Performance Evaluation for Local User Terminals Dedicated for Search and Recues Services from LEO Satellites | Chapter 07 | Advances in Mathematics and Computer Science Vol. 2
Aims:
NOAA’s (National Oceanic and Atmospheric Administration) - LEO environmental
satellites provide continuous coverage of Earth, supplying high-resolution
global meteorological, oceanic and space observation data. These satellites are
part of the international Search and Rescue Satellite Aided Tracking (SARSAT)
system. SARSAT is designed to provide distress alert and location data in order
to assist on search and rescue operation. SARSAT system detects and locates
distress beacons (406MHz) activated at distress location. System calculates the
distress event location using Doppler processing techniques. Each satellite
pass transmits information about distress location. Passes with too short
communication duration, are considered as missed passes. Communication duration
analysis, among SARSAT satellites and local user terminal (LUT) dedicated for
search and rescue services are provided. LUT implementation process and the
mask record are also given.
Study
Design:
Simulation.
Place and Duration of Study: NOAA Satellite
Operations Facility, Suitland, MD, USA, October, 28 - December 24, 2009.
Methodology: Communication analysis,
are based on the hypothetical terminal assumed to be implemented in Kosovo
(LUTKOS). Four hypothetical beacons
indicating random distress locations are considered. Satellite orbital altitude
of 860 km, orbital time of 102 minutes and inclination of 98.7º. Communication
duration is considered for period 1-30, October 2009. 57560 satellite passes
were considered to conclude about missed passes.
Results: For Doppler processing at
least four events are required. Duration of 250s is considered as the lower
margin, providing at least four Doppler events. The highest events density was
in between 300s to 700s, sufficient for distress location determination. Only
3% of total considered passes were below 250s. The ratio of missed passes over
total passes for the whole ground segment results as 0.17%, or in average
0.021% per month.
Conclusion:
Through LUTKOS simulation, it is confirmed communication reliability and proper
functionality of LUTKOS with a single SARSAT satellite.
Author(s) Details
Dr. Shkelzen Cakaj
Post and Telecommunication
of Kosovo, Prishtina, Kosovo.
Faculty of Electrical and
Computing Engineering, University of Prishtina, Kosovo.
Faculty of Information
Technology, Polytechnic University of Tirana, Albania.
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