Two Reference points Underwater Positioning System for Swarming AUVs Team Operation

This paper describes an Underwater Positioning System for plural AUVs with swarming operation. Although a conventional Underwater Positioning System needs more than three known reference points by Long Base Line (LBL) method, the proposed system only needs two GNSS supported reference points. Then the reference points of the system can be configured with only one Ship and one Buoy towed by it. However, the system additionally makes use of depth information and distance information between AUVs. Targeting system configuration is with two reference points (BS1 and BS2) and three AUVs (UE1, UE2, UE3) arranged in a triangle. The system is composed of OFDM-based Down Link (DL) and Up Link (UL) communication function to deliver GNSS information, commands etc. and Distance measurement function between all nodes by sending 10ms special sequence such as Chirp between BS and UEs as DL and Zadoff-Chu (ZC) sequence between UEs as Side Link (SL). Intensive computer-based signal processing simulation has been performed for two scenarios such as 70 m shallow case and 3000 m deep case. The simulation result has shown that any UE can identify it's and other UEs' positions even SL's Carrier to Noise Ratio CNR= 0dB with DL's CNR=6dB.