Relative Positioning of Balloons with Altitude Control and Wind Data
The positions of balloons in a communication network of balloons, such as a mesh network of high-altitude balloons, may be adjusted relative to one another in order to try to maintain a desired network topology. In one approach, the position of each balloon may be adjusted relative to one or more neighbor balloons. For example, the locations of a target balloon and one or more neighbor balloons may be determined. A desired movement of the target balloon may then be determined based on the locations of the one or more neighbor balloons relative to the location of the target balloon. The target balloon may be controlled based on the desired movement. In some embodiments, the altitude of the target balloon may be controlled in order to expose the target balloon to ambient winds that are capable of producing the desired movement of the target balloon.
1 . A method comprising:
determining a desired movement of a target balloon, wherein the target balloon is part of a high-altitude network of balloons, wherein the target balloon comprises a communication system that is operable for data communication with one or more other balloons in the high-altitude network, and wherein the desired movement of the target balloon comprises a desired horizontal movement of the target balloon; and
controlling the target balloon based on the desired movement of the target balloon, wherein controlling the target balloon based on the desired movement of the target balloon comprises controlling an altitude of the target balloon based on the desired horizontal movement of the target balloon.
2 . The method of claim 1 , wherein controlling the altitude of the target balloon based on the desired horizontal movement of the target balloon comprises:
determining that the desired horizontal movement of the target balloon can be achieved by exposing the target balloon to ambient winds of a particular velocity;
determining that ambient winds of the particular velocity are likely to be available at a particular altitude; and
adjusting the altitude of the target balloon to attain the particular altitude.
3 . The method of claim 1 , further comprising:
determining a location of the target balloon; and
determining locations of one or more neighbor balloons in the high-altitude network relative to the determined location of the target balloon,
wherein determining the desired movement of the target balloon comprises determining the desired movement of the target balloon based on the determined locations of the one or more neighbor balloons relative to the determined location of the target balloon.
4 . The method of claim 3 , further comprising identifying a predetermined number of nearest balloons in the high-altitude network as the one or more neighbor balloons.
5 . The method of claim 3 , further comprising identifying any balloons in the high-altitude network that are within a predefined distance from the target balloon as the one or more neighbor balloons.
6 . The method of claim 3 , further comprising identifying any balloons in the high-altitude network that are within a communication range of the target balloon's communication system as the one or more neighbor balloons.
7 . The method of claim 3 , wherein determining the desired movement of the target balloon based on the determined locations of the one or more neighbor balloons relative to the determined location of the target balloon comprises:
defining a potential energy function that assigns a potential energy to the target balloon as a function of the determined locations of the one or more neighbor balloons and the determined location of the target balloon;
determining a gradient of the potential energy function; and
determining the desired movement of the target balloon based on the gradient of the potential energy function.
8 . The method of claim 7 , wherein determining the desired movement of the target balloon based on the gradient comprises:
determining a direction of the gradient; and
determining a direction of the desired movement of the target balloon based on the direction of the gradient.
9 . The method of claim 7 , wherein determining the desired movement of the target balloon based on the gradient comprises:
determining a magnitude of the gradient; and
determining a magnitude of the desired movement of the target balloon based on the magnitude of the gradient.
10 . The method of claim 1 , wherein the desired movement of the target balloon comprises a desired direction of movement.
11 . The method of claim 1 , wherein the desired movement of the target balloon comprises a desired velocity.
12 . The method of claim 1 , wherein the desired movement of the target balloon comprises a desired distance of travel in a desired direction.
13 . The method of claim 1 , wherein the communication system comprises a free-space optical communication system.
14 . A balloon, comprising:
an envelope containing a gas;
a communication system operable for data communication with one or more other balloons in a high-altitude network of balloons; and
a controller coupled to the communication system, wherein the controller is configured to:
determine a desired movement of the balloon, wherein the desired movement of the balloon comprises a desired horizontal movement of the balloon; and
control an altitude of the balloon based on the desired horizontal movement of the balloon.
15 . The balloon of claim 14 , wherein the controller is configured to control an altitude of the balloon based on the desired horizontal movement of the balloon by at least:
determining that the desired horizontal movement of the balloon can be achieved by exposing the balloon to ambient winds of a particular velocity;
determining that ambient winds of the particular velocity are likely to be available at a particular altitude; and
controlling the altitude of the balloon to attain the particular altitude.
16 . The balloon of claim 14 , further comprising:
an altitude-control system that is operable to adjust the altitude of the balloon,
wherein the controller is configured to control the altitude-control system based on the desired horizontal movement of the balloon.
17 . The balloon of claim 16 , wherein the altitude-control system is configured to change at least one of a volume or density of the gas in envelope.
18 . The balloon of claim 14 , wherein the controller is further configured to:
determine a location of the balloon; and
determining locations of one or more neighbor balloons in the high-altitude network relative to the determined location of the balloon, wherein the desired movement of the balloon is determined based on the determined locations of the one or more neighbor balloons relative to the determined location of the balloon.
19 . The balloon of claim 14 , wherein the controller is configured to determine the location of the balloon using a satellite-based positioning system.
20 . The balloon of claim 14 , wherein the controller is configured to determine the locations of the one or more neighbor balloons based on information received through the communication system.