present invention includes:

[0006] A method for calibrating an anti-interference multi-beam phased array antenna comprises the following steps:

[0007] S1, for the first beam, the spread spectrum signal generation module generates a first spread spectrum baseband signal after receiving the calibration start instruction, the first spread spectrum baseband signal is passed through the DA to obtain a first intermediate frequency signal, the first intermediate frequency signal is converted to the Ka band through the transmission channel to obtain a first calibration signal, and the first calibration signal is transmitted to the switch network;

[0008] S2, the first calibration signal is output through the Ka transmitting RF interface of the switch network, and the correction antenna located in the near field of the phased array is selected by the gating switch to transmit the first calibration signal to the phased array antenna; the phased array antenna includes a plurality of TR components, each TR component includes a plurality of TR channels;

[0009] S3, the first calibration signal received by the phased array antenna is transmitted to the first Ka receiving RF interface of the switch network and the first receiving channel corresponding to the first beam in sequence through a TR channel, and then the first calibration signal is down-converted to a first intermediate frequency calibration signal; wherein each TR channel corresponds to a Ka receiving RF interface;

[0010] S4, presetting the system delay in advance, starting to search for the start code phase after the first intermediate frequency calibration signal is sampled by AD, and performing signal capture and despreading. At this time, the interference signal cannot detect the correlation peak at all due to the large delay. After despreading, carrier stripping and integral accumulation are performed to obtain the first correlation value. The first correlation value is measured in amplitude and phase by the amplitude and phase measurement module to obtain the amplitude and phase estimation result of the first TR channel;

[0011] S5, the amplitude and phase estimation result of the first TR channel is transmitted to the beam controller through the communication and control interface for comparison with the original pre-stored amplitude and phase result to obtain a first amplitude and phase correction value, and the first amplitude and phase correction value is input into a TR channel in S3 for amplitude and phase correction to obtain a corrected amplitude and phase result of a TR channel corresponding to the first beam;

[0012] S6, loop S1-S5 to obtain the corrected amplitude and phase results of all TR channels corresponding to the first beam.

[0013] Preferably, for the Nth beam cycle S1-S6, the amplitude and phase results of all TR channels corresponding to the N beams after correction are obtained; wherein the Nth beam corresponds to the Nth receiving channel.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] (1) The anti-interference multi-beam phased array antenna calibration method of the present invention completes the calibration amplitude and phase measurement estimation by sending a spread spectrum calibration signal, has a strong ability to resist self-coupling interference and space environment interference, and the interference-to-signal ratio can be achieved by adjusting the number of incoherent accumulations. The amplitude and phase correction of the multi-beam phased array antenna is completed under strong interference. The implementation principle is simple and does not require additional hardware resources, so the purpose of quickly capturing and converging signals and calculating amplitude and phase correction results is achieved.

[0016] (2) In the anti-interference multi-beam phased array antenna calibration method of the present invention, the calibration source signal system adopts a new spread spectrum signal system, which is different from the traditional single-carrier signal system. The system can complete the calibration amplitude and phase estimation by sending a spread spectrum calibration signal.

[0017] (3) Based on the characteristic of fixed system delay, a fast capture method with preset initial delay is proposed to achieve the purpose of fast signal capture convergence and calculate amplitude and phase correction results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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:

[0019] Figure 1 This is a block diagram of the correction system in the present invention;

[0020] Figure 2 This is the signal processing flow during the calibration process. DETAILED DESCRIPTION

[0021] 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.

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 The system block diagram of the present invention is shown as follows. Figure 1 It can be seen that the anti-interference multi-beam phased array antenna calibration system and method proposed in the present invention are characterized in that the satellite communication system adopts a multi-beam phased array link, and the transceiver channel of the calibration processing equipment and the multi-beam phased array antenna switch network have one Ka transmission RF interface and multiple Ka reception RF interfaces, and the receiving channel and the transmitting channel are independently calibrated in time-sharing. The calibration processing equipment provides a calibration signal source for the multi-beam phased array antenna, including a transceiver channel and a processing FPGA, wherein the core modules of the processing FPGA are a spread spectrum signal generation module, a capture accumulation module, an amplitude and phase measurement module, and a communication and control interface module; the multi-beam antenna is mainly composed of a TR component, a gating switch, a near-field beacon antenna, an active array antenna, a wave control machine, etc.

[0024] according to Figure 1 The calibration process is illustrated as shown, wherein the calibration processing device generates a spread spectrum calibration signal source and selects a beacon antenna located in the near field of the phased array to transmit the signal through a gate switch.

[0025] The phased array antenna is a multi-beam antenna with multiple TR components, each TR component contains multiple TR channels. The channel to be measured of the phased array antenna receives the calibration signal of the calibration processing device and outputs it. After the output spread spectrum signal passes through the receiving channel of the calibration processing device, it completes down-conversion processing and AD sampling. The signal capture accumulation module and the amplitude and phase measurement module complete the amplitude and phase measurement of the spread spectrum signal after AD sampling. When the calibration processing device is in the amplitude and phase correction mode, it autonomously generates the phased array antenna channel amplitude and phase correction instructions and sends them to the phased array antenna; after receiving the calibration start instruction of the calibration processing device, the phased array antenna wave controller sets the switch in the pre-amplifier to the amplitude and phase calibration mode, and prepares for calibration. Then, according to the calibration instruction of the calibration processing device, the wave controller switches the power supply of the TR components one by one until the amplitude and phase measurement of all TR channels is completed; the calibration processing device serially measures the amplitude, phase and other parameters of the return signal of the phased array antenna in time-sharing and sends the calibration result to the phased array antenna wave controller. The wave controller calculates the amplitude and phase correction amount based on the measured amplitude and phase values ​​to correct the antenna pointing.

[0026] In addition, during calibration, the transmitter and receiver need to work simultaneously, and the transmitted signal will be coupled to the receiving channel, causing interference to the normal received signal. Moreover, due to the multi-beam phased array antenna, there will be occasional strong interference between the channels and in the payload space environment, and the traditional signal system calibration scheme cannot meet the calibration requirements. Based on this, this paper proposes an anti-interference multi-beam phased array antenna calibration system and method, which fully considers that the normal signal arrival time is delayed by ≥1 pseudo code chip compared to the interference signal arrival time, and ensures that the signal can pass through the bandpass filter in the receiving channel, and designs a spread spectrum signal system that can converge quickly and has strong anti-interference ability.

[0027] Since this method is based on a hardware platform with multiple down-conversion and multiple sampling modules, and the amplitude and phase correction of the phased array antenna requires the completion of amplitude and phase consistency measurements between multiple channels, in order to avoid the phase drift caused by the system when measuring between different channels, the correction signal source needs to be phase continuous throughout the correction process and be the same source as the receiving down-conversion module, sampling module and signal amplitude and phase measurement module. At the same time, it is required to have fast capture convergence during signal reception measurement.

[0028] like Figure 2 The signal processing flow in the present invention is as follows: Figure 2 It can be seen that the steps of signal processing in the present invention are as follows:

[0029] (1) Processing flow of FPGA sending calibration signal

[0030] Receive a beam calibration command to control the signal transmission frequency

[0031] Receive the serial port calibration channel setting command and generate a calibration signal flag. After the calibration starts, a calibration channel setting command is generated at a fixed interval (hundreds of milliseconds) until all antenna TR channels are traversed;

[0032] When the calibration signal is received, the spread spectrum signal is continuously generated at the standard pseudo code rate, and the signal is not interrupted during the antenna TR switching process.

[0033] Signal interpolation filtering to achieve standard sampling rate

[0034] Output to DA according to mode judgment

[0035] (2) Processing flow of FPGA receiving calibration signal

[0036] The AD receives the calibration signal, and after sampling, the signal is down-converted to zero intermediate frequency according to different beam frequencies;

[0037] Receive the serial port calibration channel setting command and generate a start receiving calibration signal flag. After the calibration starts, generate a calibration channel setting command at a fixed interval (hundreds of ms) until all antenna TR channels are traversed.

[0038] Taking full advantage of the characteristics of fixed system delay and inconsistent interference path delay, the system delay is estimated according to the position of the pseudo code correlation peak. After receiving the calibration start signal, the system delay information is used to search for the start code phase and start capture.

[0039] The calibration processing equipment is only started once for single-channel calibration, and N-way correlation is performed on the 6-fold pseudo-code chip rate and the sampling master clock to complete the correlation operation of 4 pseudo-code chip ranges.

[0040] Perform P accumulation processing on N related signals respectively

[0041] Determine the N signals after accumulation and find the largest branch as the despreading branch

[0042] Despread and correlate the searched maximum branch signal, output the accumulated correlation value to the amplitude and phase measurement module

[0043] Amplitude and phase estimation operation

[0044] Example

[0045] This embodiment discloses an anti-interference multi-beam phased array antenna calibration method, comprising the following steps:

[0046] S1, for the first beam, the spread spectrum signal generation module generates a first spread spectrum baseband signal after receiving the calibration start instruction, the first spread spectrum baseband signal is passed through the DA to obtain a first intermediate frequency signal, the first intermediate frequency signal is converted to the Ka band through the transmission channel to obtain a first calibration signal, and the first calibration signal is transmitted to the switch network;

[0047] S2, the first calibration signal is output through the Ka transmitting RF interface of the switch network, and the correction antenna located in the near field of the phased array is selected by the gating switch to transmit the first calibration signal to the phased array antenna;

[0048] S3, the first calibration signal received by the phased array antenna is transmitted to the first Ka receiving RF interface of the switch network and the first receiving channel corresponding to the first beam in sequence through a TR channel, and then the first calibration signal is down-converted to a first intermediate frequency calibration signal;

[0049] Among them, each TR channel corresponds to a Ka receiving RF interface;

[0050] S4, presetting the system delay in advance, starting to search for the start code phase after the first intermediate frequency calibration signal is sampled by AD, and performing signal capture and despreading. At this time, the interference signal cannot detect the correlation peak at all due to the large delay. After despreading, carrier stripping and integral accumulation are performed to obtain the first correlation value. The first correlation value is measured in amplitude and phase by the amplitude and phase measurement module to obtain the amplitude and phase estimation result of the first TR channel;

[0051] S5, the amplitude and phase estimation result of the first TR channel is transmitted to the beam controller through the communication and control interface for comparison with the original pre-stored amplitude and phase result to obtain a first amplitude and phase correction value, and the first amplitude and phase correction value is input into a TR channel in S3 for amplitude and phase correction to obtain a corrected amplitude and phase result of a TR channel corresponding to the first beam;

[0052] S6, loop S1-S5 to obtain the corrected amplitude and phase results of all TR channels corresponding to the first beam.

[0053] In this embodiment, S1-S6 are cycled for each beam to obtain the amplitude and phase results of all TR channels corresponding to all beams after correction;

[0054] Among them, the Nth beam corresponds to the Nth receiving channel.

[0055] The technical solution of the present invention has been successfully applied in equipment and passed relevant application tests.

[0056] 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.

[0057] 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 an anti-interference multi-beam phased array antenna, characterized in that: The steps include: S1, for the first beam, the spread spectrum signal generation module generates a first spread spectrum baseband signal after receiving the calibration start instruction, the first spread spectrum baseband signal is passed through the DA to obtain a first intermediate frequency signal, the first intermediate frequency signal is converted to the Ka band through the transmission channel to obtain a first calibration signal, and the first calibration signal is transmitted to the switch network; S2, the first calibration signal is output through the Ka transmitting RF interface of the switch network, and the correction antenna located in the near field of the phased array is selected by the gating switch to transmit the first calibration signal to the phased array antenna; The phased array antenna includes a plurality of TR components, each TR component includes a plurality of TR channels; S3, the first calibration signal received by the phased array antenna is transmitted to the first Ka receiving RF interface of the switch network and the first receiving channel corresponding to the first beam in sequence through a TR channel, and then the first calibration signal is down-converted to a first intermediate frequency calibration signal; Among them, each TR channel corresponds to a Ka receiving RF interface; S4, presetting the system delay in advance, starting to search for the start code phase after the first intermediate frequency calibration signal is sampled by AD, and performing signal capture and despreading. At this time, the interference signal cannot detect the correlation peak at all due to the large delay. After despreading, carrier stripping and integral accumulation are performed to obtain the first correlation value. The first correlation value is measured in amplitude and phase by the amplitude and phase measurement module to obtain the amplitude and phase estimation result of the first TR channel; S5, the amplitude and phase estimation result of the first TR channel is transmitted to the beam controller through the communication and control interface for comparison with the original pre-stored amplitude and phase result to obtain a first amplitude and phase correction value, and the first amplitude and phase correction value is input into a TR channel in S3 for amplitude and phase correction to obtain a corrected amplitude and phase result of a TR channel corresponding to the first beam; S6, loop S1-S5 to obtain the corrected amplitude and phase results of all TR channels corresponding to the first beam.

2. The anti-interference multi-beam phased array antenna calibration method according to claim 1, characterized in that: For the Nth beam cycle S1-S6, the corrected amplitude and phase results of all TR channels corresponding to the N beams are obtained; Among them, the Nth beam corresponds to the Nth receiving channel.

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