Ionospheric data collection and analysis over indian region recent results
This presentation is the property of its rightful owner.
Sponsored Links
1 / 32

Ionospheric data collection and analysis over Indian region - Recent results PowerPoint PPT Presentation


  • 94 Views
  • Uploaded on
  • Presentation posted in: General

Ionospheric data collection and analysis over Indian region - Recent results. By C.L.Indi, Jt. GM (GAGAN) Surendra Sunda, Manager (GAGAN) Airports Authority of India. First Meeting of ionospheric Studies Task Force (ISTF/1) 27 th -29 th Feb 2012. Overview. Current status of GAGAN

Download Presentation

Ionospheric data collection and analysis over Indian region - Recent results

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Ionospheric data collection and analysis over indian region recent results

Ionospheric data collection and analysis over Indian region- Recent results

By

C.L.Indi, Jt. GM (GAGAN)

Surendra Sunda, Manager (GAGAN)

Airports Authority of India

First Meeting of ionospheric Studies Task Force (ISTF/1)

27th -29th Feb 2012


Overview

Overview

Current status of GAGAN

Receiver and Data formats

Data Processing

TEC variability

Recent results

Scintillation

GSAT-8

Loss of lock

Depletions


Ionospheric data collection and analysis over indian region recent results

2008

2007

2004

GAGAN

2013

GAGAN works as per ICAO SARPS

SDCM

2011

GAGAN supports for interoperability of SBAS & seamless air navigation in the World


Ionospheric data collection and analysis over indian region recent results

GAGAN Segments

GAGAN Space Segment

GPS (24)

GEO (3)

GAGAN SIS

Civilian Aircraft

GAGAN User Segment

GAGAN Ground Segment

24 GPS core Constellation

3 GEO – GSAT-8, GSAT-10, GSAT-15

(@ 55° , 82° , 83° longitude)

INMCC

(2)

INLUS

(3)

INRE

(15)

GAGAN for safety of life application. Provides GEO PRN127 & 128 with certified RNP0.1 (for Enroute) & APV1 (for Approach) level of service

128KBps/2MBps

DCN(4)

15 INRES: (GAH,GBG,GBS,GCC,GDP,GGO,GGT,GGY,GJU,

GJR,GMN,GNP.GPB,GPR,GTV)

2 INMCC (Bangalore- GBM & GBC)

3 INLUS (Bangalore – GBL & GLL & Delhi - GDL. )

4 DCN


Ionospheric data collection and analysis over indian region recent results

GAGAN – Ground Segment

GDL

Gaya

Gaya

GBL

GLL

*

GBM

GBC

GAGAN Reference Station (15)

GAGAN Master Control Centre (2)

GAGAN Land Up Link Station (3)


Ionospheric data collection and analysis over indian region recent results

INMCC CTF Building

INLUS 11m Antenna

1

2

4

3

Bangalore INRES Facility

VSAT Antenna (6.3m Dia)

GAGAN Ground Segment Sites


Ionospheric data collection and analysis over indian region recent results

GAGAN Configuration

GPS 1 to 32

INLUS #3

PRN 127 (DD)

INLUS #1

PRN 127(BG)

INLUS #2

PRN128 (BG)

DATA COMMUNICATION NETWORK @ 2 Mbps / 128 Kbps (OFC Link)

DATA COMMUNICATION NETWORK @ 2 Mbps / 128 Kbps (OFC Link)

DATA COMMUNICATION NETWORK @ 128 Kbps /2Mbps(OFC & V Sat - 4 Link)

INMCC #2

(BG)

INMCC #1

(BG)

INRES-1

INRES-2

INRES-15

GSAT-10

GSAT- 15

GSAT-8

SIS withPRN 128

GSAT-15 In-orbit Spare

SIS withPRN 127

DATA COMMUNICATION NETWORK @ 128 Kbps /2Mbps(OFC & V Sat - 4 Link)

● ● ● ●


Ionospheric data collection and analysis over indian region recent results

GAGAN Configuration


Ionospheric data collection and analysis over indian region recent results

GAGAN Space Segment Coverage

PRN128

PRN127

GSAT- 8 at 55°

GSAT-15 at 83°

GSAT-10 at 82°


Ionospheric data collection and analysis over indian region recent results

GAGAN Milestone

June 2012

July 2013

Aug 2003

May 2006

Aug 2007

June 2009

Dec 2010

May 2011

July 2011

July 2011

Dec 2011

Mar 2012

GAGAN Certification

TEST SIS

GSAT-8 Launch

GSAT-10 Launch

TDS FSAT

MLDF Model

TDS PSAT

FOP PSAT

FOP FSAT

GEO-8 Integration

TDS START

FOP START

TDS RFP(2002)

TDS Phase(2003-07)

TDS RFP(2009)

FOP Phase(2009-13)

1 Yrs

4 Yrs

1 Yrs

4 Yrs


Ionospheric data collection and analysis over indian region recent results

Grid Based Ionosphere Model For GAGAN

  • IGM-MLDF (Indian GIVE Model- Multi Layer Data Fusion):

    • New Multi layer Grid Based Model

    • Uses Data Fusion Technique

    • Provides GIVD, GIVE at 350 km (as per MOPS)

  • This model does not call for any change to the existing SBAS

  • message structure

  • No change for the legacy users

  • Algorithm evaluated using :

    • GAGAN TEC receiver data

    • High quality live data (supertruth) collected over 15 INRES locations

  • Achievable APV1 performance during nominal days:

  • 76% over Indian land mass


Gps tec data stations

GPS- TEC data Stations

Total 26 receiver stations

Latitude range – 8.5o N to 31o N

Longitude range- 72.2 o E to 92.7o E

Minimum separation- 400 Km


Receiver and data format

Receiver and Data Format


Data format continued

Data format-continued

  • RINEX (Level 1)

    • Raw binary data is converted into RINEX V.2.10 using the Novatel’s ‘Convert4’ tool.

    • Sampling interval is 10 seconds.

    • Format is different from that of IGS stations.

  • ISMR (Level 2)

    • Standard output format in GSV receivers.

    • Provides slant TEC, Scintillation index, C/No, satellite position, Lock time etc. at one minute interval.

    • Kalman filter is used for receiver bias still there is an issue in bias estimation.


Rinex v 2 10 sample

RINEX V.2.10 sample

2.10 OBSERVATION DATA G (GPS) RINEX VERSION / TYPE

Convert 27-Aug-2009 09:58 PGM / RUN BY / DATE

Signal Strength values S1,S2 are in dBHz COMMENT

MARKER NAME

MARKER NUMBER

OBSERVER / AGENCY

NovAtel GPSCard REC # / TYPE / VERS

ANT # / TYPE

1668621.9862 5475083.1776 2805416.9267 APPROX POSITION XYZ

0.0000 0.0000 0.0000 ANTENNA: DELTA H/E/N

1 1 WAVELENGTH FACT L1/2

1 1 7 G02 G03 G04 G06 G07 G08 G09WAVELENGTH FACT L1/2

1 1 7 G10 G11 G12 G13 G14 G15 G16WAVELENGTH FACT L1/2

1 1 7 G17 G18 G19 G20 G21 G22 G23WAVELENGTH FACT L1/2

1 1 7 G24 G25 G26 G27 G28 G29 G30WAVELENGTH FACT L1/2

1 1 2 G31 G32 WAVELENGTH FACT L1/2

COMMENT

COMMENT

8 C1 L1 D1 S1 P2 L2 D2 S2 # / TYPES OF OBSERV

10.000 INTERVAL

2008 09 11 06 24 40.0000000 GPS TIME OF FIRST OBS

2008 09 12 06 24 30.0000000 GPS TIME OF LAST OBS

Leap Seconds Unknown COMMENT

END OF HEADER

08 09 11 06 24 40.0000000 0 9G23G13G08G27G25G07G28G03G19

-33768328.06149-177453830.89549 -2902.06249 49.619 -33768324.54448

-138275715.81748 -2261.50048 46.266

-35328933.82449-185654810.44349 -1173.87549 51.669 -35328931.46449

-144666068.99349 -914.87549 51.600

-33034931.25049-173599714.79949 2254.62549 48.078 -33034927.88447

-135272481.22747 1756.68847 44.583

-33946541.40549-178390264.37449 1471.25049 50.869 -33946538.78749

-139005377.87249 1146.25049 50.019

-34300753.31149-180251685.45049 227.31249 51.596 -34300750.36449

-140455847.24249 176.93849 51.127


Data processing

DATA PROCESSING

Raw binary data

ISMR

CODE

Website

P1C1 Bias

APPLY SATELLITE BIAS

Monthly

APPLY RECEIVER BIAS

KALMAN FILTER

Rx Bias

Monthly

ISMR OUTPUT

( EXCEL)


Tec variability

TEC Variability

TEC shows a good correlation with solar activity.

Annual, semi-annual, seasonal and diurnal variations of TEC have been studied using the continuous data measurement from 2004 onwards.

Large day-to-day variations are prominent feature of anomaly region.


Ionospheric data collection and analysis over indian region recent results

Scintillation Effects on GNSS

GPS

SBAS

Reduced Availability

Grid based

model

Loss of lock

Loss of

lock

Under Sampling

user position

Outage of GNSS

Service

Poor

GDOP

Signal

Fading

GIVE

Reduced Accuracy


Recent results on scintillation

Recent results on scintillation

A sharp rise in the number of scintillation events with their strength and duration has been observed with increasing solar activity in 2011.

Total scintillation epochs (S4>0.4) from all the receivers in 2004 were around 6000 whereas in 2011 they shoot up to 60,000 i.e. 900% increase in the scintillation occurrence.

The maximum duration of scintillation event/patch (continuous S4>0.4) observed in 2004 was of 25 minute whereas it is of 80 min in 2011.

October 2011 witnessed the maximum scintillation of moderate to severe intensity. It was almost a daily phenomena during this month.


Continued

-continued

  • The characteristics have been defined very well using the continuous data of 2004-2011 over the Indian equatorial and low latitude region.

  • Maximum probability of scintillation occurrence is between 2000 hrs to 2230 hrs local time.

  • The strength of scintillation increases in accordance with EIA. It is severe at the crest of EIA due to high background electron density and moderate to low at magnetic equator from where it originates.


Day wise scintillation occurrence in october 2011

Day-wise Scintillation occurrence in October 2011


Scintillation examples in 2011

Scintillation examples in 2011

13/10/2011

Hyd

12/10/2011

MUM

PRN-15

PRN-15

12/10/2011

VIZ

12/10/2011

Hyd

PRN-18

PRN-22


Scintillation observations from gsat 8

Scintillation observations from GSAT-8

Observations from GAGAN satellite GSAT-8 (PRN-127) may give new insight into the spatial and temporal variations of scintillation due to its fixed position (IPP) contrary to GPS satellites.

It can be helpful in determining the plasma bubble drift velocity.

Very strong scintillation of the duration of about 2 hours have been observed.

Scintillation impact on SBAS satellite is more severe as it directs affects the GNSS Service and its availability.

Two to Three SBAS satellites at different positions may help in avoiding the scintillation impact.


Examples of gsat 8 scintillation measurements

Examples of GSAT-8 Scintillation measurements

28/10/2011

IPP- 23.20 N, 780 E

IPP- 21.50 N, 71.20 E


Comparison of gps and gsat 8

Comparison of GPS and GSAT-8

GSAT-8

Nov 9

Nov 10

GPS

PRN-31


Impact of scintillation loss of lock

Impact of Scintillation- Loss of lock

Loss of lock is one of the major effects of scintillation.

Severe scintillation over a large coverage area may impact more than 2 satellites leading to loss of lock.

This may lead to poor GDOP thereby reducing the accuracy of position.

A case study on quantitative analysis of loss of lock is carried out on a severe scintillation day.

Though L2 gets unlock more often than L1 due to weaker strength, the analysis was done on L1 signal unlock which is also used as downlink frequency for SBAS satellites.

The analysis is based on RINEX data (10 sec interval),.


Loss of lock effect on satellite availability

Loss of lock- effect on satellite availability

Gaya

Kolkata

April 6

April 6

Severe

Scintillation

Day

No. of Visible

satellites

going down

due to scintillation

April 9

April 9

Scintillation

Free day


Impact of scintillation loss of lock1

Impact of Scintillation – Loss of lock

6 April, 2011- Severe Scintillation Day

9 April,2011- Scintillation Free day

Total number of IPPs drop down drastically during scintillation period starting from ~14 UT to ~19 UT.

There is ~15% reduction in the number of IPPs during severe scintillation period (14UT to 16 UT).


Depletion

Depletion

  • Deep depletions (plasma bubbles) have been observed at various stations during 2011.

  • Depletions are mostly associated with scintillation.

  • Depth of depletion in the order of 30-80 Slant TEC units ( 5 m - 13m slant delay) are observed.

MUM

13/10/11

PRN-3

90 TEC

Bubble

Loss of Lock


Depletion1

A very large depletion / plasma bubble, with the depth of 46 TEC units ~ 7.5 meters is observed at Ahmedabad for PRN-13 on March 29, 2011 between 16-17 UT.

The width of bubble is ~ 200 Km through which satellite signal traverses for close to 30 min.

The onset IPP is 19.430 N, 73.300 E and end IPP is 17.620 N, 73.630 E, thus satellite was traveling in opposite direction of bubble.

Depletion

bubble

Ahmedabad


Slant differential range delay

Slant differential range delay

  • Slant Differential range delay is calculated using 3 GPS receivers at Ahmedabad for PRN -13.

  • RX ID – 925 and 214 are collocated at SAC and RX ID 527 is installed at Ahmedabad Airport having a radial distance of ~15 km

  • Sharp rise in differential delay for SAC and Ahmedabad airport receivers is observed at the boundaries of bubble.


Ionospheric data collection and analysis over indian region recent results

Thank You


  • Login