Draft Thesis: Imaging Payload System Design for Nano-Satellite Applications for Low-Earth Orbit

IFCAM and IFBATT undergoing Random Vibration Test in the Z-axis at SaTRec, Daejon

I have been coming to school every single forsaken day for the past three weeks to write up a draft version of my thesis for my impending defense next week. So much so that I thought yesterday was thursday when the whole world was cheering that it was friday.

Turns out, i missed a class, missed an appointment, forgot stuff I was supposed to do on friday because I seriously believed it was thursday. Anyways, I got the draft done, which is kind of nice.

I still have a whole month before I submit my thesis officially, so the final thesis will certainly turn out to be very different than one here. I am not even sure if I am allowed to do this...

My Prof teaching me how to bind my thesis 

Draft Abstract:

[ENGLISH]

This study presents a complete design of an imaging payload for CubeSat standard. The payload is intended to perform basic remote sensing and is a non-critical mission payload for Seoul National University’s first CubeSat, SNUSAT-1. The camera has a MT9D111 2M pixel image sensor with a STM32F429ZI processor which can run up to 180MHz. The downlink bandwidth is limited and so forth, the camera is configured to take images at QQVGA format with 2x binning and 4x row/column skipping. While the internal SRAM is used to store image buffer, the design can incorporate an external 8MB SDRAM if required. For non-volatile storage, 8MB flash and 4GB SD card is in place.

Initial outdoor testing showed a need for 680nm Infra-Red cut-off filter. Optics was revised to a micro lens from Edmund Optics with a Ground Sampling Distance of about 650m with a Ground Swath of about 570x400km which covers South Korea. Random Vibration and Vacuum testing showed no issues on the design. Furthermore, the design proposed is modular and has been used for developing the On-Board Computer for SNUSAT-1.

Keywords: CubeSat, Imaging Payload, Remote Sensing, Modular Design

[KOREAN] (thanks to Hyunjin)

본 논문에서는 큐브위성의 영상 탑재체에 대한 총괄 설계 연구에 대해 다룬다. 해당 영상탑재체는 궤도상에서의 기본적인 원격 탐지를 위해 설계되었으며, 서울대학교 최초의 큐브위성인 SNUSAT-1에 장착되어 영상 촬영 등의 추가 임무를 수행할 예정이다. 탑재체에 내장된 카메라는 2메가 픽셀 해상도의 MT9D111 이미지 센서를 사용하며, 측정한 영상정보를 처리하기 위해 180MHz로 구동되는 STM32F429ZI 프로세서를 사용하였다. 또한 촬영된 이미지는 기본적으로 내부 SRAM 버퍼에 저장되며, 외장 8MB SDRAM도 사용할 수 있도록 설계하였다. 본 시스템에서는 비휘발성 저장장치로 8MB 플래시 메모리와 4GB SD카드를 장착하였다. 

초기 야외 실험에서는, 680nm 대역의 적외선 컷오프 필터가 필요한 것이 확인되었다. 광학계는 Edmund Optics 사의 마이크로 렌즈를 사용하는 것으로 수정하였으며, 이 때 지상샘플링거리는 650m, 지상관측폭은 570x400km로 남한 전역을 촬영할 수 있다. 진동 및 진공 환경 시험을 통해 시스템 설계 관련 특이사항이 없는 것으로 확인되었으며, 유동성을 가진 본 설계는 SNUSAT-1의 온-보드 컴퓨터 개발에 사용되었다. 

주요어: 큐브워성, 영상탑재체, 원격 감지, 모듈 설계

Draft V1.1 copy can be downloaded [HERE]. Has been watermarked, btw. 

Now need to head out and get my suit from the dry cleaners.