1. A method implemented in a global satellite navigation receiver for acquisition of signals received from navigational satellites, the method comprising:
in a coarse acquisition phase:
for a selected dwell in a list of code-frequency dwells, calculating a non-coherent accumulated power from the signals,
if the non-coherent accumulated power is less than a low threshold value then eliminating the selected dwell from the list of code-frequency dwells and continuing the coarse acquisition phase,
if the non-coherent accumulated power is greater than a high threshold then initiating a fine acquisition phase using the selected dwell;
if a number of integration intervals for the selected dwell exceeds a predetermined duration then initiating the fine acquisition phase using the list of code-frequency dwells
in the fine acquisition phase:
for a given dwell, calculating a fast Fourier transform of a set of recent signal samples to determine coherent accumulated powers for a set of frequencies, and
discarding frequencies whose coherent accumulated powers are less than an average power.
2. The method of claim 1 wherein the average power is calculated from the set of recent signal samples based on Parseval’s theorem.
3. The method of claim 1 wherein calculating the fast Fourier transform comprises determining navigation data bits using an optimal estimation algorithm.
4. The method of claim 3 wherein the optimal estimation algorithm comprises selecting a data sequence with maximum energy.
5. The method of claim 1 wherein calculating the non-coherent accumulated power comprises adding a square of an in-phase signal component and a square of a quadrature signal component to a prior non-coherent accumulated power.
6. The method of claim 1 wherein the high threshold is equal to the product of a constant power threshold, a number of integration intervals, and a power of a constant attenuation factor.
7. The method of claim 1 wherein the low threshold value is a function of a noise power level in a coherent integration interval.
8. The method of claim 1 further comprising: if multiple dwells have non-coherent accumulated powers greater than the high threshold, then performing additional integrations to obtain the selected dwell and initiating a fine acquisition phase using the selected dwell.
9. The method of claim 1 further comprising: if multiple frequencies remain after discarding frequencies whose coherent accumulated powers are less than the average power, then collecting additional signal samples and re-computing the fast Fourier transform.
10. A global satellite navigation system receiver device comprising an RF front end for receiving signals from navigational satellites, a baseband section receiving IF signals from the RF front end, and a processor receiving I,Q signal samples from the baseband section, wherein the processor implements a two-phase signal acquisition process comprising a coarse acquisition phase and a fine acquisition phase,
wherein the coarse acquisition phase comprises:
for a selected dwell in a list of code-frequency dwells, calculating a non-coherent accumulated power from the signals,
if the non-coherent accumulated power is less than a low threshold value then eliminating the selected dwell from the list of code-frequency dwells and continuing the coarse acquisition phase,
if the non-coherent accumulated power is greater than a high threshold then initiating a fine acquisition phase using the selected dwell;
if a number of integration intervals for the selected dwell exceeds a predetermined duration then initiating the fine acquisition phase using the list of code-frequency dwells
wherein the fine acquisition phase comprises:
for a given dwell, calculating a fast Fourier transform of a set of recent signal samples to determine coherent accumulated powers for a set of frequencies, and
discarding frequencies whose coherent accumulated powers are less than an average power.
11. The device of claim 10 wherein the average power is calculated from the set of recent signal samples based on Parseval’s theorem.
12. The device of claim 10 wherein calculating the fast Fourier transform comprises determining navigation data bits using an optimal estimation algorithm.
13. The device of claim 12 wherein the optimal estimation algorithm comprises selecting a data sequence with maximum energy.
14. The device of claim 10 wherein calculating the non-coherent accumulated power comprises adding a square of an in-phase signal component and a square of a quadrature signal component to a prior non-coherent accumulated power.
15. The device of claim 10 wherein the high threshold is equal to the product of a constant power threshold, a number of integration intervals, and a power of a constant attenuation factor.
16. The device of claim 10 wherein the low threshold value is a function of a noise power level in a coherent integration interval.
17. The device of claim 10 further comprising: if multiple dwells have non-coherent accumulated powers greater than the high threshold, then performing additional integrations to obtain the selected dwell and initiating a fine acquisition phase using the selected dwell.
18. The device of claim 10 further comprising: if multiple frequencies remain after discarding frequencies whose coherent accumulated powers are less than the average power, then collecting additional signal samples and re-computing the fast Fourier transform.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of processing a set of transformation rules defining a mapping of a plurality of source tags in a source markup language to a plurality of target tags in a target markup language, said method comprising:
receiving said set of transformation rules; and
identifying a plurality of referenced tags in said set of transformation rules, wherein each of said plurality of referenced tags is one of said plurality of source tags the content of which is to be determined to apply at least one transformation rule of another source tag.
2. The method of claim 1, further comprising storing a unique identifier of each of said plurality of referenced tags in a memory.
3. The method of claim 2, further comprising changing any relative paths of any of said plurality of referenced tags in said set of transformation rules to corresponding unique identifiers and storing a resulting changed set of transformation rules in another memory.
4. The method of claim 3, wherein each of said memory and said another memory comprises a non-volatile memory.
5. The method of claim 2, wherein said unique identifier comprises an absolute path or a unique name.
6. A method of transforming a source data in a source markup language to a target data in a target markup language according to a set of transformation rules, wherein said source markup language defines a plurality of source tags, said target markup language defines a plurality of target tags, said set of transformation rules defines a mapping of a source tag to one or more target tags, said method comprising:
receiving a first referenced tag the content of which is to be determined to apply a transformation rule defining a mapping of a second source tag, wherein said first referenced tag and said second source tag are contained in said plurality of source tags and said transformation rule is contained in said set of transformation rules;
reading said first referenced tag from said source data;
storing a content of said first referenced tag in a memory;
reading said second source tag from said source data; and
generating a portion of said target data from said transformation rule and said content.
7. The method of claim 6, wherein said storing stores said content associated with a unique identifier of said first referenced tag.
8. The method of claim 7, further comprising:
reading a third source tag from said source data, a third transformation rule contained in said set of transformation rules defining a mapping of said third source tag to a subset of target tags contained in said plurality of target tags, said third transformation rule not requiring content of any other source tags for completion of mapping;
generating another portion of said target tags from said third transformation rule andor a content of said third source tag.
9. The method of claim 7, further comprising:
reading a fourth source tag from said source data, a fourth plurality of transformation rules defining a mapping of said fourth source tag to a fourth subset of target tags, said fourth plurality of transformation rules containing said transformation rule;
generating a third portion of said target data from said fourth subset of target tags and said content.
10. A computer readable medium carrying one or more sequences of instructions for causing a system to process a set of transformation rules defining a mapping of a plurality of source tags in a source markup language to a plurality of target tags in a target markup language, wherein execution of said one or more sequences of instructions by one or more processors contained in said system causes said one or more processors to perform the actions of:
receiving said set of transformation rules; and
identifying a plurality of referenced tags in said set of transformation rules, wherein each of said plurality of referenced tags is one of said plurality of source tags the content of which is to be determined to apply at least one transformation rule of another source tag.
11. The computer readable medium of claim 10, further comprising storing a unique identifier of each of said plurality of referenced tags in a memory.
12. The computer readable medium of claim 11, further comprising changing any relative paths of any of said plurality of referenced tags in said set of transformation rules to corresponding unique identifiers and storing a resulting changed set of transformation rules in another memory.
13. A computer readable medium carrying one or more sequences of instructions for causing a system to transform a source data in a source markup language to a target data in a target markup language according to a set of transformation rules, wherein said source markup language defines a plurality of source tags, said target markup language defines a plurality of target tags, said set of transformation rules defines a mapping of a source tag to one or more target tags, and execution of said one or more sequences of instructions by one or more processors contained in said system causes said one or more processors to perform the actions of:
receiving a first referenced tag the content of which is to be determined to apply a transformation rule defining a mapping of a second source tag, wherein said first referenced tag and said second source tag are contained in said plurality of source tags and said transformation rule is contained in said set of transformation rules;
reading said first referenced tag from said source data;
storing a content of said first referenced tag in a memory;
reading said second source tag from said source data; and
generating a portion of said target data from said transformation rule and said content.
14. The computer readable medium of claim 13, further comprising:
reading a third source tag from said source data, a third transformation rule contained in said set of transformation rules defining a mapping of said third source tag to a subset of target tags contained in said plurality of target tags, said third transformation rule not requiring content of any other source tags for completion of mapping;
generating another portion of said target tags from said third transformation rule andor a content of said third source tag.
15. The computer readable medium of claim 13, further comprising:
receiving a fourth source tag from said source data, a fourth plurality of transformation rules defining a mapping of said fourth source tag to a fourth subset of target tags, said fourth plurality of transformation rules containing said transformation rule;
generating a third portion of said target data from said fourth subset of target tags and said content.
16. A system of processing a set of transformation rules defining a mapping of a plurality of source tags in a source markup language to a plurality of target tags in a target markup language, said system comprising:
means for receiving said set of transformation rules; and
means for identifying a plurality of referenced tags in said set of transformation rules, wherein each of said plurality of referenced tags is one of said plurality of source tags the content of which is to be determined to apply at least one transformation rule of another source tag.
17. The system of claim 16, further comprising means for storing a unique identifier of each of said plurality of referenced tags in a memory.
18. The method of claim 17, further comprising means for changing any relative paths of any of said plurality of referenced tags in said set of transformation rules to corresponding unique identifiers and means for storing a resulting changed set of transformation rules in another memory.
19. A system transforming a source data in a source markup language to a target data in a target markup language according to a set of transformation rules, wherein said source markup language defines a plurality of source tags, said target markup language defines a plurality of target tags, said set of transformation rules defines a mapping of a source tag to one or more target tags, said system comprising:
means for receiving a first referenced tag the content of which is to be determined to apply a transformation rule defining a mapping of a second source tag, wherein said first referenced tag and said second source tag are contained in said plurality of source tags and said transformation rule is contained in said set of transformation rules;
means for reading said first referenced tag from said source data;
means for storing a content of said first referenced tag in a memory;
means for reading said second source tag from said source data; and
means for generating a portion of said target data from said transformation rule and said content.
20. The system of claim 19, further comprising:
means for reading a third source tag from said source data, a third transformation rule contained in said set of transformation rules defining a mapping of said third source tag to a subset of target tags contained in said plurality of target tags, said third transformation rule not requiring content of any other source tags for completion of mapping;
means for generating another portion of said target tags from said third transformation rule andor a content of said third source tag.
21. The system of claim 19, further comprising:
means for receiving a fourth source tag from said source data, a fourth plurality of transformation rules defining a mapping of said fourth source tag to a fourth subset of target tags, said fourth plurality of transformation rules containing said transformation rule; means for generating a third portion of said target data from said fourth subset of target tags and said content.