Mobile structure heading and piloting systems and methods
Techniques are disclosed for systems and methods for navigating mobile structures. The mobile structure may include a main attitude & heading reference system (AHRS) and one or more devices. The one or more devices may include a slave AHRS such as a gyroscope. Data may be transmitted from the main AHRS to the one or more devices through a network. Latency may be present in the transmission of data. As such, data from the slave AHRS may be used to determine changes in heading and/or attitude of the mobile structure to compensate for such latency. In addition, such data may be used to determine changes in wind direction and/or heading experienced by the mobile structure.
1. An apparatus comprising: a gyroscope; an attitude and heading reference system (AHRS); a controller configured to communicate with a plurality of navigational sensors comprising at least the gyroscope and the AHRS, wherein each navigational sensor is configured to provide navigational data associated with a mobile structure, and the controller is configured to: receive first attitude and/or heading data from the AHRS over a network comprising a network latency; receive first angular velocity data from the gyroscope, wherein the first angular velocity data is received according to no latency or lower latency than the network latency; determine a first orientation of the mobile structure from the first attitude and/or heading data from the AHRS; determine a first slave orientation of the mobile structure based, at least in part, on the first angular velocity data from the gyroscope; receive updated attitude and/or heading data from the AHRS over the network; determine a time delay indicative of the network latency, wherein the determining the time delay is based, at least in part, on comparing the first slave orientation and the updated attitude and/or heading data from the AHRS; and determine a second orientation of the mobile structure based, at least in part, on the first slave orientation and the time delay.
2. The apparatus of claim 1 , wherein:
the determining the first slave orientation is based, at least in part, on the first angular velocity data from the gyroscope and the first attitude and/or heading data from the AHRS; and
the determining the second orientation of the mobile structure is based, at least in part, on the first slave orientation, the time delay, and the updated attitude and/or heading data from the AHRS.
3. The apparatus of claim 1 , wherein the controller is further configured to:
determine a first true orientation based, at least in part, on a comparison of the first slave orientation and the first AHRS orientation.
4. The apparatus of claim 1 , wherein determining the time delay comprises:
determining a mean delay indicative of a latency associated with the ARHS communicating the first attitude and/or heading data and the controller receiving the first attitude and/or heading data; and
determining a fine-tune term for use within an integration portion of a Kalman filter arrangement, wherein the fine-tune term comprises a difference between the first attitude and/or heading data and the first slave orientation after time shifting the first slave orientation by the mean delay.
5. The apparatus of claim 1 , wherein the first attitude and/or heading data is received at a first time period and the first angular velocity data is received at a second time period.
6. The apparatus of claim 5 , wherein a difference between the first time period and the second time period comprises a latency between the AHRS sensing the first attitude and/or heading and the controller receiving the first attitude and/or heading data.
7. The apparatus of claim 1 , wherein the controller is communicatively coupled to and remote from the AHRS.
8. The apparatus of claim 1 , wherein the controller is further configured to:
calibrate a coordinate frame of the gyroscope to a coordinate frame of the AHRS.
9. The apparatus of claim 1 , wherein the mobile structure comprises a watercraft.
10. The apparatus of claim 1 , wherein the controller is further configured to:
determine a wind speed and/or direction experienced by the mobile structure based, at least in part, on the second slave orientation.
11. The apparatus of claim 10 , wherein determining the wind speed and/or direction further comprises:
determining a mobile structure control input; and
correcting the second slave orientation based, at least in part, on the mobile structure control input.
12. The apparatus of claim 1 , further comprising an actuator for changing an orientation of the mobile structure and/or of at least one said sensor in response to the determining the second orientation.
13. A method comprising: receiving by a controller, over a network comprising a network latency, first attitude and/or heading data from an attitude and heading reference system (AHRS) coupled by the network to the controller; receiving, by the controller, first angular velocity data from a gyroscope, wherein the first angular velocity data is received according to no latency or lower latency than the network latency; determining by the controller a first orientation of a mobile structure from the first attitude and/or heading data from the AHRS; determining by the controller a first slave orientation of the mobile structure based, at least in part, on the first angular velocity data from the gyroscope; receiving, by the controller, updated attitude and/or heading data from the AHRS over the network; determining by the controller a time delay indicative of the network latency, wherein the determining the time delay is based, at least in part, on comparing the first slave orientation and the updated attitude and/or heading data from the AHRS; and determining by the controller a second orientation of the mobile structure based, at least in part, on the first slave orientation and the time delay.
14. The method of claim 13 , wherein:
the determining the second orientation of the mobile structure is based, at least in part, on the first slave orientation, the time delay, and the updated attitude and/or heading data from the AHRS.
15. The method of claim 13 , further comprising:
determining a first true orientation based, at least in part, on a comparison of the first slave orientation and the first AHRS orientation.
16. The method of claim 13 , wherein determining the time delay comprises:
determining a mean delay indicative of a latency associated with the ARHS communicating the first attitude and/or heading data and the controller receiving the first attitude and/or heading data; and
determining a fine-tune term for use within an integration portion of a Kalman filter arrangement, wherein the fine-tune term comprises a difference between the first attitude and/or heading data and the first slave orientation after time shifting the first slave orientation by the mean delay.
17. The method of claim 13 , wherein the first attitude and/or heading data is received at a first time period and the first angular velocity data is received at a second time period, and wherein a difference between the first time period and the second time period comprises a latency between the AHRS sensing the first attitude and/or heading and the controller receiving the first attitude and/or heading data.
18. The method of claim 13 , further comprising:
determining a wind speed and/or direction experienced by the mobile structure based, at least in part, on the second slave orientation.
19. The method of claim 13 , further comprising changing an orientation of the mobile structure and/or of at least one said sensor in response to the determining the second orientation.