US 12,474,484 B2
POS high-accuracy positioning method under occlusion
Guoqing Zhou, Guangxi (CN); Jianwu Liu, Guangxi (CN); Jiasheng Xu, Guangxi (CN); Ertao Gao, Guangxi (CN); and Xinkun Yuan, Guangxi (CN)
Assigned to GUILIN UNIVERSITY OF TECHNOLOGY, Guangxi (CN)
Filed by GUILIN UNIVERSITY OF TECHNOLOGY, Guangxi (CN)
Filed on Feb. 6, 2024, as Appl. No. 18/434,754.
Application 18/434,754 is a continuation of application No. PCT/CN2023/135334, filed on Nov. 30, 2023.
Prior Publication US 2024/0280707 A1, Aug. 22, 2024
Int. Cl. G01S 19/37 (2010.01); G01S 19/25 (2010.01); G01S 19/53 (2010.01)
CPC G01S 19/37 (2013.01) [G01S 19/256 (2013.01); G01S 19/53 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A positioning method under occlusion for a position and orientation system (POS), comprising following steps of:
step 1: calculating a delay time for data sampling from a received sampled value (SV) message, and obtaining an accurate sampling time Tsample in combination with a receiving time of an SV message header;
step 2: arranging a RAM buffer in an FPGA to cache sampled GNSS positioning data and the sampling time Tsample;
step 3: searching out, in response to a positioning data loss being detected by the POS, five positioning data immediately before the positioning data loss, from the buffer and temporarily storing the five positioning data in a register;
step 4: storing, in response to detecting positioning data again, top five positioning data detected again in the register so that the register has ten positioning data, and using a filtering algorithm to filter out noise from the ten positioning data in the register; and
step 5: calculating filtered data by using an occlusion algorithm to calculate out a coefficient α of a fitted curve equation at an occluded position, and substituting an occluded sampling time t at the occluded position in the fitted curve equation with the calculated coefficient to calculate an occluded positioning datum P(t) at the occluded position;
wherein the occlusion algorithm is denoted as:

OG Complex Work Unit Math
wherein two positioning data P(−1) and P(0) detected immediately before the positioning data loss and top two positioning data P(1) and P(2) detected again after the positioning data loss are stored in the register, wherein P(−1) and P(2) are control points, the coefficient α is a parameter between 0 and 1, indicating a degree of parallelism between a tail of a fitted curve and the control points, and a value of the coefficient α is adjusted to minimize an error of the POS, and the P(−1), P(0), P(1) and P(2) satisfy following equation:
P(0)=P0,
P(−1)=P−1,
P(2)=P2,
P(1)=P1,
P′(0)=α(P1−P−1),
P′(1)=α(P2−P0).