In recent years, China's aerospace technology has continued to develop. The distance of deep-space exploration has been continuously increasing, and the attenuation of signal energy has become more and more serious, which has gradually increased the requirements for the signal reception and demodulation capabilities of ground receiving equipment. Antenna array technology can achieve the gain of an equivalent large-aperture antenna by synthesizing the signals of multiple small-aperture antennas, which can give full play to the efficiency of each antenna resource and achieve the purpose of extending the measurement and control distance. It is one of the effective ways to solve the problem of receiving weak signals in deep space. The measurement and control range of the antenna array of the ground fixed base station is limited by factors such as terrain, region, and obstructions, and it cannot achieve full coverage of the existing measurement and control tasks. Therefore, a shipborne platform is needed to make up for the measurement and control blind area. Based on the real satellite signal, this paper conducts an antenna array signal synthesis experiment on a shipborne mobile platform. For platform states such as docking at the wharf, anchoring on the river surface, and hull swaying, full-spectrum synthesis and symbol stream synthesis demodulation processing are carried out. Especially for the hull swaying state, a signal synthesis scheme based on carrier-to-noise ratio estimation is proposed. This scheme constructs a model of ship sway frequency, amplitude, and signal strength based on the measured ship sway data, analyzes the signal synthesis efficiency under different ship sway states, designs a carrier-to-noise ratio estimation scheme according to the signal change law, and dynamically optimizes the signal weighting coefficient, so as to improve the signal synthesis effect. The paper also compares the influence of different signal-to-noise ratio estimations and weighting coefficient update periods on the synthesis efficiency, and the results are consistent with the theoretical analysis. By comparing the synthesis efficiencies of the traditional signal synthesis scheme and the synthesis scheme based on carrier-to-noise ratio estimation, the test results show that the traditional symbol stream synthesis result is less affected by ship sway, and the synthesis efficiency can reach more than 90%; the traditional full-spectrum synthesis result is greatly affected by ship sway, and the synthesis efficiency is less than 80%. By adopting the carrier-to-noise ratio estimation-assisted scheme proposed in this paper, the synthesis efficiency can be significantly improved to more than 89%, providing a technical basis for the subsequent antenna array synthesis scheme of the shipborne mobile platform.