ELEVATION-TIME DOPPLER METHOD FOR DETERMINING COORDINATES OF EMERGENCY OBJECT Russian patent published in 2007 - IPC G01S5/02 H04B7/185 B64G3/00 G01C21/00 

FIELD: methods for determining locations of objects by ground-based and space-based radio-navigation devices, possible use in rotation-stabilized spacecrafts.

SUBSTANCE: suggested method includes measuring Doppler frequency by query-less method on detection of emergency object transmitter signal within detection range of receiving antenna of spacecraft. Spatial location of spacecraft is measured in moments when Doppler frequency of received signal equals zero. Measured twice in these moments is the angle between antenna axis and horizon sensor axis with alignment of measurement to onboard time of spacecraft, and coordinates of sub-satellite points are calculated. Position of emergency object on Earth surface is determined using coordinates of given points and values of aforementioned angle. Additionally, when spacecraft appears in receipt zone at ground control station a high frequency oscillation is generated on original frequency, which is transformed by means of first heterodyne to signal (voltage) on first intermediate frequency. This signal is amplified, emitted into ether and received on spacecraft, where it is transformed by means of second heterodyne to signal on second intermediate frequency. Given signal is phase-manipulated by modulating code with information about position of emergency object, emitted into ether and received at ground control station. There it is transformed by means of third heterodyne to voltage with third intermediate frequency, from which after phase transformations the harmonic oscillation at original frequency is selected. The oscillation is used as supporting voltage for synchronous detection of aforementioned signal at third intermediate frequency. Low frequency voltage, proportional to modulating code, is selected, harmonic oscillations at original frequency are compared, Doppler frequency is measured by query method and spacecraft orbit elements are determined. For realization of aforementioned method, appropriate equipment is suggested, mounted onboard the spacecraft or at ground control station.

EFFECT: expanded functional capabilities of suggested method due to control over transfer of information from spacecraft to ground-based station and to more precise determining of spacecraft orbit elements.

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