UHF RFID-Assisted Identification and Positioning for the Quadrotor Slung-Payload

Abstract

In this work, the indoor positioning of quadrotor using UHF RFID is studied. Compared to the existing optical positioning approach, the RFID based positioning offers low cost and portability for quadrotor applications. In particular, the quadrotor with slung-payload is investigated for some fixed height hover. To ease this fixed-height hover, a 1 and 1.5 meter long cable is considered. For said UHF RFID positioning development, some conformal antennas designed over 3D print technology are attempted, the 3D printer using FDM technology for the drone's fuselage, the antenna is integrated with the fuselage as a part. The UAV size is 20 cm long and 17 cm wide and the weight of 1.1kg. The antenna on the fuselage is divided into four parts, which work as a whole. All four antennas have the same center frequency of 920 MHz, for UHF RFID positioning and commutation. These four antennas are covered with copper foil on the fuselage, and there is a chip at the junction of the center and the wing, and the impedance is 109.42+j205.04 Ω, at 920MHz. The maximum gain is 4.1 dBi; the |�11| of the single antenna is -23 dB. At -10 dB, the tag has a bandwidth of 100 MHz. Based on this array of 4 RFID tag antennas, the positioning study is completed by an 4x4 array with an accuracy of 1 meter; accurately locating the UAV by the UHF RFID tag antenna RSSI values, range from 40 dBm to 90dBm. Also, the hollow UAV fuselage design is designed. Hollow UAV fuselage added water equivalent to half the volume of the hollow in the hollow part. When the drone moves, the water in the hollow will flow with it, affecting its RSSI reading, this effect can be used in the positioning system interface.