초록 ▼

A three-axis accelerometer (4) mounted on board a spacecraft (10) proximate a fuel tank (3) is used to derive an estimate of the amount of fuel (2) remaining within the tank (3). The output of the accelerometer (4) is converted (at 7) to a signal representing the rate of change of the polarity of th

A three-axis accelerometer (4) mounted on board a spacecraft (10) proximate a fuel tank (3) is used to derive an estimate of the amount of fuel (2) remaining within the tank (3). The output of the accelerometer (4) is converted (at 7) to a signal representing the rate of change of the polarity of the acceleration; amplitude information is ignored. This signal is then filtered by bandpass filter (8) or Fourier transform means and applied against an empirically derived function (stored within storage medium 9) relating frequency of oscillation to fuel (2) remaining in the tank (3). The function is stored for three axes; information from one axis is accessed, corresponding to the vector of a perturbing force such as caused by a thruster (11) firing. Some or all of the above described items can be located on board the spacecraft (10) itself. The accelerometer (4) can also be used directly to estimate the force imparted by the thruster, from the expression F=MA. This force is then related, by empirical data, to amount of fuel used during thruster (11) firing, which, when subtracted from an initial amount of fuel (2), provides a second check on the amount of fuel (2) remaining in the tank (3).

대표청구항 ▼

A method for determining the amount of liquid fuel remaining in a fuel tank on board a spacecraft, wherein an accelerometer having at least one axis has been mounted on board the spacecraft proximate the fuel tank, said method comprising the steps of: empirically generating on earth a set of retriev

A method for determining the amount of liquid fuel remaining in a fuel tank on board a spacecraft, wherein an accelerometer having at least one axis has been mounted on board the spacecraft proximate the fuel tank, said method comprising the steps of: empirically generating on earth a set of retrievable data which converts frequency of oscillation of fuel sloshing within the tank to amount of fuel remaining within the tank; after the spacecraft has been launched, imparting a force along an axis of the accelerometer; in response to said force, obtaining from the accelerometer an output signal proportional to the instantaneous acceleration along said axis; converting said output signal into an oscillation frequency signal indicating the rate of change of the direction of the instantaneous acceleration along said axis, said oscillation frequency signal being proportional to the frequency of oscillation of the sloshing fuel; and applyig said oscillation frequency signal to a storage medium which contains said set of retrievable data.