About Sun outage, Causes & Prediction

What is Sun outage?

One of the most popular problem with satellite systems is known as “Satellite Solar Outage” or “Sun Outage”. During the sun outage problem, it is not possible to receive the proper signal from the satellite. That means the signal quality will be low. Sun outages affect the whole satellite systems and they are fully predictable. They arise from the operation of a satellite system and radio communications link. Elementary level physics can describe this solar outage problem.

Sun-outage

For Geosynchronous orbit: A circle 22, 300 miles above the earth in the equatorial plane. The centrifugal force and the force of gravity on an object in this orbit are exactly balanced when it rotates in synchronism with the earth. Satellites located in the geosynchronous orbit. GEO satellites, the sun outage can typically cause disruption to the received signal for a few minutes each day for a few days. The exact time, duration and date of this event depends on a some of factors including:

□ Orbital position of the particular satellite

□ Downlink antenna geographical location

□ The beam width or size of the antenna

□ The apparent sun radius as seen from the surface of the  earth (about 0.25°).

□ Alignment accuracy of the antenna direction towards the satellite

Sun-outage_calculation

(Where, Frequency= Downlink Frequency in GHz and Diameter = Antenna Diameter in meter)

 

Causes of Sun Outage

The sun is a powerful broadband microwave source with a noise temperature well in excess of 25,000 degrees Celsius. This is the cause of solar outage. When viewed from the earth, the sun passes directly behind the satellite and reception of the satellite signal which is relatively weak signal is affected by the sun microwave. Interference varies zero to high level, means slight signal distortion to complete loss of signal as the downlink signal is overcome by the noisy microwave signal from the sun.

The duration of sun outage last for several minutes in each day during that time period.  As the antenna size is smaller, the solar outage duration is last longer. For example, a 30cm dish will have a longer period of interference than a 100cm dish. Because the acceptance angle of a small dish greater than a big dish.

Solar outage event can happen for several days both before and after the peak day. This event occur at roughly in the same time in each day and may repeat for a week or more on a daily basis.

 

Prediction

Season: Spring Local Time : GMT + 6   Hours
Satellite: APSTAR-7 Longitude: 76.5 E degrees
Longitude: 90.37 E degrees Latitude: 23.7   degree
Antenna: 4.8 m C Band AZ: 211.56 EL: 58.17
Date Duration Begin End
MM/DD/YYYY mm hh:mm hh:mm
3/7/2016 2 13:12 13:15
3/8/2016 7 13:10 13:17
3/9/2016 8 13:09 13:17
3/10/2016 8 13:08 13:17
3/11/2016 7 13:08 13:16
3/12/2016 5 13:09 13:15

 

Season: Autumn Local Time : GMT + 6   Hours
Satellite: APSTAR-7 Longitude: 76.5 E degrees
Longitude: 90.37 E degrees Latitude: 23.7   degree
Antenna: 4.8 m C Band AZ: 211.56 EL: 58.17
Date Duration Begin End
MM/DD/YYYY mm hh:mm hh:mm
9/30/2016 3 12:50 12:54
10/1/2016 7 12:48 12:56
10/2/2016 8 12:47 12:56
10/3/2016 9 12:47 12:56
10/4/2016 8 12:47 12:55
10/5/2016 5 12:48 12:53
Updated: June 13, 2019 — 2:27 PM

2 Comments

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  1. Dear viewers,
    Please be alert for the Sun Outage of satellite 2016 Spring. In this post, you will get the example date and time. If you give your satellite name and your earth station location and antenna size, we will try to feedback your correct Sun Outage date and time.

  2. Thanks a lot for the article post.Really thank you! Great.

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