Calibration method and calibration system for calibrating a direction finding device

A calibration method of calibrating a direction finding (DF) device, the calibration method comprising the steps of

• positioning a mobile test device at a first position relative to the DF device to be calibrated, wherein the mobile test device comprises a GNSS circuit and a transmission circuit, wherein the GNSS circuit is configured to determine a GNSS position of the mobile test device, and wherein the transmission circuit is configured to generate and transmit a wireless test signal;
• obtaining, by an analysis circuit, the GNSS position of the mobile test device;
• generating and transmitting, by the transmission circuit, a wireless test signal;
• receiving, by the DF device to be calibrated, the wireless test signal;
• determining, by the DF device, a DF heading based on the wireless test signal;
• and
• determining, by the analysis circuit, an error angle based on the DF heading and based on the GNSS position obtained.