KR20110048933A - Method and apparatus for acquiring weak gps l1 c/a code modulated signal - Google Patents

Abstract

In the GPS signal acquisition method, a first digital signal is generated by sampling an input signal corresponding to a GPS signal during a first integration period corresponding to a multiple of a repetition period of a C / A code. The second digital signal is generated by compensating the Doppler effect on the first digital signal during the first integration period. A duplicate carrier corresponding to the second digital signal is generated, and a first complex signal is generated by mixing the second digital signal and the duplicate carrier. The second complex signal is generated by overlapping the first complex signal in units of repetition periods during the first integration period, and a C / A code is obtained through the second complex signal.

Description

METHOD AND APPARATUS FOR ACQUIRING WEAK GPS L1 C / A CODE MODULATED SIGNAL

The present invention relates to a GPS signal acquisition method and apparatus, and more particularly, to a weak GPS C / A code modulated signal acquisition method and apparatus.

The present invention is derived from a study conducted as part of the IT source technology development project of the Ministry of Knowledge Economy [Task Management Number: 2007-F-040-03, Task name: Indoor and outdoor continuous positioning technology development].

In general, global positioning system (GPS) satellites use two carriers and three binary messages. Two carriers are the L1 carrier and the L2 carrier, and three binary messages are the navigation data message at 50 Hz, the private coarse / acquisition (C / A) code at 1.023 MHz, and the P code at 10.23 MHz. Here the navigation data message contains the system parameters needed to calculate the location. The L1 carrier carries a navigation message modulated with a C / A code and a P code, and the L2 carrier carries a navigation message modulated with a P code. The C / A code and the P code are both pseudo-random codes, but have a repeated property after a certain period of time. The P code repeats after 7 days, but the C / A code repeats after 1 [ms].

Each satellite is assigned a unique C / A code, and the C / A code assigned to each satellite is known to all receivers. The GPS receiver correlates with the C / A code that received its local C / A code to identify satellites in the visible range and to measure the propagation delay time. Since the C / A code is repeated every 1 [ms], the receiver needs an input signal of adequate power for at least 1 [ms] for successful acquisition. This period is called the coherent integration period.

On the other hand, when the GPS signal is weak (for example, a signal having a power of 33 dB-Hz or less) such as a room, a GPS signal, that is, a C / A code cannot be obtained only by the coherent integration period. Acquire C / A codles during the integral period that is a multiple of the runt integral period. However, the magnitude of the Doppler effect can be modeled as a function of the length of the integration period and the Doppler value. The Doppler effect can be ignored for relatively short integration periods such as 1-10 [ms], but in the case of long integration periods, the Doppler effect causes variations in the code phase, making it difficult to obtain C / A codes.

In addition, when the sampling rate used in the analog / digital converter of the GPS receiver is different from the actual sampling rate, a problem of sample fraction occurs. These sample fragments can also be ignored for short integration periods, but for longer integration periods, it is difficult to obtain C / A codes by increasing the deviation of the code phase.

An object of the present invention is to provide a GPS signal acquisition method and apparatus capable of acquiring a weak GPS signal in an indoor environment.

According to an embodiment of the present invention, a method for obtaining a GPS signal of a GPS receiver is provided. The method includes sampling an input signal corresponding to a GPS signal during a first integration period corresponding to a multiple of a repetition period of a C / A code to generate a first digital signal, wherein the first digital signal during the first integration period. Compensating a Doppler effect on the signal to generate a second digital signal, generating a duplicate carrier corresponding to the second digital signal, and mixing the second digital signal and the duplicate carrier to generate a first complex signal. And generating a second complex signal by overlapping the first complex signal in units of the repetition period during the first integration period, and obtaining a C / A code through the second complex signal.

According to another embodiment of the present invention, there is provided an apparatus for obtaining GPS signals including an analog / digital converter, an oscillator, a mixer, a compensator, and a determiner. The analog-to-digital converter samples the input signal corresponding to the GPS signal, and the oscillator generates a duplicate carrier. The mixer generates a complex signal by mixing the digital signal and the replica carrier. The compensator generates the digital signal by compensating the Doppler effect for the output of the analog-to-digital converter during the first integration period corresponding to a multiple of the repetition period of the C / A code, and generates the complex signal during the first integration period. Overlapping in the repeating cycle unit. The determination unit obtains the C / A code based on the output of the compensation unit.

According to another aspect of the present invention, there is provided a method for acquiring a GPS signal of a GPS receiver by sampling an input signal corresponding to a GPS signal during a first integration period corresponding to a multiple of a repetition period of a C / A code. Generating a second digital signal in consideration of a position compensation value according to a sample fragment, an actual number of samples during the first integration period, and a position according to a Doppler effect, from the first digital signal during the first integration period Generating a duplicate carrier corresponding to the second digital signal, generating a first complex signal by mixing the second digital signal and the duplicate carrier, for the first complex signal during the first integration period Generating a second complex signal by overlapping the first complex signal in units of the repetition period while compensating for the difference in points caused by the sample fragments; Multiplying a second complex signal with a local C / A code, accumulating at least a portion of a multiplication result for each first integration period during a second integration period corresponding to a multiple of the first integration period, and peaking from the accumulation result Detecting a point to obtain a C / A code.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

1 is a schematic block diagram of a GPS signal acquisition apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the GPS signal acquisition apparatus includes an analog / digital converter (hereinafter referred to as “A / D”) converter 110, an oscillator 120, a mixer 130, a compensator 140, and a fast Fourier transform (fast). Fourier transform (FFT) unit 150, CA code generation unit 160, multiplier 170, inverse fast Fourier transform (IFFT) unit 180, accumulation unit 190 and determination unit 200 It may include, and may be part of a GPS receiver or a GPS receiver.

The A / D converter 110 outputs a digital signal by sampling an input signal having a length T _c [ms] (hereinafter referred to as “segment”) corresponding to an integration period according to a predetermined sampling rate F _s . The input signal input to the A / D converter 110 may be a signal received from a GPS satellite (not shown), and may be a signal obtained by down-converting the signal received from the GPS satellite to an intermediate frequency (IF). The compensator 140 may compensate for Doppler effects and / or sample fragments in the digital signal sampled by the A / D converter 110. For example, assuming that the total number of samples of the A / D converter 110 for 1 [ms] is n _r and the actual number of samples for 1 [ms] is n, every 1 [ms] | n _r -n As many sample fragments are generated, the compensator 140 may extract n × T _c points from the digital signal sampled by the A / D converter 110. In addition, the compensator 140 may compensate for the Doppler effect by assuming one of the plurality of Doppler shifts as a Doppler shift.

Oscillator 120 generates the generated replication (replica), carrier (C _I) of the T _c [ms], and the length, the carrier replica (C _I) 90 DEG shift carrier (C _Q). In this case, the oscillator 120 compensates for the Doppler effect to generate a duplicate carrier (C _I , C _Q ).

The mixer 130 mixes the digital signal compensated by the compensator 140 with the duplicated carrier C _I and the shifted duplicated carrier C _Q output from the oscillator 120 to base-band complex signal I + jQ. Outputs Specifically, the mixer 130 includes two multipliers 132 and 134 and a summer 136. The multiplier 132 multiplies the digital signal by the duplicate carrier and outputs the in-phase signal I. The multiplier 134 multiplies the digital signal by the 90 프트 shifted duplicate carrier and quadratures the quadrature. Output the signal Q. The summer 136 combines the in-phase signal I and the quadrature signal Q to output a baseband complex signal I + jQ.

The compensator 140 generates a baseband complex signal having a length of 1 [ms] by overlapping the complex signals T _{c in} units of 1 [ms] for each segment. In this case, the compensator 140 may compensate the number of points due to the sample fragment for each segment before the complex signal overlaps. For example, the compensation unit 140 includes a baseband complex having n × T _c hayeoseo point compensation the segment consisting of the vector with the n _r point T _c dog as rolled up 1 [ms] in length (i. E., N _r point) Generate a signal. The FFT unit 150 performs an n _r point FFT operation on the baseband complex signal output from the compensator 140.

The C / A code generator 160 generates a local C / A code known between the GPS receiver and the satellite, converts the C / A code into a frequency domain, and provides the converted C / A code to the multiplier 170. To this end, the C / A code generation unit 160 includes a code generator 162 for generating a local C / A code, an FFT unit 164 for performing an FFT operation on the local C / A code, and converting the frequency into a frequency domain; A complex conjugate 166 may be provided to the multiplier 170 by performing a complex conjugate operation on the C / A code converted into the frequency domain.

The multiplier 170 multiplies the baseband complex signal output from the FFT unit 150 and the C / A code provided from the C / A code generation unit 160 for each segment.

The IFFT unit 180 performs an IFFT operation on the multiplication result of each segment output from the multiplier 170. The accumulation unit 190 squares the results output from the IFFF unit 180 and accumulates them, that is, integrates them incoherent. In this case, the accumulator 180 may separately integrate incoherent odd-numbered segments and even-numbered segments as shown in Equations 1 and 2 below. The determination unit 200 may detect peak points for the accumulated odd-numbered segments and the accumulated even-numbered segments.

Here, R _odd (i) is the multiplication result of the odd-numbered [(2i-1) th] segment among all segments, R _even (i) is the multiplication result of the _even- numbered [(2i) th] segment, and N is all The number of segments. For example, if the total integration period is 1 second and one segment consists of an integration period of 10 [ms], N is 100, and it is determined that 50 odd-numbered segments and even-numbered segments are accumulated by 50, respectively.

On the other hand, the determination unit 200 repeats the peak point detection each time the compensation unit 140 changes the hypothetical Doppler shift used for the Doppler effect compensation to another Doppler shift among the plurality of Doppler shifts. If the detected peak point exceeds the threshold after performing peak point detection for all Doppler shifts, the determination unit 200 determines the peak point as the start point of the C / A code, and obtains the C / A code.

As described above, according to an embodiment of the present invention, since a baseband signal of a plurality of coherent integration periods is superposed in one segment, and a result value for the plurality of segments is accumulated, a C / A code is obtained. Weak GPS signals in the environment and the like can be easily obtained. In addition, since the Doppler effect and the sample fragments caused by the long integration period can be compensated, the code phase deviation due to the Doppler effect and the sample fragments can be reduced.

Next, a GPS signal acquisition method according to an embodiment of the present invention will be described in detail. In the following, the coherent integration period corresponding to the repetition period of the C / A code is 1 [ms], and the input signal is processed for an integration period T _i of 1 second (= 1000 [ms]). It is assumed that the period of 1 second is divided into 100 segments, and each segment has an integration period T _c of 10 [ms].

First, the sample fragment problem and its solution will be described in detail with reference to FIGS. 2 to 6B.

2 is a diagram illustrating a sample fragment problem of the present invention, FIG. 3 is a diagram illustrating a code phase deviation caused by sample fragments for 1 second, and FIG. 4 is a sample fragment compensation according to an embodiment of the present invention. It is a figure which shows. 5A and 5B are diagrams showing the cumulative result of the even and odd segments before compensating the sample fragments, respectively. FIGS. 6A and 6B are the even numbers after compensating the sample fragments according to one embodiment of the present invention. It is a figure which shows the accumulation result of a 1st segment and an odd numbered segment.

Assuming a sampling rate (F _s ) of the A / D converter 110 at 16.3676 MHz per second, the total number of samples (n _r ) during the coherent integration period of 1 [ms] is 16368 [= round (F _s / l0 ³ )] points. However, since the actual number of samples (n = F _s / l0 ³ ) during 1 [ms] is 16367.6 points, the sample fragment problem occurs because the actual number of samples n is different from the total number of samples n _r . This results in a deviation of | n _r -n | every 1 [ms] in the code phase during the integral period of length T _i , so that the total deviation d _t is | n _r -n | × T _i samples, which is T increases as _i increases.

As shown in FIG. 2, the actual number of samples 210 for one second is 16367600 (= n × 1000) points, and the total number of samples 220 is 16368000 (= n _r × 1000) points, so the total deviation 230 Is 400 points. Specifically, as shown in FIG. 3, as the time increases, the deviation of the code phase increases. This variation in magnitude results in a loss of integral gain.

In order to solve such a sample fragment problem, first, the compensator 140 sets the pointer p at the current position of the data pointer in advance or backward as shown in Equation 3 for each segment corresponding to the T _c [ms] period. If (n _r -n) is greater than zero, the pointer p lags by the size of c ₁ , and if (n _r -n) is less than zero, the pointer p is advanced by the size of c ₁ .

p = 1 + ((s-1) × (T _c × n _r )) ± c ₁

Here, s has a value from 1 to 100 as an index of a segment, and c ₁ is a sample fragment compensation value as given by Equation 4 below.

c ₁ = T _c × (n _r −n) × (s-1)

In this way, the total number of points read at the current position from the digital signal sampled and output by the A / D converter 110 for each segment is (T _c × n). Oscillator 120 generates the same number of pointers for the duplicate carrier to convert the input signal to baseband.

Next, the compensator 140 rounds or adds T _c × n points to form an n _r length vector including a baseband value of 1 [ms]. To this end, the compensation unit 140 sets the pointer p 'ahead or behind every T _c [ms] period, that is, every k th millisecond (ms) in each segment s _i as shown in Equation (5). If (n _r -n) is greater than zero, the pointer p 'is behind by c ₁ , and if (n _r -n) is less than 0, the pointer p' is advanced by c ₂ .

p '= (1+ (k-1) × n _r ) ± c ₂

Here, c ₂ is defined as in Equation 6.

Here, ceil () is a function that returns an integer greater than or equal to the argument of ceil ().

Referring to FIG. 4, reference numeral 410 denotes a data list corresponding to one segment when having n _r points for 1 [ms]. Reference numeral 420 denotes a data list in the case of having n points for 1 [ms], which corresponds to a signal input to the compensator 140. The compensation unit 140 does not compensate the pointer p 'when (k <T _c / 2), and the pointer p in the data list 420 when (T _c / 2 ≦ k <T _c ). after being kept in a position of _{') [ceil (c 1/} 2)] as long as until the compensation and the compensation size satisfying the following index (k) a (k mod k = 0), (k = T c) of In this case, the position of the pointer p 'in the data list 420 is compensated by c ₁ . When (n _r -n) is 0.4 and T _c is 10, the data list 430 is not compensated for during the first to fourth 1 [ms] (c ₂ = 0) and the fifth to ninth 1 [ms]. ] Is compensated by ₂ (c ₂ = 2), and by the tenth 1 [ms] by 4 (c ₂ = 4).

Therefore, the compensator 140 generates ten folds having n _r points for a T _c [ms] (for example, 10 [ms]) period and adds them to generate a combined baseband signal of n _r points. Can be.

5A, 5B, 6A, and 6B, according to an embodiment of the present invention, when the compensator 140 compensates for the sample fragment, the peak beyond the threshold is higher than before the sample fragment is compensated. It can be seen that the detection can be easily performed.

Next, the Doppler effect and its solution will be described in detail with reference to FIGS. 7 to 9B.

FIG. 7 is a diagram for explaining the Doppler effect, and FIGS. 8A and 8B are diagrams showing code phases in a case where a positive Doppler effect and a negative Doppler effect occur, and FIGS. 9A and 9B are each an embodiment of the present invention. According to an example, a diagram showing a phase when a positive Doppler effect and a negative Doppler effect are compensated for.

The Doppler offset according to the Doppler effect is modeled as a function of the length of the integration period and the Doppler value. The Doppler effect can be neglected for relatively short integration periods such as 1 to 10 ms. However, for weak signals, such as less than 33 dB-Hz, a long integration period of 1000 times is required depending on the power. This integration, however, requires as many Doppler shifted replica carriers as possible.

According to one embodiment of the present invention, in order to use a non-remarkable Doppler shifted duplicated carrier, it is possible to coherently integrate each segment after dividing the signal into 100 segments as previously assumed. Then all the even-numbered segments may be incoherent integrated and all the odd-numbered segments may be incoherent integrated. In this way, the frequency search spatial resolution can be maintained at 100 Hz (fd) for each segment that is easy to calculate, and sign switching of navigation bits can occur in odd or even segments. That is, odd and even segments may not be involved in sign conversion.

The signal can be extended or reduced by the positive / negative Doppler effect. Therefore, a 1 [ms] signal contains more or fewer samples as Δ samples than n samples. If this Doppler effect is not properly compensated for, an offset of Δ size occurs every millisecond, as shown in FIG. Accumulating such offsets over long integration periods is a large error, which can cause deviations in the code phase estimate in the sign direction of the Doppler value. That is, as shown in FIG. 8A, the positive Doppler effect causes the code phase estimate to decrease with a negative slope as the integral period elapses, and as shown in FIG. As a result, the positive slope increases. This code phase deviation makes peak detection difficult. The following describes in detail how to compensate for this Doppler effect.

First, the oscillator 120 generates a replica carrier C _I having a length of T _c [ms] for each segment, and the replica carrier C _I is given by Equation 7.

C _I = cos (2πF _r t)

Here, F _r is a Doppler shifted copy carrier frequency and is given by Equation (8).

F _r = IF + f _di

In this case, IF is an intermediate frequency, and f _di is a Doppler shift.

f _di = f _d × i

Here, f _d is 1 / T _c = 100, and i is [-d _r / f _d ... -5 -4 -3 -2 -1 +1 +2 +3 +4 +5 ... + d _r / f _d ] Either, d _r is the Doppler range and has a value of, for example, ± 5000.

First, the compensator 140 compensates the Doppler compensation value d _c for each segment having a length of T _{c and sets} the pointer p at the start position as shown in Equation 10.

p = 1 + ((s-1) × (T _c × n _r )) + d _c ± c ₁

Here, s is an index of the segment and has a value from 1 to 100.

As shown in Equation 10, the compensator 140 sets the pointer p ₃ of the starting position for each segment to be advanced or backward by the size of the Doppler compensation value d _c . Then, for the segment, data having a length of (T _c × n) from the p position to the [p + (T _c × n) -1] position is extracted from the digital signal output from the A / D converter 110. On the other hand, as shown in Equation 8, in the case where the sample fragment exists, the compensator 140 further reflects the position (c ₁ ) described in Equation 1 to output data from the digital signal output from the A / D converter 110. Can be extracted. If there is no sample fragment, c ₁ is 0 in Equation 8.

Meanwhile, the Doppler compensation value d _c is determined by the Doppler compensation point dc _p and the index j of the current millisecond, as shown in Equation (11).

Here, the current millisecond index j and the Doppler compensation point dc _p are given by Equations 12 and 13, respectively.

j = (s-1) x 10 + fo _j -1

Where s is the index of the segment and fo _j is the index of the fold in each segment and has a value from 1 to 10.

dc _p = 1 / Δ

As shown in Equation 9, the compensator 140 performs a Doppler compensation value according to the sign of the Doppler shift f _di whenever the index j of the current millisecond becomes a multiple of the Doppler compensation point dc _p . d _c) by increasing or decreasing the determined Doppler compensation value (d _c). In this case, the initial value of the Doppler compensation value d _c is zero.

9A and 9B, it can be seen that the code phase can be kept constant when compensating the Doppler effect as in an embodiment of the present invention.

Next, a GPS signal acquisition method in a GPS signal acquisition apparatus according to an embodiment of the present invention will be described with reference to FIG. 10.

10 is a schematic flowchart of a GPS signal acquisition method according to an embodiment of the present invention.

Referring to FIG. 10, first, the GPS signal obtaining apparatus checks whether an unidentified Doppler shift remains among a plurality of Doppler shifts f _di , and if one remains, selects one of the unidentified Doppler shifts and selects a variable. Initialize (S914). That is, the GPS signal obtaining apparatus calculates the Doppler compensation value d _c as 0, the pointer p as 1, the index s of the segment as 1, and the Doppler shifted duplicate carrier frequency and the Doppler compensation point, respectively. Initialize with Next, GPS signal acquisition device is to advance the entire integration period (T _i) by increasing the index (s) of the segment by 1 (S984) a peak detection process for.

Specifically, the GPS signal obtaining apparatus calculates the sample fragment and the Doppler effect for the corresponding segment as shown in Equation 10 (S920), and considers the sample fragment and the Doppler effect as shown in Equation 10 from the input signal of the corresponding segment n × T. _The digital signal corresponding to the _c point is extracted (S930). The GPS signal obtaining apparatus generates a duplicate carrier corresponding to n × T _c points (S940), and generates a baseband signal by mixing the duplicate carrier with n × T _c points and a digital signal (S950).

Next, the GPS signal acquisition apparatus overlaps the baseband signal in units of a length corresponding to the repetition period of the C / A code (1 [ms] in the previous example) during the T _c period for the corresponding segment, and the baseband of 1 [ms]. Generate a signal (S960). Specifically, while increasing the index (fo _j ) of the fold in the segment (S962), and compensates for the sample fragment by the sample fragment compensation value (c ₂ ) as shown in equation (5) (S964), the Doppler compensation value (d) as shown in equation (11) After calculating _c ) (S966), the fold is overlapped with the previous folds to generate a baseband signal of 1 [ms] corresponding to n _r points (S968).

The GPS signal obtaining apparatus performs n _r point FFT operations on the overlapped baseband signals of 1 [ms] to convert them to the frequency domain (S972), and multiplies the signals converted to the frequency domain by the C / A code (S974).

Subsequently, the GPS signal obtaining apparatus accumulates the multiplication result for the current segment and the multiplication result for the previous segment. In this case, the odd-numbered segment and the even-numbered segment are separated and accumulated (S982). The GPS signal obtaining apparatus determines whether the index s of the current segment is the last index T _i / T _c (S984), and if not, increases the index s by 1 (S986) and repeats from step S920. If the index s of the current segment is the last index T _i / T _c , the GPS signal obtaining apparatus outputs a cumulative value of the last odd-numbered segment and an even-numbered segment, and repeats from step S912.

If all the Doppler shifts are confirmed by repeating the above process (S912), the GPS signal acquisition apparatus obtains a C / A code by detecting peak points from the accumulated values (S990).

11A and 11B are diagrams showing cumulative results of even-numbered and odd-numbered segments after compensating sample fragments and Doppler effects, respectively, according to an embodiment of the present invention, and measuring the weak GPS signal of 17 dB-Hz. One result.

As shown in Figs. 11A and 11B, according to one embodiment of the present invention, even a weak GPS signal can easily detect peak points exceeding a threshold.

The embodiments of the present invention described above are not only implemented through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a schematic block diagram of a GPS signal acquisition apparatus according to an embodiment of the present invention.

2 is a view for explaining the problem of sample fragments of the present invention.

3 is a diagram showing code phase deviation caused by sample fragments for 1 second.

4 illustrates sample fragment compensation according to an embodiment of the present invention.

5A and 5B are graphs showing the cumulative result of the even and odd segments before compensating the sample fragments, respectively.

6A and 6B are diagrams illustrating cumulative results of even-numbered and odd-numbered segments after compensating sample fragments, respectively, according to one embodiment of the present invention.

7 is a diagram for explaining the Doppler effect.

8A and 8B are diagrams showing code phases when a positive Doppler effect and a negative Doppler effect occur.

9A and 9B are diagrams illustrating phases when the positive Doppler effect and the negative Doppler effect are compensated according to an embodiment of the present invention, respectively.

10 is a schematic flowchart of a GPS signal acquisition method according to an embodiment of the present invention.

11A and 11B are diagrams illustrating cumulative results of even-numbered and odd-numbered segments after compensating sample fragments and Doppler effects, respectively, according to one embodiment of the present invention.

Claims (10)

In the GPS signal acquisition method of a global positioning system (GPS) receiver, Generating a first digital signal by sampling an input signal corresponding to a GPS signal during a first integration period corresponding to a multiple of a repetition period of a coarse / acquisition (C / A) code, Compensating a Doppler effect on the first digital signal during the first integration period to generate a second digital signal; Generating a duplicate carrier corresponding to the second digital signal; Generating a first complex signal by mixing the second digital signal and a duplicate carrier; Generating a second complex signal by overlapping the first complex signal in units of the repetition period during the first integration period, and Acquiring a C / A code via the second complex signal GPS signal acquisition method comprising a. The method of claim 1, Generating the second digital signal, Selecting one Doppler shift among the plurality of Doppler shifts, Determining a Doppler compensation value based on a Doppler compensation point determined by an index of the repetition period and a magnitude of a selected Doppler shift and a sign of the selected Doppler shift in the first digital signal, and Extracting the second digital signal from the first digital signal in consideration of the Doppler compensation value GPS signal acquisition method comprising a. The method of claim 1, Generating the second digital signal, And further compensating sample fragments for the first digital signal to generate the second digital signal. The method of claim 3, Extracting the second digital signal from the first digital signal in consideration of the position compensation value according to the sample fragment, the actual number of samples during the first integration period, and the position according to the Doppler effect. Way. The method of claim 1, Generating the second complex signal may include: Compensating for the difference in points caused by the sample fragments in the first complex signal before overlapping the first complex signal in the repetition period unit. The method of claim 1, The obtaining step, Multiplying the second complex signal by a local C / A code during the first integration period, and Accumulating at least a portion of the multiplication result for each first integration period during a second integration period corresponding to a multiple of the first integration period, and Acquiring the C / A code by detecting a peak point in a cumulative result GPS signal acquisition method comprising a. An analog / digital converter that samples an input signal corresponding to a GPS signal, An oscillator generating a duplicate carrier, A mixer for mixing a digital signal with a duplicate carrier to produce a complex signal, Compensating the Doppler effect for the output of the analog-to-digital converter during a first integration period corresponding to a multiple of the repetition period of a C / A code to generate the digital signal, and repeating the complex signal during the first integration period. Compensation unit overlapping in cycle unit, and Determination unit for obtaining the C / A code based on the output of the compensation unit GPS signal acquisition device comprising a. The method of claim 7, wherein The compensator further generates the digital signal by compensating the sample fragments with respect to the output of the analog-to-digital converter, and before the overlapping of the complex signal by the repetition period unit, the difference of the points caused by the sample fragments with respect to the digital signal. Compensating GPS signal acquisition device. The method of claim 7, wherein C / A code generation unit for generating local C / A code, A multiplier for multiplying the local C / A code by the output of the compensation unit; An accumulator for accumulating at least a part of the multiplication result of the multiplier for each first integration period during a second integration period corresponding to a multiple of the first integration period, and Determination unit for detecting the peak point in the cumulative result to obtain the C / A code GPS signal acquisition device further comprising. In the GPS signal acquisition method of the GPS receiver, Generating a first digital signal by sampling an input signal corresponding to the GPS signal during a first integration period corresponding to a multiple of the repetition period of the C / A code, Extracting a second digital signal from the first digital signal during the first integration period in consideration of a position compensation value according to a sample fragment, an actual number of samples during the first integration period, and a position according to a Doppler effect; Generating a duplicate carrier corresponding to the second digital signal; Generating a first complex signal by mixing the second digital signal and a duplicate carrier; Generating a second complex signal by overlapping the first complex signal in units of the repetition period while compensating for the difference in points caused by the sample fragment with respect to the first complex signal during the first integration period; Multiplying the second complex signal by a local C / A code; Accumulating at least a part of a multiplication result for each first integration period during a second integration period corresponding to a multiple of the first integration period, Acquiring a C / A code by detecting peak points from the cumulative result GPS signal acquisition method comprising a.

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