Specific embodiment
This application describes multiple embodiments, but the description is exemplary, rather than restrictive, and for this
It is readily apparent that can have more in the range of embodiments described herein includes for the those of ordinary skill in field
More embodiments and implementation.Although many possible feature combinations are shown in the attached drawings, and in a specific embodiment
It is discussed, but many other combinations of disclosed feature are also possible.Unless the feelings specially limited
Other than condition, any feature or element of any embodiment can be with any other features or element knot in any other embodiment
It closes and uses, or any other feature or the element in any other embodiment can be substituted.
The application includes and contemplates the combination with feature known to persons of ordinary skill in the art and element.The application is
It can also combine with any general characteristics or element through disclosed embodiment, feature and element, be defined by the claims with being formed
Unique scheme of the invention.Any feature or element of any embodiment can also be with features or member from other scheme of the invention
Part combination, to form the unique scheme of the invention that another is defined by the claims.It will thus be appreciated that showing in this application
Out and/or any feature of discussion can be realized individually or in any suitable combination.Therefore, in addition to according to appended right
It is required that and its other than the limitation done of equivalent replacement, embodiment is not limited.Furthermore, it is possible in the guarantor of appended claims
It carry out various modifications and changes in shield range.
In addition, method and/or process may be rendered as spy by specification when describing representative embodiment
Fixed step sequence.However, in the degree of this method or process independent of the particular order of step described herein, this method
Or process should not necessarily be limited by the step of particular order.As one of ordinary skill in the art will appreciate, other steps is suitable
Sequence is also possible.Therefore, the particular order of step described in specification is not necessarily to be construed as limitations on claims.This
Outside, the claim for this method and/or process should not necessarily be limited by the step of executing them in the order written, art technology
Personnel are it can be readily appreciated that these can sequentially change, and still remain in the spirit and scope of the embodiment of the present application.
Fig. 1 show the module diagram of GNSS receiver.As shown in Figure 1, GNSS receiver can be received by antenna
Signal, after the signal received is by radio-frequency front-end and digital front-end processing, into base band signal process process.Wherein, signal
Capture be base band signal process first step, executed by capture engine, be whether there is for detecting the signal received
Signal from some GNSS satellite;Capturing signal, there are also signal trace, position (bit) synchronization and PVT (Position later
Velocity and Time, Position, Velocity and Time) calculating process.
The embodiment of the present application provides the method and device for inhibiting cross-correlation in a kind of capture of GNSS signal, can be applied to
In the capture engine of GNSS receiver, for example, can be used for capturing the weak satellite-signal coexisted with strong satellite-signal.
Fig. 2 is the flow chart for inhibiting the method for cross-correlation in GNSS signal provided by the embodiments of the present application capture.Such as Fig. 2 institute
Show, method provided in this embodiment includes following processing:
S101, by carrying out relevant calculation between the ranging code being locally generated and the signal received, obtain two-dimentional product
Divide result;
S102, the SNR and peak value ratio for calculating two-dimensional integration result;
S103, according to the comparison result of SNR and SNR threshold value, peak value than the comparison result with peak value than threshold value, it is determined whether
Capture satellite-signal.
Wherein, two-dimensional integration result may include following two dimension: code phase, Doppler frequency domain.Code phase dimension can
To be indicated by phase index, Doppler frequency domain dimension can be indexed by Doppler bin and be indicated, each frequency point instruction Doppler's frequency
The basic unit of domain search range, the i.e. corresponding doppler searching unit of a frequency point.
In one exemplary embodiment, the SNR of two-dimensional integration result can be defined as peak-peak divided by noise, peak value ratio
Peak-peak can be defined as divided by maximum side peak value.Wherein, peak-peak can be the maximum value in two-dimensional integration result, most
Big side peak value can be the maximum value in two-dimensional integration result in addition to the neighbours of peak-peak and peak-peak.Peak-peak
Neighbours may include neighbours, peak-peak neighbours on Doppler frequency domain dimension of the peak-peak in code phase dimension.
In one exemplary embodiment, S103 may include: when the SNR of two-dimensional integration result is greater than SNR threshold value, and two dimension
The peak value ratio of integral result is greater than peak value and compares threshold value, it is determined that captures satellite-signal;Be less than as the SNR of two-dimensional integration result or
Equal to SNR threshold value, alternatively, the peak value ratio of two-dimensional integration result, which is less than or equal to peak value, compares threshold value, it is determined that do not capture satellite
Signal.
In the present embodiment, judge whether to capture satellite letter by using dual threshold (i.e. SNR threshold value and peak value are than threshold value)
Number, signal detection false-alarm caused by cross-correlation in GNSS signal capture can be mitigated.For example, ought be in the presence of strong signals
When detecting weak signal, the peak-peak found in two-dimensional integration result may be the peak value as caused by the cross-correlation of strong signal,
Rather than actual weak signal.If the SNR being calculated at this time is greater than SNR threshold value, the only Rule of judgment the case where
Under, the decision of acquisition success will become false-alarm, after scheme provided in this embodiment, by additionally considering peak value ratio as the
After two Rule of judgment, the false-alarm as caused by cross-correlation can be mitigated.Wherein, when peak-peak is the void as caused by cross-correlation
When alert, maximum side peak value can keep relatively large value, and in this case, peak value is smaller, no more than peak value than threshold value,
I.e. peak value ratio is less than peak value and compares threshold value.In this way, carry out capture judgement using double detection threshold values, it can mitigate and be drawn by cross-correlation
The false-alarm risen.
In one exemplary embodiment, the setting of SNR threshold value can depend on which kind of non-coherent integration used.For example, can
To use quadratic sum method, i.e., the quadratic sum with phase and quadrature component is taken after coherent integration calculating.Noise is normalized non-
Coherent integration is the sum of accumulative to be expressed asWherein, IiAnd QiIt is coherent integration results respectively
With phase and quadrature component.When signal is not present, V follows center chi square distribution;When there are signal, V is followed with non-central
Property parameter KA2Non-central chi square distribution, wherein K indicate non-coherent integration times, A is signal strength.If the wrong report allowed
Probability is P, then theoretically SNR threshold can be arranged with probability 1-P by using the inverse cumulative density function of center chi square distribution
Value.In addition, peak value can be arranged and adjust according to practical application realization than threshold value.The application does not limit this.
In one exemplary embodiment, in order to improve there are the signal detection rating in the case of cross-correlation, two kinds can be used
The two-dimensional integration result of format.Illustratively, S101 may include: when search signal strength is greater than or equal to defending for first threshold
Star signal obtains the first format by carrying out relevant calculation between the ranging code being locally generated and the signal received
Two-dimensional integration result;When satellite-signal of the search signal strength less than first threshold, by the ranging code being locally generated and connect
Relevant calculation is carried out between the signal received, obtains the two-dimensional integration result of second of format.Wherein, first threshold can be used for
Tell the men from the boys signal.For example, first threshold can be -136dBm.However, the application does not limit this.
As shown in figure 3, may include: a peak-peak, the peak-peak in the two-dimensional integration result of the first format
The neighbours and maximum side peak value of neighbours, the peak-peak in code phase dimension in Doppler frequency domain dimension;The maximum
Side peak value is the maximum value in two-dimensional integration result in addition to the neighbours of the peak-peak and the peak-peak.In Fig. 3, three
Angular mark indicates that the peak-peak in two-dimensional integration result, hexagon mark indicate the maximum side peak in two-dimensional integration result
Value, circular indicia indicate neighbours of the peak-peak in Doppler frequency domain dimension and the neighbours in code phase dimension, for example, +/- 1 surveys
Away from chip.Compared to second of format two-dimensional integration as a result, the memory space that the two-dimensional integration result of the first format occupies
It is less.
In one exemplary embodiment, after obtaining the two-dimensional integration result of the first format, S102 may include: from
Search peak-peak and maximum side peak value in a kind of two-dimensional integration result of format;Using the peak-peak divided by noise, obtain
The SNR of the two-dimensional integration result of the first format;Using the peak-peak divided by maximum side peak value, the two of the first format are obtained
Tie up the peak value ratio of integral result.
Wherein, noise can be determined according to the following formula: noise=[the sum of all two-dimensional integration results-(peak-peak+
Peak-peak neighbours)]/(two-dimensional integration result number-1-peak-peak neighbours number).However, the application does not limit this.
In the present example embodiment, when the SNR of the two-dimensional integration result of the first format is greater than SNR threshold value, and first
The peak value ratio of the two-dimensional integration result of kind format is greater than peak value than threshold value, then can determine that capturing signal strength is greater than or equal to
The satellite-signal of first threshold;When the SNR is less than or equal to SNR threshold value, alternatively, the peak value ratio, which is less than or equal to peak value, compares threshold
Value, it is determined that do not capture the satellite-signal that signal strength is greater than or equal to first threshold.In the present embodiment, in the strong letter of search
Number when, since cross-correlation will not have an impact the decision of the successful capture of strong satellite-signal, can configure using first
The two-dimensional integration result of kind format.
As shown in figure 4, may include: in each doppler searching unit in the two-dimensional integration result of second of format
Neighbours, each Doppler of the peak-peak in Doppler frequency domain dimension in peak-peak, each doppler searching unit searches
Neighbours of the peak-peak in code phase dimension in cable elements, the peak-peak in each doppler searching unit maximum side
Peak value;The maximum side peak value of peak-peak in any one doppler searching unit can be in the doppler searching unit except most
Maximum value except the neighbours of big peak value and the peak-peak.In Fig. 4, triangle mark is indicated in two-dimensional integration result
Peak-peak, hexagon mark indicate that the maximum side peak value in two-dimensional integration result, circular indicia indicate peak-peak how general
The neighbours of frequency domain dimension and the neighbours in code phase dimension are strangled, for example, +/- 1 ranging chip.
In one exemplary embodiment, after obtaining the two-dimensional integration result of second of format, S102 may include: from
The peak-peak and maximum side peak value in each doppler searching unit are searched in the two-dimensional integration result of two kinds of formats;For every
A doppler searching unit obtains the Doppler using the peak-peak in the doppler searching unit divided by maximum side peak value
The peak value ratio of search unit;Determine peak-peak ratio of the peak value of multiple doppler searching units than in;Utilize the peak-peak
Than place doppler searching unit peak-peak divided by noise, obtain SNR.
In the present example embodiment, when the above-mentioned SNR being calculated be greater than SNR threshold value, and peak-peak ratio be greater than peak
Value compares threshold value, it is determined that captures the satellite-signal that signal strength is less than first threshold;When the SNR be less than or equal to SNR threshold value,
Alternatively, peak-peak ratio, which is less than or equal to peak value, compares threshold value, it is determined that do not capture the satellite that signal strength is less than first threshold
Signal.In the present embodiment, when searching for weak signal, the two-dimensional integration according to the first format is as a result, due to cross-correlation meeting
Cause weak signal that can not be captured, by using second of format two-dimensional integration as a result, it is possible to increase weak signal verification and measurement ratio.
Fig. 5 is that a kind of of the embodiment of the present application applies exemplary diagram.As shown in figure 5, in the present example embodiment, can incite somebody to action
Acquisition procedure is divided into following three phases: capture strong signal (stage 0), the medium weak signal (stage 1) of capture, capture weak signal
(stage 2).For example, strong signal can be greater than or equal to the signal of -136dBm for signal strength;Medium weak signal can be signal
Intensity is less than -136dBm and is greater than or equal to the signal of -142dBm;Weak signal can be less than the letter of -142dBm for signal strength
Number.However, the application does not limit this.
In the present example embodiment, in stage 0 (capture strong signal stage), two using the first format can be configured
Tie up integral result.Wherein, peak-peak and maximum side peak value are searched in the two-dimensional integration result of the first format, utilize maximum
Peak value obtains SNR divided by noise;Using peak-peak divided by maximum side peak value, peak value ratio is obtained;When SNR be greater than SNR threshold value,
And peak value ratio is greater than peak value than threshold value, then judgement is successfully acquired strong signal;Remaining situation is adjudicated captures satellite not successfully
Signal.
In the present example embodiment, in stage 1 (capturing the medium weak signal stage) and (the capture weak signal rank of stage 2
Section), the two-dimensional integration result using second of format can be configured.For example, in the stage 1, in each doppler searching unit
In find corresponding peak-peak and maximum side peak value, (peak value ratio is equal to the peak value ratio for calculating in each doppler searching unit
Peak-peak is divided by maximum side peak value);Peak-peak ratio is found from the peak value ratio being calculated;Judge whether to meet following two
A condition: peak-peak is greater than SNR threshold than the SNR of the doppler searching unit at place than threshold value, peak-peak than being greater than peak value
Value (SNR is equal to peak-peak of the peak-peak than place doppler searching unit divided by noise);It is above-mentioned two when meeting simultaneously
Condition then adjudicates and successfully captures medium weak signal, and the peak value of medium weak signal is that peak-peak is searched than the Doppler at place
Peak-peak in cable elements.When not meeting above-mentioned two condition simultaneously, then it can adjudicate and not capture medium weak signal.
Similarly, in the stage 2, can the two-dimensional integration result based on second of format to determine whether capturing weak signal.Stage 2
Processing is similar with the stage 1, therefore repeats no more in this.
Fig. 6 is the schematic diagram for inhibiting the device of cross-correlation in GNSS signal provided by the embodiments of the present application capture.Such as Fig. 6 institute
Show, device provided in this embodiment, comprising: the first computing module 601, the second computing module 602 and capture determining module
603;Wherein, the first computing module 601, suitable for related by being carried out between the ranging code being locally generated and the signal received
It calculates, obtains two-dimensional integration result;Second computing module 602, suitable for calculating the SNR and peak value ratio of two-dimensional integration result;Capture
Determining module 603, the comparison result of the SNR and SNR threshold value that are calculated suitable for basis, the peak value ratio and peak value ratio being calculated
The comparison result of threshold value, it is determined whether capture satellite-signal.
In one exemplary embodiment, capture determining module 603 may be adapted to what basis in the following manner was calculated
The comparison result of SNR and SNR threshold value, the peak value being calculated are than the comparison result with peak value than threshold value, it is determined whether capture
Satellite-signal: when the SNR being calculated be greater than SNR threshold value, and the peak value ratio being calculated be greater than peak value compare threshold value, it is determined that catch
Receive satellite-signal;When the SNR being calculated is less than or equal to SNR threshold value, alternatively, the peak value ratio being calculated is less than or equal to
Peak value compares threshold value, it is determined that does not capture satellite-signal.
In one exemplary embodiment, the first computing module 601 may be adapted in the following manner by being locally generated
Ranging code and the signal that receives between carry out relevant calculation, obtain two-dimensional integration result: when search signal strength is greater than or
Equal to the satellite-signal of first threshold, by carrying out relevant calculation between the ranging code being locally generated and the signal received,
Obtain the two-dimensional integration result of the first format;When search signal strength is less than the satellite-signal of first threshold, by local
Relevant calculation is carried out between the ranging code of generation and the signal received, obtains the two-dimensional integration result of second of format.
Related description about device provided in this embodiment is referred to the description of above method embodiment, therefore not in this
It repeats again.
Fig. 7 is the schematic diagram of receiver provided by the embodiments of the present application.As shown in fig. 7, receiver provided in this embodiment
700, comprising: receiving antenna 703, memory 701 and processor 702;Receiving antenna 703 connects processor 702, defends suitable for receiving
Star signal;Memory 701 is suitable for storage computer program, which realizes above-mentioned implementation when being executed by processor 702
The step of method that example provides, such as
Step shown in Fig. 2.
It will be understood by those skilled in the art that structure shown in Fig. 7, only part relevant to application scheme is tied
The schematic diagram of structure, does not constitute the restriction for the receiver 700 being applied thereon to application scheme, and receiver 700 can wrap
It includes than more or fewer components as shown in the figure, perhaps combines certain components or with different component layouts.
Wherein, processor 702 can include but is not limited to microprocessor (MCU, Microcontroller Unit) or can
The processing unit of programmed logic device (FPGA, Field Programmable Gate Array) etc..Memory 701 can be used for
The software program and module for storing application software, such as the corresponding program instruction of method or module in the present embodiment, processor
702 software programs and module being stored in memory 701 by operation, at various function application and data
Reason, for example realize method provided in this embodiment.Memory 701 may include high speed random access memory, may also include non-volatile
Memory, such as one or more magnetic storage device, flash memory or other non-volatile solid state memories.In some examples
In, memory 701 may include the memory remotely located relative to processor 702, these remote memories can pass through network
It is connected to receiver 700.The example of above-mentioned network includes but is not limited to internet, intranet, local area network, mobile radio communication
And combinations thereof.
The description of above method embodiment is referred to about the related implementing procedure of receiver provided in this embodiment, therefore
It is repeated no more in this.
In addition, the embodiment of the present application also provides a kind of computer readable storage medium, it is stored with computer program, the calculating
Machine program is performed the step of realizing method provided by the above embodiment, for example, step shown in Fig. 2.
It will appreciated by the skilled person that whole or certain steps, system, dress in method disclosed hereinabove
Functional module/unit in setting may be implemented as software, firmware, hardware and its combination appropriate.In hardware embodiment,
Division between the functional module/unit referred in the above description not necessarily corresponds to the division of physical assemblies;For example, one
Physical assemblies can have multiple functions or a function or step and can be executed by several physical assemblies cooperations.Certain groups
Part or all components may be implemented as by processor, such as the software that digital signal processor or microprocessor execute, or by
It is embodied as hardware, or is implemented as integrated circuit, such as specific integrated circuit.Such software can be distributed in computer-readable
On medium, computer-readable medium may include computer storage medium (or non-transitory medium) and communication media (or temporarily
Property medium).As known to a person of ordinary skill in the art, term computer storage medium is included in for storing information (such as
Computer readable instructions, data structure, program module or other data) any method or technique in the volatibility implemented and non-
Volatibility, removable and nonremovable medium.Computer storage medium include but is not limited to RAM, ROM, EEPROM, flash memory or its
His memory technology, CD-ROM, digital versatile disc (DVD) or other optical disc storages, magnetic holder, tape, disk storage or other
Magnetic memory apparatus or any other medium that can be used for storing desired information and can be accessed by a computer.This
Outside, known to a person of ordinary skill in the art to be, communication media generally comprises computer readable instructions, data structure, program mould
Other data in the modulated data signal of block or such as carrier wave or other transmission mechanisms etc, and may include any information
Delivery media.