Global positioning system signal capture method
Global positioning system signal capture method
 CN 101,004,442 A
 Filed: 01/08/2007
 Published: 07/25/2007
 Est. Priority Date: 01/06/2006
 Status: Active Application
First Claim
1. global positioning system signal capture method, the method includes the steps of:
 Receive a global positioning system signal, comprise the complex data position, each data bit has a bit period, and each cycle comprises the plural number sample period;
Construction one comprises the region of search of plural elements, a corresponding hypothesis sideplay amount of each element and a hypothesis pseudocode phase;
Before the position conversion takes place, with the element value of described data bit substitution one people having the same aspiration and interest combination algorithm with each element that adds up;
AndAfter the position conversion takes place, with the element value of described data bit substitution one difference people having the same aspiration and interest combination algorithm with each element that adds up;
AndJudge one group of hypothesis sideplay amount in the described region of search and suppose that pseudocode phase is the global positioning system signal capture result according to the accumulation result of element value.
Chinese PRB Reexamination
Abstract
The present invention brings forward a global position system signal capturing method. The method includes the following steps: first, receiving a GPS signal which includes plural data bits, each data bit has a bit cycle that includes plural sample cycles; forming a searching field which includes plural elements corresponding to a supposed offset and a supposed false code phase; substituting a data bit into a homology combination algorithm before the bit conversion in order to accumulate element value for each element; substituting the data bit into a difference homology combination algorithm after the bit conversion in order to accumulate element value for each element; at last, judging a group of supposed offsets and supposed false code phases in the searching field are GPS signal capture result based on the accumulation result. The present invention can avoid the problem that the accumulation result of the element value during the bit conversion may be destroyed by using CC algorithm solely and the problem that the square lost caused by using the NCC algorithm solely, and can be adapted to the situation of faint signal.

2 Citations
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Current Assignee

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No References
12 Claims

1. global positioning system signal capture method, the method includes the steps of:

Receive a global positioning system signal, comprise the complex data position, each data bit has a bit period, and each cycle comprises the plural number sample period; Construction one comprises the region of search of plural elements, a corresponding hypothesis sideplay amount of each element and a hypothesis pseudocode phase; Before the position conversion takes place, with the element value of described data bit substitution one people having the same aspiration and interest combination algorithm with each element that adds up;
AndAfter the position conversion takes place, with the element value of described data bit substitution one difference people having the same aspiration and interest combination algorithm with each element that adds up;
AndJudge one group of hypothesis sideplay amount in the described region of search and suppose that pseudocode phase is the global positioning system signal capture result according to the accumulation result of element value.


2. global positioning system signal capture method as claimed in claim 1 is characterized in that, the step of described construction one region of search further comprises following steps:

Described region of search is divided into the complex operator region of search;
AndCalculate the relating value of respectively supposing sideplay amount and hypothesis pseudocode phase in described data bit and the described subregion of search with the method for exhaustion.


3. global positioning system signal capture method as claimed in claim 1 is characterized in that, described method further comprises a signal to noise ratio (S/N ratio) that measures described global positioning system signal.

4. global positioning system signal capture method as claimed in claim 3 is characterized in that, the element value accumulation step before and after the conversion on the throne comprises:

Calculate the relating value of respectively supposing sideplay amount and hypothesis pseudocode phase in described data bit and the described region of search with the method for exhaustion, and produce plural relating value;
AndRespectively with the described people having the same aspiration and interest of each relating value substitution in conjunction with or difference people having the same aspiration and interest combination algorithm and the result is added to each corresponding element value.


5. global positioning system signal capture method as claimed in claim 4, it is characterized in that, described people having the same aspiration and interest combination algorithm will the continuous relating value of a corresponding element adds up in the plural number sample period after square, to produce a people having the same aspiration and interest, in order to be added to described element value in conjunction with the result.

6. global positioning system signal capture method as claimed in claim 4 is characterized in that, described difference people having the same aspiration and interest combination algorithm comprises:

In each sample period, the present relating value and a last relating value of each element multiplied each other, longpending to obtain a forwardbackward correlation;
AndThe forwardbackward correlation of each element in the continuously plural sample period amassed addition, to produce a difference people having the same aspiration and interest, in order to be added to each corresponding element value in conjunction with the result.


7. global positioning system signal capture method as claimed in claim 3 is characterized in that, described method further comprises following steps:

According to one first critical value, in described region of search, seek a greatest member value;
Wherein said first critical value determines according to described signal to noise ratio (S/N ratio);
AndIf find described greatest member value, pairing hypothesis sideplay amount of then described element and hypothesis pseudocode phase are the global positioning system signal capture result.


8. global positioning system signal capture method as claimed in claim 7 is characterized in that, the searching step of described greatest member value comprises following steps:

Find out the maximum and once big person described the grade in the element value; Calculate described the maximum and described big person'"'"'s a ratio;
AndIf described ratio surpasses described first critical value, determine that then described the maximum is described greatest member value, the element value otherwise the continuation recurrence adds up in the described region of search.


9. global positioning system signal capture method as claimed in claim 2 is characterized in that, described method further comprises the time point that utilizes one second critical value to detect each accumulation period meta conversion;
 Wherein said second critical value determines according to a signal to noise ratio (S/N ratio).

10. global positioning system signal capture method as claimed in claim 9 is characterized in that, the step of described detecting position point switching time comprises following steps:

Use people having the same aspiration and interest combination algorithm to carry out an accumulation step forward, try to achieve one first value and one second value of continuous two sample periods in the bit period, wherein said first be worth described second be worth before; Calculate a ratio of described first value and described second value;
AndMore described ratio and described second critical value if described ratio surpasses described second critical value, determine that then the position conversion occurs in described second value on the pairing sample period.


11. global positioning system signal capture method as claimed in claim 9 is characterized in that, the step of described detecting position point switching time comprises following steps:

Use people having the same aspiration and interest combination algorithm to carry out an accumulation step backward, try to achieve one first value and one second value of continuous two sample periods in the bit period, wherein said first is worth after described second is worth; Calculate a ratio of described second value and described first value;
AndMore described ratio and described second critical value if described ratio surpasses described second critical value, determine that then the position conversion occurs in described first value on the pairing sample period.


12. global positioning system signal capture method as claimed in claim 1 is characterized in that,
Described bit period is 20ms, and the described sample period is 1ms; 
Comprise 21 hypothesis sideplay amounts in the described region of search, scope from10KHz to+10KHz, 1KHz at interval;
AndComprise 5000 hypothesis pseudocode phase in the described region of search.

Specification(s)