阅读说明：本技术 一种导航卫星信号接收方法及接收机 (Navigation satellite signal receiving method and receiver ) 是由 陈丽 李胜 李金立 陈春阳 于 2020-07-31 设计创作，主要内容包括：本发明涉及一种导航卫星信号接收方法及接收机,属于卫星导航技术领域,在接收方法捕获步骤的匹配滤波算法中,将降采样后的卫星基带信号与本地生成的PN码进行短时相关累加,并将短时相关累加结果存储到一块设定容量的存储器中；从存储器中读取相关累加结果进行FFT扫频；将FFT扫频的结果进行非相干累加以及峰值判断后捕获卫星信号；其中,短时相关累加采用N路M点的并行短时相关累加；所述存储器的设定容量为M*N,M为一个相位的PN码短时相关累加得到的样本数；存储器基于地址排序进行短时相关累加数据的存储和读出,用于实现短时相关累加数据的存储和FFT扫频读取数据的乒乓衔接操作。本发明可以节约一倍的短时相关存储资源。(The invention relates to a method and a receiver for receiving a navigation satellite signal, belonging to the technical field of satellite navigation.A matched filtering algorithm in the capturing step of the receiving method carries out short-time correlation accumulation on a satellite baseband signal after down sampling and a PN code generated locally, and stores the short-time correlation accumulation result into a memory with set capacity; reading the correlation accumulation result from the memory to perform FFT frequency sweep; performing incoherent accumulation and peak judgment on the FFT frequency sweeping result, and then capturing a satellite signal; the short-time correlation accumulation adopts parallel short-time correlation accumulation of N paths of M points; the set capacity of the memory is M × N, M is the number of samples obtained by short-time correlation accumulation of PN codes of one phase; the memory stores and reads the short-time correlation accumulated data based on address sequencing, and is used for realizing ping-pong connection operation of storing the short-time correlation accumulated data and reading the FFT frequency sweep data. The invention can save one time of short-time related storage resources.)

1. A navigation satellite signal receiving method is characterized by comprising an acquisition step; in the matched filtering algorithm of the capturing step, the method comprises the following steps:

performing short-time correlation accumulation on the satellite baseband signal subjected to the down sampling and a locally generated PN code, and storing a short-time correlation accumulation result into a memory with set capacity;

reading the correlation accumulation result from the memory to perform FFT frequency sweeping;

performing incoherent accumulation and peak judgment on the FFT frequency sweeping result, and then capturing a satellite signal; wherein the content of the first and second substances,

the short-time correlation accumulation adopts N paths of parallel short-time correlation accumulation of M points; the set capacity of the memory is M × N, M is the number of samples obtained by short-time correlation accumulation of PN codes of one phase;

the memory stores and reads the short-time correlation accumulated data based on address sequencing and is used for realizing ping-pong connection operation of storing the short-time correlation accumulated data and reading the FFT frequency sweeping data.

2. The navigation satellite signal receiving method according to claim 1, wherein the short-time correlation accumulated data storing and reading method comprises:

storing the odd round of related accumulated data by adopting an address interval sorting storage mode; reading by adopting an address sequence sequencing reading mode;

storing the even-numbered round of related accumulated data in an address sequence ordering storage mode, and reading the data in an address interval ordering reading mode;

the address interval sorting storage mode is the same as the address interval sorting mode of the address interval sorting reading mode;

and immediately releasing the storage space of the data after the data of the previous round is read so as to store the data of the next round.

3. The navigation satellite signal receiving method according to claim 1,

the specific address operation sequence of the address interval sequencing is as follows:

1,(M+1),(2M+1),...,M*(N-1)；

2,(M+2),(2M+2),...,M*(N-1)+1；

…；

M,2M,3M,...,M*N。

4. the navigation satellite signal receiving method according to claim 1,

the point number of the FFT frequency sweep meets the requirement of frequency searching resolution.

5. The navigation satellite signal receiving method of claim 4, wherein the frequency search resolution is based on frequency mismatch loss of coherent integration

6. The navigation satellite signal receiving method according to claim 4, wherein zero padding is performed on the short-time correlation accumulated samples of M points, so that the number of samples for frequency sweeping satisfies the number of FFT frequency sweeping points.

7. A navigation satellite signal receiver applying the navigation satellite signal receiving method according to any one of claims 1 to 6, comprising an acquisition module, wherein the acquisition module comprises a memory with a set capacity;

the acquisition module is used for performing short-time correlation accumulation on the satellite baseband signals subjected to the down sampling and the PN codes generated locally and storing the short-time correlation accumulation results into the memory;

reading the correlation accumulation result from the memory to perform FFT frequency sweeping;

performing incoherent accumulation and peak judgment on the FFT frequency sweeping result, and then capturing a satellite signal; wherein the content of the first and second substances,

the short-time correlation accumulation adopts N paths of parallel short-time correlation accumulation of M points; the set capacity of the memory is M × N, M is the number of samples obtained by short-time correlation accumulation of PN codes of one phase;

the memory stores and reads the related accumulated data based on address sequencing and is used for realizing ping-pong connection operation of short-time related accumulated data storage and FFT frequency sweep reading data.

8. The navigation satellite signal receiver of claim 7, wherein the acquisition module further comprises a down-conversion module, a down-sampling storage module, a short-time correlation accumulation module, an FFT sweep frequency module, a non-coherent accumulation storage module, and a peak threshold detection module;

the down-conversion module is used for down-converting the intermediate frequency data of the satellite signal to obtain a baseband signal of the satellite signal;

the down-sampling storage module is used for down-sampling the baseband signal and storing down-sampling data;

the short-time correlation accumulation module is used for reading the down-sampling data, performing N-path M-point parallel short-time correlation accumulation with a locally generated PN code, and storing the correlation accumulation data into the memory module;

the FFT frequency sweep module is used for carrying out FFT frequency sweep on the relevant accumulated data read out from the memory module in a set frequency sweep range;

the incoherent accumulation storage module is used for performing incoherent accumulation on the FFT frequency sweeping result for a set number of times and storing an incoherent accumulation result;

and the peak threshold detection module is used for carrying out peak detection on the incoherent accumulation result to obtain a satellite signal acquisition result.

9. The navigation satellite signal receiver of claim 8, wherein the memory module storing and reading method comprises:

storing the odd round of related accumulated data by adopting an address interval sorting storage mode; reading by adopting an address sequence sequencing reading mode;

storing the even-numbered round of related accumulated data in an address sequence ordering storage mode, and reading the data in an address interval ordering reading mode;

the address interval sorting storage mode is the same as the address interval sorting mode of the address interval sorting reading mode;

and immediately releasing the storage space of the data after the data of the previous round is read so as to store the data of the next round.

10. The navigation satellite signal receiver of claim 9,

the specific address operation sequence of the address interval sequencing is as follows:

1,(M+1),(2M+1),...,M*(N-1)；

2,(M+2),(2M+2),...,M*(N-1)+1；

…；

M,2M,3M,...,M*N。

Technical Field

The invention relates to the technical field of satellite navigation, in particular to a navigation satellite signal receiving method and a receiver.

Background

The Beidou satellite navigation system provides all-weather, real-time and accurate position information, greatly improves the efficiency and the productivity in a plurality of industries, has important significance for economic development and national defense construction, and is widely applied to civil and military fields. The low unit price of the receiver is a very important prerequisite for the wide application of satellite navigation. The resource of the implementation scheme of the Beidou navigation receiver is very important and is an important index directly related to the cost of the receiver. Therefore, it is a very important technique to achieve the acquisition of high dynamic signals with small computational resources.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a navigation satellite signal receiving method and a receiver; the method is used for realizing the acquisition of high dynamic signals under the premise of small computing resources.

The invention discloses a navigation satellite signal receiving method, which comprises a capturing step; in the matched filtering algorithm of the capturing step, the method comprises the following steps:

performing short-time correlation accumulation on the satellite baseband signal subjected to the down sampling and a locally generated PN code, and storing a short-time correlation accumulation result into a memory with set capacity;

reading the correlation accumulation result from the memory to perform FFT frequency sweeping;

performing incoherent accumulation and peak judgment on the FFT frequency sweeping result, and then capturing a satellite signal; wherein the content of the first and second substances,

the short-time correlation accumulation adopts N paths of parallel short-time correlation accumulation of M points; the set capacity of the memory is M × N, M is the number of samples obtained by short-time correlation accumulation of PN codes of one phase;

the memory stores and reads the short-time correlation accumulated data based on address sequencing and is used for realizing ping-pong connection operation of storing the short-time correlation accumulated data and reading the FFT frequency sweeping data.

Further, the method for storing and reading out the short-time correlation accumulated data includes:

storing the odd round of related accumulated data by adopting an address interval sorting storage mode; reading by adopting an address sequence sequencing reading mode;

storing the even-numbered round of related accumulated data in an address sequence ordering storage mode, and reading the data in an address interval ordering reading mode;

the address interval sorting storage mode is the same as the address interval sorting mode of the address interval sorting reading mode;

and immediately releasing the storage space of the data after the data of the previous round is read so as to store the data of the next round.

Further, the specific address operation sequence of the address interval ordering is as follows:

1,(M+1),(2M+1),...,M*(N-1)；

2,(M+2),(2M+2),...,M*(N-1)+1；

…

M,2M,3M,...,M*N。

further, the number of points of the FFT frequency sweep meets the requirement of frequency search resolution.

Further, the frequency search resolution is based on frequency mismatch loss of coherent integrationDetermining; wherein, ω is_IFIs the frequency of the carrier of the signal,

t is the coherent integration time for the local carrier frequency.

Further, zero padding is carried out on the short-time correlation accumulated samples of the M points, so that the number of the samples of frequency sweeping meets the number of the FFT frequency sweeping points.

The invention also discloses a navigation satellite signal receiver applying the navigation satellite signal receiving method, which comprises a capturing module, wherein the capturing module comprises a memory with set capacity;

the acquisition module is used for performing short-time correlation accumulation on the satellite baseband signals subjected to the down sampling and the PN codes generated locally and storing the short-time correlation accumulation results into the memory;

reading the correlation accumulation result from the memory to perform FFT frequency sweeping;

performing incoherent accumulation and peak judgment on the FFT frequency sweeping result, and then capturing a satellite signal; wherein the content of the first and second substances,

the short-time correlation accumulation adopts N paths of parallel short-time correlation accumulation of M points; the set capacity of the memory is M × N, M is the number of samples obtained by short-time correlation accumulation of PN codes of one phase;

the memory stores and reads the related accumulated data based on address sequencing and is used for realizing ping-pong connection operation of short-time related accumulated data storage and FFT frequency sweep reading data.

Furthermore, the capturing module also comprises a down-conversion module, a down-sampling storage module, a short-time correlation accumulation module, an FFT frequency sweep module, an incoherent accumulation storage module and a peak threshold detection module;

the down-conversion module is used for down-converting the intermediate frequency data of the satellite signal to obtain a baseband signal of the satellite signal;

the down-sampling storage module is used for down-sampling the baseband signal and storing down-sampling data;

the short-time correlation accumulation module is used for reading the down-sampling data, performing N-path M-point parallel short-time correlation accumulation with a locally generated PN code, and storing the correlation accumulation data into the memory module;

the FFT frequency sweep module is used for carrying out FFT frequency sweep on the relevant accumulated data read out from the memory module in a set frequency sweep range;

the incoherent accumulation storage module is used for performing incoherent accumulation on the FFT frequency sweeping result for a set number of times and storing an incoherent accumulation result;

and the peak threshold detection module is used for carrying out peak detection on the incoherent accumulation result to obtain a satellite signal acquisition result.

Further, the storage and readout method of the memory module comprises the following steps:

storing the odd round of related accumulated data by adopting an address interval sorting storage mode; reading by adopting an address sequence sequencing reading mode;

storing the even-numbered round of related accumulated data in an address sequence ordering storage mode, and reading the data in an address interval ordering reading mode;

the address interval sorting storage mode is the same as the address interval sorting mode of the address interval sorting reading mode;

and immediately releasing the storage space of the data after the data of the previous round is read so as to store the data of the next round.

Further, the specific address operation sequence of the address interval ordering is as follows:

1,(M+1),(2M+1),...,M*(N-1)；

2,(M+2),(2M+2),...,M*(N-1)+1；

…

M,2M,3M,...,M*N。

the invention has the following beneficial effects:

the invention can save one time of short-time related storage resources. If the hardware resources are not changed, the saved resources can be doubled by opening one more parallel channel number because the storage related to the short time is reduced to half of the original storage, so that the capture speed can be doubled.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a flowchart illustrating a derivative matched filter algorithm according to a first embodiment of the present invention;

fig. 2 is a schematic diagram illustrating the connection of the capturing module in the second embodiment.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.