Observation system on TEC (Total Electron Content) in the ionosphere is a device measuring the electron density and scintillation (satellite signal fading) in the ionosphere in real-time by receiving signals from several GPS satellites. It is used for research on the impact of ionospheric changes on communications between the Earth and satellites.

[TECs]

With a surface temperature of approximately 6000˚C, the Sun emits its energy throughout the entire electromagnetic spectrum. Measuring the absolute value of energy emitted from the Sun at the correct chosen observation wavelength is significantly important to quantitatively predict the Sun's influence on space weather conditions and on the Earth.

In order to receive the absolute solar flux within the radio waveband, each wavelength requires its own receiver. Moreover, maintaining the accuracy of the absolute solar flux values demands considerable effort. Accordingly, selecting the correct wavelength is greatly important. Taking into account the continuous growth in use of various broadcasting and communications devices, and the resulting increase in demand for usable frequency range, it is now necessary that in order to accurately observe the absolute solar flux, a 'new' radio waveband must be employed despite the fact that the 2.8GHz frequency is currently used globally for space weather prediction.

An ionosonde is the most basic method of measuring the electron density in the ionospheric plasma, depending on altitude. An ionosonde measures the distribution of electrons depending on their altitude, and functions by measuring radio waves reflected by electron layers in the ionosphere following vertical incidence of radio waves.

The ionosonde used by the RRA is Digisonde-256, a model produced by the Lowell Center for Atmospheric Research at the University of Massachusetts in the United States. The frequency coverage is 0.1MHz-30MHz and pulse power, bandwidth, and observed frequency are set to 5kW, 20 kHz and 100 kHz, respectively. The result is displayed in the form of an ionogram, a graph showing received data of radio wave reflection. The interpretation of an ionogram provides data on the state of the ionosphere at a specific time when it is being observed.

[Receiving antenna]

[Transmission antenna]

[Control system]

The korea space weather center installed continuous geomagnetic observation system at the Icheon and the Yongin (Kyunghee University) and has been operated as a pair station since August 1996 to research the near-earth space environment that affects on the communication satellite through the continuous geomagnetic field observation. In 2007, the space radio center installed equivalent system additionally at the Jeju Island to monitor the variation of the geomagnetic field by latitude within the peninsula. (At July 2010, the Yongin system has moved to Gangneung and it’s on operation)

The observation network system of real-time continuous geomagnetic system consist sections of sensor, data logger and power supply, and each sensor is connected to data logger with 200m main cable. Data obtained by Magnetometer are converted to binary type data, and automatically sends to Icheon station through the private access and data collecting PC by saving at the buffer memory for temporary. Also the data at buffer memory are sending to memory card every hour, and the memory card can hold the observed data for 16 days. The geomagnetic field data observed with the data synchronizes its time by PC controller or data logger from GPS clock through the RS232C. The standard time is set up with UT (Universal Time).

Measure the three components of geomagnetic fields.To prevent temperature fluctuation, it is installed under the ground. The data resolution is 0.01nT and range of the measurements are +- 65,000 nT. Data sampling can be selected among 1,2,4,8 times/sec.

Measure the total component of the geomagnetic fieldThe instruments needs to be installed at least 1m above the ground to prevent surface geomagnetic field effects.The data sampling rate is 60seconds.

The data logger consists of magnetometer interface, Data formatter, Buffer memory, memory card drive, RS232C interface, GPS clock and display panel.

Magnetometer and data logger are operated with DC 24V and not just supplied by battery charger but also can be supplied its power for 12 hours during the power suspension.

Solar wind refers to a stream of charged particles called plasma that is ejected from the Sun and mostly consists of protons and electrons. These particles fly out toward the Earth’s atmosphere in the event of solar flares, and often affect electronic devices in satellites or cause communication problems by disturbing the geomagnetic field after colliding with particles in the Earth’s ionosphere. Interplanetary scintillation is the only ground instrument that is capable of monitoring the direction of solar wind.

The interplanetary scintillation instrument installed in KSWC measures fluctuations in speed and density of solar wind particles by observing the scintillation phenomena, which can be seen when a radio source in space passes solar wind particles. It is composed of a total of 768 antennas in 32 tiles - each tile has 24 antennas- in a phased array. Contrary to existing antennas which use motor tracking systems, the interplanetary scintillation instrument traces its object through a beam phase control system, which facilitates quick and accurate tracing of the object.

Each tile of the interplanetary scintillation consist 24 dipole antennas.
4tiles form 1 node, 32 tiles installed for total.

The Solar Radio Noise Monitor for broadband directly monitors solar flares by measuring the signal intensity of solar radio emissions at 500MHz -18GHz. It generally consists of two functions: one is absolute solar flux observation that measures the absolute values of solar flux, and the other is low frequency spectrum observation that measures the relative intensity of signals.

KSWC measures absolute intensity values of solar radio flux based on 20 frequencies at 0.5GHz -18GHz. KSWC assigns and transmits certain radio waves depending on communications frequencies’ specific required roles. As the intensity of these artificial signals is usually much stronger than the intensity of solar radio emission, communications are not affected. However, when solar flares occur, the solar radio emissions can be similar in intensity to the artificial signals, which in turn can cause problems in communications. Thus, in the event of solar flares, it is vital to promptly identify which frequency bands caused problems and establish countermeasures by monitoring the absolute values of solar radio intensity.

Compared to the fact that the absolute solar flux observation system used in countries such as the United States is operated by fixed frequencies, the system adopted in KSWC provides users with changeable frequencies. KSWC's system is more advanced because it remains constant, regardless of the variation in demand for frequency range owing to the continuous growth in telecommunications.

The relative values of solar radio intensity are measured throughout the entire spectrum between 30MHz to 500MHz. Spectrum measurement of solar radio flux is one of the representative methods to monitor solar flares along with absolute solar flux observation. It enables prediction of types of solar flares and their possible future impact by monitoring the spectrum during solar flares.

Positioned at a L1 (Lagrangian) point between the Earth and the Sun where attractive force balances centrifugal force, ACE satellite observes the passing solar wind, which is comprised of a stream of charged particles, called plasma, ejected from the upper atmosphere of the Sun. The raw data received by ACE antenna are transmitted to SWPC and then analyzed. In order to prevent a breakdown in communications and unexpected damage in the environment, related preventative systems are established based on the analyzed data.

[Antenna]

Changes in the space radio environment caused by solar black spot explosions affect the Earth in the form of geomagnetic disturbances and induced currents (GIC). Solar wind particles emitted by solar black spot explosions can cause major changes in the earth's magnetosphere and ionosphere as well as impact on the earth's magnetic field, which can lead to direct current components in ground transmission facilities. Accordingly, the Space Radio Center established a constant monitoring system that immediately provides information on the scale of induction current generated by geomagnetic disturbance by installing induction current observation machines at major substations.

The STEREO (Solar Terrestrial Relations Observatory) is a satellite launched in August 2006, with two identical satellites placed back and forth along Earth's orbit to observe solar activity images as three-dimensional images and monitor solar emissions in real time and transmit results to Earth. The STEREO satellite enables observation of the back of the sun, enabling advance forecasting and warning according to the rotation of the sun.