Abnormality detection device, abnormality detection method, and non-transitory computer-readable medium storing abnormality detection program

A method for detecting an abnormality in a number of electrons in an ionosphere, the method comprising:

• acquiring an observation value of a number of electrons at each of a plurality of observation stations that are for observation of a number of electrons in an ionosphere;
• selecting a central observation station from among the plurality of observation stations;
• selecting a plurality of peripheral observation stations from among the plurality of observation stations based on a distance from the central observation station;
• calculating a predicted observation value of a number of electrons at the central observation station based on the observation value of the number of electrons at each of the plurality of peripheral observation stations;
• calculating an estimation error between the predicted observation value of the number of electrons and an actual measured value of the number of electrons at the central observation station;
• and
• determining whether or not the actual measured value of the number of electrons at the central observation station is abnormal, based on the estimation error and a threshold value to detect an electromagnetic abnormality in the ionosphere in a sky above the central observation station.

A non-transitory computer-readable medium storing a program for causing a computer to execute a method, the method comprising:

• acquiring an observation value of a number of electrons at each of a plurality of observation stations that are for observation of a number of electrons in an ionosphere;
• selecting a central observation station from among the plurality of observation stations;
• selecting a plurality of peripheral observation stations from among the plurality of observation stations based on a distance from the central observation station;
• calculating a predicted observation value of a number of electrons at the central observation station based on the observation value of the number of electrons at each of the plurality of peripheral observation stations;
• calculating an estimation error between the predicted observation value of the number of electrons and an actual measured value of the number of electrons at the central observation station;
• and
• determining whether or not the actual measured value of the number of electrons at the central observation station is abnormal, based on the estimation error and a threshold value to detect an electromagnetic abnormality in the ionosphere in a sky above the central observation station.