The invention relates to an attitude testing apparatus and method based on an autocollimator. The apparatus mainly comprises the autocollimator, an optical hexahedron, a double-shaft electronic level meter and a pedestal with a leveling function. The method comprises the following steps: putting the attitude testing apparatus on a firm base, allowing the autocollimator to collimate a reflecting surface of an object, then collimating the optical hexahedron with an autocollimation gyro theodolite and measuring the included angle between the apparatus and a true north azimuth reference; starting the autocollimator for recording and retrieving of continuous data of the attitude of the reflecting surface of the object and starting the double-shaft electronic level meter for recording and retrieving of continuous data of horizontal attitude; and after completion of recording and retrieving of the data, processing the data of the autocollimator and the double-shaft electronic level meter by using a data processing method for the attitude testing apparatus so as to eventually obtain continuous changes of the attitude of the reflecting surface of the object in a geographic coordinate system, thereby meeting demands of continuous absolute measurement.

Attitude testing apparatus and method based on autocollimator

In this Letter, we propose and demonstrate a novel wireless communications link using an illuminating optical fiber as a transmitter (Tx) in optical camera communications. We demonstrate an indoor proof-of-concept system using an illuminating plastic optical fiber coupled with a light-emitting diode and a commercial camera as the Tx and the receiver, respectively. For the first time, to the best of our knowledge, we experimentally demonstrate flicker-free wireless transmission within the off-axis camera rotation angle range of 0–45° and the modulation frequencies of 300 and 500 Hz. We also show that a reception success rate of 100% is achieved for the camera exposure and gain of 200 µs and 25 dB, respectively.

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Optical camera communications link using an LED-coupled illuminating optical fiber.

Yb3+-doped YMgB5O10 (Yb:YMB) crystals with better crystalline quality were grown successfully using the optimized flux of Li2O–B2O3–LiF instead of the traditional K2O3–MoO3 flux by the top-seeded solution growth method. The systematic investigation of the crystal growth, structure characteristics, polarized absorption and emission spectra, fluorescence decay curve and laser properties of the Yb:YMB crystal was reported for the first time. The main spectroscopic and laser parameters, such as the absorption coefficients and cross-sections, energy level schema and barycenter plot, radiative and fluorescence lifetime, emission and gain cross-sections, minimum inversion fraction, pump saturation intensity and minimum absorbed pump intensity, have been calculated and analysed in detail. The broad absorption band (FWHM, 18.4 nm, E//Z) at around 936 nm matches very well with the emission wavelength of InGaAs laser diodes. The intense spectra anisotropy and multi-wavelength emission characteristics make it possible to realize the multi-wavelength laser operation at about 1 μm. The dual-wavelength Yb:YMB laser working at 1036 and 1062 nm with a maximum output power of 3.02 W and a slope efficiency of 46.9% was achieved, which may be a potential light source for THz generation with a large frequency difference of 7.1 THz. The results reveal that Yb:YMB is a promising multi-wavelength laser crystal.

Optimization of fluxes for Yb3+:YMgB5O10 crystal growth and intense multi-wavelength emission characteristics in spectra and laser performances

The invention discloses a star simulator test platform and a test calibration method. The test platform comprises a graphical display device, a smooth platform with the adjustable height, a sliding rail with a sliding block, and a three-axis precision displacement platform, wherein the graphical display device is positioned on the smooth platform with the adjustable height and is vertical to the sliding rail; the three-axis precision displacement platform is arranged on the sliding block and can slide relative to the sliding rail; a star sensor is arranged above the three-axis precision displacement platform. The test calibration method comprises the following steps: simulating a star map; erecting the star simulator test platform, and calibrating the levelness, the verticality and the center position of an imaging part of the graphical display device; imaging the simulated star map on the graphical display device; acquiring the simulated star map on the graphical display device, and verifying the star map through using a star identification algorithm. The test platform has the advantages of simplicity, convenience and effectiveness in equipment, small size, light weight, simple erection method and low cost and is a portable function detection type star simulator test platform.

Star simulator test platform and test calibration method

The invention provides a dynamic LCOS (liquid crystal on silicon) spliced-type star simulator and a ground calibrating device of a star sensor. The dynamic LCOS spliced-type star simulator comprises a star atlas display system, an illumination system and an optical system, wherein the star atlas display system comprises an LCOSI and a LCOSII which act as display devices of the dynamic star simulator by adopting an image surface splicing mode. According to the ground calibrating device of the star sensor, by means of the advantages of small pixel size, good dynamic property, high definition, high contrast ratio, high aperture opening ratio and low cost of the LCOS, a two-LCOS splicing technique is adopted for expanding the pixel surface, so that not only is the resolution ratio for star atlas simulation improved, but also the atlas simulation precision is improved.

Dynamic LCOS (liquid crystal on silicon) spliced-type star simulator and ground calibrating device of star sensor

The invention provides a star simulator and a star sensor ground calibration device. The star simulator comprises an illumination system and an optical system. The illumination system comprises a control module, an analogue switch module, a light-emitting module, a star map target incident plate and a target. The control module generates a control signal and a star magnitude analogue signal and outputs the control signal and the star magnitude analog signal. The analogue switch module selects an analog access according to the received control signal and outputs the received star magnitude analog signal through the selected analog access. The light-emitting module includes a plurality of amplification and current drive circuits and a plurality of LEDs. And the optical system comprises a first negative lens, a first positive lens, a second positive lens, and a second negative lens. The first negative lens, the first positive lens, the second positive lens, and the second negative lens are successively arranged on optical axes of light paths at a same level. According to the star simulator and the star sensor ground calibration device in the invention, a resolution ratio and contrastof star map simulation can be improved and precision of the star map simulation can also be enhanced.

Star simulator and star sensor ground calibration device

To improve the efficiency of fiber coupling with white LED, According the fiber coupling condition, based on the optical expansion in non-imaging optics theory. Designing two coupled systems of free surface lens and elliptical reflector. Then, the coupled system was simulated and analyzed by LightTools, the results showed that the coupling system of free surface lens has the highest efficiency. Therefore, building the experimental platform of free surface lens coupling system, the results show that the coupling efficiency of fiber coupling system with LED base on Free surface lens as high as 65%. The coupling has the advantages of excellent concentrating efficiency, high coupling efficiency and low cost which can be used for reference to improve the light energy utilization of LED fiber coupling.

Fiber coupling technology of white LED

The invention provides a divergent type solar simulator optical system realizing large spot diameter and high uniformity. The system comprises an ellipsoidal condenser lens 1, a xenon lamp light source 2, a turning plane mirror 3, an optical integrator 4, an optical axis indicating device 5 and an optical filter 6, wherein the xenon lamp light source 2 is located at a first focus F1 of the ellipsoidal condenser lens 1, light passes through the ellipsoidal condenser lens 1 and is converged at a second focus F2 of the ellipsoidal condenser lens 1, and the optical integrator 4 and the optical filter 6 are sequentially arranged at the second focus F2. The system can simulate solar irradiation with the spot diameter of 1 m and the uniformity higher than 10% in the working position of 10 m and has an optical axis aligning function, and the aligning precision is high than 2'.

Divergent type solar simulator optical system realizing large spot diameter and high uniformity

The invention discloses an ultraviolet fixed star and earth simulator. The ultraviolet fixed star and earth simulator comprises a fixed star simulator body and an ultraviolet earth simulator body. The fixed star simulator body is used for simulating a constellation image from infinity, and the earth simulator body is used for simulating an ultraviolet earth image from infinity. The ultraviolet fixed star and earth simulator is installed on an ultraviolet navigation sensor through a vertical type adjusting mechanism, and the constellation image and the ultraviolet earth image are overlapped and recognized by the ultraviolet navigation sensor at the same time.

Sun Gaofei

Papers

Star simulator and star sensor ground calibration device

Fiber coupling technology of white LED

Dynamic LCOS (liquid crystal on silicon) spliced-type star simulator and ground calibrating device of star sensor

Divergent type solar simulator optical system realizing large spot diameter and high uniformity

Ultraviolet fixed star and earth simulator