Optical measurement systems suffer from a fundamental tradeoff between the field of view (FOV), the resolution and the update rate. A compound eye has the advantages of a wide FOV, high update rate and high sensitivity to motion, providing inspiration for breaking through the constraint and realizing high-performance optical systems. However, most existing studies on artificial compound eyes are limited by complex structure and low resolution, and they focus on imaging instead of precise measurement. Here, a high-performance lensless compound eye microsystem is developed to realize target motion perception through precise and fast orientation measurement. The microsystem splices multiple sub-FOVs formed by long-focal subeyes, images targets distributed in a panoramic range into a single multiplexing image sensor, and codes the subeye aperture array for distinguishing the targets from different sub-FOVs. A wide-field and high resolution are simultaneously realized in a simple and easy-to-manufacture microelectromechanical system (MEMS) aperture array. Moreover, based on the electronic rolling shutter technique of the image sensor, a hyperframe update rate is achieved by the precise measurement of multiple time-shifted spots of one target. The microsystem achieves an orientation measurement accuracy of 0.0023° (3σ) in the x direction and 0.0028° (3σ) in the y direction in a cone FOV of 120° with an update rate ~20 times higher than the frame rate. This study provides a promising approach for achieving optical measurements with comprehensive high performance and may have great significance in various applications, such as vision-controlled directional navigation and high-dynamic target tracking, formation and obstacle avoidance of unmanned aerial vehicles.

For celestial measurement, it is difficult to enable a single optical system to image and measure both stars and the sun due to vastly different light intensity of targets and limited response capability of the image sensor pixel. Here, we develop an all-day optical attitude sensor integrating stars and the sun measurement based on extended pixel response model of the CMOS APS (Active-pixel sensor) imager. For extremely large light intensity, we extend the conventional pixel response model to the oversaturated stage where the pixel values reverse and drop below the saturation value. Based on this, the integration of the star sensor and the sun sensor is realized. The pixels image the starry sky with linear response, and make use of the oversaturation response to image the sun and obtain a black spot on the bright background. This principle enables the capability of all-day high-precision attitude measurement using a single miniaturized sensor. An integrated optical attitude sensor is designed and manufactured. Ground-based observation results show that the orientation accuracy from sun measurement is better than 9" (3σ), and the attitude accuracy from star measurement is better than 5" (3σ) for pointing and 11" (3σ) for rolling. The sensor can be applied to high-precision all-day navigation systems for miniaturized spacecrafts and aircrafts.

No abstract

No abstract