# US 2021/0344215 A1 · Power Saving Modes for Subsystems in Solar Powered Aircraft > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344215 A1 - Document ID: US20210344215A1 - Status: Published application - Kind: A1 - Application number: 16/863,883 - Filed: 2020-04-30 - Published: 2021-11-04 - Earliest claimed: 2020-04-30 - Assignees: Loon LLC - Applicants: Loon LLC - Inventors: Sailesh Prabhu; Jean-Laurent Plateau; Nidhi Gulia; Benjamin Wojtowicz - Web page: https://patentgrep.com/patent/US20210344215A1 ## CPC - H02J 7/35: with light sensitive cells - B64C 19/00: Aircraft control not otherwise provided for - G06F 30/34: for reconfigurable circuits, e.g. field programmable gate arrays [FPGA] or programmable logic devices [PLD] - H02J 1/14: Balancing load and power generation in DC networks - H02J 7/34: Parallel operation in networks using both storage and other DC sources, e.g. providing buffering (H02J7/14 takes precedence) - H02J 7/865: {Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence)} - B64D 2221/00: Electric power distribution systems onboard aircraft - H02J 2101/24: Photovoltaics - H02J 2105/50: for selectively controlling the operation of the loads - Y02E 10/56: Power conversion systems, e.g. maximum power point trackers - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - B64C: AEROPLANES; HELICOPTERS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The technology relates to power saving modes for subsystems in solar powered aircraft. An onboard subsystem of an aircraft includes a first processor configured to monitor a state of the subsystem and generate state data; a heating component configured to heat the subsystem to at least a minimum viable temperature; an operational component; and a hardware controller configured to control power to the heating component, the first processor, and the operational component, at least during a preservation mode and a monitoring mode. The subsystem draws a moderate amount of power when the heating component is on and a minimum threshold amount of power in the preservation mode. The subsystem draws a moderate amount of power in the monitoring mode in order to generate and communicate state data by the first processor, a moderate amount of power being lower than the higher amount of power required to operate the operational component. ## Claims ### Claim 1 An onboard subsystem of an aircraft comprising: a first processor configured to monitor a state of the subsystem and generate state data; a heating component configured to heat the subsystem to at least a minimum viable temperature; an operational component; and a hardware controller configured to control power to the heating component, the first processor, and the operational component, at least during a preservation mode and a monitoring mode, wherein the subsystem draws a first moderate amount of power when the heating component is on and a minimum threshold amount of power in the preservation mode, wherein the subsystem draws a second moderate amount of power in the monitoring mode in order to generate and communicate state data by the first processor, and wherein the first and second moderate amounts of power are lower than a high amount of power required to operate the operational component. ### Claim 2 (depends on 1) The subsystem of claim 1, wherein the subsystem comprises a communications unit. ### Claim 3 (depends on 2) The subsystem of claim 2, wherein the communications unit comprises an LTE eNodeB. ### Claim 4 (depends on 1) The subsystem of claim 1, wherein the first processor comprises a high-level FPGA. ### Claim 5 (depends on 1) The subsystem of claim 1, further comprising a second processor configured to implement a software stack. ### Claim 6 (depends on 1) The subsystem of claim 1, wherein the operational component comprises a radio head configured to transmit and receive radio waves. ### Claim 7 (depends on 1) The subsystem of claim 1, wherein the first processor and the hardware controller are implemented as a system on chip. ### Claim 8 (depends on 1) The subsystem of claim 1, wherein the hardware controller is configured to receive a command from the first processor to control power to the first processor during the preservation mode. ### Claim 9 (depends on 1) The subsystem of claim 1, wherein the hardware logic is configured to monitor a temperature sensor in the preservation mode. ### Claim 10 (depends on 1) The subsystem of claim 1, wherein the hardware logic is configured to power on the heating component to the first moderate amount of power in response to a temperature sensor reading below a minimum viable threshold temperature. ### Claim 11 (depends on 1) The subsystem of claim 1, wherein the minimum threshold amount of power is within a range of 3 W-30 W. ### Claim 12 (depends on 1) The subsystem of claim 1, wherein the first moderate amount of power and the second moderate amount of power are both within a range of 20 W-100 W, the first moderate amount of power being higher than the second moderate amount of power. ### Claim 13 A method for implementing one or more power saving modes in a communication subsystem of a solar-powered aircraft, the method comprising: receiving, by a hardware controller, a command to enter a preservation mode; entering the preservation mode by powering off, by the hardware controller, a processor and an operational component of the communication subsystem; maintaining a minimum threshold amount of power to the communication subsystem during the preservation mode; powering on, by the hardware controller, a heating component after a first time period; powering off, by the hardware controller, a heating component after a second time period; powering on, by the hardware controller, the processor after a third time period to enter a monitoring mode, the processor configured to monitor a state of the communication subsystem and generate state data while in the monitoring mode; and powering on, by the hardware controller, the processor and the operational component after a fourth time period to return to an operational mode. ### Claim 14 (depends on 14) The method of claim 14, wherein the first period of time, the second period of time, and the third period of time, are predetermined. ### Claim 15 (depends on 14) The method of claim 14, wherein powering on the heating component occurs in response to a temperature sensor measuring below a minimum viable threshold temperature, the temperature sensor configured to measure a temperature of a circuit board on which the processor and the hardware controller are implemented. ### Claim 16 (depends on 14) The method of claim 14, wherein powering off the heating component occurs in response to a temperature sensor registering above a higher threshold temperature, the temperature sensor configured to measure a temperature of a circuit board on which the processor and the hardware controller are implemented. ### Claim 17 (depends on 14) The method of claim 14, wherein the state data generated in the monitoring mode comprises sensor data. ### Claim 18 (depends on 14) The method of claim 14, wherein the state data generated in the monitoring mode comprises a time elapsed in the preservation mode. ### Claim 19 (depends on 14) The method of claim 14, wherein the state data generated in the monitoring mode comprises a time elapsed since the processor last broadcasted a set of state data in the monitoring mode. ### Claim 20 (depends on 14) The method of claim 14, wherein the state data generated in the monitoring mode comprises a time elapsed since a last sunset. ### Claim 21 (depends on 14) The method of claim 14, wherein the state data comprises a next expected sunrise time. ### Claim 22 (depends on 14) The method of claim 14, wherein the operational component comprises a radio head configured to transmit and receive radio waves. ### Claim 23 (depends on 14) The method of claim 14, wherein the communication subsystem is a non-flight critical component of the solar-powered aircraft. ### Claim 24 (depends on 14) The method of claim 14, wherein receiving the command to enter the preservation mode occurs shortly before, at, or after, a sunset. ### Claim 25 (depends on 14) The method of claim 14, wherein powering on the processor and the operational component after a fourth period of time to return to an operational mode occurs after a sunrise.