Method for generating a location signal

• US 8,063,823 B2
• Filed: 12/15/2008
• Issued: 11/22/2011
• Est. Priority Date: 12/15/2008
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Gonzalez, Armando J., Swope, Charles B., Ruelke, Charles R.
• Primary Examiner(s): Issing; Gregory C
• Application Number:
  US12/335,091
• Publication Number:
  US 20100149040A1
• Time in Patent Office: 1,072 Days
• Field of Search: 342/385, 342/386
• US Class Current: 342/386
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder

Abstract

A communication device uses its FGU to generate a location signal that can be used by a reference device to calibrate the communication device and to determine the distance of the communication device from the reference device. The communication device: receives, from a reference device, at least one location signal control parameter that defines pulse shape characteristics for a location signal; configures its FGU based on the at least one location signal control parameter; generates a linear first part of a phase-incoherent location signal having the defined pulse shape characteristics by progressively sweeping an output of the FGU over a range of frequencies from a first frequency to a second frequency within a first time period; and transmits at least one iteration of the first part of the location signal.

Claims

1. A method for generating and transmitting signals including location signals, the method comprising:

in a first frequency generation unit (FGU) mode of operation for generating and transmitting non-location signals, configuring the FGU to;

maintain a phase relationship between an output of the FGU and a reference clock,

output a non-location output signal for use in transmitting non-location information signals to another wireless device; and

in a second FGU mode of operation for generating and transmitting location signals, configuring the FGU to;

receive, from a reference device, at least one location signal control parameter that defines a pulse shape characteristics for a location signal;

refrain from maintaining the phase relationship between the output of the FGU and the reference clock;

generate a linear first part of a location signal, being phase incoherent relative to the reference clock as a result of the refraining, and having the defined pulse shape characteristic by progressively sweeping an output of the FGU over a range of frequencies from a first frequency to a second frequency within a first time period in accordance with the location signal control parameter; and

transmitting at least one iteration of the first part of the location signal.

2. The method of claim 1 further comprising:

generating a linear second part of the location signal having the defined pulse shape characteristic by progressively sweeping the output of the FGU back over at least a portion of the range of frequencies from the second frequency to a final frequency within a second time period; and

transmitting the second part of the location signal directly following transmission of the first part of the location signal.

3. The method of claim 2, wherein the first frequency is the same as the final frequency.

4. The method of claim 2 further comprising, in the second mode of FGU operation, communicating a data parameter in the location signal by modulating values of at least one of the first frequency, the second frequency, or the final frequency.

5. The method of claim 4, wherein the first frequency, the second frequency, and the final frequency are all different.

6. The method of claim 2, wherein progressively sweeping the output of the FGU over the range of frequencies comprises sweeping the output of the FGU along a plurality of changing linear frequency slopes to communicate a data parameter in the location signal based on at least one of the linear frequency slopes.

7. The method of claim 6, wherein the plurality of changing linear frequency slopes comprises:

a first linear slope from the first frequency to the second frequency, with the first linear slope having a first polarity; and

a second linear slope from the second frequency to the final frequency, with the second linear slope having an opposite polarity from the first polarity.

8. The method of claim 6, wherein the plurality of changing linear frequency slopes comprises a first plurality of different linear frequency slopes in the first part of the location signal, with each of the first plurality of slopes having the same first polarity.

9. The method of claim 8, wherein the plurality of changing linear frequency slopes comprises a second plurality of different linear frequency slopes in the second part of the location signal, with each of the second plurality of slopes having the opposite polarity from the first polarity.

10. The method of claim 1 further comprising, in the second FGU mode of operation:

setting, to a calibrated state, internal processing of a device that generates the location signal, wherein the calibrated state generates a calibrated time delay within the device, wherein the calibrated time delay comprises a steady state internal processing delay for the device; and

generating the first part of the location signal while in the calibrated state.

11. The method of claim 10, wherein the calibrated state is determined by:

iteratively,

generating and transmitting the first part of the location signal; and

adjusting the internal processing to reduce internal processing delay, until the calibrated time delay is determined; and

when the calibrated time delay is determined, associating the calibrated time delay to an internal processing state, which is stored as the calibrated state.

12. The method of claim 11, wherein the calibrated state is further determined by:

iteratively,

receiving an intermediate time delay value in response to the location signal transmission; and

adjusting the internal processing based on the intermediate time delay value, until the calibrated time delay is determined.

13. The method of claim 1, wherein the at least one location signal control parameter is received over a narrowband wireless channel while the FGU is in the first FGU mode of operation and the location signal is transmitted over a wideband wireless channel while the FGU is in the second FGU mode of operation.

14. The method of claim 1, wherein the FGU comprises a timing source, a control signal source having variable gain to generate a current control signal or a voltage control signal, and an oscillator responsive to the control signal.

15. The method of claim 14, wherein progressively sweeping the output of the FGU over the range of frequencies comprises:

for the first time period, sweeping an output of the oscillator along a first linear frequency slope from the first frequency to the second frequency, wherein the first linear frequency slope has a first polarity and is set based on a first gain setting for the control signal source and the first time period as set by the timing source.

16. A method for generating a location signal comprising:

receiving, in a communication device from a reference device, at least one location signal control parameter that defines a pulse shape characteristic for a calibrated location signal;

setting internal processing of the communication device to a calibrated state, wherein the calibrated state generates a calibrated time delay within the communication device, wherein the calibrated time delay comprises a steady state internal processing delay for the communication device;

configuring a frequency generation unit (FGU) of the communication device based on the at least one location signal control parameter;

starting at a first frequency and progressively sweeping an output of the FGU over a first range of frequencies to a second frequency, wherein the output is swept along at least one linear frequency slope having a first polarity to generate a first part of the calibrated location signal having the defined pulse shape characteristics;

progressively steering the output back over at least part of the first range of frequencies from the second frequency to a final frequency, wherein the output is swept along at least one linear frequency slope having an opposite polarity from the first polarity to generate a second part of the calibrated location signal having the defined pulse shape characteristics; and

sequentially transmitting the first and second parts of the calibrated location signal.

17. The method of claim 16, wherein at least the first frequency and the second frequency have different values, the method further comprising:

communicating a data parameter in the calibrated location signal by modulating at least one of the values of the first frequency, the second frequency, or the final frequency.

18. The method of claim 16 further comprising communicating a data parameter in the calibrated location signal by modulating at least one of the linear frequency slopes.