CN106526633B - A kind of GNSS baseband signal acquisition method and device - Google Patents
A kind of GNSS baseband signal acquisition method and device Download PDFInfo
- Publication number
- CN106526633B CN106526633B CN201611168683.7A CN201611168683A CN106526633B CN 106526633 B CN106526633 B CN 106526633B CN 201611168683 A CN201611168683 A CN 201611168683A CN 106526633 B CN106526633 B CN 106526633B
- Authority
- CN
- China
- Prior art keywords
- satellite
- signal
- satellites
- frequency
- phase component
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/30—Acquisition or tracking or demodulation of signals transmitted by the system code related
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
Description
技术领域technical field
本发明涉及GNSS基带信号的处理,尤其涉及GNSS基带信号的捕获方法及装置。The present invention relates to the processing of GNSS baseband signals, in particular to a method and device for acquiring GNSS baseband signals.
背景技术Background technique
随着科技的迅速发展,出现了多种多样的导航系统。单一导航系统很难满足全球、全天候、各种复杂环境下的导航需求,利用两种或多种系统组成的组合导航系统成为了各国研究的热点。With the rapid development of technology, a variety of navigation systems have emerged. It is difficult for a single navigation system to meet the navigation needs in the global, all-weather, and various complex environments. The integrated navigation system composed of two or more systems has become a research hotspot in various countries.
然而卫星传输到地面的只是被调制了信息的高频载波,为了获得卫星的测距码和导航电文等有用信息必须对卫星信号进行处理。北斗、GPS和GLONASS卫星所发射的信号结构和方式相互虽存在着差异,但是对其信号处理的方法是相似的。However, what the satellite transmits to the ground is only a high-frequency carrier that modulates the information. In order to obtain useful information such as the satellite's ranging code and navigation message, the satellite signal must be processed. Although the structures and methods of signals transmitted by Beidou, GPS and GLONASS satellites are different from each other, their signal processing methods are similar.
对于卫星信号的处理一般都是首先对信号结构进行分析、捕获并跟踪,最后得到导航电文。而随着国内的北斗导航系统的公开,则就需要一种针对北斗导航系统中GNSS基带信号的处理系统。另外,对于现有的卫星信号处理时,其处理速度慢,尤其在捕获信号时,不能够支持多通道数据捕获。The processing of satellite signals is generally to first analyze, capture and track the signal structure, and finally obtain the navigation message. With the disclosure of the domestic Beidou navigation system, a processing system for GNSS baseband signals in the Beidou navigation system is required. In addition, for the existing satellite signal processing, its processing speed is slow, especially when capturing signals, it cannot support multi-channel data capture.
发明内容SUMMARY OF THE INVENTION
为了克服现有技术的不足,本发明的目的之一在于提供一种GNSS基带信号的捕获方法,其能够实现多通道、快速捕获GNSS基带信号。In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide a method for acquiring GNSS baseband signals, which can realize multi-channel and fast acquisition of GNSS baseband signals.
本发明的目的之一采用以下技术方案实现:One of the objects of the present invention adopts the following technical solutions to realize:
本发明提供了一种GNSS基带信号的捕获方法,包括以下步骤:The present invention provides a method for acquiring a GNSS baseband signal, comprising the following steps:
S1:将当前未捕获卫星的频率划分为M个第一频段以及对每个第一频段分配一对应的相关器,在每个第一频段内通过相关器搜索卫星信号的方法对当前未捕获卫星进行搜索,并得出每个相关器的输出结果;S1: Divide the frequency of the currently unacquired satellites into M first frequency bands and assign a corresponding correlator to each first frequency band, and search for satellite signals through the correlator in each first frequency band. Do a search and get the output of each correlator;
S2:根据所有的输出结果判断当前未捕获卫星是否被捕获,若是,则将当前未捕获卫星标记为已捕获卫星,切换到下一颗卫星并记为当前未捕获卫星,执行S1;直到捕获到四颗卫星时,执行S3;S2: Determine whether the currently uncaptured satellite is captured according to all the output results. If so, mark the currently uncaptured satellite as the captured satellite, switch to the next satellite and record it as the currently uncaptured satellite, and execute S1; When there are four satellites, execute S3;
S3:根据上述四颗卫星的卫星导航电文获取当前所有的可观测卫星的卫星号;S3: Obtain the satellite numbers of all currently observable satellites according to the satellite navigation messages of the above four satellites;
S4:根据卫星号得到所有的未捕获卫星的频率,将每个未捕获卫星的频率进行划分为N个第二频段以及对每个第二频段分配一对应的相关器,在每个第二频段内通过相关器搜索卫星信号的方法依次对每个未捕获卫星进行搜索,并判断每个未捕获卫星是否已被捕获,若是,则将对应的未捕获卫星记为已捕获卫星;S4: Obtain the frequencies of all unacquired satellites according to the satellite numbers, divide the frequencies of each unacquired satellite into N second frequency bands, and assign a corresponding correlator to each second frequency band, in each second frequency band The method of searching satellite signals through the correlator searches each uncaptured satellite in turn, and judges whether each uncaptured satellite has been captured, if so, the corresponding uncaptured satellite is recorded as the captured satellite;
S5:当所有的卫星均标记为已捕获卫星时,GNSS基带信号完成捕获。S5: GNSS baseband signal acquisition is completed when all satellites are marked as acquired satellites.
优选地,还包括将每个已捕获卫星的频率划分为I个第三频段,在每个第三频段内通过相关器搜索卫星信号的方法依次对每个已捕获卫星进行二次捕获,直到对所有的已捕获卫星的完成二次捕获。Preferably, it also includes dividing the frequency of each captured satellite into one third frequency band, and in each third frequency band, the method of searching for satellite signals by a correlator sequentially performs secondary capture on each captured satellite until the Complete secondary acquisition of all captured satellites.
优选地,所述I=10。Preferably, the I=10.
优选地,所述相关器搜索卫星信号的方法具体包括以下步骤:Preferably, the method for the correlator to search for satellite signals specifically includes the following steps:
S11:将通过GNSS天线接收到的信号转换为中频数字信号s(t),该中频数字信号s(t)可用公式(1)表示:S11: Convert the signal received through the GNSS antenna into an intermediate frequency digital signal s(t), which can be expressed by formula (1):
其中,P是信号功率;D(t)是导航电文比特;C(t)是C/A码;τ表示卫星信号从卫星到接收机的传输过程中的时间延迟;fd是多普勒频移;t为观测时间;fIF=f标称+fd,表示为载波下变频的中频信号;f标称表示中频数字信号的标称频率;φ为初始载波相位;n(t)为白噪声,其功率谱密度为常量;fL1表示中频数字信号处于L1频段的频率;Among them, P is the signal power; D(t) is the navigation message bit; C(t) is the C/A code; τ is the time delay in the transmission process of the satellite signal from the satellite to the receiver; f d is the Doppler frequency t is the observation time; f IF = f nominal + f d , which is the intermediate frequency signal of carrier down-conversion; f nominal represents the nominal frequency of the intermediate frequency digital signal; φ is the initial carrier phase; n(t) is the white Noise, its power spectral density is constant; f L1 represents the frequency of the intermediate frequency digital signal in the L1 frequency band;
S12:将中频数字信号s(t)与本地载波信号相乘,得到同相分量I(t)和正相分量Q(t);S12: Multiply the intermediate frequency digital signal s(t) by the local carrier signal to obtain the in-phase component I(t) and the positive-phase component Q(t);
所述本地载波信号表示为其中 为捕获时估计的多普勒频移,floc表示中频数字信号的实际频率,Qloc(t)表示本地载波信号正相分量的信号,Iloc(t)表示本地载波信号同相分量的信号,φloc表示中频数字信号的初始相位;The local carrier signal is expressed as in is the estimated Doppler shift during acquisition, f loc represents the actual frequency of the IF digital signal, Q loc (t) represents the signal of the in-phase component of the local carrier signal, I loc (t) represents the signal of the in-phase component of the local carrier signal, φ loc represents the initial phase of the intermediate frequency digital signal;
将(1)和(2)混频后得到同相分量I(t)和正相分量Q(t),可用公式(3)表示:After mixing (1) and (2), the in-phase component I(t) and the positive-phase component Q(t) are obtained, which can be expressed by formula (3):
S13:通过低通滤波器对公式(3)的信号进行处理后得到公式(4):S13: After processing the signal of formula (3) through a low-pass filter, formula (4) is obtained:
其中,为多普勒频移估计残差;in, Estimate residual for Doppler shift;
S14:假设本地伪码序列可以表示为将其与公式(4)进行相关处理并积分,可得同相分量积分IP以及正相分量积分QP,其具体由公式(5)表示:S14: Assume that the local pseudocode sequence can be expressed as By correlating and integrating it with formula (4), the in-phase component integral IP and the positive-phase component integral Q P can be obtained, which are specifically expressed by formula (5):
其中T为预检测积分时间,表示卫星信号从卫星到接收机的传播时间; where T is the pre-detection integration time, Represents the propagation time of the satellite signal from the satellite to the receiver;
S15:对公式(5)作简化处理得到公式(6):S15: Simplify formula (5) to obtain formula (6):
最终得到的同相分量积分IP以及正相分量积分QP,也即是相关器的输出结果。 The in-phase component integral IP and the positive-phase component integral QP are finally obtained, that is, the output result of the correlator.
优选地,T为1ms、2ms、5ms或10ms。Preferably, T is 1 ms, 2 ms, 5 ms or 10 ms.
优选地,M=N+4。Preferably, M=N+4.
优选地,M=32,N=28。Preferably, M=32 and N=28.
为了克服现有技术的不足,本发明的目的之二在于提供一种GNSS基带信号的捕获装置,其能够实现多通道、快速捕获GNSS基带信号。In order to overcome the deficiencies of the prior art, the second purpose of the present invention is to provide a device for acquiring GNSS baseband signals, which can realize multi-channel and fast acquisition of GNSS baseband signals.
本发明的目的之二采用以下技术方案实现:The second purpose of the present invention adopts the following technical solutions to realize:
本发明还提供了一种GNSS基带信号的捕获装置,包括:The present invention also provides a device for capturing a GNSS baseband signal, comprising:
第一颗卫星捕获模块,用于将当前未捕获卫星的频率划分为M个第一频段以及对每个第一频段分配一对应的相关器,在每个第一频段内通过相关器搜索卫星信号的方法对当前未捕获卫星进行搜索,并得出每个相关器的输出结果;The first satellite acquisition module is used to divide the frequency of the currently unacquired satellite into M first frequency bands and assign a corresponding correlator to each first frequency band, and search for satellite signals through the correlator in each first frequency band The method searches for the currently unacquired satellites and obtains the output of each correlator;
捕获完成标记模块,用于根据所有的输出结果判断当前未捕获卫星是否被捕获,若是,则将当前未捕获卫星标记为已捕获卫星,切换到下一颗卫星并记为当前未捕获卫星,执行第一颗卫星捕获模块;直到捕获到四颗卫星时,执行卫星号获取模块;The capture completion marking module is used to determine whether the currently uncaptured satellite is captured according to all the output results. If so, mark the currently uncaptured satellite as the captured satellite, switch to the next satellite and record it as the currently uncaptured satellite, and execute The first satellite acquisition module; until four satellites are captured, execute the satellite number acquisition module;
卫星号获取模块,用于根据上述四颗卫星的卫星导航电文获取当前所有的可观测卫星的卫星号;The satellite number acquisition module is used to acquire the satellite numbers of all currently observable satellites according to the satellite navigation messages of the above four satellites;
其他卫星捕获模块,用于根据卫星号得到所有的未捕获卫星的频率,将每个未捕获卫星的频率进行划分为N个第二频段以及对每个第二频段分配一对应的相关器,在每个第二频段内通过相关器搜索卫星信号的方法依次对每个未捕获卫星进行搜索,并判断每个未捕获卫星是否已被捕获,若是,则将对应的未捕获卫星记为已捕获卫星;The other satellite acquisition modules are used to obtain the frequencies of all unacquired satellites according to the satellite number, divide the frequency of each unacquired satellite into N second frequency bands, and assign a corresponding correlator to each second frequency band. The method of searching satellite signals by correlators in each second frequency band searches for each unacquired satellite in turn, and judges whether each unacquired satellite has been acquired, if so, the corresponding unacquired satellite is recorded as an acquired satellite ;
捕获完成模块,用于当所有的卫星均标记为已捕获卫星时,GNSS基带信号完成捕获。The acquisition completion module is used to complete the acquisition of GNSS baseband signals when all satellites are marked as acquired satellites.
相比现有技术,本发明的有益效果在于:本发明通过使用多个相关器对同一颗卫星进行搜索,大大减少了系统对捕获卫星信号时的捕获时间,提高了系统的处理效率;另外,本发明还进行二次捕获,更进一步将卫星信号定位到更加精确的频段内,为后一步的处理提供了更加精确的数据。Compared with the prior art, the beneficial effects of the present invention are: the present invention greatly reduces the acquisition time of the system for capturing satellite signals by using multiple correlators to search for the same satellite, and improves the processing efficiency of the system; in addition, The present invention also performs secondary acquisition, further positioning the satellite signal in a more accurate frequency band, and provides more accurate data for the subsequent processing.
附图说明Description of drawings
图1为本发明提供的一实施例的方法流程图;1 is a flow chart of a method according to an embodiment provided by the present invention;
图2为本发明提供的一实施例的装置模块图。FIG. 2 is a block diagram of a device according to an embodiment of the present invention.
具体实施方式Detailed ways
下面,结合附图以及具体实施方式,对本发明做进一步描述:Below, in conjunction with accompanying drawing and specific embodiment, the present invention is further described:
如图1所示,对于一个接收机来说,其位置是根据卫星来确定的,也即是在确定接收机的位置时,首先需要接收到所有卫星的卫星信号,也即是对卫星信号进行搜索并捕获。一般来说卫星有32颗,每个卫星的卫星信号的频率都不同,在对32颗卫星的卫星信号进行捕获时,为了提高捕获的时间,本发明提供了一种GNSS基带信号的捕获方法,其能够快速捕获到所有卫星的卫星信号,该方法包括以下步骤:As shown in Figure 1, for a receiver, its position is determined according to satellites, that is, when determining the position of the receiver, the satellite signals of all satellites need to be received first, that is, the satellite signals need to be received. Search and capture. Generally speaking, there are 32 satellites, and the frequencies of the satellite signals of each satellite are different. When the satellite signals of the 32 satellites are captured, in order to improve the capture time, the present invention provides a method for capturing GNSS baseband signals. It can quickly capture satellite signals of all satellites, and the method includes the following steps:
S1:将当前未捕获卫星的频率划分为M个第一频段以及对每个第一频段分配一对应的相关器,在每个频段内通过相关器搜索卫星信号的方法对未捕获卫星进行搜索,并得出每个相关器的输出结果。S1: Divide the frequency of the currently unacquired satellites into M first frequency bands and assign a corresponding correlator to each first frequency band, and search for the unacquired satellites by using the method of searching satellite signals by the correlator in each frequency band, And get the output of each correlator.
首先,当对于卫星信号完成不知道的情况下,一般是凭借经验值来一个未捕获卫星的频率进行设定,也即是估算出一卫星的卫星信号在哪个频段内。在接收机中设置多个相关器,该相关器就是利用信号的相关特性将有用信号从干扰和噪声中提取出来的仪器。本发明中的相关器设置为32个,在对同一颗卫星进行搜索时,使用32个相关器同时进行并行处理,从而能够快速完成该卫星的搜索。由于每个未捕获卫星的频率的范围可能很大,因此,首先将其划分为多个第一频段,并对每个第一频段分配一对应的相关器,从而在每个频段内通过相关器搜索卫星信号的方法对未捕获卫星进行搜索,这样多个相关器同时运行,大大减少搜索的时间。而相关器搜索卫星信号的方法具体包括以下步骤:First of all, when the satellite signal is not known, the frequency of an unacquired satellite is generally set based on empirical values, that is, the frequency band of the satellite signal of a satellite is estimated. A plurality of correlators are set in the receiver, and the correlator is an instrument that extracts the useful signal from the interference and noise by using the correlation characteristics of the signal. The number of correlators in the present invention is set to 32. When searching for the same satellite, 32 correlators are used to perform parallel processing at the same time, so that the satellite search can be completed quickly. Since the frequency range of each unacquired satellite may be very large, it is firstly divided into a plurality of first frequency bands, and a corresponding correlator is allocated to each first frequency band, so as to pass the correlator in each frequency band The method of searching for satellite signals searches for unacquired satellites, so that multiple correlators run simultaneously, which greatly reduces the search time. The method for the correlator to search for satellite signals specifically includes the following steps:
S11:将通过GNSS天线接收到的信号转换为中频数字信号s(t),该中频数字信号s(t)可表示为:S11: Convert the signal received through the GNSS antenna into an intermediate frequency digital signal s(t), which can be expressed as:
其中,P是信号功率;D(t)是导航电文比特;C(t)是C/A码;τ表示卫星信号从卫星到接收机的传输过程中的时间延迟;fd是多普勒频移;t为观测时间;fIF=f标称+fd,表示为载波下变频的中频信号;f标称表示中频数字信号的标称频率;φ为初始载波相位;n(t)为白噪声,其功率谱密度为常量;fL1表示中频数字信号处于L1频段的频率。Among them, P is the signal power; D(t) is the navigation message bit; C(t) is the C/A code; τ is the time delay in the transmission process of the satellite signal from the satellite to the receiver; f d is the Doppler frequency t is the observation time; f IF = f nominal + f d , which is the intermediate frequency signal of carrier down-conversion; f nominal represents the nominal frequency of the intermediate frequency digital signal; φ is the initial carrier phase; n(t) is the white Noise, its power spectral density is constant; f L1 represents the frequency of the intermediate frequency digital signal in the L1 frequency band.
S12:将中频数字信号s(t)与本地载波信号相乘,得到同相分量I(t)和正相分量Q(t);S12: Multiply the intermediate frequency digital signal s(t) by the local carrier signal to obtain the in-phase component I(t) and the positive-phase component Q(t);
所述本地载波信号表示为其中 为捕获时估计的多普勒频移,floc表示中频数字信号的实际频率,Qloc(t)表示本地载波信号正相分量的信号,Iloc(t)表示本地载波信号同相分量的信号,φloc表示中频数字信号的初始相位。The local carrier signal is expressed as in is the estimated Doppler shift at the time of acquisition, f loc represents the actual frequency of the IF digital signal, Q loc (t) represents the signal of the in-phase component of the local carrier signal, I loc (t) represents the signal of the in-phase component of the local carrier signal, φ loc represents the initial phase of the intermediate frequency digital signal.
假设为多普勒频移估计残差,在捕获卫星信号时,只有使得Δf尽量接近0,才能够捕获到对应的卫星信号。Assumption In order to estimate the residual error for the Doppler frequency shift, when capturing satellite signals, only by making Δf as close to 0 as possible, the corresponding satellite signals can be captured.
优选地,本发明中对于信号的捕获中,一般设置Δf的值小于一定的阈值就认为完成对卫星的捕获。Preferably, in the acquisition of the signal in the present invention, generally, if the value of Δf is set to be less than a certain threshold, it is considered that the acquisition of the satellite is completed.
将(1)和(2)混频后得到同相分量I(t)和正相分量Q(t),也即是:After mixing (1) and (2), the in-phase component I(t) and the positive-phase component Q(t) are obtained, that is:
S13:通过低通滤波器对同相分量I(t)和正相分量Q(t)进行处理后得到公式(4):S13: Formula (4) is obtained after processing the in-phase component I(t) and the positive-phase component Q(t) through a low-pass filter:
S14:假设本地伪码序列可以表示为将其与式(4)进行相关处理并积分,可得同相分量积分IP以及正相分量积分QP,其可用公式(5)表示:S14: Assume that the local pseudocode sequence can be expressed as Correlate it with equation (4) and integrate it, the in-phase component integral I P and the positive-phase component integral Q P can be obtained, which can be expressed by equation (5):
其中T为预检测积分时间,且T<20ms;对C/A码而言一般取码片周期1ms的整数倍,表示卫星信号从卫星到接收机的传播时间。Among them, T is the pre-detection integration time, and T<20ms; for C/A code, it is generally an integer multiple of the chip period of 1ms, Represents the propagation time of the satellite signal from the satellite to the receiver.
S15:由于D(t)是导航电文比特,其比特率为50bps,可以认为在积分T时间内,D(t)不变化,故可将其提到积分号以外,将公式(5)简化为公式(6):S15: Since D(t) is a navigation message bit with a bit rate of 50 bps, it can be considered that D(t) does not change during the integration time T, so it can be referred to outside the integral sign, and formula (5) can be simplified as Formula (6):
也即是说每个相关器对卫星信号进行搜索后均输出一组同相分量积分IP以及正相分量积分QP的数据,也即是相关器的输出结果。That is to say, after each correlator searches the satellite signal, it outputs a set of data of the in-phase component integral IP and the positive-phase component integral QP , that is, the output result of the correlator.
S2:根据所有的输出结果判断当前未捕获卫星是否已被捕获,若是,则未捕获卫星将当前未捕获卫星记为已捕获卫星,切换到下一颗卫星并记为当前未捕获卫星,执行S1;直到捕获到四颗卫星时,执行S3。S2: Determine whether the currently uncaptured satellite has been captured according to all the output results. If so, the uncaptured satellite will record the currently uncaptured satellite as the captured satellite, switch to the next satellite and record it as the currently uncaptured satellite, and execute S1 ; Until four satellites are captured, perform S3.
对于每个未捕获卫星进行搜索时本发明中是采用多个相关器对不同的频段同时对同一颗未捕获卫星进行搜索,这样每个频段内的相关器都会有一个输出结果。也即是每个频段内所得到的同相分量的积分IP和正相分量的积分QP进行平方和计算得到的值进行比较,选取最大的值所对应的频段作为该未捕获卫星的卫星信号的频段,也即是当前未捕获卫星被捕获。当完成一颗卫星的捕获后,继续依据同样的方法对其他的未捕获卫星进行捕获,直到完成四颗卫星的捕获。When searching for each unacquired satellite, in the present invention, multiple correlators are used to search for the same unacquired satellite in different frequency bands at the same time, so that the correlators in each frequency band will have an output result. That is to say, the integral IP of the in-phase component obtained in each frequency band and the integral QP of the positive-phase component are compared with the values obtained by the square and calculation, and the frequency band corresponding to the maximum value is selected as the satellite signal of the uncaptured satellite. The frequency band, that is, the currently unacquired satellites are captured. When the capture of one satellite is completed, continue to capture other uncaptured satellites according to the same method until the capture of four satellites is completed.
S3:根据上述四颗卫星的卫星导航电文获取当前所有的可观测卫星的卫星号。S3: Obtain the satellite numbers of all currently observable satellites according to the satellite navigation messages of the above four satellites.
一般来说,只要有四颗卫星即可产生定位结果的特点,可以根据上述四颗卫星的卫星信号中的导航电文获取到所有可观测卫星的卫星号。又由于每个卫星都具有对应的卫星号,这样就可以根据卫星号得到对应的卫星的位置、频率等信息。这样,在对其他未捕获卫星进行搜索时,其搜索的频率范围也就确定了,这样对其他未捕获卫星的搜索时间就可以大大减少。Generally speaking, as long as there are four satellites, the positioning result can be generated, and the satellite numbers of all observable satellites can be obtained according to the navigation messages in the satellite signals of the above four satellites. Since each satellite has a corresponding satellite number, information such as the position and frequency of the corresponding satellite can be obtained according to the satellite number. In this way, when searching for other unacquired satellites, the frequency range of the search is also determined, so that the search time for other unacquired satellites can be greatly reduced.
S4:根据卫星号得到所有的未捕获卫星的频率,将每个未捕获卫星的频率进行划分为N个第二频段以及对每个第二频段分配一对应的相关器,在每个第二频段内通过相关器搜索卫星信号的方法依次对每个未捕获卫星进行搜索,并判断每个未捕获卫星是否已被捕获,若是,则将对应的未捕获卫星记为已捕获卫星。S4: Obtain the frequencies of all unacquired satellites according to the satellite numbers, divide the frequencies of each unacquired satellite into N second frequency bands, and assign a corresponding correlator to each second frequency band, in each second frequency band The method of searching satellite signals through the correlator searches each unacquired satellite in turn, and judges whether each unacquired satellite has been acquired. If so, the corresponding unacquired satellite is recorded as the acquired satellite.
由于获取到每个未捕获卫星的卫星号,就能够确定未捕获卫星的搜索频率。这里的未捕获卫星是指的除掉已经被捕获的4颗卫星以外的其他卫星。由于本发明中所采用的相关器总共有32个,其中4个相关器已经完成对上述四颗卫星的捕获,则还剩下28个相关器,这样为了保证搜索的时间,可将28个相关器也同时对一颗未捕获卫星进行搜索。也即是采用同样的相关器搜索卫星信号的方法对每一颗未捕获的卫星进行搜索。当一颗未捕获卫星被捕获时将其记为已捕获卫星,继续其他未捕获卫星;直到所有的未捕获卫星全部被捕获到,也即是所有的卫星被标志为已捕获卫星。Since the satellite number of each unacquired satellite is obtained, the search frequency of the unacquired satellite can be determined. The uncaptured satellites here refer to other satellites except the four satellites that have been captured. Since there are a total of 32 correlators used in the present invention, 4 of which have completed the acquisition of the above four satellites, there are still 28 correlators left. In this way, in order to ensure the search time, 28 correlators can be The detector also searches for an unacquired satellite at the same time. That is, the same method of searching satellite signals by the correlator is used to search for each unacquired satellite. When an uncaptured satellite is captured, it is recorded as a captured satellite, and the other uncaptured satellites continue; until all the uncaptured satellites are captured, that is, all satellites are marked as captured satellites.
S5:当所有的卫星均标记为已捕获卫星时,GNSS基带信号完成捕获。S5: GNSS baseband signal acquisition is completed when all satellites are marked as acquired satellites.
当所有的卫星被捕获时,也即是说所有卫星的卫星信号都被确定在对应的频段内,这样在下一步对卫星信号进行跟踪处理时,就能够将每个卫星的卫星信号确定在已知的频段内,从而可快速得到该接收机的位置信息。When all satellites are captured, that is to say, the satellite signals of all satellites are determined in the corresponding frequency band, so that when the satellite signals are tracked in the next step, the satellite signals of each satellite can be determined within the known In the frequency band, the location information of the receiver can be quickly obtained.
优选地,所述相关器搜索卫星信号时,由于卫星信号在达到地面前要穿过电离层、对流层等,存在很大的能量损耗,损耗程度随着接收机与卫星之间的距离变化,收到的信号能量有强有弱。而对于强信号来说,相关器只要在很短的时间内就可以捕获到对应的信号;对于弱信号来说,相关器在短时间内就很难捕获到对应的信号。因此,在通过相关器对卫星信号进行搜索时,对于预检测积分时间的设置采用轮流的方式。本发明中所选用的预检测积分时间为1ms、2ms、5ms以及10ms。也即是说比如对于强信号,可以采取的预检测积分时间为1ms、2ms、5ms;而对于弱信号来说,可采取的预检测积分时间为10ms。对于卫星信号一般包括PRN码和卫星导航电文;而在捕获信号时,是通过将本地载波信号与卫星信号进行混频,不断调整本地载波信号,使得本地载波信号与卫星信号中的PRN码接近时,就表示该卫星信号已被搜索到,而对于卫星信号的PRN码是每隔一段时间进行一次改变,也即是说在对信号进行捕获时,必须在卫星行的PRN码变换一次的时间内完成一次搜索,若不能完成,则就需要重新调整本地载波再次对卫星信号进行搜索,这样就会造成时间上的大量浪费。而对于强信号来说,只需要很短的时间就可以搜索到卫星信号,因此将搜索的积分时间设置较短就可以完成搜索,从而可节省较多时间,而对于弱信号,在很短的时间内很难搜索到对应的卫星信号,因此在搜索卫星信号时,可将积分时间逐步增大,直到搜索到卫星信号。当然该预检测积分时间不会超过卫星信号的PRN码的变化时间。本发明中,在对卫星进行捕获时,采用一种自适应的捕获方法,采用一种轮流的方式来对卫星进行捕获。首先设置预检测积分时间为1ms,若在此积分时间下无法捕获到任何的卫星时,自动将预检测积分时间设置为2ms;同样的道理,将预检测积分时间设置为5ms以及10ms,直到能够捕获到卫星即可。Preferably, when the correlator searches for satellite signals, since the satellite signals have to pass through the ionosphere, the troposphere, etc. before reaching the ground, there is a large energy loss. The received signal energy is strong or weak. For strong signals, the correlator can capture the corresponding signal in a short time; for weak signals, it is difficult for the correlator to capture the corresponding signal in a short time. Therefore, when the satellite signal is searched by the correlator, the pre-detection integration time is set in a round-robin manner. The pre-detection integration times selected in the present invention are 1 ms, 2 ms, 5 ms and 10 ms. That is to say, for example, for strong signals, the pre-detection integration time that can be taken is 1ms, 2ms, and 5ms; and for weak signals, the pre-detection integration time that can be adopted is 10ms. For satellite signals, it generally includes PRN codes and satellite navigation messages; when capturing signals, the local carrier signal is continuously adjusted by mixing the local carrier signal with the satellite signal, so that the local carrier signal is close to the PRN code in the satellite signal. , it means that the satellite signal has been searched, and the PRN code of the satellite signal is changed every once in a while, that is to say, when the signal is acquired, the PRN code of the satellite line must be converted once within the time. Once a search is completed, if it cannot be completed, the local carrier needs to be readjusted to search for the satellite signal again, which will cause a lot of waste of time. For strong signals, it only takes a short time to search for satellite signals. Therefore, the search can be completed by setting the integration time of the search to be shorter, thus saving more time. For weak signals, in a very short time It is difficult to search for the corresponding satellite signal in time, so when searching for the satellite signal, the integration time can be gradually increased until the satellite signal is searched. Of course, the pre-detection integration time will not exceed the change time of the PRN code of the satellite signal. In the present invention, when capturing satellites, an adaptive capturing method is adopted, and a rotation method is adopted to capture satellites. First, set the pre-detection integration time to 1ms. If any satellites cannot be captured under this integration time, the pre-detection integration time will be automatically set to 2ms. In the same way, set the pre-detection integration time to 5ms and 10ms until it is possible to Capture satellites.
另外,判断信号的强弱还与卫星的高度角有关,根据卫星的位置可计算得到卫星的高度角。也即是,卫星的高度角越大时,其对应的信号的强度越强;而卫星的高度角越小,其对应的信号的强度越弱。当得到卫星的位置时,也可以判断到该卫星对应的卫星信号为强信号还是弱信号,然后在设置积分时间,就能够进一步快速捕获到卫星。In addition, the strength of the judgment signal is also related to the altitude angle of the satellite, and the altitude angle of the satellite can be calculated according to the position of the satellite. That is, the larger the altitude angle of the satellite, the stronger the corresponding signal strength; and the smaller the satellite altitude angle, the weaker the corresponding signal strength. When the position of the satellite is obtained, it can also be determined whether the satellite signal corresponding to the satellite is a strong signal or a weak signal, and then the integration time can be set to further quickly capture the satellite.
进一步,还包括二次捕获,也即是说对于S1到S4已经对所有的卫星完成了捕获,那每一个卫星的卫星信号都已经被确定在一固定的频段内,比如首先搜索的4颗卫星的卫星信号会确定在对应的第一频段内,而后面28颗卫星的卫星信号会确定在对应的第二频段内。为了进一步将每个卫星的卫星行的频段更加精确,则对上述确定的频段进行再一次划分,然后通过上述捕获方法对所有的卫星在进行捕获,从而能够得到每个卫星的卫星信号的频率更加的精确。比如,一把来说,采用上述S1到S4完成对所有卫星的捕获后,卫星信号的频率的范围被确定为500Hz,然后对上述500Hz的频率在进行划分多个频段,比如将其划分10个频段,也即是每个频段的频率为50Hz;然后按照上述捕获方法对所有的卫星进捕获,这样得到最终所有卫星的卫星信号的频率精度就为50Hz,也即是使得GNSS基带信号的精度大大增加。Further, it also includes secondary acquisition, which means that all satellites have been acquired for S1 to S4, and the satellite signal of each satellite has been determined in a fixed frequency band, such as the first searched 4 satellites The satellite signals of 28 satellites will be determined in the corresponding first frequency band, and the satellite signals of the next 28 satellites will be determined in the corresponding second frequency band. In order to further make the frequency band of each satellite's satellite line more accurate, the above determined frequency band is divided again, and then all satellites are captured by the above acquisition method, so that the frequency of the satellite signal of each satellite can be obtained. of precision. For example, after using the above S1 to S4 to complete the acquisition of all satellites, the frequency range of the satellite signal is determined to be 500Hz, and then the above 500Hz frequency is divided into multiple frequency bands, for example, it is divided into 10 frequency bands The frequency band, that is, the frequency of each frequency band is 50Hz; then all satellites are captured according to the above acquisition method, so that the final frequency accuracy of the satellite signals of all satellites is 50Hz, which means that the accuracy of the GNSS baseband signal is greatly improved. Increase.
如图2所示,本发明还提供了一种GNSS基带信号的捕获装置,包括:As shown in FIG. 2 , the present invention also provides a device for capturing a GNSS baseband signal, including:
第一颗卫星捕获模块,用于将当前未捕获卫星的频率划分为M个第一频段以及对每个第一频段分配一对应的相关器,在每个第一频段内通过相关器搜索卫星信号的方法对当前未捕获卫星进行搜索并得出每个相关器的输出结果;The first satellite acquisition module is used to divide the frequency of the currently unacquired satellite into M first frequency bands and assign a corresponding correlator to each first frequency band, and search for satellite signals through the correlator in each first frequency band The method searches for the currently unacquired satellites and obtains the output of each correlator;
捕获完成标记模块,用于根据所有的输出结果判断当前未捕获卫星是否被捕获,若是,则将当前未捕获卫星标记为已捕获卫星,切换到下一颗卫星并记为当前未捕获卫星,执行第一颗卫星捕获模块;直到捕获到四颗卫星时,执行卫星号获取模块;The capture completion marking module is used to determine whether the currently uncaptured satellite is captured according to all the output results. If so, mark the currently uncaptured satellite as the captured satellite, switch to the next satellite and record it as the currently uncaptured satellite, and execute The first satellite acquisition module; until four satellites are captured, execute the satellite number acquisition module;
卫星号获取模块,用于根据上述四颗卫星的卫星导航电文获取当前所有的可观测卫星的卫星号;The satellite number acquisition module is used to acquire the satellite numbers of all currently observable satellites according to the satellite navigation messages of the above four satellites;
其他卫星捕获模块,用于根据卫星号得到所有的未捕获卫星的频率,将每个未捕获卫星的频率进行划分为N个第二频段以及对每个第二频段分配一对应的相关器,在每个第二频段内通过相关器搜索卫星信号的方法依次对每个未捕获卫星进行搜索,并判断每个未捕获卫星是否已被捕获,若是,则将对应的未捕获卫星记为已捕获卫星;The other satellite acquisition modules are used to obtain the frequencies of all unacquired satellites according to the satellite number, divide the frequency of each unacquired satellite into N second frequency bands, and assign a corresponding correlator to each second frequency band. The method of searching satellite signals by correlators in each second frequency band searches for each unacquired satellite in turn, and judges whether each unacquired satellite has been acquired, if so, the corresponding unacquired satellite is recorded as an acquired satellite ;
捕获完成模块,用于当所有的卫星均标记为已捕获卫星时,GNSS基带信号完成捕获。The acquisition completion module is used to complete the acquisition of GNSS baseband signals when all satellites are marked as acquired satellites.
对本领域的技术人员来说,可根据以上描述的技术方案以及构思,做出其它各种相应的改变以及形变,而所有的这些改变以及形变都应该属于本发明权利要求的保护范围之内。For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the present invention.
Claims (7)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201611168683.7A CN106526633B (en) | 2016-12-16 | 2016-12-16 | A kind of GNSS baseband signal acquisition method and device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201611168683.7A CN106526633B (en) | 2016-12-16 | 2016-12-16 | A kind of GNSS baseband signal acquisition method and device |
Publications (2)
Publication Number | Publication Date |
---|---|
CN106526633A CN106526633A (en) | 2017-03-22 |
CN106526633B true CN106526633B (en) | 2019-04-26 |
Family
ID=58339904
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201611168683.7A Active CN106526633B (en) | 2016-12-16 | 2016-12-16 | A kind of GNSS baseband signal acquisition method and device |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN106526633B (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107907893B (en) * | 2017-11-16 | 2021-07-02 | 北京卫星信息工程研究所 | Sectional configurable military code direct capturing method based on parallel frequency and parallel code search |
CN107884789A (en) * | 2017-12-19 | 2018-04-06 | 深圳先进技术研究院 | A kind of gps satellite parallel acquisition method, equipment and storage device |
CN111007550B (en) * | 2019-12-16 | 2020-07-28 | 中国人民解放军32021部队 | Satellite navigation ideal signal correlation power estimation method |
CN112327334B (en) * | 2020-09-29 | 2024-02-09 | 航天恒星科技有限公司 | A low-orbit satellite-assisted GNSS long code signal acquisition method and device |
CN113050129B (en) * | 2021-03-17 | 2023-08-01 | 广州南方卫星导航仪器有限公司 | Satellite signal capturing method and device |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1859345A (en) * | 2005-04-30 | 2006-11-08 | 中国科学院上海微系统与信息技术研究所 | Quick frequency catching method based on OFDM system |
US8270457B2 (en) * | 2007-06-27 | 2012-09-18 | Qualcomm Atheros, Inc. | High sensitivity GPS receiver |
CN101308204B (en) * | 2008-05-30 | 2011-05-04 | 北京航空航天大学 | Multisystem satellite navigation correlator |
CN101839970B (en) * | 2009-03-18 | 2012-02-29 | 杭州中科微电子有限公司 | Method for quickly acquiring GPS signal and system thereof |
CN102901973B (en) * | 2012-09-25 | 2014-08-06 | 郑州威科姆科技股份有限公司 | Beidou satellite-based method for fast capturing signals in real time |
-
2016
- 2016-12-16 CN CN201611168683.7A patent/CN106526633B/en active Active
Also Published As
Publication number | Publication date |
---|---|
CN106526633A (en) | 2017-03-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN106526633B (en) | A kind of GNSS baseband signal acquisition method and device | |
CN101903794B (en) | Suppression of multipath effects for received SPS signal | |
CN103728634B (en) | Double-antenna A-GNSS receiving machine system | |
CN104536016B (en) | A new GNSS system signal acquisition device and method | |
CN1128064A (en) | Pseudorandom noise ranging receiver which compensates for multipath distortion by making use of multiple correlator time delay spacing | |
CN104678416B (en) | GNSS-R-based normalized detection method for sea-surface target areas | |
CN102183771A (en) | Realizing method of multi-mode GNSS (Global Navigation Satellite System) software receiver based on multi-core processor | |
CN101520505B (en) | Adaptive coherent accumulation joint acquisition method under GNSS weak signal | |
CN104345322B (en) | A kind of satellite navigation signals quick capturing method and device | |
CN102037658A (en) | Multiple correlation processing in code space search | |
CN1391110A (en) | Radio signal receiver with device for calibrating multi-way signal effect and method for starting receiver | |
CN103543456A (en) | Large frequency offset GNSS signal capture method based on segmentation relative combination FFT operation | |
CN104765050A (en) | A New Beidou Signal Second Acquisition Algorithm | |
CN101881818B (en) | Device and method for rapidly detecting weak signal | |
CN105474042B (en) | Method and apparatus for the GNSS satellite signal in detection signal degradation environment | |
CN102023299A (en) | Multipath inhibiting method of correlator | |
CN107820212B (en) | Positioning method and positioning terminal realized based on mobile multimedia broadcasting system | |
CN103760578A (en) | Unambiguous GNSS satellite navigation signal tracking method | |
CN102375149B (en) | Multi-correlation branch mixed spacing delay lock loop and application method thereof | |
CN105204044B (en) | Cross correlation process device based on the straight inverted signal of the direct sampled navigation of radio frequency | |
CN115291258B (en) | GNSS baseband capturing method | |
Pany et al. | On the state-of-the-art of real-time GNSS signal acquisition—A comparison of time and frequency domain methods | |
IT202300011043A1 (en) | Procedure for detecting satellite signal replicas in a GNSS receiver, corresponding receiving apparatus and computer product | |
WO2013140910A1 (en) | Signal search method, signal search program, signal search device, global navigation satellite system (gnss) signal receiver, and information terminal | |
US20080069189A1 (en) | Low Gate Count Sequential Multitap Correlator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
C06 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant | ||
PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: GNSS baseband signal capture method and device Effective date of registration: 20191227 Granted publication date: 20190426 Pledgee: China Co. truction Bank Corp Guangzhou Liwan branch Pledgor: GUANGZHOU SOUTH SATELLITE NAVIGATION INSTRUMENT Co.,Ltd. Registration number: Y2019440000324 |
|
PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
PC01 | Cancellation of the registration of the contract for pledge of patent right |
Granted publication date: 20190426 Pledgee: China Co. truction Bank Corp Guangzhou Liwan branch Pledgor: GUANGZHOU SOUTH SATELLITE NAVIGATION INSTRUMENT Co.,Ltd. Registration number: Y2019440000324 |
|
PC01 | Cancellation of the registration of the contract for pledge of patent right | ||
PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: GNSS baseband signal capture method and device Granted publication date: 20190426 Pledgee: China Co. truction Bank Corp Guangzhou Liwan branch Pledgor: GUANGZHOU SOUTH SATELLITE NAVIGATION INSTRUMENT Co.,Ltd. Registration number: Y2025980019192 |
|
PE01 | Entry into force of the registration of the contract for pledge of patent right |