CN116973853A - Broadband active scaler under shipborne complex electromagnetic environment and scaling method thereof - Google Patents
Broadband active scaler under shipborne complex electromagnetic environment and scaling method thereof Download PDFInfo
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4052—Means for monitoring or calibrating by simulation of echoes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4052—Means for monitoring or calibrating by simulation of echoes
- G01S7/406—Means for monitoring or calibrating by simulation of echoes using internally generated reference signals, e.g. via delay line, via RF or IF signal injection or via integrated reference reflector or transponder
- G01S7/4065—Means for monitoring or calibrating by simulation of echoes using internally generated reference signals, e.g. via delay line, via RF or IF signal injection or via integrated reference reflector or transponder involving a delay line
Abstract
The application provides a broadband active scaler under a shipborne complex electromagnetic environment, which comprises a micro-control processor, an electro-optic modulator, a WIFI module, a broadband antenna and corresponding radio frequency components. The scaler is used for carrying out delay simulation on the microwave signals received through the antenna, and after delay processing is finished, the delayed microwave signals are transmitted back through the transmitting antenna; the scheme can work in multiple frequency bands and has the capacity of simultaneous calibration in multiple frequency bands. The application also provides a calibration method of the broadband active scaler under the shipborne complex electromagnetic environment. The scheme adopts various optical fiber delay line methods, can carry out delay amplification and forwarding on the received radar signals, and overcomes the influence of ground clutter.
Description
Technical Field
The application relates to the technical field of shipborne radar calibration, in particular to a broadband active calibration device and a calibration method thereof under a shipborne complex electromagnetic environment.
Background
Because the electromagnetic environment where the shipborne radar is located is complex and variable, the RCS for accurately measuring the dynamic target is often calibrated by adopting active calibration equipment as RCS measurement reference.
The broadband active scaler is used for scaling the multiband radar, and the broadband active scaler is required to meet the scaling requirements of different frequency bands of the radar system. The broadband active scaler is fully considered and suitable for the complex electromagnetic environment at sea, and can continuously work at sea for a long time. The broadband active scaler needs to fully consider the installation density of electromagnetic equipment on a ship, avoid interfering with the work of other equipment, and also needs to be capable of working normally when the other equipment works.
The common calibration mode mainly adopts passive calibration, the passive calibration has higher requirement on a calibration body, the device is required to have larger RCS, and is insensitive to the incident direction of electromagnetic waves so as to reduce the influence caused by the calibration alignment process, and meanwhile, the device is required to perform calibration operation in an open field so as to reduce the influence of clutter on a calibration result. And the traditional active scaler mainly comprises a receiving antenna, a transmitting antenna, a radio frequency module and a modulation module. The sine amplitude of the received radar signal is modulated, a radar receiving and transmitting system, an antenna, a transmission path and an external scaler closed loop test loop which are not affected by ground clutter can be realized, but the wave band is often narrower, and interference exists when the radar receiving and transmitting system works in a complex environment.
Disclosure of Invention
The application provides a broadband active scaler design and a scaling method thereof under a shipborne complex electromagnetic environment. The scaler system can delay and attenuate the microwave signals received by the receiving antenna, and after the delay and attenuation processing is finished, the delayed microwave signals are transmitted back by the transmitting antenna.
The application provides a broadband active scaler under a shipborne complex electromagnetic environment, which comprises a micro-control processor, an electro-optical modulator, a WIFI module, a broadband receiving antenna and a broadband transmitting antenna, and is characterized in that:
the micro-control processor is responsible for controlling the laser constant temperature driving controller, the electro-optic modulator, the optical fiber delay switching controller and the attenuation controller; the micro-control processor is connected with a remote control signal through a Wifi module;
the broadband receiving antenna is used for receiving signals transmitted by the radar to be calibrated, entering the photoelectric modulator through the attenuator and the frequency gating filter, and carrying out signal delay through the optical fiber delay unit; the delay signal is attenuated, and is fed back to the radar to be calibrated through a broadband transmitting antenna after passing through a multichannel filter and a circulator; wherein:
the broadband receiving antennas are assembled on two sides of a main case of the scaler, and the main case is connected with the servo and used for controlling the beam direction of the antennas;
the radar signal enters a broadband receiving antenna from an antenna end, enters a microwave selection switch after passing through an attenuator, and selects a corresponding output channel according to a frequency band required to be calibrated by the radar to enter a microwave filter; after passing through the microwave filter, the signal passes through the microwave change-over switch again and enters the electro-optic modulator;
after being loaded on the DFB laser through the electro-optical modulator, the microwave signal enters the optical fiber delay part; after delay, the microwave enters an optical attenuator, and the function of controlling and adjusting microwave attenuation is realized through optical attenuation control; the signals after attenuation adjustment enter a photoelectric conversion end, the delayed signals enter a detector to recover microwave signals, and the microwave signals are subjected to compensation amplification treatment to achieve required output power; the amplified signal enters the microwave change-over switch again, and is sent into the filter of the corresponding wave band by the switch control.
After passing through the filter, the forward signal enters a two-stage circulator, and the two-stage circulator smoothly passes through the forward signal and isolates the reverse entering radar signal; and the signal is sent to a next stage microwave switch, and the signal in the filter of the required scaling frequency band is selected to an antenna at the output end for output.
Further, the broadband receiving antenna refers to a multiband broadband antenna, which may be composed of multiple antennas, and is configured to receive a signal with a frequency specified by a radar, so as to implement receiving of a transmitted electromagnetic wave.
Further, the fiber delay is controlled by a fiber and fiber switch, and different delay values are controlled by the optical switch.
Further, there are mainly two modes of the optical delay unit, in which:
the first mode is to combine optical fibers with different lengths by adopting a cascading mode of optical switches, namely adopting a cascading method of 1×2 and 2×2 optical switches, and realizing different time delays by controlling the combining mode.
The second mode is a 1-to-N switch selection mode in which a control scheme of 1×n is adopted, that is, when the required delay value is not large, 1 of the N values is selected.
The application also provides a calibration method of the broadband active scaler in the shipborne complex electromagnetic environment, which comprises the following specific steps:
step 1, powering up and self-checking the radar, and entering a standby state;
step 2, setting a working mode, and directing a wave beam to an active calibration device;
step 3, setting radar working parameters;
step 4, setting working parameters of an active calibration system, including radar working frequency, transmitting power, antenna pitch angle, azimuth angle, transmitting time sequence planning and RCS (radar cross section) values required to be simulated;
step 5, the active calibration system searches the maximum value of the received antenna alignment signal in an antenna alignment mode;
step 6, the radar and the active calibration system enter a calibration mode, and the RCS is recorded to measure the radar antenna gain G 0 ；
Step 7, the radar divides calibration into M frequency bands according to the relevant characteristics of the antenna, the power amplifier and the receiving and transmitting channel, namely: f (F) 1 ，F 2 ，…，F M Setting N test points according to actual conditions in each section, and calibrating the frequency point f of the radar ij Wherein: i=1 to M, j=1 to N; transmitting a calibration pulse, setting the transmission power to P k K=1 to K grades, and selecting a frequency point f according to the set RCS analog value, the set calibration frequency and the set calibration distance ij Reasonable calibration transmitting power gearP ij ＝P k Wherein: i=1 to M, j=1 to N, k=1 to K, the emission frequency is f ij The power is P ij A scaling pulse with interval period of T and length of tau;
step 8, the active scaler receives the corresponding pulse and according to the simulation RCS value sigma set by the control system ij Wherein: i=1 to M, i=1 to N, and calculating corresponding accurate transmitting power, and transmitting the corresponding accurate transmitting power in a corresponding time window after delay and Doppler frequency offset processing;
step 9, the radar receives corresponding calibration signals, one path of echo data is subjected to data storage, the other path of echo data is sent to the radar real-time processing module, and the power of the echo data is calculated to obtain a measured value sigma of the RCS calibration signals ij ' wherein: i=1 to M, i=1 to N; system calculates a measurement error correction table Δσ for a radar ij ＝σ ij ′-σ ij Wherein: i=1 to M, i=1 to N, positive indicates that the radar has a positive error, and the measured value is larger; negative errors of the radar are represented by negative values, and the measured value is smaller;
and step 10, completing calibration.
The application has the advantages that:
(1) The application can work in multiple frequency bands and has the capacity of simultaneous calibration in multiple frequency bands.
(2) By adopting various optical fiber delay line methods, the received radar signals can be amplified and forwarded in a delayed manner, and the influence of ground clutter is overcome.
(3) The application adopts an optical fiber delay scheme and can work in a complex electromagnetic environment.
Drawings
Fig. 1 is a schematic diagram of a system structure according to an embodiment of the disclosure.
Fig. 2 is a schematic structural diagram of an optical fiber assembly according to an embodiment of the present disclosure.
Fig. 3 is a schematic diagram of a second optical delay principle according to an embodiment of the disclosure.
Fig. 4 is a schematic longitudinal section of the whole machine design structure according to the embodiment of the disclosure.
Fig. 5 is a scaling flow diagram of an embodiment of the present disclosure.
Detailed Description
The technical scheme of the application is described in detail below with reference to fig. 1-5.
As shown in fig. 1, this embodiment provides a broadband active scaler in a complex electromagnetic environment on board a ship, and the scaler has a basic function of performing delay simulation on a microwave signal received through an antenna, and after delay processing, transmitting the delayed microwave signal back through a transmitting antenna. The basic application parameters of the system are as follows:
(1) The application frequency range is suitable for C, X, ku three-band, and the maximum bandwidth is 1GHz.
(2) The maximum power value of the signal input power is 16dBm.
(3) Delay analog values include 5us,10us,20us,40us.
(4) The attenuation value is adjustable in steps of 1dB according to the maximum 72dB proposal.
(5) In-band relief: better than +/-0.5dB, and better than +/-10 DEG in nonlinearity
(6) The temperature stability is provided, and the temperature is recorded.
(7) Three proofings are suitable for working under severe regulation.
(8) Control may be via WiFi or short wave radio.
Specifically, the broadband active scaler in the shipborne complex electromagnetic environment comprises a micro-control processor, an electro-optic modulator, a WIFI module, a broadband antenna and corresponding radio frequency components.
The system main control module is divided into a micro control processor and is responsible for controlling a laser constant temperature driving controller, an electro-optical modulator, an optical fiber delay switching controller and an attenuation controller.
The module is connected with a remote control signal through a Wifi module.
The broadband receiving antenna is used for receiving signals transmitted by the radar to be calibrated, entering the photoelectric modulator through the attenuator and the frequency gating filter, and carrying out signal delay through the optical fiber delay unit. The delay signal is attenuated and fed back to the radar to be calibrated through the multichannel filter and the circulator by the transmitting antenna. Through the process, the target echo of the remote specified RCS can be simulated, and the aim of radar calibration is achieved.
The broadband receiving antenna refers to a multiband broadband antenna, and can be composed of a plurality of antennas, and the broadband receiving antenna aims to receive signals with the specified frequency of a radar and realize the receiving of transmitted electromagnetic waves.
As shown in fig. 4, the broadband antennas are mounted on both sides of a sealer main housing, which is connected to a servo for controlling the antenna beam pointing.
The working principle of the broadband active scaler under the shipborne complex electromagnetic environment is as follows:
the radar signal enters the broadband receiving wire from the antenna end, and has a maximum power exceeding 15.15dBW, corresponding to a power exceeding 32W, and the rear-end optical devices are small signal processing devices, so that an attenuator is added at the front end, and the front end adopts a 50W attenuator.
After passing through the attenuator, the microwave enters a microwave selection change-over switch, and the microwave selection change-over switch selects a corresponding output channel according to the frequency band required by the radar to be calibrated and enters a microwave filter.
After passing through the microwave filter, the signal passes again through the microwave switch and into the electro-optic modulator.
After the microwave signal is loaded onto the laser through the electro-optic modulator, it enters the fiber delay section. The optical fiber delay is mainly controlled by an optical fiber and an optical fiber change-over switch, and different delay values can be controlled by the change-over of the optical switch.
After the delay, the optical attenuator is carried out, and the function of controlling and adjusting the microwave attenuation is realized through the optical attenuation control.
The signals after the attenuation adjustment enter a photoelectric conversion end, the delayed signals enter a detector to recover microwave signals, and the required output power is achieved through compensation and amplification processing.
The amplified signal enters the microwave change-over switch again, and is sent into the filter of the corresponding wave band by the switch control.
After the forward signal passes through the filter, the forward signal enters the two-stage circulator, and the two-stage circulator smoothly passes through the forward signal and isolates the reverse entering radar signal. And is sent to a next stage microwave change-over switch.
The next stage microwave switch adopts a power type microwave switch to select signals in a filter of a required scaling frequency band to an antenna at an output end for output.
The output end of the antenna is again under the functions of a microwave switch, a filter, a circulator and a load, the antennas at the two ends generate strong power due to the fact that the antennas are simultaneously under radar radiation, the rear end of the antenna at the receiving end is well protected due to the fact that the attenuator with the power of 50W is adopted, but if the transmitting end directly transmits, the rear end device can be completely burnt out under the power of 32W under the condition that the transmitting end does not transmit directly. The backend also needs protection.
Meanwhile, the rear end only adopts a circulator method to emit forward small signals normally through the transmitting antenna, and simultaneously, the high-power radar signals coupled in by the transmitting antenna are absorbed through a load of 50W during reverse transmission, in addition, the isolation of the circulator can only reach about 20dB, as known before, the power of the antenna end can reach more than 32W, after 20dB of isolation, the passing signal strength is enough to burn out the rear stage, so that the first-stage isolation is insufficient to protect the rear-end device, and a second-stage circulator and a second-stage load are needed to further isolate and absorb the reversely passed signals.
In addition, for the WIFI control signal, because the radar high-power radiation effect is also provided, a high-power signal can be generated, and high-power protection is required to be performed, so that a filter capable of bearing high-power high-out-of-band rejection is required to be added at the rear end of the WIFI antenna, the radar signal is filtered, and the WIFI signal is protected to pass normally.
In this embodiment, the optical delay unit is controlled by the optical fiber delay switching controller, and the optical delay unit mainly has two designs:
in the first scheme, a cascading mode of optical switches is adopted, the method combines optical fibers with different lengths by adopting a cascading method of 1×2 and 2×2 optical switches, and different time delays are realized by controlling the combining mode. A schematic structural diagram of such an optical fiber combination is shown in fig. 2.
By adopting n+1 switch cascades, a user can select 2n different delay values (0-2 n-1) according to the requirements.
The advantage of this approach is that a combination of delay values can be achieved, both the length of the used fiber length and the delay value.
In the second scheme, the route control mode of the optical delay is 1×n N1-switch selection mode. When there are few delay values required, 1 of the N values may be selected. The schematic diagram is shown in fig. 3. The delay control route is simple and can be selected when the required delay is not large. At the same time, the delay eliminates the high loss factor caused by multi-stage optical fiber cascade because an optical switch cascade is not needed, and the mode is the optimal choice when the gear is delayed less. In this embodiment, a 4-step delay is required, and the theoretical best choice is to choose the second delay choice. The parameter performance will be optimal. The first option is also optional if multiple delays are actually required to make the alternative.
In this embodiment, when the signal link budget calculation is performed:
the first stage is an attenuator for attenuating the received power signal, using a 50w,30db attenuator.
The second stage 1×3 microwave switch has a maximum insertion loss of 3.5dB according to its parameter index.
The third stage is a frequency-selective filter, and the maximum insertion loss is 1.5dB according to the index value.
The fourth stage is a 1×3 microwave change-over switch, and the maximum insertion loss is 3.5dB according to the parameter index.
The fifth stage is an electro-optical modulator, the electro-optical characteristic of the electro-optical modulator is equivalent to a radio frequency parameter, and the electro-optical characteristic is brought into a link, so that the loss is-25 dB. The sixth level is that the loss of the optical switch and the optical fiber is converted into radio frequency loss, and the radio frequency loss is substituted into a link (-15 dB).
The seventh stage is an attenuation controller for adjusting the optical attenuator to achieve microwave attenuation adjustment, where only the insertion loss (3 dB) is calculated, and the attenuation adjustment value is further adjusted on the basis of this.
And the eighth-stage photoelectric converter is used for recovering the required microwave signal from the optical signal, and carrying out calculation (-15 dB) according to the characteristic brought-in link parameter.
The ninth stage is a small signal amplifier for amplifying weak microwave signals and carrying the weak microwave signals into the link parameters for calculation (30 dB).
The tenth stage is a microwave signal amplifier, which is used for further amplifying and outputting the microwave signal and carrying the microwave signal into the link parameters for calculation (40 dB).
The tenth stage is a 1×3 microwave change-over switch, and the maximum insertion loss is 3.5dB according to the parameter index.
The twelfth stage is the insertion loss of the frequency selective filter and the circulator, which is 1.5dB.
The tenth stage is a 1×3 microwave change-over switch, and the maximum insertion loss is 3.5dB according to the parameter index.
The constant-temperature driving controller of the laser is used for realizing constant control of the working temperature of the laser and the working environment temperature of the laser;
means for controlling a heater or other device by comparing the sensor signal with a set point and calculating from the deviation between these values
The DFB laser can provide extremely high coherence, very stable single-frequency and single-longitudinal mode optical output, has extremely high wavelength stability and has good compatibility with optical fibers.
The embodiment also provides a calibration method of the broadband active scaler in the shipborne complex electromagnetic environment, which comprises the following specific steps:
step 1, powering up and self-checking the radar, and entering a standby state;
step 2, setting a working mode, and directing a wave beam to an active calibration device;
step 3, setting radar working parameters;
step 4, setting working parameters of an active calibration system, including radar working frequency, transmitting power, antenna pitch angle, azimuth angle, transmitting time sequence planning and RCS (radar cross section) values required to be simulated;
step 5, the active calibration system searches the maximum value of the received antenna alignment signal in an antenna alignment mode, so as to realize accurate alignment, and the RCS test radar antenna orientation and the active calibration antenna are subjected to proper fine adjustment in the process;
step 6, the radar and the active calibration system enter a calibration mode, and the RCS is recorded to measure the radar antenna gain G 0 。
Step 7, the radar divides the calibration into M frequency bands (F 1 ，F 2 ，…，F M ) Setting N test points according to actual conditions in each section, and calibrating the frequency point f of the radar ij (i=1 to M, j=1 to N) transmitting the scaling pulse, setting the transmission power to P k (k=1-K) files, and selecting a frequency point f according to the set RCS analog value, calibration frequency, calibration distance and other factors ij Reasonable scaled transmit power profile P at (i=1 to M, j=1 to N) ij ＝P k (i=1 to M, j=1 to N, k=1 to K), the emission frequency is f ij The power is P ij A scaling pulse with interval period of T and length of tau;
step 8, the active scaler receives the corresponding pulse and according to the simulation RCS value sigma set by the control system ij (i=1 to M, i=1 to N), calculating corresponding accurate transmitting power, and transmitting in a corresponding time window after delay and doppler frequency offset processing;
step 9, the radar receives corresponding calibration signals, one path of echo data is subjected to data storage, the other path of echo data is sent to the radar real-time processing module, and the power of the echo data is calculated to obtain a measured value sigma of the RCS calibration signals ij ' (i=1 to M, i=1 to N); system calculates a measurement error correction table Δσ for a radar ij ＝σ ij ′-σ ij (i=1 to M, i=1 to N), wherein positive indicates that there is a positive error in the radar, and the measured value is large; negative errors of the radar are represented by negative values, and the measured value is smaller;
and step 10, completing calibration.
While the foregoing detailed description of the embodiments, embodiments and advantages of the present disclosure have been presented for purposes of illustration, description, and not limitation, it should be understood that the foregoing is intended to be illustrative only and should not be construed as limiting the application to any extent that it is within the spirit and principles of the disclosure. The scope of the application is defined by the appended claims and may include various modifications, alterations and equivalents of the application without departing from the scope and spirit of the application.
Claims (5)
1. The utility model provides a broadband active scaler under on-board complicated electromagnetic environment, includes micro-control processor, electro-optic modulator, WIFI module, broadband receiving antenna, broadband transmitting antenna, its characterized in that:
the micro-control processor is responsible for controlling the laser constant temperature driving controller, the electro-optic modulator, the optical fiber delay switching controller and the attenuation controller; the micro-control processor is connected with a remote control signal through a Wifi module;
the broadband receiving antenna is used for receiving signals transmitted by the radar to be calibrated, entering the photoelectric modulator through the attenuator and the frequency gating filter, and carrying out signal delay through the optical fiber delay unit; the delay signal is attenuated, and is fed back to the radar to be calibrated through a broadband transmitting antenna after passing through a multichannel filter and a circulator; wherein:
the broadband receiving antennas are assembled on two sides of a main case of the scaler, and the main case is connected with the servo and used for controlling the beam direction of the antennas;
the radar signal enters a broadband receiving antenna from an antenna end, enters a microwave selection switch after passing through an attenuator, and selects a corresponding output channel according to a frequency band required to be calibrated by the radar to enter a microwave filter; after passing through the microwave filter, the signal passes through the microwave change-over switch again and enters the electro-optic modulator;
after being loaded on the DFB laser through the electro-optical modulator, the microwave signal enters the optical fiber delay part; after delay, the microwave enters an optical attenuator, and the function of controlling and adjusting microwave attenuation is realized through optical attenuation control; the signals after attenuation adjustment enter a photoelectric conversion end, the delayed signals enter a detector to recover microwave signals, and the microwave signals are subjected to compensation amplification treatment to achieve required output power; the amplified signal enters the microwave change-over switch again, and is sent into the filter of the corresponding wave band by the switch control;
after passing through the filter, the forward signal enters a two-stage circulator, and the two-stage circulator smoothly passes through the forward signal and isolates the reverse entering radar signal; and the signal is sent to a next stage microwave switch, and the signal in the filter of the required scaling frequency band is selected to an antenna at the output end for output.
2. The broadband active scaler under a complex electromagnetic environment onboard according to claim 1, wherein:
the broadband receiving antenna refers to a multiband broadband antenna, and can be composed of a plurality of antennas and used for receiving signals with the specified frequency of a radar and receiving transmitted electromagnetic waves.
3. The broadband active scaler under a complex electromagnetic environment onboard according to claim 1, wherein: the optical fiber delay is controlled by an optical fiber and an optical fiber switch, and different delay values are controlled by the optical switch.
4. The broadband active scaler under a complex electromagnetic environment onboard according to claim 1, wherein: there are mainly two modes of the optical delay unit, wherein:
the first mode is to combine optical fibers with different lengths by adopting a cascading mode of optical switches, namely adopting a cascading method of 1×2 and 2×2 optical switches, and realizing different time delays by controlling the combining mode.
The second mode is a 1-to-N switch selection mode in which a control scheme of 1×n is adopted, that is, when the required delay value is not large, 1 of the N values is selected.
5. The calibration method of the broadband active scaler based on the shipborne complex electromagnetic environment of claim 1 comprises the following specific steps:
step 1, powering up and self-checking the radar, and entering a standby state;
step 2, setting a working mode, and directing a wave beam to an active calibration device;
step 3, setting radar working parameters;
step 4, setting working parameters of an active calibration system, including radar working frequency, transmitting power, antenna pitch angle, azimuth angle, transmitting time sequence planning and RCS (radar cross section) values required to be simulated;
step 5, the active calibration system searches the maximum value of the received antenna alignment signal in an antenna alignment mode;
step 6, the radar and the active calibration system enter a calibration mode, and the RCS is recorded to measure the radar antenna gain G 0 ；
Step 7, the radar divides calibration into M frequency bands according to the relevant characteristics of the antenna, the power amplifier and the receiving and transmitting channel, namely: f (F) 1 ，F 2 ，…，F M Setting N test points according to actual conditions in each section, and calibrating the frequency point f of the radar ij Wherein: i=1 to M, j=1 to N; transmitting a calibration pulse, setting the transmission power to P k K=1 to K grades, and selecting a frequency point f according to the set RCS analog value, the set calibration frequency and the set calibration distance ij Reasonable calibration transmitting power gear P ij ＝P k Wherein: i=1 to M, j=1 to N, k=1 to K, the emission frequency is f ij The power is P ij A scaling pulse with interval period of T and length of tau;
step 8, the active scaler receives the corresponding pulse and according to the simulation RCS value sigma set by the control system ij Wherein: i=1 to M, i=1 to N, and calculating corresponding accurate transmitting power, and transmitting the corresponding accurate transmitting power in a corresponding time window after delay and Doppler frequency offset processing;
step 9, the radar receives corresponding calibration signals, one path of echo data is subjected to data storage, the other path of echo data is sent to the radar real-time processing module, and the power of the echo data is calculated to obtain a measured value sigma of the RCS calibration signals ij ' wherein: i=1 to M, i=1 to dN; system calculates a measurement error correction table Δσ for a radar ij ＝σ ij ′-σ ij Wherein: i=1 to M, i=1 to N, positive indicates that the radar has a positive error, and the measured value is larger; negative errors of the radar are represented by negative values, and the measured value is smaller;
and step 10, completing calibration.
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| CN117724063A (en) * | 2024-01-25 | 2024-03-19 | 南京新频点电子科技有限公司 | Mobile unmanned aerial vehicle SAR radar active scaler device and working mode thereof |
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2023
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117724063A (en) * | 2024-01-25 | 2024-03-19 | 南京新频点电子科技有限公司 | Mobile unmanned aerial vehicle SAR radar active scaler device and working mode thereof |
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