KR101421156B1 - Apparatus and Method for acquiring GPS Signal using Multi-stage Partial Cross-Correlator - Google Patents

Abstract

The present invention relates to a GPS (Global Positioning System) signal acquisition system and method, and more particularly, to a GPS (Global Positioning System) Complexity GPS signal acquisition system for acquiring a low complexity GPS signal.
According to the present invention, the proposed carrier phase acquisition structure operates after obtaining the code phase accurately by using the delay-multiply technique robust to the carrier phase error in the one-dimensional GPS signal acquisition process, but the size of the over- It is up to 50kHz.

Description

[0001] The present invention relates to a multi-stage partial cross-correlator, and more particularly,

The present invention relates to a GPS signal acquisition system, and more particularly, to a low complexity GPS signal acquisition system, which is divided into a code phase acquisition unit and a carrier phase acquisition unit, in which a code phase acquisition unit and a carrier phase acquisition unit are arranged in a one- Complexity GPS signal acquisition system that obtains the carrier phase using a multi-stage partial cross-correlator.

In addition, the Delay-Multiply method, which is a code phase acquisition method of code phase acquisition section, is based on a known technique, and consists of a one-dimensional GPS signal acquisition system and a GPS carrier phase acquisition method using a multi-stage partial cross-correlator.

The present invention also relates to a low-complexity GPS carrier phase acquisition method using a multi-stage partial cross-correlator after acquiring an accurate code phase through a code phase acquisition process using a delay-multiply technique.

The navigation data of the GPS signal is modulated by the spreading method by a C / A (Coarse / Acquisition) code composed of 1023 chips, and the receiver estimates the navigation data from the GPS signal through the despreading process.

However, even if the receiver accurately obtains the code phase of the received GPS signal, accurate GPS navigation data can not be obtained if there is a carrier phase error. Therefore, both the code phase and the carrier phase must be estimated during GPS signal acquisition.

A general signal acquisition scheme for estimating code phase errors and carrier phase errors in parallel is performed by correlating received signals with generated signals in the code phase and carrier phase directions.

In order to improve the performance of the parallel signal acquisition structure, it is necessary to increase the integration time in the code phase direction and increase the number of cells by narrowing the intervals of the search cells in the carrier phase direction.

However, if the integration time in the code phase direction is increased to improve the performance of the parallel GPS signal acquisition structure, the magnitude of the overcorrectable carrier phase error is reduced. As a result, the increase in the number of search cells in the carrier phase direction, There is a problem that the complexity of the structure is increased.

1. Korean Registered Patent No. 10-0978535 2. Korean Patent No. 10-2010-0135594

The present invention provides a low complexity GPS signal acquisition system using a multistage partial cross-correlator that reduces the complexity of the signal acquisition structure while increasing the integration time in the code phase direction. There is a purpose.

It is another object of the present invention to provide a low-complexity GPS signal acquisition method using a multi-stage partial cross-correlator that alleviates the complexity of the signal acquisition structure while increasing the integration time in the code phase direction.

In order to achieve the above-mentioned object, the present invention provides a low complexity GPS carrier phase acquisition system using a multi-stage partial correlation processing technique based on a Dealy-Multiply technique after acquiring an accurate code phase through a code phase acquisition process using a delay- to provide.

The carrier phase acquisition system includes: a signal reception unit for generating a sampled base-band GPS signal of a GPS (Global Positioning System) signal; A code duplication unit for generating a code duplication signal as a reference signal for despreading the received GPS signal; A code phase acquisition unit that receives the code duplication signal and generates a synchronization time control signal after acquiring the code phase; A carrier phase obtaining unit that receives the generated synchronization time control signal and generates a carrier phase error value after acquiring a carrier phase; And a carrier phase error compensator for compensating the received baseband GPS signal using the carrier phase error value.

In this case, the code phase obtaining unit may include an inverse transform unit that performs inverse transform using the cross-correlation characteristic between the received signal and the code duplication signal; And a code phase detector for estimating a code phase having a maximum value in the inverse conversion process.

In this case, the code phase obtaining unit obtains a code phase using a delay-multiply approach based on a partial cross-correlation when a code phase between a received signal and a code duplication signal coincides with each other .

The carrier phase acquiring unit may include an integration time length controller for determining an integration time length (window size); A cross-correlation executing unit for performing partial cross-correlation between the received signal and the code duplication signal in units of the determined integral time length; And a noise error minimization unit that averages the correlated correlation values to minimize an error due to noise.

In this case, the carrier phase acquiring unit may acquire a carrier phase using a multi-stage partial correlation processing technique based on a delay-multiply approach.

At this time, the mean value of the delay-multiply function between partial cross-correlation values is used at the time of carrier phase acquisition.

In this case, in order to minimize the residual carrier phase error due to noises according to the stepwise partial cross-correlation integration time length in estimating the carrier phase error, the partial carrier phase time error is re-estimated by increasing the partial cross- And performing compensation on the basis of the comparison result.

On the other hand, another embodiment of the present invention includes a baseband GPS signal generating step of generating a sampled base-band GPS signal of a received Global Positioning System (GPS) signal; A code duplication signal generation step of generating a code duplication signal as a reference signal for despreading the received GPS signal; A code phase acquiring step of receiving a code duplication signal and generating a synchronization time control signal after acquiring a code phase; A carrier phase error value generation step of generating a carrier phase error value after acquiring a carrier phase by receiving the generated synchronization time control signal; And a carrier phase error compensation step of compensating the received baseband GPS signal using the carrier phase error value A low complexity GPS carrier phase acquisition method using a multi-stage partial cross-correlator is provided.

In this case, the code phase step may include a step of inversely converting the received signal and the code duplication signal using the cross-correlation property; And a code phase detection step of estimating a code phase having a maximum value in the inverse conversion process.

In this case, the code phase acquiring step acquires a code phase using a delay-multiply approach based on partial cross-correlation when a code phase between the received signal and the code duplication signal coincides with each other can do.

In this case, the carrier phase acquisition step may include: determining an integration time length; A cross-correlation performing step of performing partial cross-correlation between the received signal and the code duplication signal in units of the determined integral time length; And a noise error minimization step of averaging the correlated correlation values to minimize an error due to noise.

In this case, the carrier phase acquiring step may acquire a carrier phase using a multi-stage partial correlation processing technique based on a delay-multiply approach.

According to the present invention, the proposed carrier phase acquisition structure operates after obtaining the code phase accurately by using the delay-multiply technique robust to the carrier phase error in the one-dimensional GPS signal acquisition process, but the size of the over- It is up to 50kHz.

This can reduce the sensitivity to the carrier phase error of the GPS receiver, and by constructing the one-dimensional GPS signal acquisition structure, the receiver complexity can be reduced more than the parallel GPS signal acquisition structure.

FIG. 1 is a diagram illustrating a GPS signal acquisition structure of a one-dimensional structure according to an embodiment of the present invention.
2 is a diagram illustrating a code phase acquisition structure using a Delay-Multiplex technique according to an embodiment of the present invention.
FIG. 3 is a graph showing the influence of a partial cross-correlation integration length change using a short window size according to an embodiment of the present invention.
FIG. 4 is a graph showing the influence of a partial cross-correlation integral length change when a long window size is used according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a multi-stage structure of a carrier phase acquisition structure using a partial cross-correlation technique and a delay-multiply technique according to an embodiment of the present invention.
FIG. 6 is a graph showing an integral time length required for each step partial cross-correlation according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

To reduce the complexity of signal acquisition structure, we propose a one-dimensional signal acquisition structure as shown in Fig. This is a carrier phase acquisition structure using a multi-stage partial correlation processing technique based on a delay-multiply technique after acquiring an accurate code phase through a code phase acquisition process using a delay-multiply technique as shown in FIG. 2 which is robust against a carrier phase error.

1 is a block diagram illustrating a structure of acquiring a GPS signal of a one-dimensional structure according to an embodiment of the present invention. Referring to FIG. 1, the GPS signal acquisition structure 100 includes a signal receiver 110 for generating a sampled base-band GPS signal of a received GPS signal, a GPS receiver 110 for despreading the received GPS signal, A code phase obtaining unit 130 for receiving a reference signal generated from the code copying unit 120 and generating a synchronization time control signal after acquiring a code phase, A carrier phase acquiring unit 140 for receiving a synchronization time control signal and generating a carrier phase error value after acquiring a carrier phase, a carrier phase error compensating unit 140 for compensating a baseband GPS signal received using the carrier phase error value, (150). These components will be described as follows.

The signal receiving unit 110 generates a sampled baseband GPS signal of the received GPS signal.

The code replicating unit 120 generates a reference signal for despreading the received GPS signal, and transmits the reference signal to the code phase obtaining unit 130 and the carrier phase obtaining unit 140.

The code phase acquiring unit 130 transmits a code phase acquisition timing control signal to the carrier phase acquiring unit 140 and the carrier phase error compensating unit 150 as a block for acquiring only the code phase.

The carrier phase acquiring unit 140 transmits the carrier phase error value to the carrier phase error compensating unit 150 after the carrier phase acquisition in the block for acquiring only the carrier phase.

The carrier phase error compensator 150 generates a phase signal for compensating the received base-band GPS signal using the obtained carrier phase error.

The compensation signal 160 is finally generated using this phase signal.

2 is a diagram illustrating a code phase acquisition structure using a Delay-Multiplex technique according to an embodiment of the present invention. Referring to FIG. 2, an inverse transform unit 210 for inversely transforming a received signal and a reference signal using a cross-correlation property, a code phase detector 220 for estimating a code phase having a maximum value in the inverse transform process, and the like .

The inverse conversion unit 210 performs an inverse conversion process using a cross-correlation characteristic between a received signal and a reference signal subjected to delay-multiply signal processing at one chip intervals. To this end, the inverse conversion unit 210 includes a signal receiving unit, a first chip delay unit, a code duplication unit, a second chip delay unit, a mixer, and the like.

The code phase detector 220 estimates a code phase having a maximum value in the inversion process and transmits a synchronization time control signal.

FIG. 5 is a diagram illustrating a multi-stage structure of a carrier phase acquisition structure using a partial cross-correlation technique and a delay-multiply technique according to an embodiment of the present invention. Referring to FIG. 5, an integration time length control unit 510 for determining an integration time length, a cross-correlation execution unit 520 for performing partial cross-correlation between a received signal and a code duplication signal in units of the determined integration time length And a noise error minimization unit 530 for minimizing an error due to noise by averaging the correlated correlation values. These components will be described as follows.

The integration time length control unit 510 is a block for determining the integration time length for performing the partial cross-correlation in each step, and performs the function of transferring the integration time length in the order of 10, 20, 50, 100,

The cross-correlation performing unit 520 performs Equation 1 on the basis of the integral time length unit for performing partial cross-correlation for each step.

 The partial cross-correlation between the received signal and the code duplication signal in Eq. (1) can be expressed as follows.

(1)

(One)

은 부분 상호상관 적분 시간 길이,

는 반송파 위상 획득에 소요되는 전체 수신신호의 길이를

으로 나누었을 때 각각의 부분 상호상관 값 인덱스,

은 부분 상호상관에 소요되는 수신신호 내 샘플 인덱스,

와

는 각각

번째 신호부와 잡음부의 부분 상호상관 값이다.here,

Is the partial cross-correlation integration time length,

Is the total length of the received signal required to obtain the carrier phase

The partial cross-correlation value index,

Sample index in the received signal for partial cross-correlation,

Wow

Respectively

Th signal portion and the noise portion.

The proposed carrier phase error acquisition technique estimates the carrier phase error using the delay-multiply technique based on the partial cross-correlation technique when the code phase between the received signal and the code duplication signal is matched, The carrier phase acquisition process is repeated while extending the length of the received signal used for the correlation calculation.

The partial cross-correlation equation between the received signal and the replica of the code can increase the range of carrier phase errors that can be overcome by bringing the integration time shorter than the length of the C / A code.

The noise error minimization unit 430 minimizes the error due to noise by cumulatively averaging the partial cross-correlation values processed by the delay-multiplexed signal as shown in Equation (2). Determines the cumulative number according to the change of the integral time length for performing the partial cross-correlation at each step, and transmits the next step control signal to the integral time length control unit 510. The cumulative number for each step uses only half of each step.

개의 부분 상호상관 값에 지연-곱셈 기법(Delay-Multiply approach)을 적용하면

과

의 상관 값은 아래 식과 같이 우리가 추정하고자 하는 반송파 위상 오차를 포함하는 고정 위상을 갖는다.

If a delay-multiply approach is applied to the partial cross-correlation values of

and

Has a fixed phase including the carrier phase error to be estimated as shown in the following equation.

(2)

(2)

의 복소수

은 누적하면 잡음의 영향이 줄일 수 있으며

로부터 아래 식(3)과 같이 반송파 위상 오차를 결정하는 도플러 주파수 이동 값을 추정할 수 있다.The phase discriminator 540 estimates the carrier phase error using Equation (3) and delivers the carrier phase error estimated by the carrier phase compensator. Having a fixed phase

Complex number

The cumulative effect of noise can be reduced

, The Doppler frequency shift value for determining the carrier phase error can be estimated from the following equation (3).

(3)

(3)

의 길이가 짧을수록 추정가능한 반송파 위상 오차의 범위는 넓어지지만 도 3과 같이 적은 수의 샘플을 사용하기 때문에 잡음의 영향을 크게 받게 된다. 도 3은 짧은 적분 시간 길이(short window size)를 이용한 경우 부분 상호 상관 적분 길이 변화에 따른 영향으로 잡음 오차 범위(300)를 보여주는 그래프이다.Sample length of received signal for partial cross-correlation

The range of the carrier phase error that can be estimated is wider as the length is shorter. However, since a small number of samples are used as shown in FIG. 3, the noise is greatly affected. 3 is a graph showing a noise error range 300 due to the influence of a partial cross-correlation integral length change when a short window size is used.

의 길이가 길면 추정 가능한 반송파 위상오차의 범위는 좁아지지만 도 4와 같이 많은 수의 샘플을 사용하기 때문에 잡음의 영향을 줄일 수 있다. 도 4는 긴 적분 시간 길이(long window size)를 이용한 경우 부분 상호 상관 적분 길이 변화에 따른 영향으로 잡음 오차 범위(300)를 보여주는 그래프이다. Contrary

The range of the carrier phase error that can be estimated is narrowed. However, since a large number of samples are used as shown in FIG. 4, the influence of noise can be reduced. FIG. 4 is a graph showing a noise error range 300 due to the influence of a change in the partial cross-correlation integral length when a long window size is used.

FIG. 6 is a graph showing the integration time length required for partial cross-correlation in each step according to an embodiment of the present invention. Referring to FIG. 6, the carrier phase is estimated and compensated using the short partial cross-correlation integration time length as shown in FIG. 6, and the residual carrier phase left by the noise after the carrier phase compensation, The correlation integral time length is increased to estimate and compensate the residual carrier phase. Here, the length of the integral time of each step is as follows.

Step 1 (610): Integral time length (M) is 10.

Step 2 (620): The integral time length (M) is 20.

Step 3 (630): The integration time length (M) is 50.

Step 4 (640): The integration time length (M) is 100.

Step 5 (650): The integral time length (M) is 1000.

110:
120: Code duplication unit
130: code phase obtaining unit
140: Carrier phase acquisition unit
150: Carrier phase error compensation unit
160: compensation signal
210: Inverse section
220: code phase detector
510: integral length time control unit
520: Cross-correlation execution unit
530: Noise error minimization unit
540: phase discrimination unit

Claims (10)

A signal receiving unit for generating a sampled base-band GPS signal of the received GPS signal;
A code duplication unit for generating a code duplication signal as a reference signal for despreading the received GPS signal;
A code phase obtaining unit that receives the generated code duplication signal and generates a synchronization time control signal after acquiring the code phase;
A carrier phase obtaining unit that receives the generated synchronization time control signal and generates a carrier phase error value after acquiring a carrier phase; And
And a carrier phase error compensator for compensating a baseband GPS signal generated using the carrier phase error value,
Wherein the carrier phase obtaining unit comprises:
An integration time length control unit for determining an integration time length (window size);
A cross-correlation executing unit for performing partial cross-correlation between the received signal and the code duplication signal in units of the determined integral time length; And
And a noise error minimization unit that averages the correlated correlation values and minimizes an error caused by noise. GPS Signal Acquisition System Using Multi - stage Part Cross - Correlators.
delete The method according to claim 1,
Wherein the carrier phase acquiring unit acquires a carrier phase using a multi-stage partial correlation processing technique based on a delay-multiply approach.
The method of claim 3,
And a mean value of a delay-multiply function between the partial cross-correlation values is used when the carrier phase is obtained.
The method of claim 3,
In the case of generating the carrier phase error value, in order to minimize the residual carrier phase error due to noises according to the stepwise partial cross-correlation integration time length, the partial cross-correlation integration time length is increased for each step, Estimating and compensating the multi-stage partial cross-correlator.
A baseband GPS signal generation step of generating a sampled base-band GPS signal of a received Global Positioning System (GPS) signal;
A code duplication signal generation step of generating a code duplication signal as a reference signal for despreading the received GPS signal;
A code phase acquisition step of receiving the generated code duplication signal and generating a synchronization time control signal after acquiring the code phase;
A carrier phase error value generation step of generating a carrier phase error value after acquiring a carrier phase by receiving the generated synchronization time control signal; And
And a carrier phase error compensation step of compensating a baseband GPS signal generated using the carrier phase error value,
Wherein the carrier phase acquisition step comprises:
An integration time length determination step of determining an integration time length (window size);
A cross-correlation performing step of performing partial cross-correlation between the received signal and the code duplication signal in units of the determined integral time length; And
And minimizing a noise error by averaging the correlated correlation values to minimize an error due to noise A method for acquiring GPS signals using multi - stage partial cross - correlator.
delete The method according to claim 6,
Wherein the carrier phase acquisition step acquires a carrier phase using a multi-stage partial correlation processing technique based on a delay-multiply approach.
9. The method of claim 8,
Wherein a mean value of a delay-multiply function between partial cross-correlation values is used when the carrier phase is obtained.
10. The method of claim 9,
In the case of generating the carrier phase error value, in order to minimize the residual carrier phase error due to noises according to the stepwise partial cross-correlation integration time length, the partial cross-correlation integration time length is increased for each step, Estimating and compensating the multi-stage partial cross-correlator.

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