ORBITAL GRAVITATIONAL GRADIENT METER Russian patent published in 2025 - IPC G01V7/00 G01B9/02 

FIELD: physics.

SUBSTANCE: invention relates to devices for collecting primary data of gravitational potential for compiling navigation maps. Gravitational gradient meter has housing (1) with a displaced centre of gravity, having an evacuated part and a non-vacuum part, as well as an optical phase comparator and control module (25). Inside the evacuated part there is a first beam splitter (8) and elements of an optical phase comparator: first test mass in form of first mirror (10) having possibility of free movement under gravity, fixed on membrane (12), polarization cube (9), second mirror (11), which is movable by control module (25), first photodetector (13) configured to receive beams reflected from first (10) and second (11) mirrors, second photodetector (14) configured to receive beams from the side of the non-vacuum part of the housing, polarisers (15) mounted in front of each of photodetectors (13, 14). First beam splitter (8) and all said elements of the optical phase comparator, with the exception of the first and second mirrors, are rigidly connected to housing (1), which acts as a second test mass. Second mirror (11) has a possibility of adjustment of its position and fixation in the chosen position. Inside the non-vacuum part of housing (1) there is laser emitter (3), acousto-optical modulator (4) configured to receive the beam from the laser emitter in such a way that two beams come out of it at different angles to the longitudinal axis of the gradient meter, third mirror (7) and phase half-wave plate (6) in front of it, arranged with possibility of passing through them of second beam from acousto-optical modulator (4), as well as second beam splitter (5). Second beam splitter (5) enables superposition of the second beam with the first beam coming from acousto-optical modulator (4) directly to beam splitter (5) to form a double-frequency beam with frequency splitting determined by the frequency of acousto-optical modulator (4). Optical phase comparator also has phase detector (16), phase shifter (17) and a feedback loop based on the level of amplitude noise of the laser source, consisting of series-connected: amplitude radio frequency detector (19), band-pass filter (20), analogue adder (21) with bias voltage source (24), and double balanced modulator (22) configured to transmit a signal to the input of acousto-optical modulator (4).

EFFECT: reduced time drift of readings of the gradient meter and high accuracy thereof, as well as reduced requirements for frequency stability and fluctuation of the amplitude of the laser emitter.

3 cl, 1 dwg, 1 tbl