An anti-interference multi-beam phased array antenna calibration method

Abstract

The application relates to an anti-interference multi-beam phased array antenna calibration method, wherein a novel spread spectrum signal system is adopted in the calibration source signal system for correction, which is different from the traditional single carrier signal system; a spread spectrum calibration signal is generated by a calibration processing device, is transmitted through a beacon antenna located in the near field of the phased array, is received by a certain TR channel of the phased array antenna, is finally looped back to the calibration processing device, is down-converted to an intermediate frequency, is AD sampled and captured, and then amplitude and phase measurement is carried out and the measurement result is transmitted to a wave control machine; the wave control machine carries out data processing on the measured signal amplitude and phase to complete amplitude and phase correction. The whole has strong anti-coupling interference and space environment interference capability, the interference signal ratio can be realized by adjusting the non-coherent accumulation times, the amplitude and phase correction of the multi-beam phased array antenna is completed under strong interference, the realization principle is simple, no additional hardware resource is needed, the signal can be quickly captured and converged, and the amplitude and phase correction result can be calculated.

Description

Technical Field

[0001] This invention belongs to the field of antenna calibration technology, specifically relating to a calibration method for an anti-interference multi-beam phased array antenna. Background Technology

[0002] In spaceborne communication links employing multi-beam phased arrays, the calibration processing equipment's transceiver channels and the phased array antenna switching network share transmit and receive RF interfaces. Various components of the phased array antenna, including radiating elements, active channels, and power dividers, especially active components, are susceptible to changes in gain and phase consistency between channels due to aging and temperature variations during on-orbit operation. This impacts the performance of the synthesized beam of the phased array antenna. Therefore, precise calibration of each channel is essential. When the phased array antenna is in calibration mode, the calibration processing equipment provides the necessary signal source to the phased array antenna within a given time period, serially and time-divisionally measuring the amplitude, phase, and other parameters of the returned signal from the phased array antenna, and sending the measurement results to the phased array antenna's beam control unit.

[0003] Since amplitude and phase calibration requires simultaneous transmission and reception, the transmitted signal will couple into the receiving channel, interfering with the normal received signal. Furthermore, as it is a multi-beam phased array antenna, there will be occasional strong interference between channels and in the payload space environment. Traditional signal system calibration schemes cannot meet the calibration requirements. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide an anti-interference multi-beam phased array antenna calibration method, which solves the problems of large self-interference in traditional amplitude and phase correction co-frequency transceiver systems using a single-carrier system, and the inability to meet the system's amplitude and phase correction requirements in environments with significant space interference.

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

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

[0007] S1, For the first beam, after receiving the calibration start command, the spread spectrum signal generation module generates a first spread spectrum baseband signal. The first spread spectrum baseband signal is processed by DA to obtain a first intermediate frequency signal. The first intermediate frequency signal is converted to the Ka band by the transmission channel to obtain a first calibration signal, and the first calibration signal is sent to the switching network.

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

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

[0010] S4, the system delay is preset in advance. After the first intermediate frequency calibration signal is sampled by AD, the start code phase is searched and the signal is captured and despread. At this time, the interference signal cannot be detected at all due to the large time delay. After despreading, carrier stripping and integration accumulation are performed to obtain the first correlation value. The amplitude and phase of the first correlation value are measured 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 and compared with the original pre-stored amplitude and phase result to obtain the first amplitude and phase correction amount. The first amplitude and phase correction amount is then input into one of the TR channels in S3 for amplitude and phase correction to obtain the corrected amplitude and phase result of one TR channel corresponding to the first beam.

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

[0013] Preferably, for the Nth beam cycle S1-S6, the amplitude and phase results of all TR channels corresponding to the N beams are obtained after correction; 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 spread spectrum calibration signal. It has strong anti-self-coupling interference and space environment interference capabilities. The interference-to-signal ratio can be achieved by adjusting the number of incoherent accumulations. It completes the amplitude and phase correction of the multi-beam phased array antenna under strong interference. The implementation principle is simple and does not require additional hardware resources. It achieves the purpose of fast signal acquisition and convergence and calculation of amplitude and phase correction results.

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

[0017] (3) Based on the fixed system time delay, a fast acquisition method with a preset initial time delay is proposed to achieve the purpose of fast signal acquisition and convergence and calculation of amplitude and phase correction results. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

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

[0020] Figure 2 This describes the signal processing flow during the calibration process. Detailed Implementation

[0021] The invention is not limited to the specific embodiments described below. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of this invention. Unless otherwise specified, all components and devices in this invention utilize components and devices known in the prior art.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0023] like Figure 1 The diagram shown is a system block diagram of the present invention. Figure 1 As can be seen, the anti-interference multi-beam phased array antenna calibration system and method proposed in this invention are characterized by the use of a multi-beam phased array link in the spaceborne communication system. The calibration processing equipment's transceiver channel and the multi-beam phased array antenna switching network have one Ka-channel transmit RF interface and multiple Ka-channel receive RF interfaces, allowing for time-division independent calibration of the receive and transmit channels. The calibration processing equipment provides a calibration signal source for the multi-beam phased array antenna and includes a transceiver channel and a processing FPGA. The core modules of the processing FPGA include a spread spectrum signal generation module, a capture and accumulation module, an amplitude and phase measurement module, and a communication and control interface module. The multi-beam antenna mainly consists of a TR component, a gating switch, a near-field beacon antenna, an active array antenna, and a beam control unit.

[0024] according to Figure 1 The calibration process is illustrated below. The calibration processing equipment 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 via a gating switch.

[0025] The phased array antenna is a multi-beam antenna with multiple TR components. Each TR component contains multiple TR channels. The test channel of the phased array antenna receives the calibration signal from the calibration processing equipment and outputs it. The output spread spectrum signal undergoes down-conversion processing and AD sampling after passing through the receiving channel of the calibration processing equipment. The amplitude and phase of the spread spectrum signal after AD sampling are then measured by the signal acquisition and accumulation module and the amplitude and phase measurement module. In amplitude and phase correction mode, the calibration processing equipment autonomously generates amplitude and phase correction commands for the phased array antenna channels and sends them to the phased array antenna. After receiving the calibration start command from the calibration processing equipment, the phased array antenna wave controller sets the switch in the preamplifier to amplitude and phase correction mode, preparing for calibration. Subsequently, the wave controller switches the power supply of each TR component one by one according to the calibration command from the calibration processing equipment until the amplitude and phase measurements of all TR channels are completed. The calibration processing equipment serially and time-divisionally measures the amplitude, phase, and other parameters of the phased array antenna return signal and sends the calibration results 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] Furthermore, calibration requires simultaneous transmission and reception, and the transmitted signal can couple into the receiving channel, interfering with the normal received signal. Moreover, as it is a multi-beam phased array antenna, there will be occasional strong interference between channels and in the payload space environment. Traditional signal system calibration schemes cannot meet the calibration requirements. Based on this, this paper proposes an anti-interference multi-beam phased array antenna calibration system and method. It fully considers that the arrival time of the normal signal is delayed by ≥1 pseudo-code chip compared to the arrival time of the interference signal, and ensures that the signal can pass through the bandpass filter in the receiving channel. A spread spectrum signal system is designed, which can achieve both fast convergence and strong anti-interference capability.

[0027] Since this method is based on a hardware platform with multiple downconversion and multiple sampling modules, and phase correction of phase array antennas requires the measurement of amplitude and phase consistency between multiple channels, in order to avoid phase drift caused by the system during measurement between different channels, the correction signal source needs to be phase continuous throughout the correction process and be of the same origin as the receiving downconversion module, sampling module and signal amplitude and phase measurement module. At the same time, it needs to have fast acquisition and convergence during signal reception measurement.

[0028] like Figure 2 The signal processing flow in this invention is as follows: Figure 2 As can be seen, the signal processing steps in this invention are as follows:

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

[0030] Upon receiving a beam calibration command, control the signal transmission frequency.

[0031] Upon receiving the serial port calibration channel setting command, a calibration start signal flag is generated. After calibration begins, a calibration channel setting command is generated every fixed interval (on the order of hundreds of milliseconds) until all antenna TR channels have been traversed.

[0032] Upon receiving the start of calibration signal, the spread spectrum signal is continuously generated at the standard pseudocode rate, and the signal is not interrupted during antenna TR switching.

[0033] Signal interpolation and filtering to achieve the standard sampling rate

[0034] The output is given to DA based on the pattern decision.

[0035] (2) Processing flow of FPGA received 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] Upon receiving the serial port calibration channel setting command, a start calibration signal flag is generated. After calibration begins, a calibration channel setting command is generated every fixed interval (on the order of hundreds of milliseconds) until all antenna TR channels have been traversed.

[0038] Taking full advantage of the fixed system delay and the inconsistent delay of interference paths, the system delay is estimated based on the position of the pseudocode correlation peak. After receiving the calibration start signal, the system delay information is used to search for the start code phase and acquisition begins.

[0039] The calibration processing equipment only starts once during single-channel calibration, performing N-way correlation at 6 times the pseudo-code chip rate and the sampling master clock to complete correlation calculations for 4 pseudo-code chip ranges.

[0040] Perform P accumulation operations on each of the N related signals.

[0041] After summing the N signals, find the branch with the largest value and use it as the despreading branch.

[0042] The maximum branch signal is despread and correlated, and the accumulated correlation value is output to the amplitude and phase measurement module.

[0043] Amplitude and phase estimation operation

[0044] Example

[0045] This embodiment discloses a method for calibrating an anti-interference multi-beam phased array antenna, including the following steps:

[0046] S1, For the first beam, after receiving the calibration start command, the spread spectrum signal generation module generates a first spread spectrum baseband signal. The first spread spectrum baseband signal is processed by DA to obtain a first intermediate frequency signal. The first intermediate frequency signal is converted to the Ka band by the transmission channel to obtain a first calibration signal, and the first calibration signal is sent to the switching network.

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

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

[0049] Each TR channel corresponds to one Ka receiver RF interface;

[0050] S4, the system delay is preset in advance. After the first intermediate frequency calibration signal is sampled by AD, the start code phase is searched and the signal is captured and despread. At this time, the interference signal cannot be detected at all due to the large time delay. After despreading, carrier stripping and integration accumulation are performed to obtain the first correlation value. The amplitude and phase of the first correlation value are measured 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 and compared with the original pre-stored amplitude and phase result to obtain the first amplitude and phase correction amount. The first amplitude and phase correction amount is then input into one of the TR channels in S3 for amplitude and phase correction to obtain the corrected amplitude and phase result of one TR channel corresponding to the first beam.

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

[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] The Nth beam corresponds to the Nth receiving channel.

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

[0056] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0057] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately. Furthermore, the various different embodiments disclosed in this solution can also be combined arbitrarily, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content of this disclosure.

Claims

1. A method for calibrating an anti-interference multi-beam phased array antenna, characterized in that, Includes the following steps: S1, For the first beam, after receiving the calibration start command, the spread spectrum signal generation module generates a first spread spectrum baseband signal. The first spread spectrum baseband signal is processed by DA to obtain a first intermediate frequency signal. The first intermediate frequency signal is converted to the Ka band by the transmission channel to obtain a first calibration signal, and the first calibration signal is sent to the switching network. S2, the first calibration signal is output through the Ka transmit RF interface of the switch network, and the first calibration signal is transmitted to the phased array antenna by selecting the correction antenna located in the near field of the phased array through the gating switch; The phased array antenna includes multiple TR components, and each TR component contains multiple TR channels; S3, the first calibration signal received by the phased array antenna is transmitted sequentially through a TR channel to the first Ka receiving radio frequency interface of the switching network and the first receiving channel corresponding to the first beam, and then the first calibration signal is down-converted to the first intermediate frequency calibration signal. Each TR channel corresponds to one Ka receiver RF interface; S4, the system delay is preset in advance. After the first intermediate frequency calibration signal is sampled by AD, the start code phase is searched and the signal is captured and despread. At this time, the interference signal cannot be detected at all due to the large time delay. After despreading, carrier stripping and integration accumulation are performed to obtain the first correlation value. The amplitude and phase of the first correlation value are measured 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 and compared with the original pre-stored amplitude and phase result to obtain the first amplitude and phase correction amount. The first amplitude and phase correction amount is then input into one of the TR channels in S3 for amplitude and phase correction to obtain the corrected amplitude and phase result of one TR channel corresponding to the first beam. S6, repeat S1-S5 to obtain the amplitude and phase results of all TR channels corresponding to the first beam after correction.

2. The anti-interference multi-beam phased array antenna calibration method as described in claim 1, characterized in that, For the Nth beam loop S1-S6, obtain the amplitude and phase results of all TR channels corresponding to the N beams after correction; The Nth beam corresponds to the Nth receiving channel.

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