Ionospheric scintillation observation using GPSdata at UKM, Malaysia
Aramesh Seif ª, Mardina Abdullahª̕ ᵇ, Alina Marie Hasbi ª̕ ᵇ,ª Department of Electrical, Electronics and Systems Engineering, Faculty of Engineering and Built
Environment, Universiti Kebangsaan Malaysia (UKM), 43600 Selangor, Malaysia
ᵇ Institute of Space Science (ANGKASA), Faculty of Engineering and Built Environment, Universiti
Kebangsaan Malaysia (UKM), 43600 Selangor, Malaysia
arameshseif@yahoo.com

Aramesh Seif
arameshseif@yahoo.com

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Outline1) Introduction.
2) Methodology.
3) Result & discussion.
4) Conclusion.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Introduction•

Ionospheric scintillation: Rapid variations of amplitude and phase inradio signals caused by small scale irregularities of electron density
known as scintillation.

•Two main parameters of scintillation are :1. Amplitude scintillation(S4 index)
2. Phase scintillation (sigmaphi)

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Introduction
 Scintillations are intense in the equatorial region; they are strong athigh latitudes and weak at mid latitudes (Basu et al, 1988). The worst
source of ionosphere scintillation is at the equatorial region.

 Scintillation activity in equatorial region highly depend on thegeomagnetic condition, local time (LT), seasonal variations and the
11-year solar cycle (Basu et al, 1988).
 Scintillation phenomena has an influence on both reliability andaccuracy of the communication systems like GPS. Therefore, it isdesirable to obtain further understanding of ionosphere scintillationand effects on GPS.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Methodology
 Data recorded by GISTM with a dual frequency receiver at UKM wasused to examine ionospheric scintillation activities between January
and December 2010.

1. GISTM , type GSV4004B
EuroPak-3M
2 .GPS Antenna
3,4,5,6 .Connection cable < 30m
7. PC processing data,
8. UPS

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

 A network of GPS
Ionospheric Scintillation andTEC Monitor (GISTM)
systems
installedinMalaysia.
 Four GSV4004 receivers
have been deployed at UKM(2.55° N, 101.46° E),
UTHM (1.55° N, 103.6° E),
LANGKAWI (06.19° N,99.51° E) and UNIMAS(1.28° N, 110.25° E), inMalaysia.

Aramesh Seif

Fig.1. GPS TEC and Scintillation network over Malaysia.

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

GSV4004B dual frequency receiver The GSV4004B receiver is capable of tracking up to11GPS signals at
both the L1 and L2 frequencies of 1575.42MHz and 1227.6MHz,respectively.
 The sampling rate of the amplitude scintillation (S4 index) and phase
scintillation used in this work is 50Hz for each satellite on L1 frequency.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Amplitude scintillation
 Amplitude scintillation calculated over 60-s intervals as the standard
deviation of the detrended signal intensity (SI) and is referred to as total
S4, in (S4t) column.

 The correction to the total S4(S4cor) due to ambient noise. Then thecorrected S4 with the effects of ambient noise removed is computed bythis formula: In order to detect the occurrence of amplitude scintillation activity, theanalysis took into consideration that the S4 measurements from the GPS
satellites must exceed values of 0.2 with elevation angel greater than 30.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

ResultFig. 2. Month-to-month variations of the S4 index scintillation activities observed at UKM stationfrom January to December2010.(published by j.actaastro.2012 ( A. Seif et al.))Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

It is noted that in the equatorial region nighttime amplitude scintillations activity is associatedwith electron density irregularities occurring in F region while daytime amplitude scintillation isoften attributed to E region.
Table1. Percentage of the amplitude scintillation events detected at UKM station fromJanuary to December 2010.

MonthJanuary 2010
February 2010
March 2010
April 2010
May 2010
June 2010
July 2010
August 2010
September 2010
October 2010
November 2010
December 2010
Total

Aramesh SeifDaytime Scintillation (%) Nighttime Scintillation (%)
77.412.9
22.58
45.16
25.8
35.4
90
16.12
93.5
90
93.5
35.61%
79.63%

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Seasonal variations ofamplitude scintillation
Summer : (May, June, July and August)Equinox: (September, October, March andApril)

Winter : (November, December, January andFebruary)Fig. 3. The monthly percentage of the amplitude scintillation events occurred during
the year of 2010 at UKM station.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Seasonal variations of amplitude scintillation
 As can be seen from
Figure 4 highest percentage
occurrence of scintillations
is observed for the equinox
months and lowest isobserved for summer.

Figure 4: Percentage occurrence of GPS amplitude scintillations (S4>0.2) for
different seasons (winter, summer and equinox) during the year of 2010.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Discussion
Equinox :Ionospheric scintillation were found maximum due to the close alignment of solar
terminator with magnetic meridian. This result in simultaneous decreasing
conductivity of E region. However severe scintillations may be due to the intense
irregularities generated by quite large electric field events.
Summer:High conductivity of E region the growth rate of instability becomes slow. Electron
density is small in equatorial region during summer.

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Summary Ionospheric scintillation at UKM station was investigated using
GISTM recorded between January 2010 and December 2010.
 The results of this investigation show that amplitude scintillation withS4 ≥ 0.2 occurred mainly in January, March, August, SeptemberDecember 2010.
 The month-to-month occurrence rate of ionospheric scintillationshows that amplitude scintillation activities are maximum during theequinox months and minimum during the summer months.
 Further statistical results of the amplitude scintillation events revealed
more occurrence of nighttime amplitude scintillation (79.63%) thandaytime amplitude scintillation (35.61%).

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012

Aramesh Seif

Ionospheric scintillation observation using GPS data at Malaysia

16.08.2012