Radio-communication service for limited-area purposes in RWC Warsaw
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Radio-communication service for limited-area purposes in RWC Warsaw

RWC Warsaw is operating in the International Space Environments Service. It conducts heliogeophysical forecasting for the government and local commercial communications, geodetic and geological services. One of the main line of its activity is radio-communication prediction and forecast for national professionals and amateurs. Paper presents the review of the physical basis of developed algorithms and methods for radio-communication assessments. Stress is putting to the impact of different space weather phenomena, their understanding and necessary mitigation techniques applied. The technical description of the elaborated systems is demonstrated.

Z. Kłos, I. Stanisławska, G. JuchnikowskiSpace Research Centre PASBartycka 18a str, Warsaw, Poland


Space Research Centre maintains a team in charge of actual heliogeophysical data acquisition and forecasting. The team has been working within the ISES organization (International Space Environment Service). It conducts heliogeophysical forecasting for the government and commercial communications, geodetic and geological services.

Various versions of predictions and forecasts are available to interested communications professionals and radio hamsfrom a WWW site of the service http://www.cbk.waw.pl/rwc/rwc.html and from anonymous FTP site ftp://www.cbk.waw.pl/pub/ftp/rwc/idce/

This work is carried out with the use of software packages HELGEO and Ray-Route developed at SRC. The HELGEO is an automatic system of solar-geophysical data processing for analysis and forecast of solar-geophysical and the Ray-Route is a system of forecasting of HF communications conditions, including signal to noise ratio at recommended frequencies. It organizes proper data base for operational data-driven models and runs the subroutines based on such models creating at the end set of messages and files addressed to different users requirements.

This presentation puts the stress to methods and algorithms developed within last few years in the area directly linked to the radio-communication and to the related domains which their issues lead to the improvement of this.


Domain heliogeophysical data acquisition and - solar activity

Goal - CME forecasting

Tool:

Direct information from ISES and from Cracow Observatory (real-time solar radio flux at 10 frequencies) allows to forecast the potential coronal mass ejections (CMEs) appearance basing on the constructing U-type radio burst from single frequency radiospectrometr.

Direct observations of CMEs do not provide the real latitude of their origin, what is the crucial point of the geoeffectivness of this event. That is why research work in this topic has been undertaken (Skirgiello, 2003). It has been shown on the base of SOHO LASCO observations how the projection effects can be eliminated from CME latitude distribution. The proposed method is based on the assumption that events move radially, their longitudinal distribution is uniform, and they are all detected. The distributions of real latitudes have cut off at about 20o in minimum solar activity and about 50oin rise phase. The events observed at higher latitudes proved to be only apparent projections of events really originated at lower latitudes. The relevant procedure for application in the HELGEO system is under development.

The application of the inverse projection method to SOHO LASCO data. Top panel – the distributions of apparent latitudes, bottom – the distribution after elimination of projection effects.

M. Skirgiełło, Inverse projection method for determination of distribution of real CME latitudes applied to the 1997-1998 SOHO LASCO observations, Geophys. Res. Lett., Vol. 30, No. 19, 2003.


Domain heliogeophysical data acquisition and - solar and ionospheric activity

Goal - GPS signal reliability

Tool:

The TEC values for 10, 11 and 12 August 1999 obtained from five computation methods

The reliability for IGS stations BOR1 and GRAZ with the use of ROGUE SNR-8000 receivers with relative solar radio data in the period of 01.01.2000 – 08.04.2000 and 2800 MHz solar flux for the years 1970-2000

A. Świątek, L. Jaworski, R. Zdunek, I. Stanisławska, and G. Juchnikowski, 2000, High Solar Radio Activity Impact onGPS Observations, Artificial Satellites, Vol. 35, No. 1, 51-54.

A. Światek and I. Stanislawska, 2003, Total electron content obtained with the use of different GPS satellites, Cosmic Res., vol. 41(4), pp. 315-318, July-August 2003.


Domain heliogeophysical data acquisition and - radio-communication

Goal - ionospheric characteristics mapping and forecasting

Tool:

foF2 forecasted at Sofia station by means of autocovariance method

foF2 instantaneous maps for Eas Asia region by means of PLES model

I. Stanisławska and Z. Zbyszyński, 2002, Forecasting of the ionospheric characteristics during quiet and disturbed conditions, Annals ofGeophisics, 45, 1.

I. Stanisławska and Z. Zbyszyński, 2001, Forecasting of the ionospheric quiet and disturbed foF2 values at single location, Radio Sci., 36, 5, 1065-1071.

I. Stanisławska, G. Juchnikowski, and Z. Zbyszyński, 2001, Generation of instantaneous maps of ionospheric characteristics, Radio Sci., 36, 5, 1073-1081.

I. Stanisławska, G. Juchnikowski, R. Hanbaba, H. Rothkaehl, G. Sole, and Z. Zbyszyński, 2000, COST 251 Recommended Instantaneous Mapping Model of Ionospheric Characteristics - PLES, Phys. Chem. Earth (C), 25, 4, 291-294.


Domain heliogeophysical data acquisition and - radio-communication and navigation

Goal - ionospheric profiles mapping

Tool:

Plasma frequency height profiles at Pruhonice station for 15.07.2000 12 UT – inverted ionogram (full line) and two models: kriging and fitting, respectively, background NeQuITUR.

Instantaneous maps for 13.11.1998 13, 14 UT created with fitting model and as background NeQuITUR for heights between 100 km and 300 km.

I. Stanislawska, H. Rothkael, and D. Bureshova, 2003,Limited-area electron concentration height profile instantaneous maps. Adv. Space Res. (in press)

I. Stanislawska, D. Bureshova, and H. Rothkael, 2003,Stormy Ionosphere Mapping over Europe. Adv. Space Res. (in press)


Domain heliogeophysical data acquisition and - radio-communication and navigation

Goal - TEC mapping and forecasting

Tool:

Scaling factor (longitude/latitude) introduces the anisotropyof the region to the mapping procedure.

Scaling factor and the errors of optimalisation for foE, foF1, foF2 characteristics and the TEC.

One-hour-ahead forecast of TEC (TEC units) for the period October 9-13 1999 at Matera station. For comparison, real data and what is expected from persistence is shown.

TEC maps for 27 Januray 1998 6UT. Left SF=1, right SF=5

I. Stanisławska and Z. Zbyszyński, 2003, Forecasting of the Total Electron Content at a Single Location, Cos. Res., vol. 41(4), pp. 340-343, July-August 2003.

I.Stanisławska, P.A.Bradley, andG.Juchnikowski, 2002, Spatial correlation assessment of ionospheric parameters for limited-area mapping, URSI Proc., Maastricht.


Domain heliogeophysical data acquisition and - radio-communication and navigation

Goal - TEC mapping

Tool:

IONEX map constructed on the base of GPS observations from IGS stations in CODE (University of Bern, Switzerland) for day 3-th of May 2000, respectively from left: at 9:00, 11:00 and 13:00 UT.

TEC instantaneous maps at hourly intervals for 23 September 1999 (disturbance) and for 25 September 1999 (quiet conditions) constructed by means of kriging. Plus signs show locations of measurements. Values are in TEC units 1016 el/m2.

I.Stanislawska, G. Juchnikowski, Lj. R. Cander, L. Ciraolo, P.A.Bradley, Z. Zbyszynski, and A.Swiatek, 2002, The kriging method of TEC instantaneous mapping, , Adv. Space Res., Vol. 29, No. 6, 945-948

A. Świątek and I. Stanisławska, 2001, Generation of limited-area map of TEC, EGS Proc.


Domain heliogeophysical data acquisition and - radio-communication and navigation Goal - GPS-derived TEC accuracy and variability Tool:

11.02.1998 – strong positive ionospheric disturbance.

Latitudinal variation of quiet (Q) and stormy (D) slab thickness at nighttime and noon for solarminimum and maximum (longitude 30E).

A. Światek and I. Stanislawska, 2002,TEC during regional ionospheric disturbances, URSI Proc., Maastricht.

T. Gulyaeva and I. Stanisławska, 2003, Instantaneous maps of ionospheric slab thickness derived from GPS-TEC and foF2 observations, COST 271 Proceedings.


Domain heliogeophysical data acquisition and – radio-communication

Goal – propagation conditions forecasting

Tool:

The model is based on the ITU-R algorithms updated by means of 3D instantaneous mapping model.

Broadcasting field - map of S/N (signal to noise ratio) for a given transmitting station and a given moment of time. The picture illustrates in a comprehensive way localization of the regions of good or poor reception of the signal. Such plots are good illustration of the fact that quality of reception is not a simple function of distance transmitter-receiver.There are regions more distant but with better reception quality. This is off course a consequence of the nature of HF propagation. In use there are also similar pictures - sensing fields. They differ from broadcasting fields in the fixed position of the receiver and a field of transmitters is considered. It may be surprising that the two plots usually differ - guess why.


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