Signal performance and measurement noise assessment of the first L2C signal-in-space

Design and assessment of composite civil moderate code structure for efficient global positioning system L2 civil signal acquisition

“…4 a , we can see that if the required detection probability is 0.9, the RZCM method would acquire signals not less than − 27 dB. From [16], we know the normally received L2C signal is not less than 42 dBHz for clear sky conditions when elevation is larger than 10 0 . It means the SNR is not less than − 21 dB.…”

“…Furthermore, the larger the composite coefficient K is, the more are the CM chips accumulated together, the worse are the correlation properties of the CCM code, and the worse is the detection performance. Despite of this, for normally received L2C signal, whose SNR is larger than − 21 dB [16], the CCM code having K = 2 has a detection probability of more than 0.9. For weak signals, we can improve detection performance through non‐coherent integration, as shown in Fig.…”

“…When SNR is larger than − 22 dB, the worst acquisition performance is better than the best one of the RZCM code. Since the SNR of normally received L2C signal is probably larger than − 21 dB [16], from the point of view, the CCM code is better than the RZCM code. Fig.…”

“…Then, especially we pay more attentions to comprehensively assessing the performance of the CCM code, including the required FFT size when implemented, the effect of navigation data and carrier Doppler, and the detection performance and mean acquisition time performance. Overall, compared with the previous RZCM code, the CCM code has the following advantages: (a) it is capable of testing all the CM code phases simultaneously by an FFT block of much smaller than 20 460‐point, and thus it is attractive for resource‐limited receivers; (b) it is more robust against navigation data and performs more reliable detection performance; (c) it is more robust against carrier Doppler, and is in favour of enlarging frequency search step and reducing the cells to test; (d) for normally received L2C signal, which is usually not less than 42 dBHz [16], it spends less time on acquisition. Theoretical and simulation results demonstrate the advantages.…”

Double-chipwise correlation technique for efficient L2C signal acquisition

“…8, the double-chipwise correlation technique performs better at acquisition. Particularly, when the SNR of the received signal is larger than −23 dB, which is available for an L2C signal received in clear sky conditions [17], the saving is about 75%.…”