Systems and methods for low-power location determination using terrestrial signals

• US 10,194,395 B2
• Filed: 04/13/2017
• Issued: 01/29/2019
• Est. Priority Date: 04/25/2016
• Status: Active Grant

• Current Assignee: NextNav, LLC
• Original Assignee: NextNav, LLC
• Inventors: Raghupathy, Arun, Meiyappan, Subramanian S.
• Primary Examiner(s): West, Lewis
• Application Number:
  US15/487,219
• Publication Number:
  US 20170311264A1
• Time in Patent Office: 656 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 a position of the receiver 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,

wherein identifying a power reduction strategy using the determined power reduction strategy information comprises;

(a) 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

(b) selecting, from the set of transmitters, a subset of transmitters that includes at least a threshold minimum number of transmitters, wherein selecting the subset of transmitters comprises;

(i) identifying a first subset of transmitters that includes at least the threshold minimum number of transmitters and that transmitted 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;

(ii) identifying a second subset of transmitters that includes at least the threshold minimum number of transmitters and that transmitted 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;

(iii) selecting the first subset of transmitters as the selected subset of transmitters when a number of transmitters in the first subset of transmitters is less than a number of transmitters in the second subset of transmitters;

(iv) selecting the second subset of transmitters as the selected subset of transmitters when the number of transmitters in the second subset of transmitters is less than the number of transmitters in the first subset of transmitters; and

(v) selecting either the first subset of transmitters or the second subset of transmitters as the selected subset of transmitters when the number of transmitters in the first subset of transmitters is equal to the number of transmitters in the second subset of transmitters,

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

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

3. The method of claim 1, wherein the threshold minimum number of transmitters is four transmitters.

4. The method of claim 1, wherein the transmission time slots that are not used by any transmitter of the subset of transmitters are not contiguous.

5. A method for reducing power consumption of a receiver in association with estimating a position of the receiver 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,

wherein identifying a power reduction strategy using the determined power reduction strategy information comprises;

(a) 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

(b) selecting, from the set of transmitters, a subset of transmitters that includes at least a threshold minimum number of transmitters, wherein selecting the subset of transmitters comprises;

(i) identifying, from the set of transmitters, two or more subsets of transmitters that each provide less than a threshold value of dilution of precision; and

(ii) selecting the subset of transmitters from the two or more subsets of transmitters,

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

6. The method of claim 5, wherein the one or more modules of the receiver are placed into the reduced power state by clock gating, power gating, or by turning off power to the one or more module.

7. The method of claim 5, wherein the threshold minimum number of transmitters is four transmitters.

8. The method of claim 5, wherein the transmission time slots that are not used by any transmitter of the subset of transmitters are not contiguous.

9. 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 a position of the receiver 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,

wherein identifying a power reduction strategy using the determined power reduction strategy information comprises;

(a) 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

(b) selecting, from the set of transmitters, a subset of transmitters that includes at least a threshold minimum number of transmitters, wherein selecting the subset of transmitters comprises;

(i) identifying a first subset of transmitters that includes at least the threshold minimum number of transmitters and that transmitted 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;

(ii) identifying a second subset of transmitters that includes at least the threshold minimum number of transmitters and that transmitted 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;

(iii) selecting the first subset of transmitters as the selected subset of transmitters when a number of transmitters in the first subset of transmitters is less than a number of transmitters in the second subset of transmitters;

(iv) selecting the second subset of transmitters as the selected subset of transmitters when the number of transmitters in the second subset of transmitters is less than the number of transmitters in the first subset of transmitters; and

(v) selecting either the first subset of transmitters or the second subset of transmitters as the selected subset of transmitters when the number of transmitters in the first subset of transmitters is equal to the number of transmitters in the second subset of transmitters,

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

10. The one or more non-transitory machine-readable media of claim 9, wherein the threshold minimum number of transmitters is four transmitters.

11. The one or more non-transitory machine-readable media of claim 9, wherein the transmission time slots that are not used by any transmitter of the subset of transmitters are not contiguous.

12. The one or more non-transitory machine-readable media of claim 9, wherein the one or more modules of the receiver are placed into the reduced power state by clock gating, power gating, or by turning off power to the one or more module.

13. 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 a position of the receiver 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,

wherein identifying a power reduction strategy using the determined power reduction strategy information comprises;

(a) 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

(b) selecting, from the set of transmitters, a subset of transmitters that includes at least a threshold minimum number of transmitters, wherein selecting the subset of transmitters comprises;

(i) identifying, from the set of transmitters, two or more subsets of transmitters that each provide less than a threshold value of dilution of precision; and

(ii) selecting the subset of transmitters from the two or more subsets of transmitters,

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

14. The one or more non-transitory machine-readable media of claim 13, wherein the threshold minimum number of transmitters is four transmitters.

15. The one or more non-transitory machine-readable media of claim 13, wherein the transmission time slots that are not used by any transmitter of the subset of transmitters are not contiguous.

16. The one or more non-transitory machine-readable media of claim 13, wherein the one or more modules of the receiver are placed into the reduced power state by clock gating, power gating, or by turning off power to the one or more module.