Vol 14, No 1 (2010) > Articles >

Software Design of Mobile Antenna for Auto Satellite Tracking Using Modem Correction and Elevation Azimuth Method

Djamhari Sirat 1 , Muhamad Asvial 1 , Arman Diponegoro 1 , Himawan Sidharta 1

Affiliations:

  1. Departemen Elektro, Fakultas Teknik, Universitas Indonesia, Depok 16424, Indonesia

 

Abstract:

Pointing accuracy is an important thing in satellite communication. Because the satellite’s distance to the surface of the earth's satellite is so huge, thus 1 degree of pointing error will make the antenna can not send data to satellites. To overcome this, the auto-tracking satellite controller is made. This system uses a microcontroller as the controller, with the GPS as the indicator location of the antenna, digital compass as the beginning of antenna pointing direction, rotary encoder as sensor azimuth and elevation, and modem to see Eb/No signal. The microcontroller use serial communication to read the input. Thus the programming should be focused on in the UART and serial communication software UART. This controller use 2 phase in the process of tracking satellites. Early stages is the method Elevation-Azimuth, where at this stage with input from GPS, Digital Compass, and the position of satellites (both coordinates, and height) that are stored in microcontroller. Controller will calculate the elevation and azimuth angle, then move the antenna according to the antenna azimuth and elevation angle. Next stages is correction modem, where in this stage controller only use modem as the input, and antenna movement is set up to obtain the largest value of Eb/No signal. From the results of the controller operation, there is a change in the value of the original input level from -81.7 dB to -30.2 dB with end of Eb/No value, reaching 5.7 dB.

Keywords: azimut, controller, digital compass, elevasi, GPS, microcontroller, modem, rotary encoder, UART
Published at: Vol 14, No 1 (2010) pages: 15-21
DOI:

Access Counter: 2157 views, 3 Untitled downloads, 1430 PDF downloads, .

Full PDF Download

References:

D. Roddy, Satellite Communications, McGrawHill Professional, New York, 2001, p.569.

T. Yoshida, K. Ohata, M. Ueba, NTT Technical Review 3/9 (2005) 60.

ITU-R Radio Regulations, Resolution 902, The World Radiocommunication Conference, Geneva, 2003.

M.O. Kolawole, Satellite Communication Engineering, Marcel Dekker, Inc., Basel, 2002, p.263.

G. Coe, CMPS03-Robot Compass Module, http://www.robot-electronics.co.uk/htm/cmps3doc.htm, diakses 24 Juni 2009.

Anon., Magnetoresistance, http://en.wikipedia.org/wiki/Magnetoresistance,diakses 23 Juni 2009.

T. Avianto, Rotary Encoder, http://tiyoavianto.com/2008/11/rotary-encoder.html, diakses 7 September 2009.

Anon., General Magnetoresistive sensors for magnetic field measurement, http://www.nxp.com/acrobat_download/various/SC17_GENERAL_MAG_2-1.pdf,diakses 7 September 2009.

Jyh-ChingJuang, Proceedings of American Control Conference, 2 (2003) 1098.

S. Basu, D. Voelz, JOSA Journal, 25/7 (2008) 1594.