METHOD FOR AUTONOMOUS MEASUREMENT OF GRAVITATIONAL FIELD PARAMETERS ON BOARD A SPACECRAFT Russian patent published in 2022 - IPC G01V7/06 G01V7/16 

FIELD: Earth's gravitational field measuring,

SUBSTANCE: invention relates to methods for measuring the parameters of the Earth's gravitational field (GPF). Signals from navigation spacecraft (NSC) of global navigation satellite systems are received on board the spacecraft. The current coordinates of the spacecraft and the reference value of the gravitational acceleration of the spacecraft are determined. Additionally, on board the spacecraft, three signals are received from the spacecraft located relative to the spacecraft near three selected directions: the zenith direction in the orbit plane, the local horizon line along and against the spacecraft orbital motion, as well as the normal to the spacecraft orbit plane on both sides. Of all three additional signals, a monochromatic carrier is isolated, freeing it from all types of modulation. According to the parameters of the three received additional signals, as well as the current orbital parameters of the spacecraft and the satellite, the necessary delay of the signals is preliminarily calculated to ensure the regulation of the digital delay of these signals when measuring the parameters of the GPF. Doppler frequency signals are extracted from all three additionally received monochromatic signals, digitized and fed to three independent digital delay lines with a set calculated delay for each point of the spacecraft's orbit. The direct and delayed Doppler signals corresponding to the three received additional signals are fed to the inputs of three independent digital mixers. Then, three signals with a difference frequency from the output of the mixers are fed to three low-frequency meters. Based on the measurement result of the low frequency corresponding to the received additional signal from the SV from the zenith direction, the current value of the SC gravitational acceleration is calculated and compared with the reference value. Based on the low frequency measurement result corresponding to the received additional signal from the satellite along the direction of the local horizon, the current component of the deviation of the vertical line of the GPF in the plane of the orbit of the spacecraft is calculated. Based on the measurement result of the low frequency corresponding to the received additional signal from the satellite along the normal to the orbit, the current component of the deviation of the vertical line of the GPF along the normal to the plane of the orbit of the spacecraft is calculated.

EFFECT: improving the accuracy of measuring GPF parameters.

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