SYSTEMS AND METHODS FOR LOW-POWER LOCATION DETERMINATION USING TERRESTRIAL SIGNALS

• US 20170311264A1
• Filed: 04/13/2017
• Published: 10/26/2017
• Est. Priority Date: 04/25/2016
• Status: Active Grant

• Current Assignee: NextNav, LLC
• Original Assignee: NextNav, LLC
• Inventors: RAGHUPATHY, ARUN, MEIYAPPAN, SUBRAMANIAN S.
• Granted Patent: US 10,194,395 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 5/0221 Receivers
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/373 Predicting channel quality or other radio frequency [RF] parameters
• CPC Class Codes: H04B 7/2643 using time-division multiple access [TDMA] H04B7/2615, H04B7/2618 take precedence
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 52/0254 detecting a user operation or a tactile contact or a motion of the device
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Reducing power consumption of a receiver in association with estimating the receiver'"'"'s position using ranging signals. Systems and methods may determine power reduction strategy information, identify a power reduction strategy using the determined power reduction strategy information, and place one or more modules of the receiver into a reduced power state using the identified power reduction strategy. The power reduction strategy may result in powering off different circuitry of the receiver at different times, and under different circumstances.

Claims

1. A method for reducing power consumption of a receiver in association with estimating the receiver'"'"'s position using terrestrial signals, the method comprising:

determining power reduction strategy information;

identifying a power reduction strategy using the determined power reduction strategy information; and

placing one or more modules of the receiver into a reduced power state using the identified power reduction strategy.

2. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining whether a signal strength of a first signal transmitted from a first transmitter during a first transmission time slot is above a predefined threshold; and

after determining that the signal strength is above the predefined threshold, identifying a sub-duration of the first transmission time slot after which a module of the one or more modules is placed into a reduced power state,

wherein the identified power reduction strategy places the module of the one or more modules into the reduced power state after the sub-duration ends.

3. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining a set of transmitters from which the receiver has received signals,

wherein each of the transmitters in the set of transmitters transmitted a respective signal using a different TDMA transmission time slot; and

identifying, from the set of transmitters, a subset of transmitters that includes a threshold minimum number of transmitters,

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state during transmission time slots that are not used by any transmitter of the subset of transmitters.

4. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining a set of transmitters from which the receiver has received signals,

wherein each of the transmitters in the set of transmitters transmitted a respective signal using a different TDMA transmission time slot;

identifying a first subset of transmission time slots used by a first subset of transmitters to transmit a first subset of signals used to derive a first subset of range measurements that were used to compute a first estimated position of the receiver that meets a position quality threshold condition;

identifying a second subset of transmission time slots used by a second subset of transmitters to transmit a second subset of signals used to derive a second subset of range measurements that were used to compute a second estimated position of the receiver that meets the position quality threshold condition; and

identifying the first subset of transmission time slots or the second subset of transmission time slots as a selected subset of transmission time slots by (1) identifying the first subset of transmission time slots as the selected subset of transmission time slots when the first subset of transmission time slots is less than the second subset of transmission time slots, (2) identifying the second subset of transmission time slots as the selected subset of transmission time slots when the second subset of transmission time slots is less than the first subset of transmission time slots, and (3) identifying either the first subset of transmission time slots or the second subset of transmission time slots as the selected subset of transmission time slots when the first subset of transmission time slots is equal to the second subset of transmission time slots,

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state during transmission time slots that are not included in the selected subset of transmission time slots.

5. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining a set of transmitters from which the receiver has received signals,

wherein each of the transmitters in the set of transmitters transmitted a respective signal using a different TDMA transmission time slot; and

identifying, from the set of transmitters, a subset of transmitters that provide less than a threshold value of dilution of precision;

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state during transmission time slots not used by the subset of transmitters.

6. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining an initial estimated position of the receiver; and

identifying a set of transmitters that are within a threshold distance of the initial estimated position,

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state when the receiver is not receiving signals from the identified set of transmitters.

7. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

identifying first and second times for estimating positions of a receiver based on an update rate for estimating positions of the receiver,

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state during a time period between the first and second times.

8. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining whether the receiver is in motion;

after determining that the receiver is not in motion, identifying a previously identified subset of transmitters that includes a threshold minimum number of transmitters,

wherein the identified power reduction strategy places a module of the one or more modules into a reduced power state during transmission time slots that are not used by any transmitter of the subset of transmitters.

9. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining that signal jammers are detected,

wherein the identified power reduction strategy places one or more analog circuitry modules of the receiver into a low linearity mode after the signal jammers are detected.

10. The method of claim 1, wherein identifying a power reduction strategy using the determined power reduction strategy information comprises:

determining that signal jammers are detected, and

wherein the identified power reduction strategy places one or more analog circuitry modules of the receiver into a low dynamic range mode after the signal jammers are detected.

11. The method of claim 1, wherein the one or more modules of the receiver are placed into the reduced power state by clock gating.

12. The method of claim 1, wherein the one or more modules of the receiver are placed into the reduced power state by power gating.

13. The method of claim 1, wherein the one or more modules of the receiver are placed into the reduced power state by turning off power to the one or more modules.

14. The method of claim 1, wherein the one or more modules include analog circuitry.

15. The method of claim 1, wherein the one or more modules include digital circuitry.

16. One or more non-transitory machine-readable media embodying program instructions that, when executed by one or more machines, cause the one or more machines to implement a method for reducing power consumption of a receiver in association with estimating the receiver'"'"'s position using terrestrial signals, the method comprising:

determining power reduction strategy information;

identifying a power reduction strategy using the determined power reduction strategy information; and

placing one or more modules of the receiver into a reduced power state using the identified power reduction strategy.

17. A system for reducing power consumption of a receiver in association with estimating the receiver'"'"'s position using terrestrial signals, wherein the system includes one or more modules that are operable to perform a method for reducing power consumption of a receiver in association with estimating the receiver'"'"'s position using terrestrial signals, the method comprising:

determining power reduction strategy information;

identifying a power reduction strategy using the determined power reduction strategy information; and

placing one or more modules of the receiver into a reduced power state using the identified power reduction strategy.