CN102981162A - Spatial synchronization device and synchronization method for bistatic SAR - Google Patents

Abstract

The invention discloses a spatial synchronization device and a synchronization method for bistatic SAR (synthetic aperture radar). The device comprises a transmission station part and a receiving station part, and particularly comprises a positioning and attitude determination system, an antenna server, a transmission synchronization system, a wireless transmit-receive system, a receiving synchronization system and a display unit. According to the spatial synchronization device and the method, direction angles at which antenna beams of transmit-receive aerial carrier platforms aim at an target area are revolved and obtained by utilizing actual spatial positions of the transmit-receive aerial carrier platforms; the antenna server is utilized to accomplish aiming of the beams to allow the antenna beams of the transmit-receive platforms to aim at the target area; the spatial synchronization of the onboard bistatic SAR is achieved; a signal-to-noise ratio of a radar echo is ensured; and the precision of the spatial synchronization is improved.

Description

Spatial synchronization device and the method for synchronous of double-base SAR

Technical field

The invention belongs to the Radar Signal Processing Technology field, relate to the GPS location technology, specially refer to airborne double-base synthetic aperture radar (SyntheticAperture Radar, SAR) spatial synchronization technology.

Background technology

The characteristics such as double-base SAR is the synthetic-aperture radar of the New System that splits of a kind of sending and receiving, has different space geometry coordinate relations, and interference free performance, disguise, anti-interception capability are strong.Double-base SAR comprises the spaceborne bistatic SAR of satellite launch, satellite reception, the satellite-machine double-base SAR that satellite launch, aircraft receive, the systems such as airborne double-base SAR that aircraft emission, aircraft receive.

The space structure synoptic diagram of airborne double-base SAR as shown in Figure 1 because bistatic, airborne double-base SAR has new space geometry structure, has therefore brought the spatial synchronization problem of airborne double-base SAR.Spatial synchronization requires the antenna beam of cell site and receiving station that there is the irradiated region of coincidence same target area, thereby guarantees that the imaging area echo has enough property ratio of making an uproar, and is the guarantee of synthetic aperture radar image-forming.Because bistatic and transmitting-receiving carrier aircraft all are among the motion, the locus constantly changes, and the synchronous difficulty in airborne double-base SAR implementation space is larger.

Document: the research of two stations polarization sensitive synthetic aperture radar system stationary problem, Tang Ziyue; Zhang Shourong, modern radar, Vol.26, No.1, pp.1-2, in 2004, a kind of method that solves the spatial synchronization problem of airborne double-base SAR is proposed, be specially: before the transmitting-receiving carrier aircraft is carried out imaging work, flight track and imaging area position according to predetermined transmitting-receiving carrier aircraft are calculated the controlling antenna wave beam to point angle of receiving and dispatching carrier aircraft in advance, before test, adjust the controlling antenna wave beam to point angle of transmitting-receiving carrier aircraft, make the antenna beam of transmitting-receiving carrier aircraft all aim at imaging area by the control to the speed of a ship or plane, course and attitude in the transmitting-receiving carrier aircraft flight course.The shortcoming of the method is can not be by the real space position automatic control antenna beam position angle of system according to aircraft, and the alignment precision of dual-mode antenna wave beam is subjected to the differentia influence of the actual flight path of aircraft flight and preset flight path very large.

Summary of the invention

The objective of the invention is to have proposed a kind of spatial synchronization device of double-base SAR in order to solve the problems referred to above of prior art existence, reach the method for synchronous based on a kind of double-base SAR of this device.

Content of the present invention for convenience of description, at first make following term definition:

Definition 1, synchro system

In the present invention, synchro system is divided into the emission synchro system and receives synchro system, uses respectively in cell site and receiving station.It can be realized by the FPGA technology, play the hardware system of core control action in the spatial synchronization device.

Definition 2, serial ports

Serial ports is the abbreviation of serial communication interface, and its data mode is to transmit by one one ground order, and serial communication interface is divided into RS-232, RS-422, RS485 etc. by electrical standard and agreement.

The appearance system is surveyed in definition 3, location

The location is surveyed the appearance system and is referred to provide in real time the attitude data (crab angle, the angle of pitch and roll angle) of carrier and the system of locus (longitude, latitude and sea level elevation) information.

Definition 4, cyclic redundancy check (CRC)

CRC is Cyclical Redundancy Check, be called for short CRC, it is to utilize the principle of division and remainder to do wrong detecting, during practical application, dispensing device calculates crc value also and data together send to receiving trap, receiving trap recomputates CRC to the data of receiving and compares with the CRC that receives, if two crc value differences illustrate that then mistake appears in data communication.

Definition 5, antenna servo device

Antenna servo device (hereinafter to be referred as " servomechanism ") is comprised of data computation module, servomotor and turntable, wherein, data computation module receives control data and the attitude data of synchro system by serial ports and is calculated, and forms in real time the control information of servomechanism; Servomotor utilizes above-mentioned control information control turntable to turn to assigned direction, and utilizes above-mentioned attitude data stabilized antenna to point to; Settle antenna on the turntable; Servomechanism can the real-time actual sensing with antenna rotating platform return to synchro system by serial ports simultaneously.

Definition 6, wireless transceiver system

Wireless transceiver system refers to realize the system of long distance wireless data transmission.

Definition 7, aobvious control unit

Aobvious control unit refers to by serial ports and receiving station's synchro system communication, can show the state of flight of receive and dispatch carrier aircraft and the sensing situation of receiving and dispatching the carrier aircraft antenna beam, spatial synchronization played the application software of supervision effect.Aobvious control cellular installation is on display end (main frame etc.), and aobvious control unit is specifically as follows display and control software.

Definition 8, controlling antenna wave beam to point angle

The controlling antenna wave beam to point angle refers to position angle and the angle of pitch of antenna beam center line.The position angle refers to from the north pointer direction line of carrier aircraft platform, is docile and obedient clockwise to the horizontal sextant angle between the antenna beam center line; The angle of pitch refers to the angle between carrier aircraft platform place surface level and the antenna beam center line.

The spatial synchronization device of a kind of double-base SAR provided by the invention, comprise cell site's part and receiving station's part, wherein, described cell site end specifically comprises: appearance system, the first antenna servomechanism, emission synchro system and the first wireless transceiver system are surveyed in the first location; Described receiving station end specifically comprises: the second location is surveyed appearance system, the second antenna servomechanism, is received synchro system, the second wireless transceiver system and display unit;

Attitude data information and the spatial positional information that the appearance system is used for obtaining carrier aircraft surveyed in described the first location, and the communication that obtains is arrived the emission synchro system;

Described emission synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the first location, sensing angle when calculating antenna beam target area, cell site, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the first antenna servomechanism;

Sensing angle when described the first antenna servomechanism basis receives antenna beam target area, cell site, control cell site antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the emission synchro system;

The locus that the appearance system is used for obtaining locus and known target area is surveyed in described the second location, and the positional information of obtaining is transferred to the reception synchro system;

Described the first wireless transceiver system is used for the spatial positional information of cell site, attitude information and the actual angle of pointing to are sent to described the second wireless transceiver system;

Described the second wireless transceiver system is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Described reception synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the second location, sensing angle when calculating receiving station antenna beam target area, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the antenna servo device of receiving station;

Sensing angle when described the second antenna servomechanism receives antenna beam target area, receiving station cell site, control receiving station antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the reception synchro system;

Described reception synchro system also is used for the actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfers to display unit;

Described display unit be used for to show actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station.

Further, the spatial positional information of described carrier aircraft comprises: the longitude of locus, latitude, sea level elevation, described attitude data information is specially the attitude angle of carrier aircraft, comprising: crab angle, the angle of pitch, roll angle.

Further, the sensing angle during the antenna beam target area concrete to resolve process as follows:

Process intermediate variable X, Y, N are resolved in introducing, wherein

$X=\mathrm{ac}\tan \left\{\frac{\cos \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$Y=\mathrm{ac}\tan \left\{\frac{\sin \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$N=\mathrm{ac}\tan \left\{\frac{\cos X\·\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}{\cos Y\·\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}\right\}$

Azimuthal angle beta is:

βX-Y

Pitching angle theta is:

$\mathrm{\θ}=\mathrm{ac}\tan \left(\frac{\mathrm{Hm}-\mathrm{Hr}}{N\·(R+\min (\mathrm{Hm},\mathrm{Hr}))}\right).$

Wherein, Lor represents the latitude of the longitude of the locus of carrier aircraft, locus that Lar represents carrier aircraft, the sea level elevation of locus that Hr represents carrier aircraft, Lom represents the longitude of the locus of target area, Lam represents the latitude of the locus of target area, Hm represents the sea level elevation of the locus of target area, and R represents earth radius.

In order to address the above problem, the invention allows for a kind of spacing synchronization process of double-base SAR, comprise the steps:

Step 1: obtain spatial positional information and the attitude data information of carrier aircraft,

Spatial positional information and the attitude data information of appearance system acquisition carrier aircraft is surveyed in the second location that appearance system and receiving station's end are surveyed in the first location of cell site, and respectively the spatial positional information of the carrier aircraft obtained and the attitude data information of carrier aircraft is transferred to respectively the emission synchro system of cell site and the reception synchro system of receiving end;

Step 2: resolve the controlling antenna wave beam to point angle,

The controlling antenna wave beam to point angle that the emission synchro system of cell site is resolved the antenna beam target area that obtains the cell site according to the spatial positional information of the spatial positional information of the cell site's end carrier aircraft that obtains and known target area; The controlling antenna wave beam to point angle that the reception synchro system of receiving station is resolved the antenna beam target area that obtains receiving station according to the spatial positional information of the spatial positional information of the receiving station's end carrier aircraft that obtains and known target area;

Step 3: step 2 is resolved the controlling antenna wave beam to point angle that obtains send to servomechanism, the adjustment of servomechanism control antenna is pointed to,

The controlling antenna wave beam to point angle that emission synchro system and reception synchro system will be resolved respectively the antenna beam target area that obtains the cell site, the controlling antenna wave beam to point angle of the antenna beam target area of the attitude angle of carrier aircraft and receiving station, the attitude angle of carrier aircraft sends to the first antenna servomechanism of cell site and the second antenna servomechanism of receiving station, the first antenna servomechanism and the second antenna servomechanism are controlled respectively cell site's antenna according to the controlling antenna wave beam to point angle that receives and are adjusted antenna direction and receiving station's antenna adjustment antenna direction, servomechanism can be according to the stabilization of carriage angle antenna direction of described carrier aircraft, and actual sensing angle that antenna is current transfers to the emission synchro system and receives synchro system respectively;

Step 4: the data demonstration,

The first wireless transceiver system of cell site sends to spatial positional information, attitude information and the actual sensing angle of cell site the second wireless transceiver system of receiving station;

The second wireless transceiver system of receiving station is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Receive the synchro system actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfer to display unit;

The display unit of receiving station transfers to actual sensing angle information that display unit shows that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle information of spatial positional information, attitude information and antenna of receiving station according to the current actual sensing angle of spatial positional information, attitude information and antenna of the current actual sensing angle of spatial positional information, attitude information and the antenna of the cell site that receives and receiving station.

Further, the spatial positional information of described carrier aircraft comprises: the longitude of locus, latitude, sea level elevation, described attitude data information is specially the attitude angle of carrier aircraft, comprising: crab angle, the angle of pitch, roll angle.

Further, the sensing angle during the antenna beam target area concrete to resolve process as follows:

Process intermediate variable X, Y, N are resolved in introducing, wherein

$X=\mathrm{ac}\tan \left\{\frac{\cos \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$Y=\mathrm{ac}\tan \left\{\frac{\sin \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$N=\mathrm{ac}\tan \left\{\frac{\cos X\·\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}{\cos Y\·\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}\right\}$

Azimuthal angle beta is:

βX-Y

Pitching angle theta is:

$\mathrm{\θ}=\mathrm{ac}\tan \left(\frac{\mathrm{Hm}-\mathrm{Hr}}{N\·(R+\min (\mathrm{Hm},\mathrm{Hr}))}\right)$

Wherein, Lor represents the latitude of the longitude of the locus of carrier aircraft, locus that Lar represents carrier aircraft, the sea level elevation of locus that Hr represents carrier aircraft, Lom represents the longitude of the locus of target area, Lam represents the latitude of the locus of target area, Hm represents the sea level elevation of the locus of target area, and R represents earth radius.

Beneficial effect of the present invention: the spatial synchronization apparatus and method of double-base SAR of the present invention, utilize the real space position of transmitting-receiving carrier aircraft platform to resolve respectively the sensing angle that obtains receiving and dispatching carrier aircraft platform antenna beam target area separately, and utilize the antenna servo device to finish the wave beam alignment work, make the antenna beam of the transmit-receive platform district that can both aim at the mark accurately, realize the spatial synchronization of airborne double-base SAR, guarantee the signal to noise ratio (S/N ratio) of radar return, improved the precision of spatial synchronization.

Description of drawings

Fig. 1 is the space structure synoptic diagram of airborne double-base SAR.

Fig. 2 is the spatial synchronization apparatus structure synoptic diagram of airborne double-base SAR of the present invention.

Fig. 3 is the spacing synchronization process schematic flow sheet of airborne double-base SAR of the present invention.

Fig. 4 is the system construction drawing of the emission synchro system of the specific embodiment of the invention.

Fig. 5 is the system construction drawing of the reception synchro system of the specific embodiment of the invention.

Fig. 6 is that the boat appearance of synchro system in the specific embodiment of the invention is resolved module's logic structure figure.

Fig. 7 is the data processing module building-block of logic of synchro system in the specific embodiment of the invention.

Fig. 8 is the antenna servo device module's logic structure figure of synchro system in the specific embodiment of the invention.

Fig. 9 receives synchro system radio station receiver module building-block of logic in the specific embodiment of the invention.

Figure 10 is cell site's synchro system radio station sending module building-block of logic in the specific embodiment of the invention.

Figure 11 is the aobvious control module's logic structure figure that receives synchro system in the specific embodiment of the invention.

Embodiment

The present invention is described further below in conjunction with the drawings and specific embodiments.

The structural representation of the spatial synchronization device of double-base SAR of the present invention as shown in Figure 2, comprise cell site's part and receiving station's part, wherein, described cell site end specifically comprises: appearance system, the first antenna servomechanism, emission synchro system and the first wireless transceiver system are surveyed in the first location; Described receiving station end specifically comprises: the second location is surveyed appearance system, the second antenna servomechanism, is received synchro system, the second wireless transceiver system and display unit;

Attitude data information and the spatial positional information that the appearance system is used for obtaining carrier surveyed in described the first location, and the communication that obtains is arrived the emission synchro system;

Described emission synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the first location, sensing angle when calculating antenna beam target area, cell site, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the first antenna servomechanism;

Sensing angle when described the first antenna servomechanism basis receives antenna beam target area, cell site, control cell site antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the emission synchro system;

The locus that the appearance system is used for obtaining locus and known target area is surveyed in described the second location, and the positional information of obtaining is transferred to the reception synchro system;

Described the first wireless transceiver system is used for the spatial positional information of cell site, attitude information and the actual angle of pointing to are sent to described the second wireless transceiver system;

Described the second wireless transceiver system is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Described reception synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the second location, sensing angle when calculating receiving station antenna beam target area, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the antenna servo device of receiving station;

Sensing angle when described the second antenna servomechanism receives antenna beam target area, receiving station cell site, control receiving station antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the reception synchro system;

Described reception synchro system also is used for the actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfers to display unit;

Described display unit be used for to show actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station.

The CHA-4G type strapdown attitude instrument (hereinafter to be referred as " boat appearance instrument ") of electric group the 26th Research Institute in the employing of appearance system is surveyed in the location here, the servomechanism of electric group the 54th Research Institute during the antenna servo device adopts, wireless transceiver system adopts the MDS wireless station that is produced by GE company, the model that emission synchro system and the concrete processor that adopts of reception synchro system are Xilinx companies is the FPGA of Spantan3, utilize Verilog as hardware description language, adopt the crystal oscillator of 20MHz.

Specifically describe the detailed construction of emission synchro system and reception synchro system below in conjunction with the spacing synchronization process of airborne double-base SAR.

The schematic flow sheet of the spacing synchronization process of the airborne double-base SAR that proposes in the present invention of the spatial synchronization device of above-mentioned airborne double-base SAR as shown in Figure 3, concrete steps are as follows:

Step 1: obtain the attitude data information of spatial positional information and the carrier of carrier aircraft,

Spatial positional information and the attitude data information of appearance system acquisition carrier aircraft is surveyed in the second location that appearance system and receiving station's end are surveyed in the first location of cell site, and respectively the spatial positional information of the carrier aircraft obtained and the attitude data information of carrier aircraft is transferred to respectively the emission synchro system of cell site and the reception synchro system of receiving end.

First location here surveys the appearance system and the second location survey appearance system is specially boat appearance instrument, the locus (longitude Lor, latitude Lar, sea level elevation Hr) of exportable carrier aircraft and the attitude angle (crab angle, the angle of pitch, roll angle) of carrier aircraft after the normal operation of boat appearance instrument, its serial port protocol is RS422, data protocol is: baud rate 115200bps, 8 bit data positions, 1 position of rest, no parity check, data output period are the 10ms/ frame.

The structural representation of emission synchro system specifically comprises as shown in Figure 4: the boat appearance is resolved module (Hz_uart_module), data processing module (Data_process_module), radio station sending module (Dt_uart_module_tx) and antenna servo module (SIFU_uart_module).

Receive the structural representation of synchro system as shown in Figure 5, specifically comprise: the boat appearance is resolved module (Hz_uart_module), data processing module (Data_process_module), radio station receiver module (Dt_uart_module_rx), antenna servo module (SIFU_uart_module) and aobvious control module (XK_uart_module).

The locus of carrier aircraft and attitude angle are resolved module (Hz_uart_module) by the boat appearance and are obtained in the FPGA of emission synchro system and reception synchro system, comprise in this module and receive baud rate and select module (speed_select_rx), string to turn and module (Hz_uart_rx) and data are deposited three submodules of module (dat_an_Hz), as shown in Figure 6.

In receiving baud rate selection module, need calculate the clock period that receives 1 bit data needs according to system's crystal oscillator frequency in advance.Because the crystal oscillator that adopts is 20MHz, the corresponding reception required clock period of 1 bit data of baud rate (9600,19200,38400,115200) commonly used is (1152,576,288,96), and module is output as the sampling pulse (clk_bps_rx) of receive data; String turn and module with the serial data (rs232_rx) that receives, the data layout according to boat appearance instrument converts 8 bit data positions to parallel data (rx_data); Data are deposited module according to the form of Frame, parallel data is deposited in each output register, comprise longitude (Hz_lor), latitude (Hz_lat), sea level elevation (Hz_h), course angle (Hz_Hangxiang), the angle of pitch (Hz_Fuyang), roll angle (Hz_Gundong).

Illustrate: the clk in Fig. 6 ~ 11 and rst_n represent respectively clock signal and reset signal.

Step 2: resolve the controlling antenna wave beam to point angle,

The controlling antenna wave beam to point angle that the emission synchro system of cell site is resolved the antenna beam target area that obtains the cell site according to the spatial positional information of the spatial positional information of the cell site's end carrier aircraft that obtains and known target area; The controlling antenna wave beam to point angle that the reception synchro system of receiving station is resolved the antenna beam target area that obtains receiving station according to the spatial positional information of the spatial positional information of the receiving station's end carrier aircraft that obtains and known target area.

According to step 1, synchro system has obtained the spatial positional information of carrier aircraft, and the spatial positional information of target area (longitude Lom, latitude Lam, sea level elevation Hm) is determined before imaging work.Sensing angle when synchro system can calculate the antenna beam target area according to the locus of the locus of carrier aircraft and target area.

Process intermediate variable X, Y, N are resolved in introducing, wherein

$X=\mathrm{ac}\tan \left\{\frac{\cos \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}---\left(1\right)$

$Y=\mathrm{ac}\tan \left\{\frac{\sin \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}---\left(2\right)$

$N=\mathrm{ac}\tan \left\{\frac{\cos X\·\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}{\cos Y\·\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}\right\}---\left(3\right)$

Azimuthal angle beta is:

βX-Y(4)

Pitching angle theta is:

$\mathrm{\θ}=\mathrm{ac}\tan \left(\frac{\mathrm{Hm}-\mathrm{Hr}}{N\·(R+\min (\mathrm{Hm},\mathrm{Hr}))}\right)---\left(5\right)$

Wherein, Lor represents the latitude of the longitude of the locus of carrier aircraft, locus that Lar represents carrier aircraft, the sea level elevation of locus that Hr represents carrier aircraft, Lom represents the longitude of the locus of target area, Lam represents the latitude of the locus of target area, Hm represents the sea level elevation of the locus of target area, and R represents earth radius.

The calculating at controlling antenna wave beam to point angle realizes by data processing module (Data_process_module) among the FPGA.Data processing module comprises angle and turns radian module (degree_to_radian), angle calculation module (count_beta_theta) and three submodules of sensing angle computing module (radian_to_degree), as shown in Figure 7.In order to make things convenient for the sine and cosine computing in realization formula (1) ~ (5), multiplying, plus and minus calculation, data storage in arctangent cp cp operation and the processing procedure has added the SINCOS of Xilinx, MULT in the data processing module, ADD, SUB, these six kinds of data blocks of ARCTAN and RAM.

Because the used input angle of SINCOS computing all is as unit take radian, and the longitude (Hz_lor), latitude (Hz_lat), target longitude (M_lor) and the target latitude (M_lat) that solve from the data of boat appearance instrument all degree of being be unit, therefore utilize angle to turn the radian module and will input longitude and latitude and convert radian to, the method for conversion is that longitude and latitude all multiply by a conversion constant factor D TR (32 decimal numbers 1572052833).Angle turns the radian module will input longitude and latitude and convert radian to after, be entered into the angle calculation module, the angle calculation module calculates antenna beam azimuth angle beta_temp and antenna beam angle of pitch theta_temp according to the sea level elevation (Hz_h) of platform and the sea level elevation (M_h) of target according to formula (1) ~ (5) again.

Because the operation result of ARCTAN is radian, so antenna beam azimuth angle beta_temp and antenna beam angle of pitch theta_temp unit that the angle calculation module obtains all are radians, need to convert antenna beam azimuth angle beta_temp and antenna beam angle of pitch theta_temp to angle, the method of conversion is to multiply by a conversion constant factor R TD (32 decimal numbers 1201579585), and then obtain antenna beam azimuth angle beta and antenna beam angle of pitch theta, and export to resolve and finish pulse (process_finish).

Step 3: step 2 is resolved the controlling antenna wave beam to point angle that obtains send to servomechanism, the adjustment of servomechanism control antenna is pointed to,

The controlling antenna wave beam to point angle that emission synchro system and reception synchro system will be resolved respectively the antenna beam target area that obtains the cell site, the controlling antenna wave beam to point angle of the antenna beam target area of the attitude angle of carrier aircraft and receiving station, the attitude angle of carrier aircraft sends to the first antenna servomechanism of cell site and the second antenna servomechanism of receiving station, the first antenna servomechanism and the second antenna servomechanism are controlled respectively cell site's antenna according to the controlling antenna wave beam to point angle that receives and are adjusted antenna direction and receiving station's antenna adjustment antenna direction, servomechanism can be according to the stabilization of carriage angle antenna direction of described carrier aircraft, and actual sensing angle that antenna is current transfers to the emission synchro system and receives synchro system respectively.

The antenna servo module is divided into two parts of sending and receiving, and as shown in Figure 8, transmitting portion is finished the controlling antenna wave beam to point angle is sent to the antenna servo device; Receiving unit is finished the data of receiving antenna servomechanism passback.The serial ports of servomechanism is RS232, and data protocol is: baud rate 19200bps, 8 bit data positions, 1 position of rest, no parity check.

Transmitting portion comprises and sends baud rate and select module (speed_select_tx) and and turn and go here and there module (SIFU_uart_tx) and three submodules of data read module (SIFU_dat_tx).Antenna servo module controls data output period is the 100ms/ frame.Send baud rate and select module to calculate transmission 1 required clock period (576) according to the actual baud rate (19200bps) of servomechanism, output sends the sampling pulse (clk_bps_tx) of data; Data read module sends to antenna beam azimuth angle (Cal_Beta) and the antenna beam angle of pitch (Cal_Theta) successively take byte as unit by the data frame format of servomechanism and turns the string module; And turn the string module and will need data (tx_data) transformed into serial datas (rs232_tx) that send, order sends to the serial ports pin of the corresponding servomechanism of FPGA, and exports one and be sent completely pulse signal (SIFU_finish).

Receiving unit comprises and receives baud rate and select module (speed_select_rx) and string to turn also module (SIFU_uart_rx) and data are deposited three submodules of module (SIFU_dat_rx).The data passback cycle of servomechanism is the 100ms/ frame, and it is 576 that the reception baud rate selects module to calculate corresponding 1 required clock period of reception of servomechanism baud rate 19200bps, and module is output as the sampling pulse (clk_bps_rx) of receive data; String turns also, and module according to the serial port protocol of servomechanism, converts the serial data (rs232_rx) that receives to parallel data (rx_data) with 8 bit data positions; Data are deposited module according to the data frame format of servomechanism, parallel data are resolved and are deposited in antenna direction position angle (Local_Beta) and two registers of the antenna direction angle of pitch (Local_Theta).

Step 4: the data demonstration,

The first wireless transceiver system of cell site sends to spatial positional information, attitude information and the actual sensing angle of cell site the second wireless transceiver system of receiving station;

The second wireless transceiver system of receiving station is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Receive the synchro system actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfer to display unit;

The display unit of receiving station transfers to actual sensing angle information that display unit shows that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle information of spatial positional information, attitude information and antenna of receiving station according to the current actual sensing angle of spatial positional information, attitude information and antenna of the current actual sensing angle of spatial positional information, attitude information and the antenna of the cell site that receives and receiving station.

Emission synchro system control MDS radio station, cell site begins constantly to send data to receiving station, realize by the radio station sending module among the FPGA that the radio station sending module comprises and receives baud rate and select module (speed_select_tx) and and turn and go here and there module (dt_uart_tx) and three submodules of data read module (dt_dat_tx_).Whenever send frame data and produce a trigger pulse (dt_finish), trigger antenna servo module (SIFU_uart_module) to the antenna servo device transmitting antenna sensing angle of cell site.

Receive synchro system and can constantly receive the data that the cell site sends over, realize by radio station receiver module (Dt_uart_module_rx) among the FPGA, the radio station receiver module comprises that receiving baud rate selects module (speed_select_rx) and string to turn also module (dt_uart_rx) and data are deposited three submodules of module (dat_an_dt), as shown in Figure 9.Whenever finish receiving frame data and produce a trigger pulse (Dt_start_rx), trigger antenna servo module (SIFU_uart_module) to the antenna servo device transmitting antenna sensing angle of cell site.

The emission synchro system sends to the MDS radio station with longitude, latitude, sea level elevation, course angle, roll angle, the angle of pitch, antenna beam azimuth angle and the packing of the antenna beam angle of pitch of cell site, sends to receiving station by the radio station.Realize by radio station sending module (Dt_uart_module_tx) among the FPGA, the radio station sending module comprise receive baud rate select module (speed_select_tx) and and turn and go here and there module (dt_uart_tx) and three submodules of data read module (dt_dat_tx_), as shown in figure 10.

The serial ports in MDS radio station is RS232, and data protocol is: baud rate 19200bps, 8 bit data positions, 1 position of rest, no parity check.Radio station module controls data output period is the 100ms/ frame, and each frame data latter two byte are the CRC check code.Send baud rate and select module to calculate the transmission needed clock period of 1 bit data (576) according to the actual baud rate (19200bps) in radio station, output sends data sampling pulse (clk_bps_tx); Data read module sends to according to the data frame format in radio station longitude, latitude, sea level elevation, roll angle, course angle, the angle of pitch, antenna beam azimuth angle and the antenna beam angle of pitch of cell site and turns the string module take byte as unit sequence; And turn the string module and will need data (tx_data) transformed into serial datas (rs232_tx) that send, order sends to the serial ports pin in the corresponding radio station of FPGA, and output is sent completely pulse (dt_finish).

Simultaneously, and turn the string module also to realize the CRC check computing, the CRC generator polynomial of employing is CRC-16-IBM(x16+x15+x2+1).Serial data circulation to be sent divided by polynomial expression (11000000000000101), is obtained 16 CRC check codes at last.

The reception synchro system sends to display end with spatial positional information, attitude information and the antenna directional angle packing of cell site and receiving station, display and control software is installed on the display end, spatial positional information, attitude information and antenna directional angle in order to show cell site and receiving station play supervisory function bit to spatial synchronization.The transmission of packing data realizes by aobvious control module (XK_uart_module), aobvious control module comprises and sends baud rate and select module (speed_select_tx) and turn string module (XK_uart_tx) and three submodules of data read module (XK_tx_n) are finished, as shown in figure 11.

The serial ports of display end is RS232, and data protocol is: baud rate 19200bps, 8 bit data positions, 1 position of rest, no parity check.Aobvious control module controls data output period is the 100ms/ frame.Send baud rate and select module to calculate transmission 1 required clock period (576) according to the actual baud rate (19200bps) in radio station, output sends the sampling pulse (clk_bps_tx) of data; Data read module is with spatial positional information (the longitude Hz_lor_dt of cell site, latitude Hz_lat_dt, sea level elevation Hz_h_dt), attitude information (roll angle Hz_Gundong_dt, course angle Hz_Hangxiang_dt, angle of pitch Hz_Fuyang_dt) and antenna directional angle (position angle beta, angle of pitch theta) and the spatial positional information of receiving station (longitude Hz_lor, latitude Hz_lat, sea level elevation Hz_h), attitude information (roll angle Hz_Gundong, course angle Hz_Hangxiang, angle of pitch Hz_Fuyang) and antenna directional angle (position angle Cal_Beta, angle of pitch Cal_Theta) send to successively according to data frame format and turn the string module; And turn the string module and will need data (XK_tx_dat) transformed into serial datas (rs232_tx) that send, order sends to the serial ports pin of the corresponding display end of FPGA, and exports one and be sent completely pulse signal (XK_finish).

By above-mentioned steps, the antenna beam of airborne double-base SAR cell site and the receiving station district that can both aim at the mark can realize the spatial synchronization of double-base SAR.

Those of ordinary skill in the art will appreciate that embodiment described here is in order to help reader understanding's principle of the present invention, should to be understood to that protection scope of the present invention is not limited to such special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combinations that do not break away from essence of the present invention according to these technology enlightenments disclosed by the invention, and these distortion and combination are still in protection scope of the present invention.

Claims (6)

1. the spatial synchronization device of a double-base SAR comprises cell site's part and receiving station's part, and wherein, described cell site end specifically comprises: appearance system, the first antenna servomechanism, emission synchro system and the first wireless transceiver system are surveyed in the first location; Described receiving station end specifically comprises: the second location is surveyed appearance system, the second antenna servomechanism, is received synchro system, the second wireless transceiver system and display unit;

Attitude data information and the spatial positional information that the appearance system is used for obtaining carrier aircraft surveyed in described the first location, and the communication that obtains is arrived the emission synchro system;

Described emission synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the first location, sensing angle when calculating antenna beam target area, cell site, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the first antenna servomechanism;

Sensing angle when described the first antenna servomechanism basis receives antenna beam target area, cell site, control cell site antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the emission synchro system;

The locus that the appearance system is used for obtaining locus and known target area is surveyed in described the second location, and the positional information of obtaining is transferred to the reception synchro system;

Described the first wireless transceiver system is used for the spatial positional information of cell site, attitude information and the actual angle of pointing to are sent to described the second wireless transceiver system;

Described the second wireless transceiver system is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Described reception synchro system is surveyed the locus of appearance system acquisition and the locus of known target area according to the second location, sensing angle when calculating receiving station antenna beam target area, and the attitude angle of the sensing angle that will calculate and carrier aircraft sends to the antenna servo device of receiving station;

Sensing angle when described the second antenna servomechanism receives antenna beam target area, receiving station cell site, control receiving station antenna is adjusted antenna direction, and the actual sensing angle that antenna is current transfers to the reception synchro system;

Described reception synchro system also is used for the actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfers to display unit;

Described display unit be used for to show actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station.

2. the spatial synchronization device of double-base SAR according to claim 1, it is characterized in that, the spatial positional information of described carrier aircraft comprises: the longitude of locus, latitude, sea level elevation, described attitude data information is specially the attitude angle of carrier aircraft, comprising: crab angle, the angle of pitch, roll angle.

3. the spatial synchronization device of double-base SAR according to claim 2 is characterized in that, the sensing angle during the antenna beam target area is concrete, and to resolve process as follows:

Process intermediate variable X, Y, N are resolved in introducing, wherein

$X=\mathrm{ac}\tan \left\{\frac{\cos \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$Y=\mathrm{ac}\tan \left\{\frac{\sin \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$N=\mathrm{ac}\tan \left\{\frac{\cos X\·\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}{\cos Y\·\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}\right\}$

Azimuthal angle beta is:

β＝X-Y

Pitching angle theta is:

$\mathrm{\θ}=\mathrm{ac}\tan \left(\frac{\mathrm{Hm}-\mathrm{Hr}}{N\·(R+\min (\mathrm{Hm},\mathrm{Hr}))}\right).$

Wherein, Lor represents the latitude of the longitude of the locus of carrier aircraft, locus that Lar represents carrier aircraft, the sea level elevation of locus that Hr represents carrier aircraft, Lom represents the longitude of the locus of target area, Lam represents the latitude of the locus of target area, Hm represents the sea level elevation of the locus of target area, and R represents earth radius.

4. the spacing synchronization process of a double-base SAR comprises the steps:

Step 1: obtain spatial positional information and the attitude data information of carrier aircraft,

Spatial positional information and the attitude data information of appearance system acquisition carrier aircraft is surveyed in the second location that appearance system and receiving station's end are surveyed in the first location of cell site, and respectively the spatial positional information of the carrier aircraft obtained and the attitude data information of carrier aircraft is transferred to respectively the emission synchro system of cell site and the reception synchro system of receiving end;

Step 2: resolve the controlling antenna wave beam to point angle,

The controlling antenna wave beam to point angle that the emission synchro system of cell site is resolved the antenna beam target area that obtains the cell site according to the spatial positional information of the spatial positional information of the cell site's end carrier aircraft that obtains and known target area; The controlling antenna wave beam to point angle that the reception synchro system of receiving station is resolved the antenna beam target area that obtains receiving station according to the spatial positional information of the spatial positional information of the receiving station's end carrier aircraft that obtains and known target area;

Step 3: step 2 is resolved the controlling antenna wave beam to point angle that obtains send to servomechanism, the adjustment of servomechanism control antenna is pointed to,

The controlling antenna wave beam to point angle that emission synchro system and reception synchro system will be resolved respectively the antenna beam target area that obtains the cell site, the controlling antenna wave beam to point angle of the antenna beam target area of the attitude angle of carrier aircraft and receiving station, the attitude angle of carrier aircraft sends to the first antenna servomechanism of cell site and the second antenna servomechanism of receiving station, the first antenna servomechanism and the second antenna servomechanism are controlled respectively cell site's antenna according to the controlling antenna wave beam to point angle that receives and are adjusted antenna direction and receiving station's antenna adjustment antenna direction, servomechanism can be according to the stabilization of carriage angle antenna direction of described carrier aircraft, and actual sensing angle that antenna is current transfers to the emission synchro system and receives synchro system respectively;

Step 4: the data demonstration,

The first wireless transceiver system of cell site sends to spatial positional information, attitude information and the actual sensing angle of cell site the second wireless transceiver system of receiving station;

The second wireless transceiver system of receiving station is used for transmission spatial positional information, attitude information and the actual sensing angle of the cell site of reception, and transfers to the reception synchro system;

Receive the synchro system actual sensing angle that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle of spatial positional information, attitude information and antenna of receiving station and transfer to display unit;

The display unit of receiving station transfers to actual sensing angle information that display unit shows that spatial positional information, attitude information and the antenna of cell site is current and the current actual sensing angle information of spatial positional information, attitude information and antenna of receiving station according to the current actual sensing angle of spatial positional information, attitude information and antenna of the current actual sensing angle of spatial positional information, attitude information and the antenna of the cell site that receives and receiving station.

5. the spacing synchronization process of double-base SAR according to claim 4, it is characterized in that, the spatial positional information of described carrier comprises: the longitude of locus, latitude, sea level elevation, described attitude data information is specially the attitude angle of carrier aircraft, comprising: crab angle, the angle of pitch, roll angle.

6. the spacing synchronization process of double-base SAR according to claim 5 is characterized in that, the sensing angle during the antenna beam target area is concrete, and to resolve process as follows:

Process intermediate variable X, Y, N are resolved in introducing, wherein

$X=\mathrm{ac}\tan \left\{\frac{\cos \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$Y=\mathrm{ac}\tan \left\{\frac{\sin \left(\frac{\mathrm{Lam}-\mathrm{Lar}}{2}\right)\·\cos \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}{\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)\·\sin \left(\frac{|\mathrm{Lom}-\mathrm{Lor}|}{2}\right)}\right\}$

$N=\mathrm{ac}\tan \left\{\frac{\cos X\·\cos \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}{\cos Y\·\sin \left(\frac{\mathrm{Lam}+\mathrm{Lar}}{2}\right)}\right\}$

Azimuthal angle beta is:

β＝X-Y

Pitching angle theta is:

$\mathrm{\θ}=\mathrm{ac}\tan \left(\frac{\mathrm{Hm}-\mathrm{Hr}}{N\·(R+\min (\mathrm{Hm},\mathrm{Hr}))}\right)$

Wherein, Lor represents the latitude of the longitude of the locus of carrier aircraft, locus that Lar represents carrier aircraft, the sea level elevation of locus that Hr represents carrier aircraft, Lom represents the longitude of the locus of target area, Lam represents the latitude of the locus of target area, Hm represents the sea level elevation of the locus of target area, and R represents earth radius.

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