A kind of combination metering device of machine interference synthetic aperture radar base line
Technical field
The present invention relates to the combination metering device of a kind of airborne Interference synthetic aperture radar (interference SAR) baseline, relate in particular to a kind of two digital cameras, two laser range finders and Inertial Measurement Unit (IMU) of utilizing, to the position and the attitude of two radar receiving antennas hanging the interference synthetic aperture radar (interference SAR) under aircraft wing carry out accurately, the composite set of kinetic measurement.
Background technology
The system that the baseline of interference synthetic aperture radar (InSAR) the is carried out kinetic measurement space shuttle that mainly contains the U.S. and Germany's cooperation carries interference SAR system (SRTM) and U.S. GeoSAR airborne interference SAR system at present.
60 meters of the length of SRTM interference baseline, measuring system is made up of GPS location, inertial reference unit, star tracker, electronic distance measuring instrument, target tracker.The location of track mainly is to realize that with gps system bearing accuracy is better than 1m, and the main antenna attitude is measured by star tracker and inertial reference unit.Target tracker is a key device of measuring base linc motion, and it follows the tracks of three LEDs that are positioned on the outside antenna with the high precision camera.Five degree of freedom in the six-freedom degree of energy measurement outside antenna, another degree of freedom of outside antenna, promptly base length utilizes the electronic distance instrument to measure.
The baseline precision measurement apparatus of GeoSAR comprises two of inertial navigation unit, laser baseline measuring system and DGPS Receiver composition.And laser baseline measuring system comprises 5 laser range finders, 8 cameras, 5 wing gondola reverberators and 8 LED signs.Each side lay 4 cameras and 4 LED signs at fuselage, accurately measure the angle at LED sign center with camera; Lay a stadimeter on the radar antenna, all the other 4 are laid in respectively about fuselage, respectively to two reflecting prism measuring distances; Angle value and distance value are combined, calculate the three-dimensional coordinate of 1 point on each antenna and the two-dimensional coordinate of two points thus, utilize three-dimensional point to calculate base length, utilize two-dimensional points can calculate the orientation of baseline simultaneously.
Apparatus of the present invention are installed in two antennas of airborne Interference synthetic aperture radar (interference SAR) under the left and right sides wing of aircraft, use for radar emission and reception wireless signal.Still do not utilize it to do other purposes at present.
Summary of the invention
The combination metering device that the purpose of this invention is to provide a kind of machine interference synthetic aperture radar base line, two antennas that utilize existing airborne Interference synthetic aperture radar (interference SAR) are as measuring object, through synchronous data sampling, measure and calculate and obtain the accurately dynamic baseline of interference synthetic aperture radar (interference SAR).
For achieving the above object, technical solution of the present invention provides a kind of combination metering device of machine interference synthetic aperture radar base line, comprise two receiving antennas of interference synthetic aperture radar, platform, two digital cameras, two laser range finders, Inertial Measurement Unit and a processor controls, the ventral of its aircraft is installed a rigid platfor down, on platform, be installed with two digital cameras, two laser range finders and an Inertial Measurement Unit, on two antennas, settle several tangible LED markers simultaneously respectively;
LED marker on two antennas about the camera lens of two digital cameras faces toward respectively;
Two digital cameras, two laser range finders and Inertial Measurement Unit all electrically connect with processor controls, and carry out signal and communication.
Described combination metering device, the light emitting diode of settling respectively on its described two antennas is at least three.
Described combination metering device, it gathers the image of two receiving antennas, the measuring distance of laser range finder and the data of Inertial Measurement Unit by the center processor controls, realizes accurate kinetic measurement to the interference synthetic aperture radar baseline through Combined Treatment afterwards.
Described combination metering device, the LED marker of installing on its described receiving antenna, used the fixedly geometric relationship between these monumented points, the separate unit digital camera is measured the three-dimensional position of a receiving antenna in the digital camera coordinate system, adopt the collinearity equation of close-range photogrammetry, the Three-Dimensional Dynamic of receiving antenna that achieves a butt joint is measured.
Described combination metering device, its described laser range finder and digital camera synchronous acquisition data, trigger the laser pulse emission of the shutter of digital camera and laser range finder by a center processor controls, make the view data that digital camera obtains and the strictness coupling of laser ranging data.
Described combination metering device, its described two digital cameras and two laser range finder measurement data realize data fusion closely, utilize laser range finder distance to the high precision characteristic and digital camera measure on the plane to high precision, characteristic fast, realize that the complete three-dimensional high-precision of two receiving antennas is measured.
Described combination metering device, its described processor controls, position vector according to the digital camera center and the Inertial Measurement Unit center of indoor standardization, adopt the geometric transformation principle, the Inertial Measurement Unit data and digital camera, the laser range finder measurement data that obtain are carried out Combined Treatment, calculate the absolute position of receiving antenna under world geodetic system.
Description of drawings
Fig. 1 is the combination metering device scheme of installation of machine interference synthetic aperture radar base line of the present invention;
Fig. 2 is each parts annexation figure of combination metering device of machine interference synthetic aperture radar base line of the present invention.
Embodiment
Two antennas that the present invention is directed to existing airborne Interference synthetic aperture radar (interference SAR) are installed in the situation under the aircraft wing, have invented the device of following two the receiving antenna exact positions of a kind of kinetic measurement wing.Integrated two digital cameras of this device, two laser range finders and an Inertial Measurement Unit (IMU).
Digital camera and laser range finder are measured the instantaneous position and the attitude of interference synthetic aperture radar (interference SAR) antenna, Inertial Measurement Unit (IMU) is measured the position and the attitude of digital camera and laser range finder place platform, and the three combines and finally realizes the kinetic measurement of interference synthetic aperture radar (interference SAR) double antenna.
Apparatus of the present invention are according to the operation characteristic of low-to-medium altitude aircraft, integrated use the principle and the technology of digital close range photogrammetry and Inertial Measurement Unit (IMU), the composition of system and installing as shown in the figure.Two receiving antennas 1 of interference synthetic aperture radar (interference SAR), receiving antenna 2 mount in aircraft both sides wing below, the ventral of aircraft is installed a rigid platfor down, on this platform, be installed with two digital cameras 1, digital camera 2, two laser range finders 1 and a laser range finder 2 and an Inertial Measurement Unit (IMU) are settled 3 tangible light emitting diodes (LED) sign respectively simultaneously on two antennas 1 of synthetic aperture radar (SAR), antenna 2.Two antennas 1 about the camera lens of two digital cameras 1, digital camera 2 faces toward respectively, the LED marker on the antenna 2.
During apparatus of the present invention work, by digital camera 1, light emitting diode (LED) sign that 2 pairs of digital cameras are laid on the receiving antenna is measured, while laser range finder 1, laser range finder 2 is measured platform and antenna 1 in real time synchronously, accurate distance between the antenna 2, adopt the collinearity equation of close-range photogrammetry to calculate two receiving antennas 1, the instantaneous position of antenna 2 and attitude, Inertial Measurement Unit (IMU) is measured digital camera 1 simultaneously, the exact position and the attitude of digital camera 2 place platforms, concrete annexation is referring to Fig. 2, wherein, each parts on the platform: two digital cameras 1, digital camera 2, two laser range finders 1, laser range finder 2 and Inertial Measurement Unit (IMU) all electrically connect with processor controls, and carry out signal and communication.Processor controls is located in the cabin.
Digital camera 1 on the platform, digital camera 2 can accurately be measured receiving antenna 1, antenna 2 is at digital camera 1, position and attitude under digital camera 2 coordinate systems (local coordinate), because at receiving antenna 1, post 3 light emitting diodes (LED) characteristic indication point on the antenna 2 respectively, these monumented points have carried out accurate demarcation and measurement indoor in advance, with they as the constraint and the reference mark, while laser range finder 1, laser range finder 2 can provide platform and antenna 1 again, distance between the antenna 2, according to the close-range photogrammetry principle, adopt collinearity equation, just can calculate receiving antenna 1, antenna 2 centers are at digital camera 1, coordinate under digital camera 2 coordinate systems, and this coordinate information passed to processor controls.Inertial Measurement Unit on the platform (IMU) can accurately be measured the position and the attitude of digital camera 1, digital camera 2 and laser range finder 1, laser range finder 2 place platforms, and the position and the attitude information of platform are passed to processor controls.Processor controls just can be converted into the digital camera local coordinate system world geodetic system of the overall situation by the calculating of lever arm, thereby obtain two receiving antennas 1, exact position and the attitude of antenna 2 centers under the earth coordinates of the WGS8 whole world, provide the dynamic base measurement result of interference synthetic aperture radar (interference SAR).