Page 207 - 卫星导航2021年第1-2合期

Wang et al. Satell Navig (2021) 2:4 Page 7 of 9

Fig. 8 ROC performance ( C N = 35 dB·Hz) Fig. 10 Binary phase hopping modulation constellation ( σ i = 5°)
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Fig. 9 ROC performance ( C N = 40 dB·Hz)

0 Fig. 11 Binary phase-hopping modulation constellation ( θ e = 5°)
hopping based SCA technique has lower C N degrada-

0
tion and better compatibility with the existing receiver two SCA techniques. Under the same false alarm prob-
architecture. ability, the authentication success rates of the two SCA
techniques are almost 100%. When C N is reduced to

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35 dB·Hz, the coherent integration time of 600 ms is
Simulation of detection probability not enough. Under the same false alarm probability, the
Tis section simulates the Receiver Operating Charac- authentication success rate of the phase hopping based
teristic (ROC) performance for the two SCA techniques, SCA technique improves obviously. One reason is that
and the binary phase hopping based SCA technique uses in the same coherent integration time, the authentication
the third authentication method. In the following fgures code length of the phase hopping based SCA technique
the abscissa represents the false alarm probability P fa and is R c · T coh , and the authentication code length of the
the ordinate is for the detection probability P d . Te simu- inserting chip based SCA technique is R c · p u · T coh . For
lated ROC performances are plotted in Figs. 8 and 9 with a GNSS signal, the longer the spreading code sequence is,
the coherent integration time T coh = 600 ms , code rate the higher the spreading gain will be, meaning stronger
R c = 1.023 Mcps , phase jump amplitude ϕ PH = 5 , and
◦
C N being 35 dB·Hz and 40 dB·Hz, respectively. anti-multiple access interference ability.

Considering the errors in PLL, such as phase jitter and
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When C N is 40 dB·Hz, the coherent integration time

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of 600 ms is long enough. Tere is no signifcant difer- dynamic stress error, Fig. 10 shows the constellation dia-
gram of demodulation with the root-mean-square error
ence between the authentication success rates of the
(RMSE) of phase jitter σ i being 5°. Te phases of actual