GNSS-5G Hybrid Positioning Based on TOA/AOA Measurements

Global Navigation Satellite System (GNSS) has been widely used in people’s life. Generally, GNSS signals suffer from severe attenuation in urban canyon environments. the 5th generation wireless systems (5G) and GNSS hybrid positioning technique is a promising localization technique because 5G base stations are able to help GNSS relieve the problem of lacking visible satellites in urban environments. However, 5G-GNSS hybrid positioning faces the time synchronization problem. The conventional methods based on time of arrival (TOA) or time difference of arrival (TDOA) require that the time synchronization accuracy between two base stations should at least be 30-nanosecond level to make sure the range error is below 10 m, which is difficult to achieve in real applications. This work proposes a 5G-GNSS hybrid positioning scheme basing on AOA-TOA measurements. We combine the angle of arrival (AOA) estimates from 5G base stations and TOA measurements from GNSS satellites to perform hybrid localization. Moving averaging operation is then performed on the raw position estimates to further reduce the effect of noise. The principle of the proposed algorithm is explained detailedly. Numerical results demonstrate that the proposed method can be free from the influence of the time synchronization error, thus it improves the accuracy and robustness of hybrid positioning system in comparison with conventional methods.