Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correl...Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correlation with high efficiency. In order to improve the performance of the correlator, this paper proposes a new 1.5 bit quantization method. Theoretical analyses are made from the aspects of complexity and quantization loss, and performance comparison between 1.5 bit quantization correlator and traditional correlators is discussed. The results show that the 1.5 bit quantization algorithm can save about 30 percent complexity under similar quantization loss, reduce more than 0.5 dB signal noise ratio（SNR） loss under similar complexity. It shows great performance improvement for correlators of satellite navigation software receivers.展开更多
Chang＇E-3 spacecraft was orbiting the Moon from December 6 14, 2013, and very long baseline interferometry （VLBI） observations were performed to improve the accuracy of its orbit determination. In the process of re...Chang＇E-3 spacecraft was orbiting the Moon from December 6 14, 2013, and very long baseline interferometry （VLBI） observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented. Interesting phenomenon was that signal-to-noise ratio （SNR） of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon＇s orbit, whereas SNR kept in a stable level after Chang＇E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang＇E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.展开更多
基金supported by the National Natural Science Foundation of China(61101076413741376147017)
文摘Currently, 1 bit or 2 bit signal quantization is widely used in satellite navigation software receivers. The bit-wise parallel algorithm has been proposed for 1 bit and 2 bit signal quantization, which performs correlation with high efficiency. In order to improve the performance of the correlator, this paper proposes a new 1.5 bit quantization method. Theoretical analyses are made from the aspects of complexity and quantization loss, and performance comparison between 1.5 bit quantization correlator and traditional correlators is discussed. The results show that the 1.5 bit quantization algorithm can save about 30 percent complexity under similar quantization loss, reduce more than 0.5 dB signal noise ratio（SNR） loss under similar complexity. It shows great performance improvement for correlators of satellite navigation software receivers.
基金supported by the National Natural Science Foundation of China(Nos.11473059,11273049,11403082)
文摘Chang＇E-3 spacecraft was orbiting the Moon from December 6 14, 2013, and very long baseline interferometry （VLBI） observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented. Interesting phenomenon was that signal-to-noise ratio （SNR） of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon＇s orbit, whereas SNR kept in a stable level after Chang＇E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang＇E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.
