CN104316913A - Multichannel receiver real-time calibration device and calibration and error compensation method - Google Patents

Abstract

The invention discloses a multi-channel receiver real-time calibration device, including a synchronization error calibration device for performing real-time synchronization calibration and error compensation on the multi-channel receiver; The channel receiver performs real-time amplitude and phase calibration and error compensation. And a multi-channel receiver real-time calibration method. The device and method of the present invention are comprehensive for error calibration, and the integrated architecture can realize real-time synchronous calibration and amplitude-phase calibration for multi-channel receivers at the same time. It has strong real-time performance and flexibility, and has a high degree of automation. During the whole process of system work, you only need to make corresponding selections in the system control interface, without any connection and hardware changes, you can complete the system calibration process, easy to operate, fast to use, and can accurately compensate for environmental conditions and device characteristics. The influence brought by the receiving channel effectively solves the difficulty of receiving large-bandwidth signals.

Description

Multi-channel receiver real-time calibration device and calibration and error compensation method

technical field

The invention belongs to the technical field of radar, and more specifically relates to a multi-channel receiver real-time calibration device and a calibration and error compensation method.

Background technique

Because synthetic aperture radar (SAR) can image the ground all day and all day long, and has the ability to penetrate vegetation and camouflage, it is widely used in military reconnaissance, disaster monitoring, resource exploration, terrain surveying and other fields, and is favored by the world. Countries are paying more and more attention. With the continuous development of synthetic aperture radar technology and the continuous expansion of application fields, the requirements for radar performance are getting higher and higher. Among them, resolution, as one of the core technical indicators of synthetic aperture radar, has been promoted to a higher position.

The improvement of distance resolution depends on the improvement of signal bandwidth. To achieve high-resolution imaging, the problem of receiving large-bandwidth signals must be solved. However, signals with a bandwidth of more than 1,000 MHz do not currently have high-speed A/D conversion that can be directly sampled. device. In order to solve the problem that ultra-wideband (UWB) radar signals cannot be directly A/D converted, for LFM signals, M. Skolnik et al. proposed a radar pulse compression scheme based on time-frequency conversion technology (Stretch Processing). This scheme is very effective for LFM signals under certain conditions, but it also has the following problems: (1) Distortion compensation is difficult: due to the introduction of the time-frequency conversion link, the corresponding time-frequency conversion distortion is brought, when the target moves or the frequency modulation itself When the vibration trigger time changes, the influence of this distortion changes accordingly, showing the nature of shifting, which brings great difficulty to the system compensation; (2) The bandwidth of surveying and mapping is limited: in order to reduce the signal bandwidth, deskewing The processing is at the expense of the surveying and mapping bandwidth, that is to say, if the surveying and mapping bandwidth is required to be wide, the purpose of reducing the signal bandwidth cannot be achieved after deskewing. The latter problem, in particular, severely limits the scope of use of this scheme.

Under the current technical conditions, in order to improve the range resolution of the SAR system, multi-channel synthesis is one of the main technical means currently used. The scheme is based on the channelization receiving technology, adopts the frequency domain segmentation method to divide the radar echo signal into multiple receiving sub-bands, each sub-band is sampled by a relatively low-speed A/D, and finally the frequency band is synthesized in the digital domain to obtain a complete bandwidth signal.

The reason why this method has become the mainstream technology of broadband signal processing is that it can effectively reduce the technical requirements of high-speed A/D devices, greatly reduce the pressure of single-channel A/D design and subsequent data recording, and imaging processing, making the current high-bandwidth It is possible to image the next large swath. But this method needs to focus on solving two problems, one is the synchronization problem of multi-channel A/D, and the other problem is the amplitude-phase distortion problem of multi-channel.

First of all, the synchronization problem of multi-channel A/D, that is, the inter-channel delay of the data acquisition unit, when the same signal is loaded into different acquisition channels in phase, whether the time difference reflected by the first point of the multi-group acquisition number sequence on the signal waveform is zero. It is a very important basic indicator. In the process of SAR waveform acquisition and recording with strict requirements on timing and phase, the delay time difference between channels of the data acquisition system is an indicator that must be accurately known. The subsequent amplitude and phase of the radar Error compensation and imaging processing are based on the complete synchronization of each channel.

Another problem is the amplitude and phase distortion between channels. Due to the instability and inconsistency of analog devices, their amplitude and phase differences not only change with frequency, but also often change slowly with time. The direct multi-channel synthesis of sub-band signals not only fails to improve the range resolution, but also seriously deteriorates the imaging quality. The receiving channel error of SAR includes two parts of amplitude error and phase error, the specific expression is where H _n (w) is the total amplitude and phase error function of the nth channel, A _n (w) represents the amplitude error, Indicates the phase error, w represents the frequency. The above errors will have adverse effects on the imaging results, leading to the broadening of the main lobe and the lifting of the side lobes of the impulse response to pulse compression in the range direction, and the reduction of resolution and image quality.

Estimation and compensation of synchronous error and amplitude-phase error between channels has become a key technology in multi-channel SAR system design and signal processing.

In the prior art, there is no integrated synchronization error and amplitude-phase error calibration device, which are all compensations for a single error. For the synchronization error between channels, the existing technology often solves it in the digital domain, or processes the sampling clock and trigger signal, and realizes the synchronization of multiple A/Ds by means of a phase-locked loop and optimized circuit design; for For the amplitude and phase errors between channels, the usual practice is to use radar closed-loop testing methods to obtain experimental data at one time; or, use standard measuring instruments such as vector network analyzers to measure the amplitude and phase errors between channels; or, based on feedback Wave data is directly used for error extraction.

For the synchronization error between channels, the existing technology is applicable when the sampling rate of the A/D device is low. Once high-speed A/D is involved, such as the intermediate frequency sampling rate of the receiving channel in the SAR system is above 1.5GHz, the circuit at this time It is very sensitive to clock signal jitter, and ps-level errors may cause out-of-synchronization between channels every time it is powered on or reset. In this case, it is difficult for the above method to ensure that the delay time difference between multiple acquisition channels for multiple sets of data is basically 0 or maintain a constant state, it is difficult to fundamentally solve the synchronization problem.

For the amplitude and phase errors between channels, the common problem of the three methods currently used is that the real-time performance is insufficient, and they are all processed after the data recording has been completed. The recorded data already contains many uncertain amplitude and phase errors. After compensation, the residual error component is still very large, and it is impossible to make accurate compensation for the time-varying and temperature drift of the analog channel performance, which affects the extraction and utilization of large-capacity information in large-bandwidth signals.

Contents of the invention

In view of the above technical problems, one of the objectives of the present invention is to provide a multi-channel receiver real-time calibration device and calibration and error compensation method, so as to realize the analysis and compensation of two errors in one process.

In order to achieve the above object, as an aspect of the present invention, the present invention provides a multi-channel receiver amplitude and phase error calibration device, including:

an amplitude-phase error calibration network, configured to generate an amplitude-phase error calibration signal corresponding to each channel of the multi-channel receiver; and

The amplitude-phase error compensation unit is configured to perform amplitude-phase calibration and error compensation for each channel of the multi-channel receiver based on the amplitude-phase error calibration signal generated by the amplitude-phase error calibration network.

Wherein, the amplitude and phase error calibration network includes:

A phase calibration signal source for outputting a standard signal for calibration;

A signal conditioning circuit, used to adjust the amplitude of the standard signal used for calibration, so as to adapt to the amplitude-phase calibration between channels under different echo signal-to-noise ratios; and

A phase calibration switch, used for mode selection, switching between phase calibration mode and normal mode.

Wherein, the method for the amplitude-phase error compensation unit to perform amplitude-phase calibration and error compensation for each channel is: transform the frequency domain of the collected digital signal into S(w), and calculate the frequency domain I(w) of the ideal chirp signal ), thus obtaining the transmission error of the channel Using the analyzed error H _n (w) to perform amplitude and phase calibration and error compensation processing on the receiving channel.

As another aspect of the present invention, the present invention also provides a multi-channel receiver real-time calibration device, comprising:

A synchronous error calibration device for performing real-time synchronous calibration and error compensation on the multi-channel receiver; and

The amplitude and phase error calibration device described in any one of the above is used for real-time amplitude and phase calibration and error compensation for the multi-channel receiver.

Wherein, the synchronization error calibration device includes:

A synchronization error calibration network, configured to generate a synchronization error calibration signal corresponding to each channel of the multi-channel receiver, comprising:

A synchronous calibration signal source for outputting a synchronous error calibration signal, wherein the synchronous error calibration signal is a point frequency signal with a certain amplitude;

A power dividing network for dividing the synchronization error calibration signal into multiple signals corresponding to the number of channels; and

A switch matrix for mode selection, switching between the synchronization error calibration signal and the normal operation mode signal; and

The synchronous error compensation unit is used to perform synchronous calibration and error compensation for each channel of the multi-channel receiver, wherein the method for synchronous calibration and error compensation of each channel by the synchronous error compensation unit is: evaluate the first channel of each channel The initial phase corresponding to a collection of data in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained. After the time difference is compensated, the synchronization calibration and error compensation of each channel is completed.

Wherein, the amplitude and phase error calibration device includes an amplitude and phase error calibration network and an amplitude and phase error compensation unit, and the synchronization error calibration device includes a synchronization error calibration network and a synchronization error compensation unit; and

The amplitude-phase error calibration network is between the pre-stage low-noise amplifier and the N-way power dividing network, the synchronous error calibration network is located before the input of the multi-channel A/D unit, and the synchronous error compensation unit is adjacent to the multi-channel A/D unit. Set after the /D unit, the amplitude and phase error compensation unit is set after the synchronization error compensation unit.

As another aspect of the present invention, the present invention also provides a multi-channel receiver real-time calibration and error compensation method, including the following steps:

Control the switch matrix to switch the working mode of the multi-channel receiver to the required working mode; and

When switching to the synchronous calibration mode, the synchronous calibration signal source outputs a standard point frequency signal, which is divided into multiple signals corresponding to the number of channels through the power division network, and output to the multi-channel A/D unit through the switch matrix; the multi-channel A/D unit After digitizing the signals of each channel, the synchronization error compensation unit evaluates the initial phase corresponding to the first collected data of each channel in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained; after compensating the time difference, the synchronous calibration and error compensation of each channel are completed;

When switching to the amplitude-phase calibration mode, the amplitude-phase calibration signal source outputs a pre-distortion-compensated amplitude-phase error calibration signal to the channelized receiving unit;

The channelized receiving unit performs analog processing such as channelization selection, down conversion, and MGC amplification on the amplitude and phase error calibration signals of each channel in turn, and outputs them to the A/D unit; the A/D unit converts the amplitude and phase error calibration signals Perform digital processing, and then digitally demodulate it into a digital baseband signal and output it to the amplitude-phase error compensation unit. The amplitude-phase error compensation unit converts the collected digital signal into S(w) in the frequency domain, and calculates the ideal amplitude The frequency domain I(w) of the phase error calibration signal, thereby obtaining the transfer error of the channel Using H _n (w) to perform amplitude and phase calibration and error compensation processing on the receiving channel to eliminate phase and amplitude errors in the channel.

Among them, during the working process of the system, it can be switched to the synchronous and/or amplitude-phase calibration mode for calibration at any time according to the needs of the system.

Among them, switch to the synchronous calibration mode first, and then switch to the amplitude and phase calibration mode after completion.

As another aspect of the present invention, the present invention also provides a method for real-time calibration and error compensation of a multi-channel receiver, comprising the following steps:

Switch to synchronous calibration mode;

The synchronous calibration signal source outputs the standard point frequency signal, which is output to the multi-channel A/D unit through the power dividing network and the switch matrix;

After digital processing, the synchronization error compensation unit evaluates the initial phase corresponding to the first acquisition data of each channel in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained. After compensating for the time difference, the synchronization calibration and error compensation are completed;

The system enters the amplitude and phase calibration mode, and closes the synchronous calibration mode at the same time;

The amplitude and phase calibration signal source outputs the ideal chirp signal after pre-distortion compensation, and outputs it to the channelization receiving unit through the signal conditioning unit and the amplitude and phase calibration mode selection circuit;

After the signal undergoes analog processing such as channelization selection, down-conversion, and MGC amplification in the channelized receiving unit, the digitalization process is completed in the A/D unit;

After being digitally demodulated into a digital baseband signal, frequency analysis is performed on the baseband signal in the channel amplitude and phase error compensation unit to obtain the transfer characteristics of the channel and the error under ideal conditions, that is, to transform the collected digital signal in the frequency domain is S(w), and calculate the frequency domain I(w) of the ideal chirp signal, so that the difference between the collected actual signal and the ideal chirp signal can be obtained, that is, the transmission error of the channel

Use the error H _n (w) obtained from the analysis to perform amplitude and phase calibration and error compensation processing on the receiving channel;

The entire calibration process is completed, and the system enters the normal working mode.

It can be seen from the above technical scheme that the error calibration of the present invention is comprehensive. By integrating synchronization and amplitude-phase calibration devices in the multi-channel receiver, the integrated architecture can simultaneously realize real-time synchronization calibration and amplitude-phase calibration of the multi-channel receiver, and automatically measure multiple The error information between two channels can eliminate the influence of two kinds of uncertainties on the channel. The important thing is that the invention has strong real-time and flexibility, high degree of automation, and its error calibration can run through the whole process of system work. You only need to make corresponding selections in the radar control interface, without any connection and hardware changes, to complete the calibration process of the system. The operation is simple and fast, and it can accurately compensate the influence of environmental conditions and device characteristics on the receiving channel. It lays a good foundation for multi-channel data processing and can effectively solve the problem of receiving large-bandwidth signals.

Description of drawings

Fig. 1 is a schematic structural diagram of a traditional multi-channel receiver;

Fig. 2 is a structural schematic diagram of a multi-channel receiver integrated with a real-time calibration device of the present invention;

Fig. 3 is a schematic diagram of the principle of a multi-channel receiver integrated with a real-time calibration device of the present invention;

Fig. 4 (a) is a schematic diagram of the composition and structure of the synchronous calibration device of the present invention;

Fig. 4 (b) is the schematic diagram of synchronous error analysis and compensation method of the present invention;

Fig. 5 (a) is the schematic diagram of composition and structure of the amplitude and phase calibration device of the present invention;

Fig. 5 (b) is the schematic diagram of amplitude and phase error error analysis and compensation method of the present invention;

Fig. 6 is the flow chart of multi-channel receiver integrated synchronization, amplitude and phase calibration method of the present invention;

Fig. 7 is the flow chart of the method for multi-channel receiver only synchronous calibration of the present invention (taking A/D reset as example);

Fig. 8 is a spectral line diagram of the pulse pressure processing result after the calibration device of the present invention is applied to an actual system, which includes a comparison of the signal after calibration, the signal before calibration and the standard signal.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

Under the current technical conditions, in order to improve the range resolution of systems such as synthetic aperture radar, multi-channel synthesis is one of the main technical means currently used. But this method needs to focus on solving two problems, one is the synchronization problem of multi-channel A/D, and the other problem is the amplitude-phase distortion problem of multi-channel.

Aiming at the two main error components of multi-channel received signals—synchronization error and amplitude-phase error, the present invention uses a step-by-step method to decompose the calibration into two effective steps, which correspond to the synchronization error calibration and amplitude-phase error calibration between channels respectively. The processing can complete the analysis and compensation of the two errors; the important thing is that the present invention has strong real-time performance, and you can choose to switch to the calibration mode to perform all calibrations or a certain item of calibration after each system is powered on or during the system’s working process , Automatically compensate the impact of environmental conditions and device characteristics on the receiving channel, which is very suitable for receiving large-bandwidth multi-channel signals.

The first aspect of the present invention is an integrated real-time calibration device for a multi-channel receiver, including a synchronization error calibration network and a synchronization error compensation unit, an amplitude-phase error calibration network and an amplitude-phase error compensation unit, the former is collectively referred to as a synchronization error calibration device, The latter are collectively referred to as amplitude and phase error calibration devices.

The technical solution adopted by the multi-channel receiver integrated real-time calibration device of the present invention is to integrate the synchronization, amplitude and phase calibration network and its error compensation unit inside the multi-channel receiver, and the integrated structure can realize real-time synchronization of the multi-channel receiver at the same time Calibration and amplitude and phase calibration, accurate measurement of error information between multiple channels. In the specific implementation, the step-by-step method is used for multi-channel calibration and compensation. First, the synchronization error calibration is performed. Synchronization is the basis of the entire signal processing. Subsequent amplitude and phase calibration and all data processing depend on the synchronization between multiple A/Ds. . The signal source in the synchronous calibration network outputs a bit frequency signal, the A/D unit collects the data, processes it in the synchronous error compensation unit, and converts the phase information into the time difference information between channels by extracting the phase information, thereby completing the synchronization calibration; the second step , to perform amplitude and phase error calibration, the radar receiver (behind the front end) receives the output signal of the calibration signal source, and enters the data acquisition unit after being processed by the subsequent analog channel, after digitization, it is processed in the amplitude and phase error compensation unit, and extracted by comparison The amplitude and phase information can be obtained, and the amplitude and phase error between channels can be obtained, so as to complete the amplitude and phase calibration.

The synchronous error calibration device of the present invention comprises a synchronous calibration signal source, a power dividing network, a switch matrix and a synchronous error compensation unit in the channel. The synchronization signal source outputs a point-frequency signal with a certain amplitude, and forms N channels of suitable signals after passing through a power dividing network, where N is the number of channels. The switch matrix is used for mode selection, and switches between the synchronous signal and the normal working mode signal, such as the IF signal after down-conversion. Since the synchronous calibration only compensates the synchronization error between the A/D units, it has nothing to do with other devices, so The synchronization network is placed next to the A/D unit, which can also greatly reduce the uncertainty brought by other components to the test calibration.

After the calibration signal is digitally processed by the A/D unit, the synchronization error compensation unit evaluates the initial phase corresponding to the first acquisition data of each channel in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained, and the synchronization calibration is completed after the time difference is compensated.

The amplitude and phase error calibration device of the present invention comprises a phase calibration signal source, a signal conditioning circuit, a phase calibration switch and an amplitude and phase error compensation unit in the channel. The amplitude and phase calibration signal source is used to output a standard signal for calibration. The signal can be considered as an ideal chirp signal after pre-distortion compensation. The signal conditioning circuit is mainly used to adjust the signal amplitude to meet different echo signals. Amplitude and phase calibration between channels in noise ratio state, the amplitude and phase calibration switch is used for mode selection, switching between calibration mode and normal mode. It should be noted that the amplitude and phase calibration network is set in the middle of the common terminal of the multi-channel receiver, that is, between the pre-stage low-noise amplifier and the N-way power divider network, which has two advantages. One is that it can effectively avoid receiving Second, it can also ensure that the contribution of the calibration network to the noise figure of the receiving channel can be ignored. Because the front end of the receiver belongs to the common end of multi-channel reception, this setting is very beneficial and necessary for amplitude and phase calibration.

The amplitude and phase calibration signal enters the data acquisition unit after being processed by the subsequent analog channel, and after being digitally demodulated into a digital baseband signal, the amplitude and phase error compensation unit performs frequency analysis on the baseband signal to obtain the transfer characteristics of the channel and for The error under ideal conditions is to transform the frequency domain of the collected digital signal into S(w), and calculate the frequency domain I(w) of the ideal chirp signal, so that the difference between the actual collected signal and the ideal chirp signal can be obtained , which is the transmission error of the channel Using the error H _n (w) obtained from the analysis to perform amplitude-phase calibration and error compensation processing on the receiving channel, the phase and amplitude errors in the signal channel can be eliminated.

The composition of the integrated real-time calibration device of the present invention is shown in Table 1.

Table 1 Composition of integrated real-time calibration device

The second aspect of the present invention is to provide an integrated real-time calibration and error compensation method for multi-channel receivers, which uses a step-by-step method to compensate two main errors of multiple receiving channels at one time - synchronization error and amplitude-phase error , the main steps are as follows:

Switch to the synchronous calibration mode after the system power-on state is stable;

The synchronous calibration signal source outputs the standard point frequency signal, which is output to the multi-channel A/D unit through the power dividing network and the switch matrix;

After digital processing, the synchronization error compensation unit evaluates the initial phase corresponding to the first acquisition data of each channel in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained. After the time difference is compensated, the synchronization calibration and error compensation are completed.

The system enters the amplitude and phase calibration mode, and closes the synchronous calibration mode at the same time.

The amplitude and phase calibration signal source outputs the ideal chirp signal after pre-distortion compensation, and outputs it to the channelization receiving unit through the signal conditioning unit and the amplitude and phase calibration mode selection circuit;

After the channelized receiving unit undergoes analog processing such as channelized selection, down-conversion, and MGC amplification, the signal is digitized in the A/D unit. At this time, the A/D unit has completed synchronous calibration and error compensation. Contains only amplitude and phase errors;

After being digitally demodulated into a digital baseband signal, frequency analysis is performed on the baseband signal in the channel amplitude and phase error compensation unit to obtain the transfer characteristics of the channel and the error under ideal conditions, that is, to transform the collected digital signal in the frequency domain is S(w), and calculate the frequency domain I(w) of the ideal chirp signal, so that the difference between the collected actual signal and the ideal chirp signal can be obtained, that is, the transmission error of the channel

Using the analyzed error H _n (w) to perform amplitude-phase calibration and error compensation processing on the receiving channel, the phase and amplitude errors in the signal channel can be eliminated, and high-resolution imaging of SAR can be realized.

The entire calibration process is completed, and the system enters the normal working mode.

It should be noted that if you need to calibrate from time to time during the system operation, you can switch to the calibration mode for calibration at any time; you can also perform partial calibration. If the A/D unit needs to be reset during the system operation, you only need to repeat the above Synchronous calibration during the process is enough, or if the analog channel needs to be calibrated when the ambient temperature changes after the system is working, it is only necessary to repeat the amplitude and phase calibration process.

In the following, the present invention will be further described through specific examples of specific applications in synthetic aperture radar.

Fig. 3 is a high-precision real-time calibration device for synthetic aperture radar of the present invention adopted for an ultra-high-resolution synthetic aperture radar receiving system. The device includes a real-time synchronous calibration device and an amplitude-phase calibration device. The center frequency of the radio frequency input by the receiver is 14.8GHz, and the bandwidth is 3.2GHz. It is divided into 8 subbands. After down-conversion, 8 intermediate frequencies are formed, and the frequency range of the intermediate frequencies is 1GHz±0.2GHz.

After the system is powered on, the synchronization error calibration is performed first. The real-time synchronization calibration device includes two parts: the synchronization error calibration network and the synchronization error compensation unit. The real-time synchronization calibration device is shown in Figure 4(a). A synchronization calibration signal source is used to output A standard sinusoidal signal; a power dividing network, used to divide the standard signal into 8 signals; a switch matrix, used to switch between the standard channel and the normal working channel; the synchronous error compensation unit, used for the digitized The synchronous calibration signal is processed for analysis and channel error compensation. Since the synchronization calibration only compensates the synchronization error between A/D units and has nothing to do with other devices, the synchronization error calibration network is placed next to the A/D unit, which can also greatly reduce the uncertainty brought by other components to the test calibration. The schematic diagram of synchronization error analysis and compensation between channels is shown in Fig. 4(b).

In the system, the synchronous error calibration mode is turned on, and the amplitude and phase calibration mode is turned off. At this time, the synchronous signal source outputs a one-point frequency signal, which can be provided by the high-stable frequency synthesizer of the radar system. After being divided into 8 equal parts by the power dividing network, 8 channels of amplitude and phase are formed. The completely consistent standard signal enters the 8-way A/D conversion unit after passing through the switch matrix. After digitization, the channel synchronization error compensation unit evaluates the initial phase corresponding to the first collected data of each channel in the fitted sine wave The corresponding phase difference between the initial phase values of different acquisition channels The reflected time difference Δt is the inter-channel delay time difference of the data acquisition system to be obtained. After compensating for the time difference, the system completes the synchronization calibration and error compensation tasks.

Then perform amplitude-phase calibration and error compensation. The real-time amplitude-phase calibration device is shown in Figure 5(a). A phase calibration signal source is used to output a phase calibration signal. After pre-distortion compensation, the signal can be considered as an ideal Linear frequency modulation signal; a signal conditioning circuit, used to adjust the output amplitude of the calibration signal source; a phase calibration switch, used to switch between the calibration channel and the normal working channel; the amplitude and phase error compensation unit, used for digital The calibration signal is processed for analysis and channel error compensation. The amplitude and phase calibration network is placed in the middle of the receiver, that is, behind the front end of the receiver, which has two advantages. One is that it can effectively avoid the error caused by the front end of the receiver for large bandwidth signals. Second, it can also ensure calibration The contribution of the network to the noise figure of the receive channel reaches a negligible level. Because the front end of the receiver belongs to the common end of multi-channel reception, this setting is very beneficial and necessary for amplitude and phase calibration. The schematic diagram of amplitude and phase error analysis and compensation between channels is shown in Fig. 5(b).

When the amplitude and phase calibration mode is turned on, the amplitude and phase calibration switch is placed in the mode of receiving calibration signals. The broadband signal input for calibration is an ideal chirp signal after pre-distortion compensation. After the modulated signal with lower frequency is converted into a digital baseband I/Q signal through digital demodulation, frequency analysis is performed on the baseband signal in the channel amplitude and phase error compensation unit to obtain the transfer characteristics of the channel and the error under ideal conditions , that is, transform the frequency domain of the collected digital signal into S(w), and calculate the frequency domain I(w) of the ideal chirp signal, so that the difference between the collected actual signal and the ideal chirp signal can be obtained, that is, the channel transmission error Using the analyzed error H _n (w) to perform amplitude and phase calibration and error compensation processing on the receiving channel, the phase and amplitude errors in the signal channel can be eliminated, and the amplitude and phase calibration of multiple receiving channels can be completed. High-resolution imaging lays a good foundation.

After practice and trial verification, the error calibration of the scheme of the present invention is comprehensive. By integrating synchronization and amplitude-phase calibration devices in the multi-channel receiver, the integrated architecture can simultaneously realize synchronous calibration and amplitude-phase calibration of the multi-channel receiver, which has a strong Real-time and flexibility, high degree of automation, without any connection and hardware changes, the calibration process of the system can be completed, easy to operate, fast to use, can accurately compensate the impact of environmental conditions and device characteristics on the receiving channel, and effectively Solve the problem of receiving large bandwidth signals.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. a multichannel receiver amplitude phase error calibrating installation, comprising:

Amplitude phase error calibration network, for generation of the amplitude phase error calibrating signal of described each passage of multichannel receiver of correspondence; And

Amplitude phase error compensating unit, carries out calibration of amplitude and phase and error compensation for the amplitude phase error calibrating signal produced based on described amplitude phase error calibration network to each passage of described multichannel receiver.

2. multichannel receiver amplitude phase error calibrating installation according to claim 1, wherein said amplitude phase error calibration network comprises:

One calibration of amplitude and phase signal source, for exporting the standard signal of calibration;

One signal conditioning circuit, for regulating the amplitude size of the standard signal of described calibration, to adapt to the calibration of amplitude and phase between different echo signal to noise ratio (S/N ratio) state lower channel; And

One calibration of amplitude and phase switch, for model selection, switches between calibration of amplitude and phase pattern and normal mode.

3. multichannel receiver amplitude phase error calibrating installation according to claim 1, wherein said amplitude phase error compensating unit carries out calibration of amplitude and phase and error compensation method to each passage for: gathered digital signal frequency domain is transformed to S (w), and calculate frequency domain I (w) of ideal linearity FM signal, obtain the transmission error of described passage thus utilize the error H analyzing and obtain _nw () carries out calibration of amplitude and phase and error compensation process to described receiving cable.

4. a multichannel receiver real time calibration device, comprising:

Synchronous error calibrating installation, for carrying out real-time synchronization calibration and error compensation to described multichannel receiver; And

Amplitude phase error calibrating installation as described in claims 1 to 3 any one, for carrying out real-time calibration of amplitude and phase and error compensation to described multichannel receiver.

5. multichannel receiver real time calibration device according to claim 4, wherein said synchronous error calibrating installation comprises:

Synchronous error calibration network, for generation of the synchronous error calibrating signal of each passage of the described multichannel receiver of correspondence, comprising:

One synchronous calibration signal source, for exporting synchronous error calibrating signal, wherein said synchronous error calibrating signal is the point-frequency signal with certain amplitude;

One power division network, for being divided into the multiple signals corresponding with port number by described synchronous error calibrating signal; And

One switch matrix, for model selection, completes switching between described synchronous error calibrating signal and normal mode of operation signal; And

Synchronous error compensating unit, for carrying out synchronous calibration and error compensation to each passage of described multichannel receiver, wherein said synchronous error compensating unit to the method that each passage carries out synchronous calibration and error compensation is: evaluate the initial phase that each passage first image data is corresponding in matching sine wave phase differential corresponding between different acquisition passage initial phase value namely the mistiming Δ t of reflection is the Delay Between Channels of the data acquisition system (DAS) that will obtain, and namely completes synchronous calibration and the error compensation of each passage described after compensating this mistiming.

6. multichannel receiver real time calibration device according to claim 4, wherein said amplitude phase error calibrating installation comprises amplitude phase error calibration network and amplitude phase error compensating unit, and described synchronous error calibrating installation comprises synchronous error calibration network and synchronous error compensating unit; And

Described amplitude phase error calibration network is between prime low noise amplifier and N road power division network, before described synchronous error calibration network is positioned at multi-channel A/D unit input end, arrange, after described amplitude phase error compensating unit is arranged on described synchronous error compensating unit after described synchronous error compensating unit next-door neighbour multi-channel A/D unit.

7. multichannel receiver real time calibration and an error compensating method, comprise the steps:

Gauge tap matrix, is switched to required mode of operation by the mode of operation of described hyperchannel SAR receiver; And

When switching to synchronous calibration pattern, calibration of amplitude and phase pattern is closed, and synchronous calibration signal source outputting standard point-frequency signal, is divided into the multiple signals corresponding with port number through power division network, exports to hyperchannel A/D unit via switch matrix; After hyperchannel A/D unit carries out digitized processing to each channel signal, synchronous error compensating unit evaluates each passage first image data initial phase corresponding in matching sine wave phase differential corresponding between different acquisition passage initial phase value namely the mistiming Δ t of reflection is the Delay Between Channels of the data acquisition system (DAS) that will obtain; Namely synchronous calibration and the error compensation of described each passage is completed after compensating this mistiming;

When switching to calibration of amplitude and phase pattern, synchronous calibration pattern is closed, and calibration of amplitude and phase signal source exports through the amplitude phase error calibrating signal of pre-distortion compensated to Digital Channelized Receiving unit; Described Digital Channelized Receiving unit outputs to A/D unit after carrying out the simulation process such as channelizing selection, down coversion, MGC amplification successively to each Ro-vibrational population calibrating signal; Described amplitude phase error calibrating signal is carried out digitized processing by described A/D unit, become after digital baseband signal through digital demodulation again and output to amplitude phase error compensating unit, gathered digital signal frequency domain is transformed to S (w) by described amplitude phase error compensating unit, and calculate frequency domain I (w) of desirable amplitude phase error calibrating signal, obtain the transmission error of described passage thus utilize H _nw () carries out calibration of amplitude and phase and error compensation process to described receiving cable, eliminate phase place, range error in described passage.

8. multichannel receiver real time calibration according to claim 7 and error compensating method, wherein can need to switch to synchronously according to system at any time in system work process and/or calibration of amplitude and phase pattern is calibrated.

9. multichannel receiver real time calibration according to claim 7 and error compensating method, be wherein first switched to synchronous calibration pattern, is switched to calibration of amplitude and phase pattern again after completing.

10. the real time calibration of multichannel receiver and an error compensating method, comprise the steps:

Switch to synchronous calibration pattern;

Synchronous calibration signal source outputting standard point-frequency signal, exports to hyperchannel A/D unit through power division network, switch matrix;

After digitized processing, synchronous error compensating unit evaluates each passage first image data initial phase corresponding in matching sine wave phase differential corresponding between different acquisition passage initial phase value the mistiming Δ t of reflection, is namely the Delay Between Channels of the data acquisition system (DAS) that will obtain, namely completes synchronous calibration and error compensation after compensating this mistiming;

System proceeds to calibration of amplitude and phase pattern, closes synchronous calibration pattern simultaneously;

Calibration of amplitude and phase signal source exports the ideal linearity FM signal through pre-distortion compensated, exports to Digital Channelized Receiving unit through signal condition unit, calibration of amplitude and phase mode selection circuit;

This signal successively after the simulation process such as channelizing selection, down coversion, MGC amplification, completes digitized process at Digital Channelized Receiving unit in A/D unit;

Become after digital baseband signal through digital demodulation, in Ro-vibrational population compensating unit to this baseband signal carry out frequency analysis with obtain this passage transmission characteristic and for error ideally, be about to gathered digital signal frequency domain and be transformed to S (w), and calculate frequency domain I (w) of ideal linearity FM signal, so just can obtain the difference of the actual signal collected and ideal linearity FM signal, namely the transmission error of this passage

Utilize the error H analyzing and obtain _nw () carries out calibration of amplitude and phase and error compensation process to receiving cable;

Whole calibration process completes, and system enters normal mode of operation.