• Journal of Positioning, Navigation, and Timing
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• v.4 no.3
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• pp.97-105
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• 2015

A navigation signal based on orthogonal tiered polyphase code was proposed. For the proposed signal, tiered polyphase code was used as the code of a pilot channel. Tiered polyphase code is a complex number type code, and thus the pilot channel and data channel were separated using the Walsh code which makes the correlation between different codes become 0. The results of the simulation indicated that the correlation characteristics and signal acquisition performance of the proposed signal were identical to those of tiered polyphase code, and that the disadvantage of tiered polyphase code could be supplemented through a data channel in terms of signal tracking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.970-972
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• 2013

Signal acquisition performance is evaluated for the tiered polyphase code (TPC) which is proposed as a ranging signal structure for global navigation satellite systems (GNSSs). Compared to the tiered code (TC) which is adopted in European Union's GALILEO system, the TPC shows robust performance to frequency offset in acquiring signal. Therefore the TPC should have SNR gain in signal acquisition and can reduce computational complexity in the receiver. In this paper, we compare the signal detection probability of the TC and TPC under the same receiver architecture and GALILEO E5a-I signal parameters.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.307-313
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• 2021

Modernized GNSS signal structures tend to use tiered codes, and all GNSSs use binary codes as secondary codes. However, recently, signals using polyphase codes such as Zadoff-Chu sequence have been proposed, and are expected to be utilized in GNSS. For example, there is Tiered Differential Polyphase Code (TDPC) using polyphase code as secondary code. In TDPC, the phase of secondary code changes every one period of the primary code and a time-variant error is added to the carrier tracking error, so carrier tracking ambiguity exists until the secondary code phase is found. Since the carrier tracking ambiguity cannot be solved using the general GNSS receiver architecture, a new receiver architecture is required. Therefore, in this paper, we describe the carrier tracking ambiguity and its cause in signal tracking, and propose a receiver structure that can solve it. In order to prove the proposed receiver structure, we provide three signal tracking results. The first is the differential decoding result (secondary code sync) using the general GNSS receiver structure and the proposed receiver structure. The second is the IQ diagram before and after multiplying the secondary code demodulation when carrier tracking ambiguity is solved using the proposed receiver structure. The third is the carrier tracking result of the legacy GPS (L1 C/A) signal and the signal using TDPC.