	US 11,719,784 B2
	Method for positioning underwater glider based on virtual time difference of arrival of single beacon
Huifang Chen, Zhejiang (CN); Lei Xie, Zhejiang (CN); Feng Liu, Zhejiang (CN); Chenglei Lv, Zhejiang (CN); and Wen Xu, Zhejiang (CN)
Assigned to Zhejiang University, Zhejiang (CN)
Filed by Zhejiang University, Zhejiang (CN)
Filed on Sep. 22, 2021, as Appl. No. 17/481,872.
Claims priority of application No. 202011170484.6 (CN), filed on Oct. 28, 2020.
Prior Publication US 2022/0128647 A1, Apr. 28, 2022
Int. Cl. G01S 5/26 (2006.01)

CPC G01S 5/26 (2013.01)

4 Claims

1. A method for positioning an underwater glider based on a virtual time difference of arrival (TDOA) of a single beacon, wherein the method comprises:

periodically sending, by a positioning beacon, a positioning message at a fixed time interval T, wherein the positioning message comprises longitude, latitude and depth information of the positioning beacon;

receiving, by the underwater glider, the positioning messages, and recording time of arrivals (TOAs) at which the positioning messages arrive at an acoustic positioning signal receiving module;

parsing, by the underwater glider, the positioning messages and storing positioning message data; and

calculating a position of the underwater glider, which comprises:

extracting, from the positioning message data, the TOAs t_n−1, t_n, and t_n+1of (n−1)-th, n-th, and (n+1)-th positioning messages, pitch angles θ_n−1, θ_n, and θ_n+1, heading angles ϕ_n−1, ϕ_n, and ϕ_n+1, and depths z_n−1, z_n, and z_n+1of the underwater glider at corresponding times;

creating virtual beacons VB_n−1and VB_n+1wherein plane coordinates of the VB_n−1are (X_VB,n−1,Y_VB,n−1), a depth of the VB_n−1is Z_VB,n−1, and latitude and longitude coordinates of the VB_n−1are (L_VB,n−1,B_VB,n−1); and plane coordinates of the VB_n+1are (X_VB,n+1,Y_VB,n+1), a depth of the VB_n+1is Z_VB,n+1, and latitude and longitude coordinates of the VB_n+1are (L_VB,n+1,B_VB,n+1);

calculating the position of the underwater glider based on the TDOA:

correcting TOAs of the virtual beacons VB_n−1and VB_n+1to obtain corrected TOAs t_VB,n−1and t_VB,n+1;

wherein ri is a rounding function; and

calculating latitude and longitude coordinates (L_n,B_n) of the underwater glider at the time t_nto complete the positioning of the underwater glider.