CN108226969B

CN108226969B - Method for realizing signal processing and receiver

Info

Publication number: CN108226969B
Application number: CN201611155163.2A
Authority: CN
Inventors: 宋挥师; 徐雄伟; 刘晓燕; 赵海龙; 孙涛
Original assignee: Datang Semiconductor Design Co Ltd
Current assignee: Datang Semiconductor Design Co Ltd
Priority date: 2016-12-14
Filing date: 2016-12-14
Publication date: 2020-07-28
Anticipated expiration: 2036-12-14
Also published as: CN108226969A

Abstract

A method for realizing signal processing and a receiver are disclosed, which comprises a receiver provided with two or more than two navigation systems, wherein one navigation system is a global navigation satellite positioning system (G L ONASS), the method also comprises the steps of deleting unused frequency points in the navigation process of the determined G L ONASS from the frequency points for receiving navigation signals, determining the system bandwidth of the G L ONASS according to the deleted frequency points, determining the uniform signal sampling rate of all the navigation systems according to the determined system bandwidth of the G L ONASS and the system bandwidth of other navigation systems in the receiver, generating the working clock of an analog-digital converter (ADC) of each navigation system according to the signal sampling rate, carrying out analog-digital conversion on the analog signals from a band-pass filter by each ADC according to the generated working clock, and carrying out mixing, low-pass filtering and integral multiple down-sampling processing on the digital signals after the analog-digital conversion.

Description

Method for realizing signal processing and receiver

Technical Field

The present disclosure relates to, but not limited to, signal processing techniques, and more particularly, to a method and receiver for performing signal processing.

Background

Currently, global satellite navigation systems mainly comprise a Global Positioning System (GPS) in the United states, a Beidou system in China, a global navigation satellite positioning system (G L ONASS) in Russia and a Galileo (Galileo) system in Europe, the GPS and the Beidou system are widely applied in China and Asia Pacific regions, the GPS and the G L ONASS are more applied in Russia, the Galileo system is far immature and cannot provide formal services, and in the four main satellite navigation systems, the GPS, the BD and the Galileo all adopt Code Division Multiple Access (CDMA) signal systems, and only the G L ONASS system adopts frequency division Multiple Access (FDMA, FreyDivision Multiple Access) signals.

Although single mode navigation receivers (e.g., GPS receivers) may work well, dual mode (e.g., GPS plus BD, GPS plus G L ONASS) or multi-mode (e.g., GPS, BD plus G L ONASS) navigation receivers are becoming increasingly popular for better coverage performance because dual mode navigation receivers or multi-mode navigation receivers are more complex than single mode navigation receivers.

Because the GPS system and the BD system are both of CDMA signal systems and have narrow bandwidths (the GPS bandwidth is 2.046MHz and the Beidou bandwidth is 4.092MHz), the joint design of the two systems is more intuitive and simple, the dual-mode receiving system is often a GPS plus BD mode, and the G L ONASS belongs to an FDMA signal system, the system bandwidth is very large (8.3345 MHz), and the front end of the G L ONASS is generally designed independently, or when a G L ONASS compatible receiver is designed, the GPS and/or the Beidou are/is aligned to the G L ONASS, because the system bandwidth is directly related to the complexity of the navigation receiver, when the dual-mode or multi-mode navigation receiver comprises the G L ONASS, no matter the front end of the G L ONASS is designed independently, or the GPS and/or the G L ONASS are aligned, the design of the navigation receiver is more complicated, when the front end portion comprises the working clock (signal sampling rate) of an analog-to-digital converter (ADC), the working clock (signal sampling rate) is designed independently, or the GPS and the working clock is aligned to the G L ONASS, the navigation receiver is designed more complicated, the design of the dual-mode or the navigation receiver is not only when the multi-mode receiver comprises the complexity of the navigation receiver, the multi-mode receiver is not only the multi-mode receiver, and the multi-mode receiver is designed, and the multi-mode receiver, if the multi-mode receiver, the multi-mode receiver are designed complicated receiver, the multi-mode receiver is not only the multi-mode receiver, the multi-mode receiver is not only the multi-mode receiver, but the multi-mode receiver, the multi-mode receiver is not only the multi-mode receiver, the multi-system can be the multi-mode receiver, the multi-mode.

In summary, in the related art, the front-end portion of the dual-mode or multi-mode receiver has the problems of complicated design and high power.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

Embodiments of the present invention provide a method for implementing signal processing and a receiver, which can simplify the design of the receiver and reduce the power consumption of the receiver.

The embodiment of the invention provides a receiver which is provided with two or more than two navigation systems, wherein one navigation system is a global navigation satellite positioning system G L ONASS, the front end part of the receiver comprises a first determining unit, a second determining unit, an analog-digital converter (ADC) and a digital processing unit which correspond to each navigation system, wherein,

the first determining unit is used for determining unused frequency points in the G L ONASS navigation process, deleting the determined unused frequency points from the frequency points for receiving the navigation signals, and determining the system bandwidth of G L ONASS according to the deleted frequency points;

the second determining unit is used for determining the uniform signal sampling rate of all navigation systems in the receiver according to the determined system bandwidth of G L ONASS and the system bandwidth of other navigation systems in the receiver, and providing a working clock for the analog-digital converter ADC of each navigation system according to the determined signal sampling rate;

the ADC of each navigation system is respectively used for carrying out analog-digital conversion on the analog signal from the band-pass filter of the navigation system where the ADC is located according to the working clock provided by the second determining unit, and sending the digital signal after the analog-digital conversion to the digital processing unit corresponding to the navigation system where the ADC is located;

the digital processing units of the navigation systems are respectively used for carrying out frequency mixing, low-pass filtering and integral multiple down-sampling processing on the received digital signals which are subjected to analog-digital conversion.

Optionally, the unused frequency points in the G L ONASS navigation process include a satellite test frequency point and a satellite experiment frequency point of G L ONASS;

the determined system bandwidth of the G L ONASS comprises 7.2095 MHz.

Optionally, the other navigation system includes: a Beidou BD system, and/or a Global positioning System GPS, and/or a Galileo system;

the second determining unit is configured to determine a signal sampling rate that is uniform for all navigation systems in the receiver, and includes:

and determining that the signal sampling rate unified by all navigation systems in the receiver is 16.369MHz according to the determined system bandwidth of G L ONASS and the system bandwidth of the other navigation systems.

Optionally, the digital processing unit specifically includes: the device comprises a digital frequency mixing module, a low-pass filter and an integral multiple down-sampling module; wherein the content of the first and second substances,

the digital frequency mixing module is used for carrying out frequency mixing processing on the received digital signals after completing the analog-digital conversion and sending the frequency mixing signals after the frequency mixing processing to the low-pass filter;

the low-pass filter is used for performing low-pass filtering processing on the received mixing signal from the digital mixing module and sending the filtering signal after the low-pass filtering processing to the integral multiple down-sampling module;

and the integral multiple down-sampling module is used for receiving the filtering signal from the low-pass filter and performing down-sampling processing on the received filtering signal according to the frequency multiplication of the preset multiple.

Optionally, when the digital processing unit is a G L ONASS digital processing unit, the integer-times downsampling module is specifically configured to receive the filtered signal from the low-pass filter, and perform downsampling on the received filtered signal according to 8-times frequency multiplication;

when the digital processing unit is a digital processing unit of a BD system, the integral multiple down-sampling module is specifically configured to receive a filtered signal from a low-pass filter, and perform down-sampling processing on the received filtered signal according to 4 times of frequency multiplication;

when the digital processing unit is a GPS digital processing unit, the integral multiple down-sampling module is specifically used for receiving the filtering signal from the low-pass filter and performing down-sampling processing on the received filtering signal according to 4 times of frequency multiplication;

when the digital processing unit is a digital processing unit of a Galileo system, the integral multiple down-sampling module is specifically configured to receive the filtered signal from the low-pass filter, and perform down-sampling processing on the received filtered signal according to 4 times of frequency multiplication.

In another aspect, an embodiment of the present invention further provides a method for implementing signal processing, which is applied to a receiver with two or more navigation systems, where one of the navigation systems is a global navigation satellite positioning system G L ONASS, and the method includes:

determining unused frequency points in the G L ONASS navigation process, deleting the determined unused frequency points from the frequency points for receiving navigation signals, and determining the system bandwidth of G L ONASS according to the deleted frequency points;

according to the determined system bandwidth of G L ONASS and the system bandwidth of other navigation systems in the receiver, determining the uniform signal sampling rate of all navigation systems in the receiver, and generating the working clock of the analog-digital converter (ADC) of each navigation system according to the determined signal sampling rate;

the ADC of each navigation system respectively carries out analog-digital conversion on the analog signal from the band-pass filter of the navigation system in which the ADC is positioned according to the generated working clock;

and performing frequency mixing, low-pass filtering and integral multiple down-sampling processing on the digital signals after the analog-digital conversion is completed.

the determined system bandwidth of the G L ONASS comprises 7.2095 MHz.

the determining a signal sampling rate that is uniform for all navigation systems in the receiver comprises:

Optionally, the processing of mixing, low-pass filtering, and integer-multiple down-sampling the digital signal after completing the analog-to-digital conversion includes:

for different navigation systems, respectively carrying out frequency mixing processing on the analog-digital conversion digital signals output by the ADC; performing low-pass filtering processing on the mixed frequency signal subjected to the frequency mixing processing; and performing downsampling processing on the filtering signals subjected to the low-pass filtering processing according to preset multiple frequency multiplication corresponding to each navigation system.

Optionally, the performing the downsampling process includes:

when the navigation system is G L ONASS, down-sampling the received filtering signal according to 8 times of frequency multiplication;

when the navigation system is a BD system, downsampling the received filtering signal according to 4 times of frequency multiplication;

when the navigation system is a GPS, down-sampling processing is carried out on the received filtering signal according to 4 times of frequency multiplication;

and when the navigation system is a Galileo system, down-sampling processing is carried out on the received filtering signal according to 4 times of frequency multiplication.

Compared with the prior art, the technical scheme includes that the method is applied to a receiver provided with two or more than two navigation systems, one navigation system is a global navigation satellite positioning system G L ONASS, the method comprises the steps of determining unused frequency points in the navigation process of G L ONASS, deleting the determined unused frequency points from the frequency points for receiving navigation signals, determining the system bandwidth of G L ONASS according to the deleted frequency points, determining the unified signal sampling rate of all navigation systems in the receiver according to the determined system bandwidth of G L ONASS and the system bandwidth of other navigation systems in the receiver, generating the working clock of an analog-digital converter (ADC) of each navigation system according to the determined signal sampling rate, performing analog-digital conversion on analog signals from a band-pass filter of the navigation system of the receiver according to the generated working clock, and performing mixing, low-pass filtering and integral multiple down-sampling processing on the digital signals which are subjected to the analog-digital conversion.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a block diagram of a single system front end in the related art;

FIG. 2 is a block diagram of a navigation receiver according to an embodiment of the present invention;

fig. 3 is a flowchart of a method for implementing signal processing according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

The steps illustrated in the flow charts of the figures may be performed in a computer system such as a set of computer-executable instructions. Also, while a logical order is shown in the flow diagrams, in some cases, the steps shown or described may be performed in an order different than here.

FIG. 2 is a block diagram of a navigation receiver according to an embodiment of the present invention, as shown in FIG. 2, the navigation receiver includes two or more navigation systems, one of which is a global navigation satellite positioning system G L ONASS, that is, the navigation receiver includes at least one navigation system of CDMA signal system (BD system, and/or GPS, and/or Galileo system) and one navigation system of FDMA signal system (G L ONASS), the front end of the receiver includes a first determining unit, a second determining unit, and an analog-to-digital converter (ADC) and a digital processing unit corresponding to each navigation system,

it should be noted that if the unused frequency points in the G L ONASS navigation process are not deleted, the system bandwidth of the G L ONASS is 8.3345, a large sampling rate needs to be set, otherwise signal aliasing will be caused, and therefore, the receiver obtained by design is complex and has large power consumption, and in the embodiment of the invention, the system bandwidth of the G L ONASS is determined to be 7.2095MHz according to the deleted frequency points.

Optionally, the frequency points not used in the G L ONASS navigation process include a satellite test frequency point and a satellite experiment frequency point of G L ONASS.

Optionally, the determined system bandwidth of the G L ONASS comprises 7.2095 MHz.

Table 1 shows the frequency points used in the G L ONASS navigation process in the related technology, as shown in Table 1, the frequency spectrum range occupied by the G L ONASS signals is (1598.0625-1605.375) MHz +/-0.511MHz, and the bandwidth is 8.3345MHz totally, and the analysis of the protocol can find that the channel numbers 05 and 06 are used for satellite tests and satellite experiments, namely the two frequency points are not oriented to normal civil navigation and are used by Russian navigation technology researchers, namely, the two frequency points are used as a common G L ONASS civil navigation receiver, and the navigation signals of the two frequency points with the channel numbers 05 and 06 can not be received at all.

Channel number	Central frequency point (MHz)
		06	1605.375
05	1604.8125
		04	1604.25
03	1603.6875
		02	1603.125
01	1602.5625
		00	1602.0
-01	1601.4375
		-02	1600.8750
-03	1600.3125
		-04	1599.7500
-05	1599.1875
		-06	1598.6250
-07	1598.0625

TABLE 1

Referring to the above analysis, the receiver including G L ONASS in the related art covers 14 channels from-07 to 06, whereas the receiver of the embodiment G L ONASS only needs to cover 12 channels from-07 to 04, and the signal range occupied by the 12 channels is (1598.0625 to 1604.25) MHz +/-0.511MHz, that is, the system bandwidth is 7.2095 MHz.

According to the characteristics of the common civil G L ONASS navigation receiver and the use of each frequency point of the system, the embodiment of the invention provides that 14 frequency points are not required to be completely received, thereby reducing the system bandwidth and lowering the signal sampling rate requirement of the system.

optionally, the other navigation system comprises: a Beidou BD system, and/or a Global positioning System GPS, and/or a Galileo system;

the second determining unit is used for determining the signal sampling rate unified by all navigation systems in the receiver and comprises the following steps:

It should be noted that, according to a signal sampling rate of 16.369MHz, an intermediate frequency value of each navigation system is determined, the GPS radio frequency is 1575.42MHz, the intermediate frequency value may be 3.996MHz, the bd system radio frequency is 1561.098MHz, the intermediate frequency value may be 3.996875MHz, g L ONASS adopts a scheme of receiving only 12 channels, that is, the signal frequency range is (1598.0625 to 1604.25) MHz +/-0.511MHz, and may also be written as 1597.5515MHz to 1604.761MHz (the middle point of the spectrum is 1601.15625MHz), the bandwidth is 7.2095MHz, the intermediate frequency point is selected as 1601.15625MHz to 16.369 × 97.5625 — 4.1556875MHz, half of the system bandwidth 7.2095MHz is 3.60475MHz, and it can be seen that it is reasonable to select the intermediate frequency value.

it should be noted that, the bandwidth selection of the band pass filter in each navigation system in the embodiment of the present invention is determined according to the bandwidth values of the three navigation systems; the filter usually selects an IIR filter (infinite impulse response filter), and the embodiment of the invention has no special requirement and only needs to select a common design method. Similarly, regarding the ADC, except that the three navigation systems all adopt the signal sampling rate of 16.369MHz, no special requirement is imposed on the specific design method of the ADC, and a common scheme is adopted. The digital processing units of the navigation systems are respectively used for carrying out frequency mixing, low-pass filtering and integral multiple down-sampling processing on the received digital signals which are subjected to analog-digital conversion.

In addition, the embodiment of the invention aims at the GPS and BD systems, the digital mixing has the function of removing the intermediate frequency, moving the signal frequency spectrum to the vicinity of 0 frequency, and then entering a low-pass filter, the digital low-pass filter commonly uses an FIR filter (finite impulse response filter) to filter out 2 times of intermediate frequency components brought by the digital mixing, finally, integral multiple down-sampling operation is carried out, 4 times of down-sampling operation is carried out on the GPS system and the BD system, the sampling rate is reduced from 16.369MHz to 4.09225MHz, however, for G L ONASS, the specific implementation method from the digital mixing module to the integral multiple down-sampling module is different from that of the CDMA system because the frequency point is an FDMA signal system, the signal frequency spectrum carried by each channel is only 1.022MHz, but the whole signal frequency spectrum is wider, and the table 2 is the digital mixing corresponding to each channel of G L ONASS, namely the intermediate frequency value corresponding to each channel.

TABLE 2

According to the intermediate frequency values given in table 2, the digital mixing operation is performed on the input signal, the center frequency point of the corresponding channel is moved to the 0-frequency accessory, and then the signal component which is useless to the channel is filtered out through the low-pass filter, wherein the useful system bandwidth of each channel is 1.022MHz, namely the unilateral bandwidth is 0.511 MHz. Finally, each channel is down-sampled by a factor of 8. The integral multiple down-sampling operation is to select one sample point from an integral number of consecutive sample points as an output sample. In the embodiment of the present invention, all channels may sequentially perform the baseband front end operation.

Let the signal after ADC sampling be r (k), the signal sampling rate Fs is 16.369MHz, the intermediate frequency value is f _ IF, the signal after digital mixing is denoted as s _ i (k) + j × s _ q (k), k denotes the sample number, then the calculation formula of the digital mixing operation is:

s_i(k)＝r(k)*cos(2*pi*k*f_IF/Fs)；

s_q(k)＝r(k)*sin(-2*pi*k*f_IF/Fs)；

when the digital processing unit is a digital processing unit of a BD system, the integral multiple down-sampling module is specifically used for receiving the filtering signal from the low-pass filter and performing down-sampling processing on the received filtering signal according to 4 times of frequency multiplication;

when the digital processing unit is a digital processing unit of a GPS, the integral multiple down-sampling module is specifically used for receiving the filtering signal from the low-pass filter and performing down-sampling processing on the received filtering signal according to 4 times of frequency multiplication;

It should be noted that, the foregoing structure of the embodiment of the present invention is a front-end portion of a receiver, and the front-end portion further includes a receiving device and a mixing unit before a bandpass filter. In addition, fig. 2 only illustrates two systems of navigation systems, and actually, the receiver according to the embodiment of the present invention may include a plurality of navigation systems.

The embodiment of the invention determines the low sampling rate of ADC analog-to-digital conversion by reducing the system bandwidth of G L ONASS, simplifies the design of the front end part of the receiver and reduces the power consumption of the receiver.

Fig. 3 is a flowchart of a method for implementing signal processing according to an embodiment of the present invention, applied to a receiver having two or more navigation systems, one of which is a global navigation satellite positioning system (G L ONASS), as shown in fig. 3, including:

step 300, determining unused frequency points in the navigation process of a global navigation satellite positioning system (G L ONASS), deleting the determined unused frequency points from the frequency points for receiving navigation signals, and determining the system bandwidth of G L ONASS according to the deleted frequency points;

optionally, the determined system bandwidth of G L ONASS comprises 7.2095 MHz.

Step 301, determining a uniform signal sampling rate of all navigation systems in the receiver according to the determined system bandwidth of the G L ONASS and system bandwidths of other navigation systems in the receiver, and generating a working clock of an analog-to-digital converter (ADC) of each navigation system according to the determined signal sampling rate;

optionally, the determining the signal sampling rate that is uniform for all navigation systems in the receiver includes:

Step 302, the ADC of each navigation system respectively performs analog-digital conversion on the analog signal from the band-pass filter of the navigation system in which the ADC is located according to the generated working clock;

and step 303, performing frequency mixing, low-pass filtering and integral multiple down-sampling processing on the digital signals after the analog-digital conversion is completed.

Optionally, the performing down-sampling processing includes:

and when the navigation system is a Galileo system, downsampling the received filtering signal according to 4 times of frequency multiplication.

It will be understood by those skilled in the art that all or part of the steps of the above methods may be implemented by a program instructing associated hardware (e.g., a processor) to perform the steps, and the program may be stored in a computer readable storage medium, such as a read only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may be implemented using one or more integrated circuits. Accordingly, each module/unit in the above embodiments may be implemented in hardware, for example, by an integrated circuit to implement its corresponding function, or in software, for example, by a processor executing a program/instruction stored in a memory to implement its corresponding function. The present invention is not limited to any specific form of combination of hardware and software.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A receiver is characterized in that two or more navigation systems are provided, one of the navigation systems is a global navigation satellite positioning system G L ONASS, the front end part of the receiver comprises a first determining unit, a second determining unit, an analog-digital converter (ADC) and a digital processing unit corresponding to each navigation system,

2. The receiver of claim 1, wherein the unused frequencies during the G L ONASS navigation process comprise satellite test frequencies and satellite experiment frequencies of G L ONASS;

the determined system bandwidth of the G L ONASS comprises 7.2095 MHz.

3. The receiver of claim 1, wherein the other navigation system comprises: a Beidou BD system, and/or a Global positioning System GPS, and/or a Galileo system;

4. The receiver according to any of claims 1 to 3, wherein the digital processing unit comprises: the device comprises a digital frequency mixing module, a low-pass filter and an integral multiple down-sampling module; wherein the content of the first and second substances,

5. The receiver of claim 4,

when the digital processing unit is a G L ONASS digital processing unit, the integer multiple down-sampling module is specifically configured to receive the filtered signal from the low-pass filter, and perform down-sampling processing on the received filtered signal according to 8 times of frequency multiplication;

6. A method for implementing signal processing, applied to a receiver having two or more navigation systems, one of which is a global navigation satellite positioning system G L ONASS, includes:

7. The method of claim 6, wherein the unused frequency points during the G L ONASS navigation process comprise satellite test frequency points and satellite experiment frequency points of G L ONASS;

the determined system bandwidth of the G L ONASS comprises 7.2095 MHz.

8. The method of claim 6, wherein the other navigation systems comprise: a Beidou BD system, and/or a Global positioning System GPS, and/or a Galileo system;

9. The method according to any one of claims 6 to 8, wherein the mixing, low-pass filtering and integer-times down-sampling processing of the digital signal after analog-to-digital conversion comprises:

10. The method of claim 9, wherein the performing downsampling processing comprises: