Devices and methods for passive navigation
Devices and methods are disclosed for determining position and controlling navigation by sensing movement through the Earth's magnetic field. Change in position is determined by integrating velocity which has been normalized for spatial and temporal field variation. Position is registered with respect to starting point and/or subsequently detected environmental feature. Signals are provided to actuator for guidance, navigation and control.
1. A method for controlling navigation of a platform comprising: providing a sensing element for producing a tangential velocity of a charge during translational movement of sensing element, detecting, utilizing the sensing element, compound velocity signals induced in the sensing element from a combination of the tangential velocity and a translational velocity of the charge caused by the translational movement of the sensing element, utilizing a processor connected to the sensor, processing the detected signals to determine a velocity signal, integrating the velocity signal to determine a change in position signal, and utilizing a controller coupled to or implemented by the processor, registering the change in position to an initial position or to a detected environmental feature of known location for determining a navigation signal.
2. The method of claim 1 wherein processing the detected signals includes normalizing the detected signals using a field signal.
3. The method of claim 1 wherein the navigation signal comprises position, velocity and/or attitude type.
4. The method of claim 1 further comprising determining a signal representing the effect on navigation of a disturbing force.
5. The method of claim 1 further comprising using the navigation signal to control navigation of a platform.
6. The method of claim 1 wherein the sensing element comprises at least two sensing points and wherein the field signal is determined using at least one of a signal from one of the sensing points that is axially disposed with respect to the sensing element and a signal from one of the sensing points that is radially disposed with respect to the sensing element, a magnetometer signal, and field data stored in memory.
7. The method of claim 1 comprising low pass filtering at least one of the detected compound velocity signals and the field signal.
8. The method of claim 2 wherein the field signal comprises a resampled type.
9. The method of claim 1 comprising co-processing the navigation signal with a signal from a navigational sensor separate from the sensing element.
10. The method of claim 4 wherein determining the disturbance force signal comprises quantifying a variation in at least one of AM and FM modulation of the compound velocity signals.
11. The method of claim 5 wherein using the navigation signal to control navigation of a platform comprises providing the navigation signal or a control signal derived from the navigation signal to an actuator.
12. The method of claim 1 wherein the sensing element comprises a plurality of cavity type sensing elements.
13. The method of claim 1 wherein the sensing element comprises charged particles circulating in a high mobility material.
14. A device for controlling navigation of a platform, the device comprising:
a sensing element for producing a tangential velocity of a charge greater than 1 meter per second during translational movement of the sensing element;
a sensor comprising at least two sensing points mounted to the sensing element to detect signals induced in the sensing element from a combination of the tangential velocity and a translational velocity of the charge caused by the translational movement of the sensing element;
a processor module connected to sensor for processing signals output from the at least two sensing points and providing output signals;
a controller coupled to or implemented by the processor module to produce a navigation control signal based on at least one of the output signals; and
an actuator coupled to the controller to control navigation of a platform based on the navigation control signal.
15. The device of claim 14 , wherein the sensing element comprises a spinning disk with two sensing points mounted proximate to a periphery of the disk and one sensing point mounted proximate to an axis of the disk, said sensing points being of at least one of the following types: charge, current, encoder, energy, momentum, deflection and radiation type and said sensing element being formed of slow relaxation material and having at least one detectable feature.
16. The device of claim 14 wherein the sensor comprises at least one of a magnetometer and an inertial measurement (IMU).
17. The device of claim 14 wherein the processor module comprises an analog section and a processing section.
18. The device of claim 14 wherein the sensing element comprises a charged particle circulation type.
19. The device of claim 18 wherein the sensing element comprises an evacuated cavity and/or high mobility material.
20. The device of claim 19 wherein the high mobility material comprises at least one of: graphene, indium antimonide and two dimensional charged particle gas.
21. The device of claim 14 further comprising at least one of an exciter and a deflector.
22. The device of claim 19 wherein the sensing element comprises a pair of anti-parallel arranged tube type cavities.
23. The device of claim 14 wherein controller is connected to at least one of: an output and the actuator.