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satellite tracking accuracy of the WINDS-compatible ma-rine-based earth station has been set to be ±0.2°. When errors exceed this range, an interlock function is activated which stops radio wave transmission by the station.e station’s satellite tracking accuracy is shown in Fig. 11. ese results conrmed that the tracking control system functioned adequately within the ±0.2° error margin when the ship was traveling in gure-eight patterns. e station was unable to receive beacon signals from the satel-lite when the object on the ship deck (Fig. 7) obstructed satellite communications. However, the station reacquired the satellite immediately aer the object was no longer in its path. is observation conrmed that the gyro holding system was functioning normally.5.2Transmission characteristics of TCP communications when the ship was traveling in a figure-eight patternWe established a WINDS communication line that was set at a data transmission rate of 24 Mbps and transmitted TCP data through the line while the ship traveled in gure-eight patterns as described in Subsection 5.1. Data throughput during this experiment is shown in Fig. 12. e C/N0 levels of the beacon signals indicated in Fig. 11 were also superimposed on this gure to illustrate the eect of the communication interruption caused by the xed object on the ship deck on data throughput. We measured TCP throughput using congestion control algorithms tuned to WINDS [7].When the station is unable to receive beacon signals due to obstruction by the object on the ship deck, an in-terlock function is activated to stop radio wave transmis-sion by the station. Once the object no longer impedes transmission, the station resumes receiving beacon signals and transmitting radio waves. e line speed reached maximum within several seconds aer the resumption of communications, indicating that TCP communication was stable when the ship was traveling in a gure-eight pattern, except when the object on the deck obstructed communica-tions.5.3Transmission characteristics of TCP communication via WINDS at different data ratesMajor communication delay occurs in satellite com-munications due to extremely long transmission paths. e use of TCP communication in such systems sometimes does not allow full utilization of a communication line’s network bandwidth. Congestion control techniques, which control data transmission volume based on RTT (round-trip time) values, are eective in addressing this issue [7]. In addition, previous studies conrmed that techniques to control data transmission volume which account for com-munication line conditions further stabilize communica-tion [7]. We compared the data transmission characteristics of TCP communication using two procedures: congestion control algorithms tuned to WINDS communication lines (TCP for the WINDS network) and Linux-based (CUBIC) congestion control algorithms [7][8]. e throughputs of the WINDS communication lines were measured at dier-ent data rate settings (Table 3). Temporal changes in throughput measurements using TCP for the WINDS network and CUBIC are shown in Figs. 13 and 14, respec-tively. ese measurements were carried out while the data rate was set at 24 Mbps.e throughput dierence between the two types of congestion control algorithms was small at the 6 Mbps network bandwidth setting (Table 3). However, throughput dierences between the two increased with increased net-work bandwidth. When the data rate was set at 51 Mbps, FiF11　Tracking accuracy at cruise of figure eight Time [sec] Tracking accuracy [degree] Beacon C/N0 [dB-Hz] Beacon C/N0 Tracking accuracy FiF12　TCP throughput at cruise of figure eight Time [sec] Throughput [kbps] Beacon C/N0 [dB-Hz] Beacon C/N0 Throughput 1553-10 Experiment Report of Satellite Communication at the Ocean