KR102574387B1 - Apparatus for Acquisition of a Satellite Navigation Signal - Google Patents

Abstract

An apparatus for obtaining a satellite navigation signal is disclosed. The disclosed device converts a digitized satellite navigation signal, wherein the digitized satellite navigation signal is composed of a product of a code and a carrier, and the frequency of the carrier is the sum of an intermediate frequency and a Doppler frequency, into a baseband signal A preprocessing unit configured to generate a local signal simulating the code, a first resampled signal including first samples of a number corresponding to a power of 2 by resampling the baseband signal at a resampling frequency. Provides - the resampling frequency is a frequency determined so that the number of the first samples is a power of 2 - and resamples the local signal at the resampling frequency to obtain second samples equal to the number of the first samples. A resampling unit configured to provide a second resampled signal comprising a sinusoidal wave configured to generate sinusoidal signals each having a plurality of matching frequencies including a reference frequency and frequencies sequentially shifted by a predetermined frequency deviation from the reference frequency. and an estimator configured to estimate the phase and the Doppler frequency of the code using the signal generator and the first resampled signal, the second resampled signal, and the sinusoidal wave signals.

Description

Apparatus for Acquisition of a Satellite Navigation Signal}

The disclosure below relates to satellite navigation signal processing technology.

GNSS (Global Navigation Satellite System) is known as a system for locating a target and providing visual information using a plurality of artificial satellites and receiving equipment on the ground. GNSS currently in operation includes GPS (Global Positioning System) operated by the United States, GLONASS (Global Orbiting Navigation Satellite System) operated by Russia, GALILEO (European Satellite Navigation System) operated by the European Union, and Japan operated GNSS. QZSS (Quasi-Zenith　Satellite　System) and the like. A GNSS navigation receiver performs signal processing for signal acquisition, signal tracking, and data decoding on satellite signals. Among them, signal processing for signal acquisition is for estimating the phase and Doppler frequency of a code included in a satellite signal. Conventionally, in the field of signal processing for signal acquisition, many studies have been conducted to reduce the time required for signal acquisition.

The problem to be solved by the present disclosure is to provide a technique for quickly and efficiently acquiring GNSS satellite signals.

The problem to be solved by the present disclosure is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

According to one aspect of the present disclosure, an apparatus for obtaining a satellite navigation signal is provided. The apparatus converts a digitized satellite navigation signal, wherein the digitized satellite navigation signal is composed of a product of a code and a carrier, and the frequency of the carrier is the sum of an intermediate frequency and a Doppler frequency, into a baseband signal. A preprocessing unit configured to generate a local signal simulating the code, a first resampled signal including first samples of a number corresponding to a power of 2 by resampling the baseband signal at a resampling frequency. Provides - the resampling frequency is a frequency determined so that the number of the first samples is a power of 2 - and resamples the local signal at the resampling frequency to obtain second samples equal to the number of the first samples. A resampling unit configured to provide a second resampled signal comprising a sinusoidal wave configured to generate sinusoidal signals each having a plurality of matching frequencies including a reference frequency and frequencies sequentially shifted by a predetermined frequency deviation from the reference frequency. and an estimator configured to estimate the phase and the Doppler frequency of the code using the signal generator and the first resampled signal, the second resampled signal, and the sinusoidal wave signals.

In one embodiment, the pre-processor includes a mixer configured to down-convert the digitized satellite navigation signal to baseband by mixing the digitized satellite navigation signal and the local oscillation signal of the intermediate frequency.

In one embodiment, the digitized satellite navigation signal is down-converted from the satellite navigation signal received from the antenna to a satellite navigation signal of an intermediate frequency band, and the down-converted satellite navigation signal of the intermediate frequency band is converted to a selected sampling frequency A Provided by /D conversion.

In one embodiment, the code generator is further configured to generate the local signal using the selected sampling frequency.

In one embodiment, the apparatus further comprises a memory, and the resampling unit is further configured to resample the baseband signal and store first samples corresponding to a power of 2 in the memory for a predetermined storage time. The resampling unit is further configured to resample the local signal and store second samples corresponding to a power of 2 in the memory during the predetermined storage time.

In one embodiment, the plurality of matching frequencies include the reference frequency and frequencies sequentially shifted in a positive direction by a frequency deviation selected from the reference frequency and a negative direction by a frequency deviation selected from the reference frequency. Include the frequencies shifted sequentially to .

In one embodiment, the sinusoidal signal generator is further configured to generate the sinusoidal signals using the resampling frequency.

In one embodiment, the estimator may include a first multiplier configured to multiply the first resampling signal and each of the sinusoidal signals sample by sample and provide a reference signal; a circular correlation operator configured to provide a set of correlation values, and a maximum value discriminator configured to estimate the phase of the code and the Doppler frequency based on the sets of cross-correlation values.

In one embodiment, the circular correlation operator is configured to FFT transform each of the reference signals to provide a first transformed signal and to FFT transform the second resampled signal to provide a second transformed signal. an FFT converter, a conjugate operator configured to conjugate the second transformed signal and provide a conjugate signal of the second transformed signal, each of the first transformed signals and the second transform a second multiplier configured to multiply the conjugate of the multiplied signal sample by sample to provide a product signal, and an IFFT transformer configured to IFFT transform each of the product signals to provide the set of cross-correlation values. Here, the sets of cross-correlation values are respectively associated with the sinusoidal signals.

In an embodiment, the maximum value identifier is further configured to identify a maximum cross-correlation value in the sets of cross-correlation values and a set of cross-correlation values that includes the maximum cross-correlation value, wherein the maximum value identifier is further configured to identify a time index corresponding to the maximum cross-correlation value and estimate a phase of the code based on the identified time index, wherein the maximum value identifier includes the maximum cross-correlation value , as the Doppler frequency, estimate a frequency for matching of a sinusoidal signal associated with the identified set of cross-correlation values.

According to another aspect of the present disclosure, an apparatus for obtaining a satellite navigation signal is provided. The apparatus resamples a baseband digitized satellite navigation signal at a resampling frequency to provide a first resampled signal including a number of first samples corresponding to a power of 2 - the baseband digitized satellite The navigation signal is composed of a product of a code and a sine wave of a Doppler frequency, and the resampling frequency is a frequency determined so that the number of the first samples is a power of 2 - resampling the local signal at the resampling frequency to perform the first A resampling unit configured to provide a second resampled signal including the same number of second samples as the number of samples, a code generator configured to generate a local signal simulating the code, a reference frequency, and a reference frequency selected from the reference frequency. a sinusoidal signal generator configured to generate matching sinusoidal signals each having a plurality of matching frequencies including frequencies sequentially shifted by a frequency deviation, and the first resampled signal, the second resampled signal, and the and an estimator configured to estimate the phase of the code and the Doppler frequency using sinusoidal signals for matching.

According to the disclosed embodiments, there is a technical effect of acquiring GNSS satellite signals quickly and efficiently.

1 is a block diagram showing a satellite navigation signal acquisition system according to an embodiment.
FIG. 2 is a detailed block diagram of an embodiment of the signal acquisition module of FIG. 1; FIG.
FIG. 3 is a detailed block diagram of an embodiment of the estimation unit of FIG. 2 .
FIG. 4 is a detailed block diagram of an embodiment of the circular correlation calculator of FIG. 3;
5 is a graph showing an example of a satellite navigation signal of an intermediate frequency band.
6 is a graph showing an example of a digitized satellite navigation signal of an intermediate frequency band.
7 is a graph showing an example of a local oscillation signal of an intermediate frequency.
8 are graphs illustrating an example of a baseband signal and an example of a first resampled signal obtained by resampling the baseband signal.
9 are graphs illustrating an example of a local signal and an example of a second resampled signal obtained by resampling the local signal.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only, and may be changed and implemented in various forms. Therefore, the form actually implemented is not limited only to the specific disclosed embodiment, and the scope of the present disclosure includes changes, equivalents, or substitutes included in the technical idea described in the embodiments.

Although terms such as "first" or "second" may be used to describe various components, such terms should only be construed for the purpose of distinguishing one component from another. For example, a “first element” may be termed a “second element”, and similarly, a “second element” may also be termed a “first element”.

It should be understood that when an element is referred to as being “connected” to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this disclosure, terms such as "comprise" or "having" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, but one or more other features or numbers, It should be understood that the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present disclosure, it should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same reference numerals are given to the same components regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a block diagram showing a satellite navigation signal acquisition system according to an embodiment.

As shown in FIG. 1, the satellite navigation signal acquisition system 100 may include an antenna 122, an RF unit 134, an analog-to-digital converter (ADC) 146, and a signal acquisition module 178. can The antenna 122 is a satellite navigation signal (satellite) radio-modulated from a Global Navigation Satellite System (GNSS) such as Global Positioning System (GPS), European Satellite Navigation System (GALILEO), Quasi-Zenith Satellite System (QZSS), and the like. navigation signal). The RF unit 134 down-converts the radio-modulated satellite navigation signal to an intermediate frequency (IF: Intermediate Frequency) band satellite navigation signal ( ) (see FIG. 5). Satellite navigation signal of the intermediate frequency band ( ) can be represented by Equation 1 below.

here Represents a satellite navigation signal of an intermediate frequency band, represents the magnitude of the satellite navigation signal, Is Indicates a code that has a waveform pattern having a value of and may vary for each satellite receiving a signal, Is Indicates satellite data that is a waveform pattern with a value of represents the intermediate frequency, Represents a Doppler frequency that may vary depending on the dynamic conditions of a satellite receiving a signal and a user, represents the initial phase of the signal.

ADC 146 is a satellite navigation signal of the intermediate frequency band ( ) by A/D conversion and digitized intermediate frequency satellite navigation signal ( ) can be configured to output. Satellite navigation signal of digitized intermediate frequency band ( ) An example of ) is shown in FIG. In one embodiment, the ADC 146 is a satellite navigation signal (satellite navigation signal) of the intermediate frequency band at a sampling frequency of several tens of MHz. ) may be configured to sample. For example, the ADC 146 is a satellite navigation signal (intermediate frequency band) with a sampling frequency of 20 MHz. ) may be configured to sample. In one embodiment, ADC 146 may be a 2-bit ADC. The signal acquisition module 178 is a digitized intermediate frequency satellite navigation signal ( ) may be configured to obtain a satellite navigation signal by performing signal processing on. According to the present disclosure, the signal acquisition module 178 is a code of a satellite navigation signal ( ) and the Doppler frequency ( ) may be configured to perform various signal processing to identify. The signal acquisition module 178 according to the present disclosure is a digitized intermediate frequency band satellite navigation signal ( ), it is possible to quickly and efficiently acquire satellite navigation signals by efficiently performing signal processing. Although not shown, the signal output from the signal acquisition module 178 is supplied to one or more subsequent signal processing modules to perform necessary subsequent signal processing.

FIG. 2 is a detailed block diagram of an embodiment of the signal acquisition module of FIG. 1; FIG.

As shown in FIG. 2, the signal acquisition module 178 is a digitized intermediate frequency band satellite navigation signal ( ) to the baseband signal ( ) may include a pre-processing unit 210 configured to convert to Here, the satellite navigation signal of the digitized intermediate frequency band ( ) is composed of a product of a code and a carrier, as shown in Equation 1 above, and the frequency of the carrier is an intermediate frequency ( ) and the Doppler frequency ( ) is the sum of In one embodiment, the pre-processing unit 210, the satellite navigation signal of the digitized intermediate frequency band ( ) and the intermediate frequency ( ) of the local oscillation signal ( ) (see FIG. 7) and digitized intermediate frequency band satellite navigation signal ( ) to baseband. The signal acquisition module 178 code ( ), a local signal ( ) may further include a code generating unit 220 configured to generate. The code generator 220 uses the sampling frequency used by the ADC 146 to generate a local signal ( ) can be configured to generate. For example, the ADC 146 is a satellite navigation signal (intermediate frequency band with a sampling frequency of 20 MHz) ), the code generator 220 also uses a local signal of the 20 MHz band ( ) can be created.

The signal acquisition module 178 may further include a resampling unit 230 coupled to the pre-processing unit 210 and the code generation unit 220 . The resampling unit 230 is a baseband signal ( ) to a power of two ( ) A first resampled signal including the number of first samples ( ) may be configured to provide. Here, the resampling frequency is a power of 2 when the number of first samples ( ) may be a predetermined frequency. In one embodiment, the resampling frequency is the number of first samples raised to a power of 2 ( ) and the code ( ) may be a frequency determined to be less than twice the chip rate. Set the resampling frequency to code ( ) According to an embodiment determined to be less than twice the chip rate of ), calculation time and resources used in an environment in which a signal can be obtained even in the presence of a certain level of signal loss - for example, FFT and IFFT operations There is an advantage in that the number of points in - can be reduced. In one embodiment, the resampling frequency is the number of first samples raised to a power of 2 ( ) and the code ( ) may be a frequency determined to be more than twice the chip rate. Set the resampling frequency to code ( ), there is an advantage in that the characteristics of the original signal can be maximally preserved even when signal loss is minimized and resampling is performed. The resampling unit 230 includes a baseband signal ( ) to a power of 2 ( ) may be configured to store the first samples corresponding to the number in a memory (not shown) for a predetermined storage time. For example, the code ( ) at a chip rate of 1.023 MHz, the number of samples that can be resampled and stored in memory for a storage time of 1 ms is a power of 2 ( ), 1.024 MHz, which is a frequency that makes 1,024, can be determined as the resampling frequency. As another example, the code ( ) at a chip rate of 1.023 MHz, the number of samples that can be resampled and stored in memory for a storage time of 1 ms is a power of 2 ( ), 2.048 MHz, which is a frequency that makes 2,048, can be determined as the resampling frequency. The number of samples that are resampled and stored in memory during the selected storage time is a power of 2 ( The reason why the resampling frequency is determined to be ) is that the FFT and IFFT operations performed in the signal acquisition module 178, which will be described later, are powers of 2 ( ), so that the number of samples included in the resampled signal and the number of points in FFT and IFFT operations can be matched to perform signal processing efficiently and at high speed. 8, the baseband signal ( ) and a first resampled signal obtained by resampling the baseband signal ( ) is shown together with an example.

The resampling unit 230 is a local signal ( A second resampled signal (including the same number of second samples as the number of first samples by resampling ) at a resampling frequency ( ) may be further configured to provide. Here, the resampling frequency may be the same frequency as the resampling frequency used when resampling the baseband signal, and the reason for doing so is as described above. The resampling unit 230 is a local signal ( ) to a power of 2 ( ) may be configured to store the number of second samples in a memory (not shown) for a predetermined storage time. 9, the local signal ( ) and a second resampled signal obtained by resampling the local signal ( ) is shown together with an example.

The signal acquisition module 178 has a reference frequency ( ) and reference frequency ( ), the frequency deviation ( Sinusoidal signals each having a plurality of matching frequencies including frequencies sequentially shifted by ) ( ) may further include a sinusoidal wave signal generator 240 configured to sequentially or in parallel generate. The plurality of matching frequencies are reference frequencies ( ) and reference frequency ( ), the frequency deviation ( Frequencies sequentially shifted in the positive direction by ) ( , , and so on) and reference frequency ( ), the frequency deviation ( ) Frequencies sequentially shifted in the negative direction by ( , , etc.) may be included. In one embodiment, the reference frequency ( ) may be 0 Hz. In one embodiment, the plurality of frequencies for matching is a reference frequency ( )from It may be frequencies within the 5 KHz range. In one embodiment, the plurality of frequencies for matching is a reference frequency ( )from It may be frequencies within the 17 KHz range. In one embodiment, the selected frequency deviation ( ) may be 10 Hz. In one embodiment, the sinusoidal signal generator 240 generates sinusoidal signals using a resampling frequency ( ) may be further configured to generate. The signal acquisition module 178 determines the first resampled signal ( ), the second resampled signal ( ) and sinusoidal signals ( ) using the code ( ) of the phase and Doppler frequency ( ) may further include an estimator 250 configured to estimate .

FIG. 3 is a detailed block diagram of an embodiment of the estimation unit of FIG. 2 .

As shown in FIG. 3, the estimator 250 is a first resampling signal ( ) and sinusoidal signals ( ) is multiplied sample by sample, and the reference signal ( ) may include a first multiplier 310 configured to provide Multiple sinusoidal signals ( Since multiplication is performed for each of ), the first multiplier 310 has a plurality of reference signals ( ) can be output sequentially or in parallel. The first multiplier 310 includes a plurality of reference signals ( ) in parallel, the first multiplier 310 may include a plurality of multipliers. The estimator 250 uses the reference signals ( ) and the second resampled signal ( ) A set of cross-correlation values between ( ) may further include a circular correlation operator 320 configured to provide. Multiple reference signals ( Since a circular correlation operation is performed in relation to each of ), the circular correlation operator 320 sets a plurality of cross-correlation values ( ) can be output sequentially or in parallel. A set of multiple cross-correlation values ( ) The number of sinusoidal signals ( ) may be equal to the number of Each set of cross-correlation values ( ), the cross-correlation values included in the corresponding reference signal ( ) is the second resampled signal ( ) or the second resampled signal ( ) is the corresponding reference signal ( ) represents values obtained through operation between two signals in states sequentially shifted by one sample on the time axis. That is, each set of cross-correlation values ( The cross-correlation values included in ) are the time lengths shifted on the time axis - the number of time lengths shifted on the time axis is the reference signal ( ) and the second resampled signal ( Corresponds to the number of samples included in ) - These are values functionally corresponding to time indices that specify each. Cyclic correlation calculator 320 may be configured to use FFT operations and IFFT operations, as described below, to output each set of cross-correlation values at high speed. The estimator 250 sets sets of cross-correlation values ( ) based on the code ( ) and the Doppler frequency ( ) may further include a maximum value discriminator 330 configured to estimate .

FIG. 4 is a detailed block diagram of an embodiment of the circular correlation calculator of FIG. 3;

As shown in FIG. 4, the circular correlation operator 320, the reference signals ( ) by FFT transforming each of the first transformed signals ( ) and a second resampled signal ( ) by FFT transforming the second transformed signal ( ) may include an FFT transformer 410 configured to provide. Reference signals ( Since there are a plurality of ), the FFT converter 410 has a plurality of first transformed signals ( ) can be output sequentially or in parallel. The FFT converter 410 converts a plurality of first converted signals ( ) in parallel, the FFT converter 410 may include a plurality of FFT operators. Cyclic correlation calculator 320, the second converted signal ( ) to obtain a second transformed signal ( ) of the conjugate signal ( ) may further include a conjugate operator 420 configured to provide Cyclic correlation calculator 320, the first transformed signals ( ) and the second converted signal ( ) of the conjugate signal ( ) is multiplied sample by sample to obtain a product signal ( ) may further include a second multiplier 430 configured to provide. The first converted signals ( Since there are a plurality of ), the second multiplier 430 has a plurality of product signals ( ) can be output sequentially or in parallel. The second multiplier 430 has a plurality of product signals ( ) in parallel, the second multiplier 430 may include a plurality of multipliers. The circular correlation operator 320 generates product signals ( ) by IFFT transforming each of the sets of cross-correlation values ( ) may further include an IFFT converter 440 configured to provide. product signals ( ) Since there are a plurality of cross-correlation values, the IFFT transformer 440 sets a plurality of cross-correlation values ( ) can be output sequentially or in parallel. The IFFT transformer 440 converts a set of multiple cross-correlation values ( ) in parallel, the IFFT converter 440 may include a plurality of IFFT operators. Sets of cross-correlation values ( ) are sinusoidal signals ( ), and the number of sinusoidal signals ( ) is equal to the number of

Referring back to FIG. 3 , the maximum value identifier 330 is a set of cross-correlation values ( ) at the maximum cross-correlation value ( ) and the maximum cross-correlation value ( ) A set of cross-correlation values ( ) may be further configured to identify. The maximum value identifier 330 is the maximum cross-correlation value ( ) and identify the time index corresponding to the code (based on the identified time index) ) may be further configured to estimate the phase of The maximum value identifier 330 is the maximum cross-correlation value ( ), the set of identified cross-correlation values ( ) and set the matching frequency of the sinusoidal signal to the Doppler frequency ( ) can be further configured to estimate as

In the above description, if each functional unit provides its output, it is described and illustrated that the subsequent functional unit operates in response to the output, but those skilled in the art will understand that each functional unit stores its output in memory. It will be appreciated that the functional units can be designed and implemented so that the subsequent functional unit retrieves the stored output from the memory and operates in response, and all such implementations fall within the scope of the present disclosure.

The embodiments described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. For example, the devices, methods, and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate (FPGA). array), programmable logic units (PLUs), microprocessors, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and software applications running on the operating system. A processing device may also access, store, manipulate, process, and generate data in response to execution of software. For convenience of understanding, there are cases in which one processing device is used, but those skilled in the art will understand that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it can include. For example, a processing device may include multiple processors or a processor and a controller. Other processing configurations are also possible, such as parallel processors.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. The device can be commanded. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. Software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on computer readable media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination, and the program instructions recorded on the medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in the art of computer software. may be Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. - includes hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler.

The hardware device described above may be configured to operate as one or a plurality of software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on this. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents of the claims are within the scope of the following claims.

100: signal acquisition system
122: antenna
134: RF unit
146 ADC
178: signal acquisition module
210: pre-processing unit
212: mixer
220: code generator
230: resampling unit
240: sine wave signal generator
250: estimator
310: first multiplier
320: circular correlation calculator
330: maximum value identifier
410: FFT converter
420: conjugate operator
430: second multiplier
440: IFFT converter

Claims (11)

As a device for acquiring a satellite navigation signal,
A pre-processor configured to convert a digitized satellite navigation signal, wherein the digitized satellite navigation signal is composed of a product of a code and a carrier, and a frequency of the carrier is the sum of an intermediate frequency and a Doppler frequency, into a baseband signal;
a code generator configured to generate a local signal mimicking the code;
resampling the baseband signal at a resampling frequency to provide a first resampled signal comprising a number of first samples corresponding to a power of two, wherein the resampling frequency is such that the number of first samples is a power of two; is a frequency determined to be -, a resampling unit configured to resample the local signal at the resampling frequency to provide a second resampled signal including second samples equal to the number of first samples;
A sinusoidal signal generator configured to generate sinusoidal signals each having a reference frequency and a plurality of matching frequencies including frequencies sequentially shifted by a predetermined frequency deviation from the reference frequency, and
and an estimation unit configured to estimate the phase and the Doppler frequency of the code using the first resampled signal, the second resampled signal, and the sinusoidal wave signals. According to claim 1,
The pre-processor includes a mixer configured to down-convert the digitized satellite navigation signal to baseband by mixing the digitized satellite navigation signal and the local oscillation signal of the intermediate frequency,
Satellite navigation signal acquisition device. According to claim 1,
The digitized satellite navigation signal is provided by down-converting the satellite navigation signal received from the antenna into a satellite navigation signal of an intermediate frequency band and A/D converting the down-converted satellite navigation signal of the intermediate frequency band to a selected sampling frequency. felled,
Satellite navigation signal acquisition device. According to claim 3,
The code generator is further configured to generate the local signal using the selected sampling frequency,
Satellite navigation signal acquisition device. According to claim 1,
The device further comprises a memory;
The resampling unit is further configured to resample the baseband signal and store first samples corresponding to a power of 2 in the memory for a predetermined storage time,
The resampling unit is further configured to resample the local signal and store second samples corresponding to a power of 2 in the memory for the predetermined storage time.
Satellite navigation signal acquisition device. According to claim 1,
The plurality of matching frequencies include the reference frequency and frequencies sequentially shifted in a positive direction by a frequency deviation selected from the reference frequency and frequencies sequentially shifted in a negative direction by a frequency deviation selected from the reference frequency. including them,
Satellite navigation signal acquisition device. According to claim 1,
The sinusoidal signal generating unit is further configured to generate the sinusoidal signals using the resampling frequency,
Satellite navigation signal acquisition device. According to claim 1,
The estimator,
a first multiplier configured to multiply the first resampling signal and each of the sinusoidal signals on a sample-by-sample basis to provide a reference signal;
a circular correlation operator configured to provide a set of cross-correlation values between each of the reference signals and the second resampled signal; and
a maximum value discriminator configured to estimate the phase of the code and the Doppler frequency based on the sets of cross-correlation values;
Satellite navigation signal acquisition device. According to claim 8,
The circular correlation calculator,
an FFT converter configured to FFT transform each of the reference signals to provide a first transformed signal and FFT transform the second resampled signal to provide a second transformed signal;
a conjugate operator configured to conjugate the second transformed signal to provide a conjugate signal of the second transformed signal;
a second multiplier configured to multiply each of the first transformed signals and a conjugate of the second transformed signal on a sample-by-sample basis to provide a product signal;
an IFFT transformer configured to IFFT transform each of the product signals to provide the set of cross-correlation values, wherein the sets of cross-correlation values are respectively associated with the sinusoidal signals;
Satellite navigation signal acquisition device. According to claim 8,
the maximum value identifier is further configured to identify a maximum cross-correlation value in the sets of cross-correlation values and a set of cross-correlation values comprising the maximum cross-correlation value;
The maximum value identifier is further configured to identify a time index corresponding to the maximum cross-correlation value and estimate a phase of the code based on the identified time index;
wherein the maximum value discriminator is further configured to estimate, as the Doppler frequency, a frequency for a match of a sinusoidal signal associated with the identified set of cross-correlation values that includes the maximum cross-correlation value.
Satellite navigation signal acquisition device. As a device for acquiring a satellite navigation signal,
A resampling unit configured to resample the baseband digitized satellite navigation signal at a resampling frequency and provide a first resampled signal including first samples corresponding to a power of 2 - the baseband digitized satellite navigation A signal is composed of a product of a sinusoid of a code and a Doppler frequency, and the resampling frequency is a frequency determined so that the number of first samples is a power of 2 -, and
a code generator configured to generate a local signal mimicking the code;
The resampling unit is further configured to resample the local signal at the resampling frequency to provide a second resampled signal including second samples equal to the number of first samples,
The device,
A sinusoidal signal generator configured to generate matching sinusoidal signals each having a reference frequency and a plurality of matching frequencies including frequencies sequentially shifted by a predetermined frequency deviation from the reference frequency; and
and an estimator configured to estimate the phase of the code and the Doppler frequency using the first resampled signal, the second resampled signal, and the sinusoidal wave signals for matching.