Discrete Frequency Chirp Radar Using Off-The-Shelf BLE Components
Gerrit Maus, Dieter Brückmann · 2020
A well-established radar technique is based on the analysis of the echo of a linear frequency chirp in order to get spatial information about reflecting objects. This analysis needs specialized modulation and demodulation circuits and hence requires dedicated hardware. Contrary to this, we present a coarse radar approach that can be implemented exclusively with low-cost off-the-shelf RF chipsets. The proposed method utilizes the Received Signal Strength of a discrete frequency chirp in order to resolve pairs of reflection components with common Time of Flight differences. The technique is derived in detail and it is shown that these information can be used to approximate absolute reflection depths. The real-world functionality of this low-cost radar approach is demonstrated by an experimental setup. Using standard Bluetooth Low Energy components, we extract the impact of environmental changes under certain reflection depths out of measured field strength data.