scholarly journals Desain dan Implementasi On-Board Computer/ On-Board Data Handling (OBDH) pada UGM-SAT

2015 ◽  
Vol 5 (1) ◽  
pp. 77
Author(s):  
Bakhtiar Alldino Ardi Sumbodo ◽  
Agfianto Eko Putra
Keyword(s):  
Real Time ◽  
Error Detection ◽  
Extreme Temperature ◽  
Internal Clock ◽  
Data Handling ◽  
Engineering Model ◽  
Real Time Clock ◽  
Error Detection And Correction ◽  
S Model ◽  
Industrial Standards

AbstrakTelah berhasil dibuat model teknik subsistem OBDH dari UGM-SAT. Subsistem OBDH bertugas untuk mengendalikan pertukaran data dan komunikasi antara OBDH dengan subsistem lain. Pengendali utama dari OBDH menggunakan mikrokontroler PIC16F877A dengan frekuensi clock 20 Mhz. OBDH dilengkapi dengan empat buah eksternal EEPROM tipe 24LC256, digunakan untuk menyimpan data housekeeping satelit.Sub sistem OBDH dilengkapi dengan tiga buah sensor yaitu sensor arus ACS712ELCTR-05B-T, sensor tegangan dan sensor suhu LM355Z. Akurasi pengukuran ketiga sensor tersebut yaitu lebih dari 99%.Sub sistem OBDH dilengkapi dengan IC Real Time Clock (RTC) DS3232M dengan internal clock 32,768 KHz, digunakan untuk menyesuaikan waktu antara OBDH dengan subsistem lainnya.Pemilihan komponen pada subsistem OBDH diharuskan memenuhi kriteria yaitu berstandar industri, berukuran kecil dan memiliki tingkat konsumsi listrik rendah.Desain OBDH dirancang agar sistem dapat beroperasi pada kondisi lingkungan yang ekstrim. Komunikasi antara OBDH dengan subsistem lain menggunakan standar komunikasi I2C. Protokol komunikasi data antar subsistem dirancang dengan mengimplementasikan algoritma kode Hamming(8,4), untuk mencegah kesalahan penulisan data housekeeping pada EEPROM eksternal, yang disebabkan oleh radiasi. Kecepatan deteksi dan koreksi kesalahan pada data telemetri dengan algoritma kode Hamming(8,4) yaitu 1.800 byte/s. Model teknik OBDH dari UGM-SAT telah memenuhi spesifikasi standar dari misi satelit dan siap untuk dilakukan pengujian perangkat keras dan perangkat lunak lebih lanjut. Kata kunci—OBC/OBDH, algoritma kode Hamming(8,4), deteksi dan koreksi data, I2C Abstract The engineering model of OBDH for UGM-SAT was designed to control data handling program and tointerface the satellite subsystems to OBDH. The OBDH’s based on the Microchip microcontroller PIC16F877A with 20 Mhz clock speed. The system’s equipped with four external 24LC512 EEPROM’s with a storage capacity of 256 kB. The external memories’re used to store housekeeping information. The system’s equipped with a ACS712ELCTR-05B-T current sensor, voltage sensor and LM335Z temperature sensor. The accuracy of the measurements’re more than 99%. The system’s also equipped with IC Real Time Clock (RTC) DS3232M with an internal clock of 32.768 Hz, which’s used to synchronize the time between OBDH with other subsystems.The components of OBDH was chosen with industrial standards, small packages and low power. OBDH’s designed to operate in environments with extreme temperature conditions. The communication with other subsystems was designed to use I2C-bus. Protocol data for communication between the satellite subsystems have been designed. A HammingCode(8,4) algorithm has been implemented to protect housekeeping information from being corrupted due to radiation. Error detection and correction speed is 1.800 byte/s. The engineering model of OBDH for UGM-SAT have met the standard specifications, and ready for further testing hardware and software. Keywords—OBC/OBDH, Hamming Code(8,4) algorithm, error detection and correction, I2C

Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System Behaviour

2019 ◽  
Vol 10 (2) ◽  
pp. 17
Author(s):  
Haryono Haryono ◽  
Agfianto Eko Putra ◽  
Jazi Eko Istiyanto ◽  
Agus Harjoko
Keyword(s):  
Operating System ◽  
Real Time ◽  
Error Detection ◽  
Data Handling ◽  
System Error ◽  
Real Time Operating System ◽  
The Core ◽  
Core Function ◽  
Error Detection And Correction ◽  
Correction System

The satellite requires the support of a robust sub system. On Board Data Handling (OBDH) is the core function of the satellite subsystem and has to be error free in managing the operation of the satellite. It should withstand the harsh environmental conditions in space that has a lot of hazards caused by radiations. In view of these two conditions, the OBDH design should be able to manage the operation and overcome the hazards of radiation. In order to manage the operation Real Time Operating System (RTOS) was applied. RTOS was able to manage the task efficiently and effectively. In the aerospace domain, RTOS has become popular because of its strength in managing the operating system. Error Detection and Correction System (EDAC) system was applied to make OBDH more robust. This paper discusses the implementation of the EDAC system in tandem with the RTOS behaviour to manage the operation and increase the robustness of the system. The findings show that OBDH can be programmed successfully using RTOS to handle critical and robust operations.

scholarly journals Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System Behaviour

2013 ◽  
Vol 10 (2) ◽  
pp. 17
Author(s):  
Haryono Haryono ◽  
Eko Putra ◽  
Jazi Eko Istiyanto ◽  
Agus Harjoko
Keyword(s):  
Operating System ◽  
Real Time ◽  
Error Detection ◽  
Data Handling ◽  
System Error ◽  
Real Time Operating System ◽  
The Core ◽  
Core Function ◽  
Error Detection And Correction ◽  
Correction System

The satellite requires the support of a robust sub system. On Board Data Handling (OBDH) is the core function of the satellite subsystem and has to be error free in managing the operation of the satellite. It should withstand the harsh environmental conditions in space that has a lot of hazards caused by radiations. In view of these two conditions, the OBDH design should be able to manage the operation and overcome the hazards of radiation. In order to manage the operation Real Time Operating System (RTOS) was applied. RTOS was able to manage the task efficiently and effectively. In the aerospace domain, RTOS has become popular because of its strength in managing the operating system. Error Detection and Correction System (EDAC) system was applied to make OBDH more robust. This paper discusses the implementation of the EDAC system in tandem with the RTOS behaviour to manage the operation and increase the robustness of the system. The findings show that OBDH can be programmed successfully using RTOS to handle critical and robust operations. 

A Modified Block Matching Method for Real-Time Freehand Strain Imaging

2002 ◽  
Vol 24 (3) ◽  
pp. 161-176 ◽  
Author(s):  
Yanning Zhu ◽  
Timothy J. Hall
Keyword(s):  
Real Time ◽  
Error Detection ◽  
Imaging System ◽  
Correction Method ◽  
Strain Imaging ◽  
Block Matching ◽  
Estimation Errors ◽  
Error Detection And Correction ◽  
Specific Implementation

This manuscript reports a technical innovation that has been developed for real-time, freehand strain imaging. This work is based on a well-known block-matching algorithm with two significant modifications. First, since displacements are estimated row-by-row, displacement estimates from the previous row are used to predict the displacement estimates in the current row, thereby drastically reducing the search-region size and increasing computational efficiency. Second, a displacement error detection and correction method is developed to overcome the local tracking errors that may be more severe with freehand scanning and thereby improve the robustness of the algorithm. This algorithm has been implemented on a clinical ultrasound imaging system, and with real-time imaging feedback, long sequences of high quality strain images are observed using freehand compression. Displacement estimation errors with this method are experimentally measured and compared with results from simulation. We report only a specific implementation, with no comparison to other displacement estimators in the literature and no optimization of this specific technique. Images of tissue-mimicking phantoms with small spherical targets are used to test the ability to detect small lesions using the strain imaging technique. In vivo strain images of breast and thyroid are also shown.

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