## 4 Conclusions  
In this study, a Beidou communication terminal is designed to establish remote communication with a shore base during ocean testing executed by an Argo buoy. The terminal is engineered to enable the real-time transmission of short messages, conveying critical data regarding the buoy's status, location, and environmental profiling, which assists shore-based operators in the adjustment of the buoy's operational state and the acquisition  
Figure 9: Comparison chart of data compression method compression ratios: (**a**) Multiple sets of profile data compression ratios; (**b**) Compression ratios of five data compression methods.  
of its positional data through the issuance of remote commands. Moreover, the Beidou communication terminal integrates the Beidou 4.0 protocol to facilitate transparent data transmission, thereby enhancing the clarity of the data exchanged between the terminal and the buoy's primary control board.  
The design of a BTTT tailored for low-power consumption is presented in this paper. Utilizing a low-power microcontroller and associated components, power consumption is mitigated by controlling the BDMs power states so that it remains inactive during non-communication intervals. The STM32L073 RZT6 microcontroller's low-power serial port, LPUART1, governs the transition into and out of the STOP mode for the Beidou board, further diminishing energy use. Experiments have shown that adopting the energy-saving measures mentioned in the above sections can effectively reduce the power consumption of a single communication by up to 77.282%. The hybrid data compression algorithm uses both differential encoding and Huffman to compress the profile data, which leads to an average reduction of 55 remote communications per profile and greatly reduces power consumption. When these measures are combined--reducing static power consumption and decreasing the number of communications--the system's power consumption is cut to just 6.058% of its original demand. Such reductions in the power usage of the BTTT are pivotal, promising to prolong the battery life and operational duration of oceanic buoys, which will have a positive impact on the development of ocean exploration instruments.  
In recent years, the development of compression algorithms has progressed rapidly. Employing new compression techniques and combining different algorithms for the compression of profile detection data represents an avenue for future work. Extensive testing and research in this domain would be beneficial in enhancing the compression ratio, thereby reducing communication duration and lowering energy consumption. At the same time, we will test and improve the reliability of the Beidou transparent transmission terminal through lake trials in the future.  
Conceptualization, H.L.; methodology, Y.W.; software, Y.F.; validation, H.L., Y.F. and Y.W.; formal analysis, Y.F.; investigation, Y.Z. and S.Y.; resources, Y.Z. and Q.M.; data curation, H.L.; writing--original draft preparation, Y.F.; writing--review and editing, H.L.; visualization, Y.W.; supervision, S.Y.; project administration, Q.M.; funding acquisition, H.L. All authors have read and agreed to the published version of the manuscript. This research was funded by the Shandong Natural Science Foundation (Grant No. ZR2022 MF336).  
Not applicable.  
The data used to support the findings of this study are available from the corresponding author upon request.  
The authors declare that they have no conflicts of interest to report regarding the present study.