Low-light and no-light aerial navigation

1. An unmanned aerial vehicle (UAV) comprising:

a satellite positioning system receiver;

an inertial measurement unit having an associated accelerometer; and

one or more processors configured by executable instruction to perform operations comprising:

determining a first acceleration of the UAV based at least on information from the accelerometer received at least one of prior to or during takeoff;

determining a second acceleration of the UAV based at least on location information received via the satellite positioning system receiver at least one of prior to or during takeoff;

determining a relative heading of the UAV based at least in part on the first acceleration and the second acceleration; and

directing the UAV to navigate an environment based at least on the relative heading.

2. The UAV as recited in claim 1 , the operations further comprising:

determining the first acceleration in a navigation frame referenced based at least on the information from the accelerometer; and

determining the second acceleration in a world frame of reference based at least on the location information received via the satellite positioning system receiver.

3. The UAV as recited in claim 1 , the operations further comprising:

determining a plurality of the relative headings based at least in part on determining a plurality of the first accelerations and a plurality of the second accelerations; and

selecting one of the plurality of relative headings as the relative heading based at least on a largest subset of the plurality of relative headings that match each other within a threshold amount.

4. The UAV as recited in claim 1 , wherein the operation of determining the relative heading of the UAV based at least in part on the first acceleration and the second acceleration further comprises determining the relative heading of the UAV based in part on consideration of a magnitude of at least one of the first acceleration or the second acceleration.

5. The UAV as recited in claim 1 , wherein the operation of determining the relative heading of the UAV based at least in part on the first acceleration and the second acceleration further comprises determining the relative heading of the UAV based in part on rotation of the UAV.

6. The UAV as recited in claim 1 , the operations further comprising:

receiving the first acceleration and the second acceleration prior to takeoff of the UAV based on motion induced on the UAV prior to takeoff.

7. The UAV as recited in claim 1 , the operations further comprising:

receiving the first acceleration and the second acceleration during takeoff of the UAV by causing the UAV to takeoff according to a specified acceleration.

8. A method comprising:

inducing motion on an unmanned aerial vehicle (UAV) prior to takeoff;

determining, by one or more processors, a first acceleration of the UAV based at least on information from an accelerometer onboard the UAV;

determining a second acceleration of the UAV based at least on location information received via a satellite positioning system receiver;

determining a relative heading of the UAV based at least in part on the first acceleration and the second acceleration; and

directing the UAV to navigate an environment based at least on the relative heading.

9. The method as recited in claim 8 , further comprising inducing the motion on the UAV by moving the UAV in a back-and-forth motion prior to takeoff.

10. The method as recited in claim 8 , determining the first acceleration in a navigation frame of reference based at least on an output from an inertial measurement unit (IMU) that is associated with the accelerometer.

11. The method as recited in claim 8 , further comprising determining the second acceleration in a world frame of reference based at least on the location information received via the satellite positioning system receiver by determining finite differences in velocity signals determined based on the received location information.

12. The method as recited in claim 8 , further comprising:

determining a plurality of the relative headings; and

selecting one of the plurality of relative headings as the relative heading based at least in part on a largest subset of the plurality of relative headings that match each other within a threshold amount.

13. The method as recited in claim 8 , wherein determining the relative heading of the UAV based at least in part on the first acceleration and the second acceleration further comprises determining the relative heading of the UAV based in part on consideration of a magnitude of at least one of the first acceleration or the second acceleration.

14. The method as recited in claim 8 , wherein determining the relative heading of the UAV based at least in part on the first acceleration and the second acceleration further comprises determining the relative heading of the UAV based in part on rotation of the UAV.

15. A method comprising:

configuring an unmanned aerial vehicle (UAV) to takeoff at a specified trajectory and a specified acceleration;

determining, by one or more processors, a first acceleration of the UAV during takeoff based at least on information from an accelerometer onboard the UAV;

determining a second acceleration of the UAV based at least on location information received via a satellite positioning system receiver;

determining a relative heading of the UAV based at least in part on the first acceleration and the second acceleration; and

directing the UAV to navigate an environment based at least on the relative heading.

16. The method as recited in claim 15 , wherein the specified trajectory is diagonal to a ground plane.

17. The method as recited in claim 15 , determining the first acceleration in a navigation frame of reference based at least on an output from an inertial measurement unit that is associated with the accelerometer.

18. The method as recited in claim 15 , further comprising determining the second acceleration in a world frame of reference based at least on the location information received via the satellite positioning system receiver by determining finite differences in velocity signals determined based on the received location information.

19. The method as recited in claim 15 , further comprising:

determining a plurality of the relative headings during the takeoff; and

selecting one of the plurality of relative headings as the relative heading based at least in part on a largest subset of the plurality of relative headings that match each other within a threshold amount.

20. The method as recited in claim 15 , wherein determining the relative heading of the UAV based at least in part on the first acceleration and the second acceleration further comprises determining the relative heading of the UAV based in part on rotation of the UAV.