Satellite Link Measurements
- 1. SATELLITE LINK AND METEOROLOGICAL MEASUREMENTS AT GLAMORGAN By John Philip Bhimavarapu Supervisor: Prof.Dr.Ifiok otung
- 2. Aim: To Measure the total attenuation statistics and scintillation from the analysis of HOTBIRD 6 beacon signal measured at 19.7GHz at the University of Glamorgan. Study of all sources of loss along earth-space paths. •1)Diurnal variation. •2)Gaseous (or) Clear airAttenuation. •3)Rain attenuation. •4)Scintillation.
- 3. DIURNAL VARIATION: It is the variation caused by the movement of the earth-station and the satellite.
- 4. Calculation of Gaseous (or) Clear air Attenuation. By using ITU-R P.676-8(2009-2010) model 1) Estimation of Oxygen Attenuation. 2) Estimation of Water vapour Attenuation.
- 5. Identifying the clear-sky time points. 1) Deriving the time series of moving standard deviation SDM(ti) from the beacon measurements. 2) Establishing the threshold standard deviation Usd(ti)
- 6. 2.3) Establishment of “Zero dB Reference Level”. 2.3.1) Addition of estimated gaseous attenuation to the measured signal level values. 2.3.2) Estimation of zero-db reference level relative to vacuum. 2.3.3) Estimation of zero-db reference level relative to clear sky.
- 7. 3)Calculating and plotting graphs of the total attenuation.
- 10. Scintillation: 1)Raw data is transformed to a relative signal level in db. 2)Calculation of the scintillation amplitude from the relative signal level. 3)Probability density function of scintillation over the period is calculated.
- 11. Conclusion: I here by conclude that, we achieved the calculation of the 1)Clear Air Attenuation 2)Rain Attenuation 3)Total Attenuation and 4)Scintillation by using raw beacon signal at the frequency 19.7GHz at the University of Glamorgan, Treforest, Pontypridd, Mid Glamorgan, Wales, UK.
- 12. Future Implementation: In the future, there will be demand for using higher frequencies in the satellite communications in order to meet the needs of the users. If they need to launch a new satellite then they must have a good link design which can be done by reviewing the attenuation statistics. We have calculated the attenuation statistics and will be stored in our server for record. These records are helpful for the further researchers to get an idea of the attenuation in our region and can develop a good link design for future satellites.
- 13. Bibliography: Riva, C. (2004), Seasonal and diurnal variations of total attenuation measured with ITALSAT satellite at spind' Adda at 18.7, 39.6 and 49.5GHz, Int. J. Satell. Commun.Network, 22, 449-476. ITU-R.P.676-8. (2009/2010). Attenuation by Atmospheric Gases. Radiowave propagation . Willis, M. (2006, December 26th). Absorption by Atmospheric Gases. Retrieved 03 02, 2011, from http://www.mike-willis.com/Tutorial/gases.htm Ventouras.S, A. a. (2006). Long-term statistics of tropospheric attenuation from the Ka/U band ITALSAT satellite experiment in the United Kingdom. Radio Science . I.E.Otung, M.-N. a. (1998). Extracting Scintillations from Satellite Beacon Propagation Data. Radiwave Propagation .