Signal Fingerprinting

Signal fingerprinting is a technique used in indoor positioning systems where the unique pattern of wireless signal strengths (such as Bluetooth, Wi-Fi, or RFID) at specific locations within a building is recorded and stored as a reference map. During navigation, a mobile device measures the current signal pattern and compares it against the stored fingerprints to estimate the user's position. Building an accurate fingerprint map requires sampling signal data at regular intervals throughout the environment — for example, every meter along hallways. This data collection process is one of the primary installation and maintenance costs for indoor navigation systems, as the fingerprint map must be updated when the environment or beacon infrastructure changes.