Fig. 1.
The waveform of the BPC signal.
Fig. 2.
Principle model of ground wave propagation.
Fig. 3.
Test method for field strength of BPC near-field timing signal.
Fig. 4.
Test method for time difference of BPC timing signal.
Fig. 5.
Test principle diagram for test point selection.
Table 1.
Statistics of test data for the lake test within the near-field range (25 km).
| Statistics of filed strength [dBμV/m] | Test point 1 Pass lake | Test point 2 Not pass lake |
|---|---|---|
| Max value | 94.37 | 94.60 |
| Min value | 94.13 | 94.49 |
| Peak_to_peak | 0.24 | 0.11 |
| Mean value | 94.31 | 94.55 |
| Std | 0.0249 | 0.0183 |
| Skewness | −1.07 | −1.67 |
| Kurtosis | 5.75 | 5.12 |
| Energy | 6954916.50 | 6990942.66 |
Fig. 6.
Comparison chart of the first group of lake water field strength values.
Fig. 7.
Comparison chart of lake water field strength values in the second group (After filtering).
Table 2.
Statistics of test data for the lake test within the ground wave range (138 km).
| Statistics of filed strength [dBμV/m] | Test point 1 Pass lake | Test point 2 Not pass lake |
|---|---|---|
| Max value | 78.91 | 79.39 |
| Min value | 78.43 | 79.19 |
| Peak_to_peak | 0.48 | 0.20 |
| Mean value | 78.68 | 79.28 |
| Std | 0.1170 | 0.0456 |
| Skewness | −0.0907 | 0.6331 |
| Kurtosis | 3.0129 | 2.3757 |
| Energy | 5224486.12 | 5304515.55 |
Fig. 8.
Comparison chart of the first group of lake water time difference values.
Table 3.
Statistics of test data for the lake test within the near-field range (25 km).
| Time difference [μs] | Test point 1 Pass lake | Test point 2 Not pass lake |
|---|---|---|
| Max value | 205.01 | 191.97 |
| Min value | 166.83 | 155.99 |
| Peak_to_peak | 38.18 | 35.98 |
| Mean value | 180.25 | 172.21 |
| Std | 6.86 | 6.38 |
Fig. 9.
Comparison chart of lake water time difference values in the second group.
Table 4.
Statistics of test data for the lake test within the ground wave range (138 km).
| Time difference [μs] | Test point 1 Pass lake | Test point 2 Not pass lake |
|---|---|---|
| Max value | 614.69 | 573.32 |
| Min value | 494.51 | 486.22 |
| Peak_to_peak | 120.18 | 87.10 |
| Mean value | 543.17 | 529.07 |
| Std | 24.11 | 14.97 |
Fig. 10.
Variation trend of signal field strength with distance.