## 5 Results
### Verification and Analysis of X-Band Test Data  
On the basis of the results in Section 5.1, the X-band signal system has been validated using static test data from a typical deep space probe equipped with an X-band deep space TT&C transponder. There are two groups of DOR beacon signals complying with the CCSDS specification. Meanwhile, the spacecraft adopts the regenerative pseudo-code ranging system, consistent with Queqiao-1. The spectrum of the main carrier zone under pseudo-code (T4B) and DOR tones modulation is compliant with CCSDS-related specifications. The two pairs of DOR tones are located at a distance of 3.8 MHz and 19.2 MHz from the main carrier, respectively. The frequency difference between the regenerated pseudocode ranging clock component and the main carrier is 500 kHz. The carrier-to-noise ratio estimation results of the carrier, PN code ranging clock components (\(-\)PNc, +PNc), and DOR beacon signals are shown in Figure 10. It is evident that the carrier-to-noise ratios of the two PN code ranging clock components are approximately identical, at around 7 dB/Hz. The carrier-to-noise ratio of the DOR signal is about 6.8757 dB/Hz, which is close to that of the clock component of the PN code range. The carrier-to-noise ratio of the carrier signal is about 13 dB/Hz higher than that of the PN code ranging clock component. Due to the relatively high carrier-to-noise ratio of the carrier signal, the random accuracy of the interference time delay primarily depends on either the DOR beacon signal or the clock component of the PN code ranging signal. The cross-spectrum phase is shown in Figure 11. The trends of the cross-spectrum phase of the three signals are consistent, with their random accuracies closely aligned. However, the random error of the DOR signal is relatively larger. This is consistent with the analyzed results of the carrier-to-noise ratio shown in Figure 10. The phase estimation accuracy of the three signals satisfies the criteria outlined in Equation (7). Figure 10: The carrier-to-noise ratio estimation results of carrier ((a), upper half), PN code ranging clock components (\(-\)PNc, +PNc), and DOR beacon signals ((b), lower half). In order to resolve the possible cross-phase ambiguity of \(\pm\)19.2 MHz DOR beacons, two signal combinations, carrier-DOR\({}_{1}\) (the traditional processing method) and carrier-PN code clock components (the proposed method in this paper), are used to estimate the coarse interferometry time delay, respectively. The coarse time delay estimation results of the two signal combinations are shown in Figure 12, in which the upper half shows the estimation results and the lower half is their deviation. It is evident that the carrier-DOR\({}_{1}\) combination offers superior coarse time delay accuracy. This superiority can be attributed to the relatively larger frequency interval (namely effective bandwidth) of carrier-DOR\({}_{1}\), approximately 3.85 MHz, compared to the narrower frequency interval of about 1 MHz when employing the PN code clock component. Given the equivalent random accuracy of the phase estimation, as illustrated in Figure 11, a wider effective bandwidth corresponds to the increased random accuracy of the time delay. It can be seen from the lower half of Figure 12 that the maximum deviation of the two coarse time delay estimation results is about 4.8 ns, which is almost equal to three times that of the random accuracy of the interference delay of the PN code clock component, verifying the analysis in Section 2. The cross-spectral phase deviation generated by this time delay deviation at a \(\pm\)19.2 MHz DOR signal is about 0.1 cycles (2\(\pi\)), which does not affect the final integer ambiguity resolution result.