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This paper analyzes the characteristics of satellite navigation signals received by the high-speed rotating carrier in order to solve the problems existing in the application of satellite navigation receiver in the high-speed rotating carrier, studies the influence of rotation on the received signal amplitude and carrier phase shift. This paper also establishes the received signal amplitude change model and carrier phase shift model under the condition of body rotation. The antenna phase wind-up is proposed to introduce additional carrier phase shift and improve the original system model. Based on the signal model, the system simulation is carried out, and the experimental environment is built for testing, which verifies the necessity and correctness of the system model with antenna phase wind-up, and provides theoretical support for improving the defensive and guiding performance of small-caliber rotating missile.

Background and purpose: Robotic thyroid surgery has been carried out worldwide since Kang first applied it to the thyroid in 2007. The proportion of axillary approach is increasing rapidly in China due to the continuous verification of safety, radicalness and cosmetic properties of cancer treatment. The advantages and clinical value of Da Vinci Xi robotic unilateral axillary approach in the treatment of unilateral papillary thyroid microcarcinoma (PTMC) was investigated by comparing and analyzing the clinical efficacy in 95 patients undergoing a gasless, unilateral axillary approach Da Vinci Xi robotic thyroid surgery for PTMC and 91 patients undergoing conventional surgery. Methods: The clinical data of 186 cases of unilateral PTMC undergoing thyroidectomy in the Department of Head and Neck Surgery of Shanghai cancer Hospital from March 2020 to November 2021 were retrospectively analyzed, and they were divided into the robotic group (95 cases) and the open group (91 cases) according to the surgical methods. The general clinical data, surgical results, postoperative complications, satisfaction of incision, learning curve and surgical costs were analyzed and compared between the two groups. Results: There was no statistically significant difference between the two groups in gender, age, incidence of Hashimoto’s thyroiditis, tumor diameter, location and number of lesions (P>0.05). However, the operation time was significantly longer in the robotic group [(126.65±34.76) min]than in the open group [(60.99±21.12) min], and after 36 operations, the operation time reached a stable level. The operation cost was significantly higher in the robotic group [(47 940.66±4 404.30) yuan] than in the open group [(15 807.73±2 295.35) yuan]. There was no significant difference in intraoperative hemorrhage [robotic group: (20.48±18.83) mL; open group: (16.15±13.95) mL], the number of removed lymph nodes (robotic group: 2.61±2.77; open group: 2.97±2.20) and the number of positive lymph nodes (robotic group: 1.01±1.61; open group: 0.78±1.36) between the two groups (P>0.05). The incidence of postoperative temporary vocal hoarseness and transient hypocalcemia was lower in the robotic group (1.10%, 2.10%, respectively) than in the open group (2.20%, 3.30%, respectively), however there was no statistically significant difference (P>0.05). The postoperative satisfaction of incision was significantly higher in the robotic group (very satisfied 87.4%, satisfied 11.6%) than in the open group (very satisfied 71.4%, satisfied 26.4%), and the difference was statistically significant (P

The selection of signal frequency in acoustic temperature measurement technology is the key to improve the accuracy of temperature measurement. In order to explore the optimal propagation frequency of low-frequency sound waves in loose coal, lignite, coking coal, and anthracite are used as the research objects. The acoustic loss of three coal samples under six particle sizes（0.9 mm to ＜3 mm, 3 mm to ＜5 mm, 5 mm to ＜7 mm, 7 mm to 10 mm, 9 mm to 10 mm and larger than 10 mm） by using the acoustic loss test system is tested. The experimental results show that the sound transmission loss of three coal samples presents a wave-like rising shape with the increase of the sound wave frequency. Compared with coal samples of other particle sizes, the sound transmission loss of coal samples in the range of 0.9 mm to ＜3 mm is the largest. As the particle size of coal samples increases, the sound transmission loss of coal samples continues to increase, and the sound wave frequency corresponding to the lowest point of sound transmission loss also increases. The degree of coal sample deterioration has no obvious regularity in the influence of sound transmission loss. The sample size is the main factor that affects the change of the sound transmission loss of the coal sample, and the sound waves mainly propagate along the gaps between the particle sizes of the loose coal. By comparing and analyzing the maximum and minimum values of sound transmission loss, there is a maximum value between 250 Hz to 600 Hz and 900 Hz to 1 600 Hz about the sound transmission loss of coal samples of different particle sizes, and the maximum sound transmission loss range is between 4.66 dB and 7.64 dB. By testing the sound transmission loss in the low-frequency sound waves of the mixture of three coal samples, it is determined that the optimal sound transmission frequency range in the loose coal is 600 Hz to 900 Hz.