###### Abstract  
The remarkably long distances covered by deep space probes result in extremely weak downlink signals, which poses great challenges for ground measurement systems. In the current climate, improving the comprehensive utilization of downlink signal power to increase the detection distance or enhance the measurement accuracy is of great significance in deep space exploration. Facing this problem, we analyze the delta Differential One-way Range (\(\Delta\)DOR) error budget of the X-band of the China Deep Space Network (CDSN). Then, we propose a novel interferometry method that detunes one group of DOR beacons and reuses the clock components of regenerative pseudo-code ranging signals for interferometry delay estimation. The primary advantage of this method is its ability to enhance the power utilization efficiency of downlink signals, thereby facilitating more efficient tracking and measurement without necessitating additional design requirements for deep space transponders. Finally, we analyze and verify the correctness and effectiveness of our proposed method using measured data from CDSN. Our results indicate that the proposed method can save approximately 13% of the downlink signal power and increase the detection distance by about 6.25% using typical modulation parameters. Furthermore, if the relative power of other signal components remains unchanged, the power of the DOR tone can be directly increased by more than 100%, improving the deep space exploration ability more significantly. deep space exploration; power of signals; regenerative pseudo-noise ranging; interferometry measurement; integer ambiguity resolution; QueQiao-1 relay satellite of lunar 2024 24 822 2024 24 822 2024 24 822 24 8222  
exploration mission, both employ the side-tone ranging system, achieving an accuracy of better than 1 m at the X-band [2]. The main ranging system for deep space probes of the National Aeronautics and Space Administration (NASA) and European Space Agency (ESA) is a tone-code hybrid ranging system with an accuracy of 1 m. However, it is noteworthy that both the side-tone and tone-code hybrid ranging systems are operated in the turn-around mode. This means that while the ranging signal is transmitted, the received noise and residual command signals are also turned around. This is not suitable for deep space exploration with longer distances and weaker downlink signals [3]. The downlink signal of the regenerative PN code ranging system is more suitable for deep space exploration contexts due to its absence of forwarding noise, coupled with a substantial unambiguous range and heightened measurement accuracy [4; 5]. The Chinese QueQiao-1 lunar relay satellite has carried out a regenerative pseudo-noise ranging experiment in orbit, improving the ranging accuracy by an order of magnitude compared with side-tone ranging [6]. Very long baseline interferometry (VLBI) is one of the main techniques for tracking and navigating lunar and deep space probes. In the 1970s, the NASA Deep Space Network (DSN) verified the navigation and orbit determination of the Voyager 1 and Voyager 2 spacecraft using VLBI. From the 1970s to the 1980s, the VLBI measurement accuracy for the interplanetary missions of NASA reached an impressive 30 nrad. In 2001, the accuracy of VLBI reached about 5 nrad in Mars Odyssey and further increased to 2 nrad in the Mars Reconnaissance Orbiter (MRO) exploration [7]. The Deep Space Network of the former Soviet Union consisted of three deep space stations with a 64 m antenna in Bear Lake near Moscow, a 70 m antenna in Ivpatoria in Crimea, Ukraine, and a 70 m antenna in Usurisk. At present, the tracking and measurement of Russian deep space probes are mainly carried out by the Bear Lake and Usurisk deep space stations. In the 1980s and 1990s, the Russian Deep Space Network conducted surveys of probes such as Venus-15 and Vega-1 [8]. \(\Delta\)VLBI measurement experiments were also conducted on celestial bodies in the solar system, such as Venus and Mars.