The geomagnetic field is our natural shield against solar wind particles and cosmic radiation. It is mainly generated by dynamo processes in the Earth's outer fluid core. Magnetized rocks in the Earth's crust, electrical currents in ionosphere and magnetosphere and even ocean currents add contributions to the Earth’s magnetic field. We use geomagnetic field observations and data from other plasma or atmospheric parameters obtained from ground and space instrumentation to investigate the dynamic processes inside the Earth and in the near-Earth space environment. Our aim is to better understand space weather conditions and the future evolution of the geomagnetic field.