Autonomous takeoff and landing with open loop mode and closed loop mode

1. A system, comprising:

a processor; and

a memory coupled with the processor, wherein the memory is configured to provide the processor with instructions which when executed cause the processor to:

perform autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

determine instructions for performing autonomous landing in the open loop mode including instructions for performing ground detection including by:

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

perform the autonomous flight in a closed loop mode over a second range of altitudes, wherein: the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.

2. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

determine a confidence value;

compare the confidence value against a confidence threshold; and

in response to the confidence value exceeding the confidence threshold, switch from performing the autonomous takeoff in the open loop mode, wherein the plurality of altitude-related data is ignored, to performing the autonomous takeoff in the closed loop mode, wherein the plurality of altitude-related data is used.

3. The system recited in claim 1 , wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain an altitude from the plurality of altitude-related data;

compare the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switch from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored.

4. The system recited in claim 1 , wherein:

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain an altitude from the plurality of altitude-related data;

compare the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switch from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored, wherein the altitude threshold is selected based at least in part on a landing surface, including by:

determining whether an aircraft is above land or water; and

in response to the determination whether the aircraft is above land or water, selecting a land altitude threshold or a water altitude threshold accordingly.

5. The system recited in claim 1 , wherein:

the determination of instructions for performing the autonomous landing in the open loop mode including instructions for performing ground detection further includes

obtaining a throttle value;

comparing the throttle value against a throttle threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold and the throttle value not exceeding the throttle threshold, deciding that a landing surface has been reached.

6. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

7. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing one or more of the following properties associated with the signal:

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode; or

a slope of the signal; and

use the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

8. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing.

9. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing one or more of the following properties associated with the signal:

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode; or

a slope of the signal; and

use the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing.

10. The system recited in claim 1 , wherein:

the autonomous flight includes autonomous takeoff; and

the memory is further configured to provide the processor with instructions which when executed cause the processor to:

obtain a signal associated with the autonomous takeoff;

estimate a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

use the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing, wherein updating the parameter includes using the pilot weight to select the parameter from a plurality of parameters associated with different pilot weights.

11. A method, comprising:

using a processor to perform autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

using the processor to perform autonomous landing in the open loop mode including performing ground detection including by:

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

using the processor to perform the autonomous flight in a closed loop mode over a second range of altitudes, wherein: the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.

12. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

determining a confidence value;

comparing the confidence value against a confidence threshold; and

in response to the confidence value exceeding the confidence threshold, switching from performing the autonomous takeoff in the open loop mode, wherein the plurality of altitude-related data is ignored, to performing the autonomous takeoff in the closed loop mode, wherein the plurality of altitude-related data is used.

13. The method recited in claim 11 , wherein:

the method further includes:

obtaining an altitude from the plurality of altitude-related data;

comparing the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switching from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored.

14. The method recited in claim 11 , wherein:

the method further includes:

obtaining an altitude from the plurality of altitude-related data;

comparing the obtained altitude against an altitude threshold; and

in response to the obtained altitude no longer exceeding the altitude threshold, switching from performing the autonomous landing in the closed loop mode, wherein the plurality of altitude-related data is used, to performing the autonomous landing in the open loop mode, wherein the plurality of altitude-related data is ignored, wherein the altitude threshold is selected based at least in part on a landing surface, including by:

determining whether an aircraft is above land or water; and

in response to the determination whether the aircraft is above land or water, selecting a land altitude threshold or a water altitude threshold accordingly.

15. The method recited in claim 11 , wherein:

the using the processor to perform the autonomous landing in the open loop mode including by performing ground detection further includes

obtaining a throttle value;

comparing the throttle value against a throttle threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold and the throttle value not exceeding the throttle threshold, deciding that a landing surface has been reached.

16. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

17. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing one or more of the following properties associated with the signal:

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode; or

a slope of the signal; and

using the pilot weight to generate a value which is used to control an aircraft that is performing the autonomous takeoff.

18. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing.

19. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing one or more of the following properties associated with the signal:

a time associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode;

a throttle associated with switching from performing the autonomous takeoff in the open loop mode to performing the autonomous takeoff in the closed loop mode; or

a slope of the signal; and

using the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing.

20. The method recited in claim 11 , wherein:

the autonomous flight includes autonomous takeoff; and

the method further includes:

obtaining a signal associated with the autonomous takeoff;

estimating a pilot weight, including by analyzing the signal associated with the autonomous takeoff; and

using the pilot weight to update a parameter associated with one or more of the following: the autonomous takeoff or the autonomous landing, wherein updating the parameter includes using the pilot weight to select the parameter from a plurality of parameters associated with different pilot weights.

21. A computer program product, the computer program product being embodied in a non-transitory computer readable storage medium and comprising computer instructions for:

performing autonomous flight in an open loop mode over a first range of altitudes, wherein a plurality of altitude-related data from a plurality of altitude-related sensors is not used for determining instructions for performing autonomous flight while performing the autonomous flight in the open loop mode;

performing autonomous landing in the open loop mode including performing ground detection including by:

injecting a rotation about an axis of rotation;

obtaining a measured amount of rotation about the axis of rotation;

comparing the measured amount of rotation against a rotational threshold; and

in response to the measured amount of rotation not exceeding the rotational threshold, deciding that a landing surface has been reached; and

performing the autonomous flight in a closed loop mode over a second range of altitudes, wherein: the plurality of altitude-related data from the plurality of altitude-related sensors is used while performing the autonomous flight in the closed loop mode, and the first range of altitudes is a non-overlapping, lower range of altitudes compared to the second range of altitudes.