978-1-4673-9424-6/15/$31.00 ©2015 IEEE Design of Camera Array Interface Using FPGA for Nanosatellite Remote Sensing Payload Whildan Pakartipangi, Budi Syihabuddin School of Electrical Engineering Telkom University Bandung, Indonesia whildanpakar@gmail.com, budisyihab@telkomuniversity.ac.id Denny Darlis School of Applied Science Telkom University Bandung, Indonesia dennydarlis@telkomuniversity.ac.id Abstract—Image quality is one of the important aspects in nanosatellite remote sensing missions. Image quality parameters, such as image detail and coverage area, have to be taken into consideration in designing nanosatellite remote sensing payload while limited mass, dimension, and power consumption of nanosatellite add another constraint. Lengthening the lens focal length of the camera can increase the image detail but this causes the smaller coverage area of the image. To maintain the detailed image with wide coverage area, the concept of synthetic aperture optical imaging is used in this research. Synthetic aperture optical imaging is a concept that combines images from array of camera capturing the same object from various angles. FPGA XuLA2 LX9 is used as On Board Data Handling (OBDH) in this research to increase the performance. The system built in this research is synthetic aperture optical imaging with 2 x 2 cameras, using LS Y201 camera modules which produces JPEG image with VGA resolution 640 x 480 pixels. The result achieved in this research is image with resolution 1280 x 960 pixels produced by 4 cameras with resolution 640 x 480 pixels with the average time of fetching the image data is 27.58498 s for low compressed image and 11.1972 s for high compressed image. Keywords—Nanosatellite; Synthetic Aperture Optical Imaging; FPGA; Remote Sensing Payload I. INTRODUCTION Nanosatellite is a kind of miniaturized satellite with mass between 1 kg and 10 kg [1]. Nanosatellite orbits the earth at LEO height, 700 km above the earth surface. With its small size, production cost of nanosatellite is far lower than geostationary satellite. Nanosatellite also has highly customizable payload, resulting the vast range of nanosatellite mission research. Therefore, there has been many nanosatellite researches conducted by students in academic field as well as professionals in industrial field. One of the nanosatellite missions is remote sensing. Remote sensing is the technique to get the information of an object without making physical contact with the observed object. The sensors are used in remote sensing to collect the information of the object from electromagnetic waves reflected by the object. CMOS and CCD are optical sensors which capture visible light [2]. Many nanosatellite projects use CMOS as the sensor of remote sensing payload because of its low cost, low power consumption, and its good image quality, almost as good as CCD sensor [2]. Nanosatellite Laboratory of Telkom University is also developing and researching nanosatellite with remote sensing mission. It is shown by [3], CAM130 camera module is used where it can produce image with coverage area 305.38 km x 240.81 km. The image detail can be increased by lengthening the lens focal length of camera. But the longer the lens focal length, the smaller the Ground Sample Distance (GSD) of the image, causing the smaller image coverage area [4]. To obtain wide image coverage area with long lens focal length, synthetic aperture optical imaging was applied in this research. It is a technique using array of cameras like using big virtual lens to capture the image [5]. This technique produces detailed and high resolution image by combining images from each camera. In this research, camera array interface will be designed using FPGA to enhance the ability of image capturing from [6] with combining 4 camera based on [5] which is arranged to 2 x 2 array. The main components used in this research are XuLa2 LX9 Spartan 6 as camera controller and CMOS Camera as the sensor. The camera module used in this research is LinkSprite JPEG serial Camera with CMOS as its sensor, producing image with VGA resolution 640 x 480 pixels. The consideration to choose this camera module is its low cost, low power consumption, and UART serial communication make this camera module easy to integrate and to control. II. SYSTEM OVERVIEW A. Nanosatellite Nanosatellite is an artificial satellite which has mass between 1 and 10 kg. Due to its size and mass below 500 kg, nanosatellite belongs to miniaturized satellite [1]. Nanosatellite orbits the earth at Low Earth Orbit (LEO) height, 700 km above the earth surface. The advantage of nanosatellite development is its low production cost and can carry various missions in its payload. The launching cost of nanosatellite is also low because it can be launched by piggybacking the rocket that carries another satellite. Because of its low development cost, there has been many nanosatellite researches. Nanosatellite has various missions, remote sensing is one of the missions. Nanosatellite with remote sensing missions