The use of an accelerometer for inertial navigation of a low thrust spacecraft undergoing acceleration wherein the inaccuracy of the accelerometer is less than the uncertainty in the accuracy of a modeled non-gravitational component of the acceleration that the spacecraft is undergoing is disclosed. A method of navigating a spacecraft having a low thrust propulsion system is also disclosed. The method comprises engaging the low thrust propulsion system, measuring the acceleration of the spacecraft using an accelerometer with an inaccuracy less than the uncertainty in the acceleration imparted by the low thrust propulsion system and acquiring a trajectory estimate using the measured acceleration. The trajectory estimate may be updated using an external reference navigation sensor.
B64G 1/66 - Arrangements or adaptations of apparatus or instruments, not otherwise provided for
G01C 21/16 - NavigationNavigational instruments not provided for in groups by using measurement of speed or acceleration executed aboard the object being navigatedDead reckoning by integrating acceleration or speed, i.e. inertial navigation
An absolute vector gravimeter and method of use is provided. The absolute vector gravimeter includes one or more single axis accelerometers, each capable of pointing in at least two directions and calculating an estimated gravity component. Further embodiments provide for estimating a bias in the single axis accelerometer, as well as measuring non-ballistic accelerations along multiple axes and calculating estimated gravity components for each. A resultant non-ballistic acceleration vector can be calculated. Examples for reducing the RMS error in the estimated gravity components are also provided.
G01V 7/02 - Measuring gravitational fields or wavesGravimetric prospecting or detecting Details
G01V 7/06 - Analysis or interpretation of gravimetric records
G01V 3/18 - Electric or magnetic prospecting or detectingMeasuring magnetic field characteristics of the earth, e.g. declination or deviation specially adapted for well-logging
3.
System and method for protection of spacecraft electronics
A system and method for protecting an electronics module on a spacecraft in space are described. The system includes a non-radiation hardened electronics module electrically connected to a power supply, with a switch connected between the power supply and the electronics module. The switch can disconnect the electronics module from the power supply in response to an event signal. A sensor which is capable of detecting a solar proton event is connected to the switch. The sensor emits the event signal upon detection of the solar proton event.
H01H 47/24 - Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil having light-sensitive input
H01H 47/26 - Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil having thermo-sensitive input
H03K 17/78 - Electronic switching or gating, i.e. not by contact-making and -breaking characterised by the use of specified components by the use, as active elements, of opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled
G01T 1/17 - Circuit arrangements not adapted to a particular type of detector
B64G 1/42 - Arrangements or adaptations of power supply systems
H02H 5/00 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
4.
ABSOLUTE VECTOR GRAVIMETER AND METHODS OF MEASURING AN ABSOLUTE GRAVITY VECTOR
An absolute vector gravimeter and method of use is provided. The absolute vector gravimeter includes one or more single axis accelerometers, each capable of pointing in at least two directions and calculating an estimated gravity component. Further embodiments provide for estimating a bias in the single axis accelerometer, as well as measuring non-ballistic accelerations along multiple axes and calculating estimated gravity components for each. A resultant non-ballistic acceleration vector can be calculated. Examples for reducing the RMS error in the estimated gravity components are also provided.
A system and method for protecting an electronics module on a spacecraft in space are described. The system includes a non-radiation hardened electronics module electrically connected to a power supply, with a switch connected between the power supply and the electronics module. The switch can disconnect the electronics module from the power supply in response to an event signal. A sensor which is capable of detecting a solar proton event is connected to the switch. The sensor emits the event signal upon detection of the solar proton event.
B64G 1/66 - Arrangements or adaptations of apparatus or instruments, not otherwise provided for
G01T 1/17 - Circuit arrangements not adapted to a particular type of detector
H02H 5/00 - Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
6.
ABSOLUTE VECTOR GRAVIMETER AND METHODS OF MEASURING AN ABSOLUTE GRAVITY VECTOR
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