CN117724063B - Mobile unmanned aerial vehicle SAR radar active scaler device - Google Patents
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Abstract
The invention relates to a mobile unmanned aerial vehicle SAR radar active scaler device, which comprises a dual-polarized receiving antenna array, a receiving front end, a broadband receiving and transmitting unit, a radio frequency receiving unit, a radio frequency delay unit, a signal monitoring unit, a frequency synthesis unit, a digital processing unit, a transmitting front end, a dual-polarized transmitting antenna array, an antenna two-dimensional turntable, servo control, a north-fixing instrument, a time calibration system, communication equipment, an environment control system and a power supply system; according to the invention, calibration parameters are provided and updated for the production of quantitative image products of SAR radar by analyzing and processing calibration data, and the working and running performances of each sensor on the unmanned aerial vehicle are monitored and the imaging quality of the SAR system is evaluated by analyzing the performance parameters, the changes thereof and the image quality of the SAR system.
Description
Technical Field
The invention relates to the technical field of electronic engineering, in particular to a movable unmanned aerial vehicle SAR radar active scaler device.
Background
Unmanned aerial vehicles play an increasingly important role in battlefield reconnaissance, interference suppression, navigation, and the like. The unmanned aerial vehicle is provided with the synthetic aperture radar, namely the SAR radar can scan and image various targets all the time, and the effect of the SAR radar in battlefield electronic countermeasure can not be replaced. Strict calibration approval must be performed before the idle SAR radar equipment, otherwise the imaging effect will be compromised. The SAR radar calibration method is divided into passive calibration and active calibration. Passive scaling is a physical scaling that provides various characteristics of the radar reception verification imaging signal at a standard RCS (equivalent reflection surface), and scalar scaling is performed on the radar reception signal. The active calibration is essentially analog signal calibration, and the response form is adopted to simulate the signal characteristics of various RCS, so as to verify the performance of the airborne SAR radar receiving imaging system. When the active scaler receives the SAR radar irradiation signals, equivalent reflection signals of different parameters can be simulated according to requirements and sent to the SAR radar by the transmitting device, so that the effect of verifying the radar performance index is achieved. The active scaler is not limited by the conditions of terrain, climate and the like, and is the supplement and enhancement of the passive scaler.
Disclosure of Invention
In order to solve the problems, the invention aims to provide a mobile unmanned aerial vehicle SAR radar active scaler device which can be used for carrying out high-precision radiation scaling on unmanned aerial vehicle SAR systems with different wave bands, has the functions of measuring SAR antenna patterns and monitoring SAR pulse signals, and simultaneously simulates a ground target by receiving and transmitting synthetic aperture radar signals, and obtains a larger equivalent reflection surface RCS by improving the gain of a receiving and transmitting system, thereby improving the signal-to-noise ratio of external scaling signals and reducing the requirements on external scaling sites. The method can be used for scientific tasks such as relative radiation calibration, absolute radiation calibration, radiation quality evaluation and the like of SAR unmanned aerial vehicles in different wave bands.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the mobile unmanned aerial vehicle SAR radar active scaler device is characterized by comprising a dual-polarized receiving antenna array, a receiving front end, a broadband receiving and transmitting unit, a video receiving unit, a radio frequency delay unit, a signal monitoring unit, a frequency synthesis unit, a digital processing unit, a transmitting front end, a dual-polarized transmitting antenna array, an antenna two-dimensional turntable, a servo control unit, a north-oriented instrument, a time calibration system, communication equipment, an environment control system and a power supply system; wherein,
The dual-polarized receiving antenna array is used for receiving video signals, sending the video signals to the receiving front-end broadband receiving and transmitting unit and the video receiving unit, carrying out logarithmic detection and amplification on radio frequency signals of each wave band to obtain radio frequency signals, carrying out AD sampling on the radio frequency signals, and carrying out adjustable delay processing and compensation amplification on the received radio frequency signals through the radio frequency delay unit; then digital signal processing is carried out on the radio frequency ADC, the broadband intermediate frequency ADC and the broadband intermediate frequency DAC by the digital processing unit, and then the signals are sequentially transmitted out by the transmitting front end and the dual-polarized transmitting antenna array;
the frequency synthesizer unit is used for generating a calibration signal, a clock signal and a local vibration source required by the system.
Based on the mobile unmanned aerial vehicle SAR radar active scaler device, the application also provides an operating mode thereof, wherein the operating mode comprises the following steps: self-checking mode, standby mode, internal calibration mode, receiving mode and transmitting mode 5 modes; wherein,
The self-checking mode is as follows: starting the machine before executing the task, preheating, and performing self-checking after the equipment enters a stable state; after the self-checking is normal, receiving a task instruction and working parameters issued by a command control center, and entering a task execution state;
The standby mode is: under the condition of no task, except necessary communication and the safety protection equipment is in a power-on working state, the power supply of other equipment is turned off until the next task is started;
The internal calibration mode includes: an intra-receive calibration mode and an intra-transmit calibration mode, wherein,
The receiving internal calibration mode is that the frequency synthesizer unit generates a point frequency continuous wave calibration signal with corresponding frequency according to the current working frequency band, the point frequency continuous wave calibration signal is fed into a video receiving branch through switching of a switch, and the signal after detection is subjected to A/D conversion and then is measured to obtain the signal amplitude of a calibration channel;
The internal transmitting calibration mode is that a calibration source generates a point frequency continuous wave calibration signal with corresponding frequency according to the current working frequency band, the point frequency continuous wave calibration signal is fed into a radio frequency transmitting branch through switching of a switch, and the signal after detection is subjected to A/D conversion and then is accurately measured to obtain the signal amplitude of a calibration channel;
The receiving mode is as follows: the device completes the functions of SAR emission pattern measurement and SAR emission signal acquisition and analysis;
The forwarding mode includes: a direct delay forwarding mode, a digital delay forwarding mode, and an active delay forwarding mode; the forwarding mode is used for realizing the forwarding of the radio frequency signals by the scaler device.
Further, the intra-reception calibration mode specifically includes:
The calibration signal is sent to the receiving front end through switch switching, and is coupled to the receiving link for processing, and then is fed into the video receiving branch again, and the signal amplitude of the receiving channel is obtained after the signal is detected and is subjected to A/D (analog-to-digital) measurement;
Acquiring and processing the calibration signal for multiple times in a set temperature range environment to obtain a receiving channel signal amplitude error control code, and adjusting the attenuation of the numerical control attenuator to ensure that the amplitude of the receiving channel signal is the same as the amplitude in the set temperature range under different temperature conditions, so that the gain of the receiving channel is kept constant, and the receiving channel amplitude calibration function is realized;
The transmitting internal calibration mode is the same as the receiving internal calibration mode and is used for realizing the transmitting channel amplitude calibration function.
Further, the receiving mode specifically includes: the radio frequency signals received by the dual-polarized receiving antenna enter a broadband receiving and transmitting unit after being subjected to coupling treatment by a receiving front end, the broadband receiving and transmitting unit is divided into 2 paths, one path enters the radio frequency receiving unit to finish the pulse envelope extraction and measurement of the radio frequency signals, and the pulse envelope extraction and measurement are used for antenna pattern measurement; the other path enters a down-conversion receiving processing channel, and the pulse of each received radio frequency signal is collected and stored by utilizing the repetition frequency tracking.
Furthermore, in the receiving mode, the amplitude of the collected video pulse signal sample is measured, and the amplitude of the pulse envelope obtained by radio frequency detection is compared and analyzed, so that the accuracy of the directional diagram calibration is further improved.
Further, the direct delay forwarding mode specifically includes:
and in the direct delay forwarding mode, the received radio frequency signal is subjected to delay forwarding with a set step length by using a radio frequency delay line, wherein the delay quantity is set to be 0 [ mu ] s, 0.5 [ mu ] s, 1 [ mu ] s or 2 [ mu ] s step length according to the requirement.
Further, the digital delay forwarding mode specifically includes: based on the digital radio frequency storage DRFM technology and the repetition frequency tracking technology, the method is realized by utilizing a broadband receiving and transmitting unit and a digital processing unit to extract samples, perform repetition frequency tracking and perform delay forwarding on pulses of received radio frequency signals.
Further, the active delay forwarding mode specifically includes:
In the active delay forwarding mode, constructing an outgoing frequency signal for delay forwarding, directly generating a preset broadband radio frequency signal waveform by using a calibration source, and transmitting under the guidance of a repetition frequency tracking wave gate; or the digital processing unit is used for generating the waveform of the broadband radio frequency signal and transmitting the waveform under the guidance of the repetition frequency tracking wave gate.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:
The mobile unmanned aerial vehicle SAR radar active scaler device provided by the invention is important equipment for SAR radar performance calibration, has own innovation and development with a common SAR radar active scaler, and is characterized in that:
1. Broadband and ductility thereof. The invention covers P, L, X, KU frequency bands of SAR radar, and can be extended to other frequency bands on the basis, thus having certain advancement and practicability.
2. And (3) carrying out the process. The portable integrated device is provided with a self-contained power supply, autonomous wired and wireless communication, beidou time service, positioning, convenient unfolding and the like, has strong terrain adaptability, and provides convenience for field users.
3. Remote control and unattended operation. When a single person executes a task, the invention can use the wired and wireless radars to carry out remote operation after automatic unfolding, and all functions can carry out remote motion, thus really realizing unattended operation.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed in the embodiments will be briefly described below, and it will be apparent that the drawings in the following description are only some embodiments of the present invention, and it is also possible for one of ordinary skill in the art to make the following drawings without inventive effort
Other figures are obtained from these figures.
FIG. 1 is a schematic structural diagram of one embodiment of a mobile unmanned airborne SAR active scaler apparatus provided by the present invention;
Fig. 2 is a schematic structural diagram of a second embodiment of a mobile unmanned airborne SAR radar active scaler device provided by the present invention;
FIG. 3 is a schematic diagram of the overall deployment of a mobile unmanned airborne SAR active scaler apparatus provided by the present subject matter;
FIG. 4 is a schematic diagram of the system components of the mobile unmanned airborne SAR active scaler apparatus provided by the present invention;
FIG. 5 is a block diagram of a mobile unmanned airborne SAR active scaler apparatus provided by the present invention;
FIG. 6 is a block diagram of a receive mode signal flow provided by an embodiment of the present invention;
FIG. 7 is a block diagram of a direct delay forwarding mode signal flow provided by an embodiment of the present invention;
FIG. 8 is a block diagram of a digital delay forwarding mode signal provided by an embodiment of the present invention;
Fig. 9 is a block diagram of a signal flow for constructing a signal delay forwarding mode according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to the drawings and detailed description, wherein the described embodiments are provided as examples of the invention, and other embodiments, which are obtained by persons skilled in the art without making any inventive work, are within the scope of the invention.
Example 1
The embodiment is a mobile unmanned aerial vehicle SAR radar active scaler device, as shown in figure 5. The device comprises a dual-polarized receiving antenna array, a receiving front end, a broadband receiving and transmitting unit, a video receiving unit, a radio frequency delay unit, a signal monitoring unit, a frequency synthesis unit, a digital processing unit, a transmitting front end, a dual-polarized transmitting antenna array, an antenna two-dimensional turntable, a servo control north-fixing instrument, a time calibration system, a communication device, an environment control system and a power supply system; wherein,
The dual-polarized receiving antenna array is used for receiving video signals, sending the video signals to the receiving front-end broadband receiving and transmitting unit, carrying out logarithmic detection and amplification on the received radio frequency signals in each wave band by the video receiving unit to obtain video signals, carrying out AD sampling on the radio frequency signals, and then carrying out adjustable delay processing and compensation amplification on the received radio frequency signals by the radio frequency delay unit; then digital signal processing is carried out on the radio frequency ADC, the broadband intermediate frequency ADC and the broadband intermediate frequency DAC by the digital processing unit, and then the signals are sequentially transmitted out by the transmitting front end and the dual-polarized transmitting antenna array; the frequency synthesizer unit is used for generating a calibration signal, a clock signal and a local vibration source required by the system.
As shown in fig. 1 and 2, the technical scheme of the application is applied to products, and can realize various schemes such as a P/L band SAR active scaler, an X/KU band SAR active scaler and the like, and the mobile SAR active scaler adopts a wheel type box structure, so that the mobile SAR active scaler can be conveniently transported and unfolded, and is suitable for remote control of any terrain deployment network or numerical control radio stations.
The SAR radar active scaler has the functions of measuring the external field antenna pattern of the unmanned aerial vehicle SAR radar system, monitoring the state of the SAR system, simulating targets with different radar scattering cross sections and the like, and meets the functional requirements of measuring the calibration constant, the double-pass antenna pattern and the image quality index of the P, L, ku, X-band target unmanned aerial vehicle SAR radar system. The deployment is shown in fig. 3. A group of accurately calibrated scalers are distributed in a certain area of an SAR radar swath along the distance direction, unmanned aerial vehicle SAR radar pulse signals are received, quantized through A/D sampling and stored, and the pulse sampling time is recorded at the same time; the received SAR radar pulse signals are forwarded, and accurate power control is carried out on the forwarding, so that point target echoes of different radar scattering cross sections can be simulated, and SAR radar receiving performance parameters are calibrated.
The specific composition of the scheme of the application is described in detail below by combining a mobile unmanned aerial vehicle SAR radar active scaler device with P/L wave bands and X/KU wave bands:
the active scaler of the X/KU wave band radar has basically the same composition principle block diagram as the P/L wave band, but different antenna structures. The functions of each component are as follows:
Dual polarized receiving antenna: and (3) performing polarization-variable receiving of the P/L, X/ku band radio frequency signals, and adopting a horizontal and vertical dual-polarized horn antenna.
Receiving front end: to improve performance, P, L, X, ku receives signals separately, performs band selection by switching on and off, and may reserve other band expansion functions.
Broadband receiving and transmitting unit: and finishing the compensation amplification, power division and down-conversion of the received radio frequency signals in each wave band, and the up-conversion excitation amplification of the DAC output intermediate frequency signals.
A radio frequency receiving unit: carrying out logarithmic detection and amplification on the received radio frequency signals of each wave band, and sending AD (analog-digital) samples; by switching the switch, an external signal, a calibration signal and a transmit coupling signal can be received.
A radio frequency delay unit: performing adjustable delay processing and compensation amplification on the received radio frequency signals of each wave band; by switching the switch, an external signal and a calibration signal can be received.
Frequency synthesis unit: and generating a calibration signal, a clock signal and a local oscillator required by the system. The calibration source signal can output point frequency continuous wave and pulse linear frequency modulation signals, and respectively meets the functions of in-system calibration and LFM pulse signal delay forwarding; the clock signals mainly comprise a 20MHz reference clock, a 50MHz video sampling clock, a 2400MHz broadband sampling clock and the like; the local oscillation signal comprises a local oscillation and two local oscillation.
A signal monitoring unit: and carrying out power division and detection on the received radio frequency signal, the transmitted coupling signal, the output signal of the calibration source and the like, and respectively sending the signals to a spectrometer and an oscilloscope through a signal monitoring interface.
A digital processing unit: the functions of video ADC, broadband intermediate frequency DAC, digital signal processing, data storage and the like are completed, and an external communication interface and an internal monitoring interface are provided.
Emission front end: high-linearity power amplification of P, L, ku and X wave band transmitting signals are respectively finished and sent to the antenna. In order to improve the performance, P, L, ku and the X wave bands are realized separately, the wave band selection is carried out through switch switching, and the S wave band expansion function is reserved.
Dual polarized transmitting antenna: and completing the variable polarization transmission of the radio frequency signals of each wave band, and adopting a horizontal dual-polarized horn antenna and a vertical dual-polarized horn antenna which are the same as those used for receiving.
Two-dimensional turntable/servo control: the high-precision program tracking function of the antenna to the unmanned aerial vehicle is completed, and the antenna is controlled to always point to the target unmanned aerial vehicle in the working process.
North-fixing instrument: the fiber optic gyroscope north-fixing instrument with vibration resistance is selected, and the high-precision north-fixing function is completed during equipment installation.
GPS/Beidou: and receiving the synchronous pulse to complete the time synchronization function and determine the accurate time of receiving the data.
Communication apparatus: and stable data communication between the deployment position of the scaler and the master control center is realized by adopting a communication mode mainly comprising point-to-point wireless data transmission communication.
And the environmental control system: the main components of the scaler are ensured to work stably under the constant temperature condition, and the reliability and the scaling measurement precision of the system are improved.
And (3) a power supply system: the system provides reliable power supply guarantee by adopting a combined power supply mode of combining commercial power and a storage battery, and simultaneously provides various voltage exchanges required by work for each unit inside the system.
The main function implementation mode is as follows:
1. polarization scaling
The multiband SAR active scaler mainly has two modes of operation: the forwarding mode and the receiving mode adopt a double-antenna design, namely one antenna receiving and one antenna transmitting. The scaler has two functions of radiation scaling and polarization scaling, and polarization scaling is two types of horizontal and vertical, so that the antenna is in a horizontal/vertical dual-polarized horn antenna form, the receiving antenna is the same as the transmitting antenna, and the two polarization modes are switched through the polarization switch in the receiving front end and the transmitting front end.
2. North-fixing and levelness-calibrating
North fixing: the north-oriented instrument is arranged, equipment north orientation is carried out by utilizing the north-oriented instrument, the north-oriented data are transmitted to the servo control computer, and the servo control computer carries out antenna orientation adjustment according to the north-oriented data.
3. Levelness calibration: two vertical level gauges are placed on the antenna base, and nuts at the bottom of the case are adjusted during installation until the water bubble is positioned in the middle of the level gauges.
4. Direction diagram measurement
The active scaler can directly measure the SAR antenna emission pattern in the receiving mode, the method is that the active scaler with accurate calibration is placed in a certain area of a coverage mapping zone, SAR emission signals are received, pulse amplitude information is obtained after logarithmic detection and A/D sampling quantization and stored, meanwhile, pulse sampling time is recorded, and the recorded data is further processed to obtain corresponding azimuth antenna pattern.
The active scaler has a position tracking function with the scaled SAR radar. If the sealer receive antenna is always aligned with the SAR antenna, then the radiated power of the SAR to the ground sealer receive antenna aperture can be determined by: pt=pr/GtGr, where Pt is the radiated power of SAR to the ground receiver antenna port; pr is the power measured by the receiver digital received signal; gt is the gain of the antenna feed; gr is the gain of the receive channel. After the data acquisition is finished, the computer is used for reading the temporarily stored measurement power, the data calculation is carried out according to the above formula, the radiation power of the receiving antenna port can be obtained, and the SAR azimuth direction diagram can be obtained through the data calculation and analysis.
5. Calibration accuracy
The system calibration precision (including the measurement precision of the received power, the precision of the radar cross section area and the like) is mainly ensured by calibrating a receiving channel and a transmitting channel and accurately calibrating the gain of a received signal and the gain of a forwarded signal. The channel calibration comprises two methods, namely an inner calibration method and an outer calibration method, wherein the inner calibration method is mainly used as an auxiliary calibration method, and the outer calibration method and the inner calibration method are combined to improve the calibration accuracy and the confidence coefficient.
The active scaler can be deployed within a range of tens of kilometers from the control center, and besides optical fiber arrangement, point-to-point wireless data transmission communication is additionally arranged, and the optical fiber and the wireless network are used together.
Example 2
The embodiment is an operation mode of the mobile unmanned aerial vehicle SAR radar active scaler device, where the operation mode of the system of the device includes: the system working mode is divided into 5 modes of self-checking mode, standby mode, internal calibration mode, receiving mode and forwarding mode.
1. Self-checking mode: starting the active scaler about 30 minutes before executing tasks, and performing self-checking after the equipment enters a stable state after preheating; and after the self-checking is normal, receiving a task instruction and working parameters issued by the control center, and entering a task execution state.
2. Standby mode: under the condition of no task, other equipment power supplies are turned off except necessary communication and safety protection equipment is in a power-on state until the next task starts.
3. Internal calibration mode: the internal calibration mode is divided into two types, namely, a receiving internal calibration and a transmitting internal calibration.
① In-receive calibration: the receive channel gain will vary with changes in ambient temperature, requiring calibration to keep the receive channel gain unchanged. Under normal working conditions, the system adopts an internal calibration scheme, and the basic principle is that the amplitude stability of the constant temperature logarithmic detector is utilized to accurately acquire the signal amplitude, and then the attenuation of a numerical control attenuator (MGC) is accurately adjusted to calibrate the gain of a receiving channel so as to keep the gain constant.
The internal receiving calibration mode is to generate a point frequency continuous wave calibration signal with corresponding frequency according to the current working frequency band (such as X-band), feed the point frequency continuous wave calibration signal into a video receiving branch (corresponding to a detector SP3T input port # 1) through switch switching (corresponding to a calibration source SP4T output port 1), and obtain a calibration channel signal amplitude A1 through accurate measurement after A/D conversion of the detected signal.
The calibration signal is sent to the receiving front end through switch switching (corresponding to the output port #2 of the calibration source SP 4T), and after being processed through the receiving link, the calibration signal is re-fed into the video receiving branch (corresponding to the input port #2 of the detector SP 3T), and the amplitude A2 of the receiving channel signal can be obtained through accurate measurement after the signal is detected by A/D.
Under the condition of constant temperature, A2-A1 are fixed values. However, in a wide temperature environment (the working temperature of the scaler is required to be minus 20 ℃ to plus 50 ℃), the gain of an LNA (low noise amplifier) in a receiving link, the insertion loss of a numerical control attenuator and the like are all changed due to the change of the external temperature, when calibration is performed under different temperature conditions, both A1 and A2 are changed (respectively marked as A1 'and A2'), and the values of A2 'to A1' are also changed correspondingly and are different from the values of A2 to A1. The amplitude error control code is obtained through subsequent signal acquisition and processing, and the attenuation quantity of the numerical control attenuator is adjusted to enable the A2 'to A1' value to be the same as the A2 to A1 value, so that the gain of the whole receiving channel can be kept constant, and the amplitude calibration function of the receiving channel is realized.
Under the constant temperature condition, the logarithmic detector has high precision and stability, and the amplitude information of the extracted received signal can meet the index requirement of a calibration system. Therefore, it is necessary to ensure constant temperature operation of the logarithmic detector, and even if the system is operated under wide temperature conditions, the change in the gain of the receiving channel can be calibrated by using its constant index as a reference.
In performing in-receive calibration, care needs to be taken to ensure that the power of the calibration signal is always within the dynamic range of the receiver and cannot saturate the LNA. And in particular, based on a receive link gain allocation calculation.
② Intra-transmit calibration mode: as with the intra-receive calibration mode, the transmit channel gain also varies with ambient temperature, requiring calibration such that the transmit channel gain remains unchanged.
The transmit channel gain inner calibration principle is the same as for reception.
Firstly, a continuous wave signal generated by a calibration source is sent to a video receiving link to finish logarithmic detection, AD acquisition and amplitude measurement of the calibration signal, and the amplitude A1 of the calibration signal is obtained.
And secondly, feeding the calibration signal into a radio frequency delay link and a transmitting front end, obtaining a transmitting coupling signal by using a coupler at an output port of the transmitting front end, feeding the transmitting coupling signal into a radio frequency receiving unit, and performing detection, AD acquisition and amplitude measurement on the transmitting coupling signal to obtain an amplitude A2 of the transmitting coupling signal.
Finally, by adopting a method similar to the receiving calibration, the attenuation of the numerical control attenuator in the delay unit is regulated to ensure that the values A2 'to A1' measured under different temperature conditions are the same as the values A2 to A1 measured under constant temperature conditions, thereby ensuring the constant gain of the transmitting link.
4. Reception mode:
In the receiving mode, the scaler mainly completes SAR emission pattern measurement and SAR emission signal acquisition and analysis functions, and the flow is shown in figure 6. After the SAR signal received by the antenna is subjected to post-treatment by the receiving front end, the SAR signal is divided into 2 paths of independent treatment, wherein 1 path of SAR signal enters a radio frequency receiving unit to finish pulse envelope extraction and measurement, and the SAR signal is used for antenna pattern measurement; and the other 1 path enters a down-conversion receiving processing channel, and each SAR pulse received is collected and stored by utilizing a repetition frequency tracking technology and then is further processed and analyzed. In addition, the amplitude of the collected pulse sample can be measured, and the amplitude of the pulse envelope obtained by video detection can be compared and analyzed, so that the accuracy of the directional diagram calibration is further improved.
5. Forwarding mode: the system comprises a direct delay forwarding mode, a digital delay forwarding mode and an active delay forwarding mode.
① Direct delay forwarding mode:
In the direct delay forwarding mode, the scaler receives the SAR signal, and performs delay forwarding of a specific step length on the signal by using a radio frequency delay line, and the flow is shown in fig. 7. This is the primary mode of SAR active scaling. The delay amount can be selected to be 0 [ mu ] s, 0.5 [ mu ] s, 1 [ mu ] s, 2 [ mu ] s and other step sizes according to requirements.
② Digital delay forwarding mode:
the digital delay forwarding mode is implemented based on a digital radio frequency storage (DRFM) technology and a repetition frequency tracking technology, and the flow is shown in fig. 8. And carrying out sample extraction, repetition frequency tracking and delay forwarding on the received SAR pulse by utilizing a broadband transceiving and digital processing channel. Compared with a direct delay forwarding mode, the method has the advantages that the delay amount is arbitrarily adjustable, the delay control precision depends on the repetition frequency tracking precision, the precision is different from an analog delay line, the current technical level can generally reach the order of magnitude of several ns, the low-resolution SAR calibration requirement can be met, and the method can be used as a supplement for analog radio frequency delay forwarding.
③ Constructing a signal delay forwarding mode
The construction of the signal delay forwarding mode differs from direct delay forwarding and digital delay forwarding in that the forwarded signal is internally generated, rather than receiving the SAR signal. Two specific implementation methods are provided, namely, a calibration source is utilized to directly generate broadband SAR waveforms, the broadband SAR waveforms are transmitted under the guidance of repetition frequency tracking, and the signal flow is shown in fig. 9 (red part); and secondly, a digital processing unit is utilized to generate broadband SAR waveforms, and the broadband SAR waveforms are transmitted under the guidance of a heavy frequency tracking wave gate. In the mode, signals with opposite frequency modulation slope, frequency modulation bandwidth and time width which are the same as those of SAR transmitting signals can be transmitted, meanwhile, strict synchronization with SAR working time sequence is kept, pulse compression processing is carried out on echo data by utilizing an opposite distance matching function at an SAR signal processing end, so that suppression of real SAR echo is realized, and imaging processing is carried out on point target echo transmitted by a scaler.
It will be apparent to those skilled in the art that the above-described method steps of the present invention may be implemented using a general purpose computing device, and that the means used is not limited to those provided by the present invention, but that other related means may also implement the steps of the present invention. Although the embodiments of the present invention have been described above for the purpose of illustrating the technical aspects and the main features of the present invention, it is not intended to limit the present invention, and further alterations and modifications may be made to these embodiments or equivalents of some of the technical features thereof, once the basic inventive concepts are known to those skilled in the art. Any changes or substitutions that would be easily contemplated by one of ordinary skill in the art within the scope of the present disclosure are within the principles of the present invention.
Claims (7)
1. The mobile unmanned aerial vehicle SAR radar active scaler device is characterized by comprising a dual-polarized receiving antenna array, a receiving front end, a broadband receiving and transmitting unit, a video receiving unit, a radio frequency delay unit, a signal monitoring unit, a frequency synthesis unit, a digital processing unit, a transmitting front end, a dual-polarized transmitting antenna array, an antenna two-dimensional turntable, a servo control unit, a north-oriented instrument, a time calibration system, communication equipment, an environment control system and a power supply system; wherein,
The dual-polarized receiving antenna array is used for receiving video signals, sending the video signals to the receiving front-end broadband receiving and transmitting unit and the video receiving unit, carrying out logarithmic detection and amplification on radio frequency signals of each wave band to obtain radio frequency signals, carrying out AD sampling on the radio frequency signals, and carrying out adjustable delay processing and compensation amplification on the received radio frequency signals through the radio frequency delay unit; then digital signal processing is carried out on the radio frequency ADC, the broadband intermediate frequency ADC and the broadband intermediate frequency DAC by the digital processing unit, and then the signals are sequentially transmitted out by the transmitting front end and the dual-polarized transmitting antenna array;
the frequency synthesizer unit is used for generating a calibration signal, a clock signal and a local vibration source required by the system;
The operating modes of the device include an internal calibration mode, the internal calibration mode including: an intra-receive calibration mode and an intra-transmit calibration mode, wherein,
The receiving internal calibration mode is that the frequency synthesizer unit generates a point frequency continuous wave calibration signal with corresponding frequency according to the current working frequency band, the point frequency continuous wave calibration signal is fed into a video receiving branch through switching of a switch, and the signal after detection is subjected to A/D conversion and then is measured to obtain a calibration channel signal amplitude A1;
Transmitting a calibration signal to a receiving front end through switch switching, obtaining a receiving coupling signal by using a coupler of an input port of the receiving front end, processing the receiving coupling signal through a receiving link after coupling, re-feeding the receiving signal into a video receiving branch, and obtaining a receiving channel signal amplitude A2 through accurate measurement after detecting the signal through A/D;
When calibration is carried out under different temperature conditions, A1 and A2 are changed into A1', A2'; the amplitude error control code is obtained through subsequent signal acquisition and processing, and the amplitude calibration function of the receiving channel is realized by adjusting the attenuation quantity of a numerical control attenuator in the radio frequency delay unit to ensure that the values A2 'to A1' are the same as the values A2 to A1;
The internal transmitting calibration mode is that a calibration source generates a point frequency continuous wave calibration signal with corresponding frequency according to the current working frequency band, the point frequency continuous wave calibration signal is fed into a radio frequency transmitting branch through switching of a switch, and the signal after detection is subjected to A/D conversion and then is accurately measured to obtain a calibration channel signal amplitude M1;
Secondly, feeding a calibration signal into a radio frequency delay link and a transmitting front end, obtaining a transmitting coupling signal by using a coupler at an output port of the transmitting front end, feeding the transmitting coupling signal into a radio frequency receiving unit, and performing detection, AD acquisition and amplitude measurement on the transmitting coupling signal to obtain an amplitude M2 of the transmitting coupling signal;
Finally, when calibration is carried out under different temperature conditions, the M2 'to M1' values measured under different temperature conditions are the same as the M2 to M1 values measured under constant temperature conditions by adjusting the attenuation amount of the numerical control attenuator in the radio frequency delay unit, so that the amplitude calibration function of the transmitting channel is realized.
2. A mobile unmanned airborne SAR radar active sealer apparatus according to claim 1, wherein said modes of operation comprise: self-checking mode, standby mode, internal calibration mode, receiving mode and transmitting mode 5 modes; wherein,
The self-checking mode is as follows: starting the machine before executing the task, preheating, and performing self-checking after the equipment enters a stable state; after the self-checking is normal, receiving a task instruction and working parameters issued by a command control center, and entering a task execution state;
The standby mode is: under the condition of no task, except necessary communication and the safety protection equipment is in a power-on working state, the power supply of other equipment is turned off until the next task is started;
The receiving mode is as follows: the device completes the functions of SAR emission pattern measurement and SAR emission signal acquisition and analysis;
The forwarding mode includes: a direct delay forwarding mode, a digital delay forwarding mode, and an active delay forwarding mode; the forwarding mode is used for realizing the forwarding of the radio frequency signals by the scaler device.
3. A mobile unmanned airborne SAR radar active scaler device according to claim 2, wherein said reception mode is specifically: the radio frequency signals received by the dual-polarized receiving antenna enter a broadband receiving and transmitting unit after being subjected to coupling treatment by a receiving front end, the broadband receiving and transmitting unit is divided into 2 paths, one path enters the radio frequency receiving unit to finish the pulse envelope extraction and measurement of the radio frequency signals, and the pulse envelope extraction and measurement are used for antenna pattern measurement; the other path enters a down-conversion receiving processing channel, and the pulse of each received radio frequency signal is collected and stored by utilizing the repetition frequency tracking.
4. A mobile unmanned airborne SAR radar active scaler device according to claim 3, wherein in the receiving mode, the accuracy of the pattern scaling is further improved by comparing the amplitude measurement of the acquired video pulse signal sample with the pulse envelope amplitude obtained by radio frequency detection.
5. A mobile unmanned airborne SAR radar active scaler apparatus according to claim 2, wherein said direct delay forwarding mode is specifically:
and in the direct delay forwarding mode, the received radio frequency signal is subjected to delay forwarding with a set step length by using a radio frequency delay line, wherein the delay quantity is set to be 0 [ mu ] s, 0.5 [ mu ] s, 1 [ mu ] s or 2 [ mu ] s step length according to the requirement.
6. A mobile unmanned airborne SAR radar active scaler device according to claim 2, wherein said digital delay forwarding mode is specifically: based on the digital radio frequency storage DRFM technology and the repetition frequency tracking technology, the method is realized by utilizing a broadband receiving and transmitting unit and a digital processing unit to extract samples, perform repetition frequency tracking and perform delay forwarding on pulses of received radio frequency signals.
7. A mobile unmanned airborne SAR radar active scaler apparatus according to claim 2, wherein said active delay forwarding mode is specifically:
In the active delay forwarding mode, constructing an outgoing frequency signal for delay forwarding, directly generating a preset broadband radio frequency signal waveform by using a calibration source, and transmitting under the guidance of a repetition frequency tracking wave gate; or the digital processing unit is used for generating the waveform of the broadband radio frequency signal and transmitting the waveform under the guidance of the repetition frequency tracking wave gate.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001091650A (en) * | 1999-09-20 | 2001-04-06 | Mitsubishi Electric Corp | Active ground control point device for synthetic aperture radar image precise geometrical correction |
| CN101082666A (en) * | 2006-06-02 | 2007-12-05 | 中国科学院电子学研究所 | Method for realizing high precision modulating radar pulse signal based on automatic test system |
| CN103454620A (en) * | 2013-09-23 | 2013-12-18 | 中国科学院空间科学与应用研究中心 | Tracking-type active radar calibrator based on transmitted signal reestablishing system |
| CN109103596A (en) * | 2018-08-17 | 2018-12-28 | 中国科学院电子学研究所 | Dual polarization high-isolation antenna and satellite-borne synthetic aperture radar source scaler |
| CN109884631A (en) * | 2019-02-21 | 2019-06-14 | 中国科学院电子学研究所 | The method and system of satellite-borne synthetic aperture radar internal calibration data processing |
| CN111459086A (en) * | 2020-03-30 | 2020-07-28 | 深圳市科楠科技开发有限公司 | System and method for realizing scaler control and data processing |
| CN116973853A (en) * | 2023-06-07 | 2023-10-31 | 中国人民解放军军事科学院系统工程研究院 | Broadband active scaler under shipborne complex electromagnetic environment and scaling method thereof |
-
2024
- 2024-01-25 CN CN202410104597.8A patent/CN117724063B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001091650A (en) * | 1999-09-20 | 2001-04-06 | Mitsubishi Electric Corp | Active ground control point device for synthetic aperture radar image precise geometrical correction |
| CN101082666A (en) * | 2006-06-02 | 2007-12-05 | 中国科学院电子学研究所 | Method for realizing high precision modulating radar pulse signal based on automatic test system |
| CN103454620A (en) * | 2013-09-23 | 2013-12-18 | 中国科学院空间科学与应用研究中心 | Tracking-type active radar calibrator based on transmitted signal reestablishing system |
| CN109103596A (en) * | 2018-08-17 | 2018-12-28 | 中国科学院电子学研究所 | Dual polarization high-isolation antenna and satellite-borne synthetic aperture radar source scaler |
| CN109884631A (en) * | 2019-02-21 | 2019-06-14 | 中国科学院电子学研究所 | The method and system of satellite-borne synthetic aperture radar internal calibration data processing |
| CN111459086A (en) * | 2020-03-30 | 2020-07-28 | 深圳市科楠科技开发有限公司 | System and method for realizing scaler control and data processing |
| CN116973853A (en) * | 2023-06-07 | 2023-10-31 | 中国人民解放军军事科学院系统工程研究院 | Broadband active scaler under shipborne complex electromagnetic environment and scaling method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 机载超高分辨率SAR内定标技术研究;贺彩琴;《现代雷达》;20160229;第38卷(第2期);15-18 * |
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