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Doppler frequency 1,154 Hz, which proved good agree-ment between the measured value and theoretical value.4Propagation measurement experiment4.1. Data propagation experimentUDP communication experiments were conducted in a stationary state (i.e. the vehicle earth station was not mov-ing) at nine locations in the Kinki-Shikoku area which are shown Fig. 12. e experiment-based UDP link connecting two sta-tions is shown in Fig. 13. e vehicle earth station and a xed earth station (NICT Kashima Space Technology Center, Kashima city) communicate through the satellite. e objective of this experiment was to evaluate the link margin of the up- and down-link through observation of the level of packet error occurrence using jperf[6].e data propagation experiment used the MBA in regenerative 24 Mbps mode. e Chu-Shikoku beam was used in the experiments conducted in Uwajima, Ashizuri-Misaki, and Kochi, and the Kinki beam was used in other areas. For these two beams’ comparison, both beams were used in the Kochi experiment.4.2 Results from measurementsAs the previous stage for the link margin measurement, the satellite’s antenna gain was calculated. e antenna gain information is published only for the irradiation point and irradiation range[1]. e gain values at each measurement point are not available. To obtain the gain value at the measurement point, Az and El of the irradiation point (as viewed from the satellite) and the observation point are rst calculated, and elongation between the two points is calculated. e next step is to calculate the reduction of gain at the measurement points away from the center of the antenna beam, which can be obtained mathematically from the knowledge that the shape of the central part of the antenna beam can be approximated by an axis sym-metrical parabola using 3 dB beam width. Antenna gain at an measurement point can be evaluated from the irradia-tion point gain and the gain reduction value.e link margin was obtained by designing the link budget using antenna gain and other parameters. Table 2 summarizes the results of the link margin measurements (up-link and down-link) at each measurement point. e gures shown in red in the table indicate plus margin. All the margin values measured in 24 Mbps mode are positive: on average, measured values are higher than the theoretical predictive values by 2.5 dB at up-link, and by 5.8 dB at down-link.In the measurements conducted in Kochi, two dierent beams were used for comparison: the Chu-Shikoku beam (Kochi1) and the Kinki beam (Kochi2). It is interesting to note that deviations between measured and forecast values are reversed between Kochi1 and Kochi2, and a relatively large deviation was observed in Ashizuri-misaki. ese ndings can be interpreted to indicate that the center of the Chu-Shikoku beam is shied to the south-east direc-TabT2　Results from link margin measurement (Shikoku-Kinki area)Measurement pointUwajimaAshizuri-misakiKochi 1SakaideKochi 2Muroto-misakiTokushimaWakayamaKushimotoTobaBeam Chu-Shikoku beamKinki beamBeam center and measurement point elongation [deg]0.13950.22090.20730.13920.23540.19730.06950.04340.16340.2783Up-linkAntenna gain [dBi]at measurement point47.9 44.4 45.1 46.6 42.2 443.0 8.4 48.8 45.7 39.5 Link margin [dB](predictive)7.043.554.245.621.253.357.447.844.75-1.46Link margin [dB](measured)8.9 6.8 3.8 9.7 4.5 7.3 10.5 8.8 7.6 1.9 Deviation(measured - predictive)1.86 3.25 -0.44 4.08 3.25 3.95 3.06 0.96 2.85 3.36 Down-linkAntenna gain [dBi]at measurement point46.4 45.0 45.3 47.1 45.2 46.1 47.9 48.046.7 44.1 Link margin [dB](predictive)6.80 5.42 5.71 7.49 5.61 6.51 8.30 8.407.11 4.50 Link margin [dB](measured)12.6 10.6 10.7 13.0 12.2 13.1 14.3 14.413.0 10.5 Deviation(measured - predictive)5.80 5.18 4.99 5.51 6.59 6.59 6.00 6.005.89 6.00 1633-11 A Measurement of Propagation in High Mobility Environments for Ka Band Satellite Communication