Fluid flow estimation and navigation

1 . A method comprising:

receiving one or more sensor measurements from one or more inertial sensors, wherein the sensor measurements are indicative of at least one acceleration of a vehicle;

determining a 3-dimensional force on the vehicle based on the received sensor measurements indicative of at least one acceleration;

determining a force delta, wherein the force delta is a difference between a 3-dimensional force with a change in a control surface state and a 3-dimensional force without the change in the control surface state, wherein determining the force delta comprises:

identifying an initial 3-dimensional fluid flow estimate vector;

receiving data relating to a current control surface state; and

referencing a Force Delta look-up table based on the initial 3-dimensional fluid flow estimate vector and the data relating to the current control surface state;

adding the force delta to the determined 3-dimensional force; and

determining a 3-dimensional fluid flow estimate vector corresponding to the determined 3-dimensional force based on an inverted Fluid Flow to Force mapping function, wherein the mapping function is trained based on one or more training datasets and the 3-dimensional fluid flow estimate vector is indicative of a fluid flow affecting at least the lift and drag forces acting on the vehicle.

2 . The method of claim 1 , in which the inverted Fluid Flow to Force mapping function is represented by a Force-Flow look-up table and determining the fluid flow estimate vector further comprises:

referencing the Force-Flow look-up table based on the determined force to determine the corresponding 3-dimensional fluid flow estimate vector.

3 . The method of claim 2 , in which determining the fluid flow further comprises:

interpolating the determined 3-dimensional force to a corresponding 3-dimensional fluid flow estimate vector.

4 . The method of claim 1 , further comprising:

performing a plurality of simulations on a dynamic model of the vehicle, wherein the simulations determine a 3-dimensional force with a change in a control surface state and a 3-dimensional force without the change in the control surface state, for a given fluid flow;

determining a difference between the 3-dimensional force with the change in a control surface state and the 3-dimensional force without the change in the control surface state; and

populating the Force-Delta look-up table with the determined difference.

5 . The method of claim 1 , further comprising:

modifying the sensor measurements to remove an effect of at least one external force.

6 . The method of claim 2 , further comprising:

performing a plurality of simulations on a dynamic model of the vehicle, wherein the simulations determine a 3-dimensional force for a given fluid flow; and

populating the Force-Flow look-up table with the determined simulated 3-dimensional force.

7 . The method of claim 2 , further comprising:

receiving telemetry data from a plurality of vehicle operations and/or wind tunnel experiments; and

populating the Force-Flow look-up table based on the received telemetry data.

8 . The method of claim 6 , in which the Force-Flow look-up table comprises a plurality of 3-dimensional force buckets, wherein populating the Force-Flow look- up table with the determined simulated force further comprises:

assigning each determined simulated force to one or more proximate 3-dimensional force buckets proportional to a distance between the determined simulated force and the one or more proximate force buckets.

9 . The method of claim 8 , in which each 3-dimensional force bucket is indicative of an average, or weighted average, fluid flow corresponding to the forces assigned to each force bucket.

10 . The method of claim 8 in which each 3-dimensional force bucket is indicative of a region of fluid flows corresponding to the forces assigned to each bucket.

11 . The method of claim 8 , further comprising:

applying a variable resolution to each of the 3-dimensional force buckets.

12 . The method of claim 1 , further comprising:

restricting the fluid flow function to a predefined set of fluid flows.

13 . The method of claim 1 , further comprising:

receiving a ground velocity estimate of the vehicle; and

determining a wind estimate based on the fluid flow estimate vector and the ground velocity estimate.

14 . The method of claim 1 , further comprising:

determining a ground velocity estimate based on an estimate of the prevailing wind and the 3-dimensional fluid flow estimate vector.

15 . The method of claim 14 further comprising:

determining a vehicle position estimate based on an integration of the determined ground velocity estimate; and

performing flow based navigation based on the determined vehicle position estimate.

16 . A computer program product comprising computer readable executable code for implementing a method configure to:

receive one or more sensor measurements from one or more inertial sensors, wherein the sensor measurements are indicative of at least one acceleration of a vehicle;

determine a 3-dimensional force on the vehicle based on the received sensor measurements indicative of at least one acceleration;

determine a force delta, wherein the force delta is a difference between a 3-dimensional force with a change in a control surface state and a 3-dimensional force without the change in the control surface state, wherein determining the force delta comprises:

identifying an initial 3-dimensional fluid flow estimate vector;

receiving data relating to a current control surface state; and

referencing a Force Delta look-up table based on the initial 3-dimensional fluid flow estimate vector and the data relating to the current control surface state;

add the force delta to the determined 3-dimensional force; and

determine a 3-dimensional fluid flow estimate vector corresponding to the determined 3-dimensional force based on an inverted Fluid Flow to Force mapping function, wherein the mapping function is trained based on one or more training datasets and the 3-dimensional fluid flow estimate vector is indicative of a fluid flow affecting at least the lift and drag forces acting on the vehicle.

17 . A system comprising:

a computing device; and

a vehicle;

wherein the system is configured to implement a method comprising:

receiving one or more sensor measurements from one or more inertial sensors, wherein the sensor measurements are indicative of at least one acceleration of a vehicle;

determining a 3-dimensional force on the vehicle based on the received sensor measurements indicative of at least one acceleration;

determining a force delta, wherein the force delta is a difference between a 3-dimensional force with a change in a control surface state and a 3-dimensional force without the change in the control surface state, wherein determining the force delta comprises:

identifying an initial 3-dimensional fluid flow estimate vector;

receiving data relating to a current control surface state; and

referencing a Force Delta look-up table based on the initial 3-dimensional fluid flow estimate vector and the data relating to the current control surface state;

adding the force delta to the determined 3-dimensional force; and

determining a 3-dimensional fluid flow estimate vector corresponding to the determined 3-dimensional force based on an inverted Fluid Flow to Force mapping function, wherein the mapping function is trained based on one or more training datasets and the 3-dimensional fluid flow estimate vector is indicative of a fluid flow affecting at least the lift and drag forces acting on the vehicle.