CN103163535A - P code direct capturing method based on digital signal processor (DSP) - Google Patents
P code direct capturing method based on digital signal processor (DSP) Download PDFInfo
- Publication number
- CN103163535A CN103163535A CN2013100822181A CN201310082218A CN103163535A CN 103163535 A CN103163535 A CN 103163535A CN 2013100822181 A CN2013100822181 A CN 2013100822181A CN 201310082218 A CN201310082218 A CN 201310082218A CN 103163535 A CN103163535 A CN 103163535A
- Authority
- CN
- China
- Prior art keywords
- code
- dsp
- sequence
- local
- satellite
- 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.)
- Pending
Links
Images
Landscapes
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
The invention discloses a P code direct capturing method based on a digital signal processor (DSP) and solves the problem that power consumption is overhigh when a P code is parallelly captured by using a field programmable gate array (FPGA). According to the method, the P code is directly captured through coordination of two DSPs so as to ensure that navigation data are positioned and resolved, one of the two DSPs is used for processing analog/digital (A/D) input signals, and the other DSP is used for processing locally generated P code. Compared with the conventional method in which only the FPGA is used, the method has the advantages that power consumption of a system is reduced, and convenience is brought to design of the portable miniature system. Simultaneously, 3dB of loss generated by correlated peaks is eliminated through composition and average operations, the composition and average operations aim to reduce sampling points and operation quantity, but a small amount of noise can be correspondingly introduced. By the method, the noise introduction quantity is reduced by reducing the composition frequency and the number of average points, so that the capture probability is increased.
Description
Technical field
The invention belongs to the Satellite Navigation Technique field, particularly in satellite navigation system based on the P code Fast Direct Acquisition Methods of digital signal processor (DSP, Digital Signal Processor).
Background technology
Triones navigation system and GPS (GPS, Global Positioning System) are the same, can provide standard setting service and precision positioning service for the user, and two kinds of services are respectively take C/A code and P code as the basis.In triones navigation system, speed identical (10.23M Chip/s) both, but the essence code cycle is very long, have very strong anti-interference, anti-deception ability.Usually to catch be locking and acquiring navigation message by the C/A code to the P code, the information capture P code that then utilizes the switching word in navigation message to provide.But, because the code length of C/A code is very short, very easily is interfered and cheats, and need to could begin the P code is caught after obtaining the switching word of a certain frame, its acquisition speed is slow (0.6S appears being spaced apart in the switching word) also.And the P code cycle reaches a week, have and compare strong many interference free performances with the C/A code, under complicated geography or electromagnetic environment, P code Direct Acquisition for triones navigation system can further improve the location time service precision and utilize navigational system to carry out electronic warfare, the ability of NAVIGATION WARFARE has very high practical value.
In recent years, research to P code Direct Acquisition technology roughly can be divided into two classes, and a class is to use the large-scale parallel correlator to be the time domain disposal route on basis, take STS Y-EXPRESS ASIC as representative, the another kind of various frequency domain techniques that are based on the FFT treatment technology are take XFAST as representative.
The core concept of catching based on the P code of parallel correlator is to utilize parallel correlator simultaneously a plurality of time frequency unit to be searched for, before search, during at first according to the gps system of present receiving machine, positional information and satellite position determine search time and frequency range, then disturbed condition determined according to AGC and fixed acquisition probability, false-alarm probability etc. are determined integration period, have also just determined time-frequency scope and searching times that each parallel search can cover.Satellite-signal and local code after afterwards receiver front end being processed carry out relevant treatment in correlator.To transfer tracking module to greater than the corresponding spreading code phase deviation of the peak value of thresholding and Doppler frequency deviation.Take STS Y-EXPRESS receiver as example, it can search for 32704 time frequency unit (511 time quantums and 64 frequency cells) simultaneously, and search precision is 1/2 chip, and the cover time scope can reach ± 12.5 μ s, and frequency coverage can reach ± 20kHz.In order to improve antijamming capability, Y-EXPRESS ASIC can peel off the GPS text makes the coherent integration time surpass 20ms.And utilize FFT coherent integration period can be expanded to 200ms.at document " Wolfert R, Chen S, Kohli S, Direct P (Y)-code acquisition under a jamming environment, Proceedings of IEEE PLANS, April1998, 228-235 " in Y-EXPRESS performance evaluation and emulation testing shown use single Y-EXPRESS chip to carry out the P code when directly catching, when J/S surpasses 50dB, uncertainty is ± 1ms, frequency search range is ± during 315kHz, capture time is 600s, and most of military receiver P code capture time require in uncertainty be ± during 1s less than or equal to 60s, its capture time can not meet the demands far away, thereby only have the parallel correlator of increasing quantity to increase degree of parallelism and improve capture rate.But this will be at double increase power consumption and hardware resource expense.
The straight method for catching of P code of a kind of delay multiplication that the people such as Lin M David propose.At first this method is divided into the M section according to frequency search precision and frequency uncertainty with satellite-signal and local code signal, each section has N point long data, then satellite-signal section corresponding to local code carries out related calculation, obtain M point data, again these data are done the FFT computing, then compare with thresholding, if surpass threshold value, acquisition success, repeat above processing again otherwise move a sampled point.This method is a kind of serial search mode on code phase search, realizes the frequency parallel search by the result after relevant is FFT, and search speed is slow.
Expansion copies the advantage that overlapping acquisition search technology (XFAST) has not only been utilized spectrum correlation, has also utilized the low their cross correlation of P code.In order to improve the search rate of indeterminacy section, it is N that the XFAST method is divided into M the every segment length in sub-range with local indeterminacy section, then every section corresponding stack, be configured to an auxiliary sequence, last relevant to list entries, thereby make and catch speed and accelerated M doubly, but after a large amount of stack, its signal to noise ratio (S/N ratio) reduces extremely seriously, affects on the contrary acquisition performance.
Directly the method for average is satellite-signal and the every N point of local code to be got once average, obtains a new sampled point.Respectively they are done the FFT computing again, the method and XFAST difference just be that every N point is asked and once on average obtain a new sampled point rather than segmentation stack, and its code phase precision is N, and then searches for from this N code phase.The method can directly reduce operand N doubly, but shortcoming is when code phase offset is N/2, and its relevant peaks produces the 3dB loss.
Because there is major defect in above P code serial acquisition method on acquisition speed or performance, most of receivers all adopt the P code parallel capturing method based on FPGA, but because the power consumption of FPGA is too high, for the midget receiver of the handheld receiver of similar individual soldier, high power consumption device can reduce the standby ability of receiver.
Summary of the invention
The objective of the invention is the too high problem of power consumption in order to solve the above-mentioned existing FPGA of utilization and to realize P code parallel capturing method, proposed a kind of P code Direct Acquisition Methods based on DSP.
To achieve these goals, technical scheme of the present invention is: a kind of P code Fast Direct Acquisition Methods based on DSP specifically comprises the steps:
S1. the satellite-signal through after the A/D conversion that receives inputs in first DSP, and then carry out I/Q and separate, down coversion, down-sampling, the sequence a that sampling is obtained deposits in the internal RAM of first DSP;
S2. the temporal information that provides according to local clock in second DSP determines that the current time can catch the number of satellite and defend asterisk and the corresponding P code sequence range of uncertainty that can catch satellite centre halfback asterisk minimum, becomes local P code b, deposits it in external RAM;
S3. the sequence a that sampling is obtained takes out from the internal RAM of first DSP, and local P code b takes out from the external RAM of second DSP, and it is superposeed respectively and average operation, obtains A, B, and the detailed process of stack and average operation is as follows:
S31. the sequence a that sampling is obtained and local P code b carry out segmentation by one section of N point, wherein, sequence a is divided into the M section, sequence b is divided into the K section, sequence a skew N point is obtained a ', sequence b skew N/2, N point is obtained respectively b ', b ' ', a and a ' stack are obtained sequence c, b, b ', b ', b ' ' stack are on average obtained sequence d again;
S32. every section of the two paths of signals sequence c after superposeing and sequence d are averaging and form a new sampled point, obtain A/D input signal A and K local code L that puts of M point after average;
S33. the local code L that with length is K is divided into the J section according to every section M point, afterwards all section stacks is formed local code B;
S4. in first DSP, the A that step S32 is obtained carries out zero padding, then get conjugation, do the FFT computing, in second DSP, the B that step S33 is obtained is carried out zero padding, then do the FFT computing, operation result in second DSP is inputed to first DSP, be IFFT after then the operation result in itself and first DSP being multiplied each other;
S5. IFFT result and threshold value are compared, if surpass threshold value, to surpassing N/2 the further precise search of code phase of thresholding, afterwards, this star is changed over to tracking module and judges whether to complete the search that all can catch satellite, if can catch satellite search in addition, begin to catch next satellite, if all search is completed, catch and complete, second DSP changes the navigation data positioning calculation over to;
If S6. do not surpass threshold value, according to regenerating local P code, repeating step S3-S5 after chip of range of uncertainty skew.
beneficial effect of the present invention: the present invention is by adopting two DSP to realize the quick Direct Acquisition of P code, a DSP is responsible for the processing of A/D input signal, an other DSP is responsible for the processing of the local P of generation code, compare with FPGA, reduced system power dissipation, be conducive to the realization of the portable small-sizedization design of system, can eliminate the loss of the 3dB of relevant peaks generation at acquisition phase by step S31 in addition, its principle is by input signal a and local code b are done the skew overlap-add operation, the blanking code skew is to the correlation peak loss, by step S32, S33 can find out, because thereby the purpose of average and overlap-add operation is all to reduce sampled point to reduce operand, but because the impact of P code cross correlation can be introduced a small amount of noise, therefore the method is that to introduce noise be thereby that cost reduces and catches operand and reduce capture time, this method is again by with stacking fold with on average count to reduce and then reduce and introduce noise, thereby raising acquisition probability.
Description of drawings
Fig. 1 is the signal subsection front and back N/2 point stack schematic diagram of the inventive method.
Fig. 2 is the local code J section stack schematic diagram of the inventive method.
Fig. 3 is the treatment scheme schematic diagram of catching of P code of the present invention.
Fig. 4 is navigational system location receiver internal system structure and the annexation schematic diagram that utilizes the inventive method.
Embodiment
The invention will be further elaborated below in conjunction with accompanying drawing and specific embodiment.
Because needing signal to be processed, catching of P code have two, A/D input signal and the local P code that generates.Because DSP is the serial processing device, if only use a monokaryon DSP, must first process one of them signal and process again another, such structure can affect the real-time that signal is processed, method of the present invention designs with regard to being based on above consideration, adopts two DSP to unite and completes catching of P code.Two DSP here can be two monokaryon High Performance DSP, can be also multi-core DSPs.
The present embodiment adopts a multi-core DSP TI C6000 series high-performance signal processor, and more than its monokaryon dominant frequency can reach 1GHz, the huge operand of directly catching for processing P code provided strong guarantee.In the present embodiment, DSP mainly is responsible for following functions: I/Q separation, down coversion, down-sampling, data storage, local code generation, the processing of overlapping average FFT, frequency deviation search, Threshold detection.
The treatment scheme of catching of P code is as shown in Figure 3, and is specific as follows:
S1. the satellite-signal through after the A/D conversion that receives inputs in DSP core 1, and then carry out I/Q and separate, down coversion, down-sampling, the sequence a that sampling is obtained deposits in the internal RAM of core 1;
S2. the temporal information that provides according to local clock in DSP core 2, determine that the current time can catch the number of satellite and defend asterisk and the corresponding P code sequence range of uncertainty that can catch satellite centre halfback asterisk minimum, afterwards, generate local P code b, deposit it in external RAM.
Concrete, can generate local P code b by precision code chip (PRM) here.
S3. the sequence a that sampling is obtained takes out from the internal RAM of DSP core 1, and local P code b takes out from external RAM, and it is superposeed respectively and average operation, obtains A, B, and the detailed process of stack and average operation is as follows:
S31. as shown in Figure 1, sequence a and local P code b that sampling is obtained carry out segmentation by one section of N point, wherein, sequence a is divided into the M section, sequence b is divided into the K section, and sequence a skew N point is obtained a ', and sequence b skew N/2, N point is obtained respectively b ', b ' ', a and a ' stack are obtained sequence c, b, b ', b ', b ' ' stack are on average obtained sequence d again; Those skilled in the art should be appreciated that the N here can select according to actual conditions.
S32. every section of the two paths of signals sequence c after superposeing and sequence d are averaging and form a new sampled point, obtain A/D input signal A and K local code L that puts of M point after average;
S33. as shown in Figure 2, be that the local code L of K is divided into the J section according to every section M point with length, afterwards all section stacks are formed local code B;
S4. in DSP core 1, the A that step S32 is obtained carries out zero padding, then get conjugation, do the FFT computing, in DSP core 2, the B that step S33 is obtained carries out zero padding, then does the FFT computing, operation result in DSP core 2 is inputed to DSP core 1, be IFFT after then the operation result in itself and DSP core 1 being multiplied each other;
S5. IFFT result and threshold value are compared.If surpass threshold value, to surpassing the further precise search of phase place of N/2 yard of thresholding.Afterwards, change this star over to tracking module and judge whether that all can catch satellite acquisition and complete, if can catch satellite search in addition, begin to catch next satellite, if all search is completed, catch and complete, DSP changes the navigation data positioning calculation over to.
If S6. do not surpass threshold value, according to regenerating local P code, repeating step S3-S5 after chip of range of uncertainty skew.
Concrete, can after being offset a chip according to range of uncertainty, PRM regenerate local P code by controlling.
can find out from the method introduction of front background technology, method of the present invention is eliminated the loss of the 3dB of relevant peaks generation by step S31 at acquisition phase, its principle can be found out by formula (1), with crossing, input signal a and local code b are done the skew overlap-add operation, the blanking code skew is to the correlation peak loss fully, by step S32, S33 can find out, because thereby the purpose of average and overlap-add operation is all to reduce sampled point to reduce operand, but because the impact of P code cross correlation can be introduced a small amount of noise, if also do not surpass threshold value after repeating to catch 3 times, abandon catching this star, then catch other visible stars.
Cor
peak=max{∑[(x
m+x
m+N)×(y
0+y
N/2+y
N/2+y
N)/4]}
=max{∑[x
my
0+2(x
my
N/2+x
m+Ny
N/2)+x
my
N+x
m+Ny
0+x
m+Ny
N]/4}
=max{ ∑ [(x
my
0+ x
m+Ny
0)+2 (x
my
N/2+ x
m+Ny
N/2)+(x
m+Ny
0+ x
m+Ny
N)]/4} formula (1)
=max{∑[x
0y
0+2x
0y
0+x
0y
0]/4}
=max{∑x
0y
0}
Utilize the navigational system location receiver internal system structure of the inventive method and annexation as shown in Figure 4, at first antenna receiving signal enters the prime amplifier amplifying signal, then down coversion, analog to digital conversion, enter afterwards DSP and carry out the P code and catch, catch and to catch satellite after completing and send into that tracking module carries out carrier synchronization and the P code phase is synchronous.Because positioning calculation needs minimum 4 satellites, the tracking module satellite number of tracking satellite at least simultaneously is 4, so use FPGA to utilize the advantage of its parallel processing to set up this tracking module, position when above and resolve when the satellite number is 4, be responsible for this module by DSP core 2, and with the certain hour interval, the losing lock satellite is recaptured, after positioning calculation is completed, result is inputed to user interface for the user.
In sum, the P code Direct Acquisition Methods in the present invention adopts multi-core DSP to replace the FPGA that generally adopts to reduce receiver power consumption and hardware resource, and improves overlapping average zero padding algorithm and adapt to this platform, therefore substantially can not increase capture time.The method is specially adapted to the handheld navigation location receiver.
Those of ordinary skill in the art will appreciate that, embodiment described here is in order to help reader understanding's principle of the present invention, should to be understood to that the protection domain of inventing is not limited to such special statement and embodiment.Everyly make various possible being equal to according to foregoing description and replace or change, all be considered to belong to the protection domain of claim of the present invention.
Claims (1)
1. the P code Direct Acquisition Methods based on DSP, specifically comprise comprising the steps:
S1. the satellite-signal through after the A/D conversion that receives inputs in first DSP, and then carry out I/Q and separate, down coversion, down-sampling, the sequence a that sampling is obtained deposits in the internal RAM of first DSP;
S2. the temporal information that provides according to local clock in second DSP determines that the current time can catch the number of satellite and defend asterisk and the corresponding P code sequence range of uncertainty that can catch satellite centre halfback asterisk minimum, becomes local P code b, deposits it in external RAM;
S3. the sequence a that sampling is obtained takes out from the internal RAM of first DSP, and local P code b takes out from the external RAM of second DSP, and it is superposeed respectively and average operation, obtains A, B, and the detailed process of stack and average operation is as follows:
S31. the sequence a that sampling is obtained and local P code b carry out segmentation by one section of N point, wherein, sequence a is divided into the M section, sequence b is divided into the K section, sequence a skew N point is obtained a ', sequence b skew N/2, N point is obtained respectively b ', b ' ', a and a ' stack are obtained sequence c, b, b ', b ', b ' ' stack are on average obtained sequence d again;
S32. every section of the two paths of signals sequence c after superposeing and sequence d are averaging and form a new sampled point, obtain A/D input signal A and K local code L that puts of M point after average;
S33. the local code L that with length is K is divided into the J section according to every section M point, afterwards all section stacks is formed local code B;
S4. in first DSP, the A that step S32 is obtained carries out zero padding, then get conjugation, do the FFT computing, in second DSP, the B that step S33 is obtained is carried out zero padding, then do the FFT computing, operation result in second DSP is inputed to first DSP, be IFFT after then the operation result in itself and first DSP being multiplied each other;
S5. IFFT result and threshold value are compared, if surpass threshold value, to surpassing N/2 the further precise search of code phase of thresholding, afterwards, this star is changed over to tracking module and judges whether to complete the search that all can catch satellite, if can catch satellite search in addition, begin to catch next satellite, if all search is completed, catch and complete, second DSP changes the navigation data positioning calculation over to;
If S6. do not surpass threshold value, according to regenerating local P code, repeating step S3-S5 after chip of range of uncertainty skew.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013100822181A CN103163535A (en) | 2013-03-15 | 2013-03-15 | P code direct capturing method based on digital signal processor (DSP) |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013100822181A CN103163535A (en) | 2013-03-15 | 2013-03-15 | P code direct capturing method based on digital signal processor (DSP) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103163535A true CN103163535A (en) | 2013-06-19 |
Family
ID=48586777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2013100822181A Pending CN103163535A (en) | 2013-03-15 | 2013-03-15 | P code direct capturing method based on digital signal processor (DSP) |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103163535A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104158559A (en) * | 2014-07-31 | 2014-11-19 | 上海航天电子通讯设备研究所 | Long code fast-acquisition method on basis of direct spread system |
| CN106896382A (en) * | 2015-12-18 | 2017-06-27 | 大唐半导体设计有限公司 | A kind of navigation signal catching method and device |
| CN111190344A (en) * | 2018-11-15 | 2020-05-22 | 北京自动化控制设备研究所 | Design method of satellite navigation military code time service equipment |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5535278A (en) * | 1994-05-02 | 1996-07-09 | Magnavox Electronic Systems Company | Global positioning system (GPS) receiver for recovery and tracking of signals modulated with P-code |
| WO2003067279A2 (en) * | 2002-02-08 | 2003-08-14 | Qualcomm, Incorporated | Directly acquiring precision code gps signals |
| CN201532467U (en) * | 2009-11-09 | 2010-07-21 | 上海华测导航技术有限公司 | Structure of base-band circuit for double-frequency GPS satellite signal receiver |
| WO2011054225A1 (en) * | 2009-11-09 | 2011-05-12 | 上海华测导航技术有限公司 | Baseband circuit structure for realizing dual-frequency global positioning system (gps) satellite signal receiver and method thereof |
-
2013
- 2013-03-15 CN CN2013100822181A patent/CN103163535A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5535278A (en) * | 1994-05-02 | 1996-07-09 | Magnavox Electronic Systems Company | Global positioning system (GPS) receiver for recovery and tracking of signals modulated with P-code |
| WO2003067279A2 (en) * | 2002-02-08 | 2003-08-14 | Qualcomm, Incorporated | Directly acquiring precision code gps signals |
| CN201532467U (en) * | 2009-11-09 | 2010-07-21 | 上海华测导航技术有限公司 | Structure of base-band circuit for double-frequency GPS satellite signal receiver |
| WO2011054225A1 (en) * | 2009-11-09 | 2011-05-12 | 上海华测导航技术有限公司 | Baseband circuit structure for realizing dual-frequency global positioning system (gps) satellite signal receiver and method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 陈红光: "GPS微弱信号捕获关键技术研究", 《中国优秀硕士学位论文全文数据库信息科技辑》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104158559A (en) * | 2014-07-31 | 2014-11-19 | 上海航天电子通讯设备研究所 | Long code fast-acquisition method on basis of direct spread system |
| CN106896382A (en) * | 2015-12-18 | 2017-06-27 | 大唐半导体设计有限公司 | A kind of navigation signal catching method and device |
| CN106896382B (en) * | 2015-12-18 | 2019-06-28 | 大唐半导体设计有限公司 | A kind of navigation signal catching method and device |
| CN111190344A (en) * | 2018-11-15 | 2020-05-22 | 北京自动化控制设备研究所 | Design method of satellite navigation military code time service equipment |
| CN111190344B (en) * | 2018-11-15 | 2022-01-11 | 北京自动化控制设备研究所 | Design method of satellite navigation military code time service equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102520423B (en) | Rapid capturing method for Circuit for rapidly capturing long period pseudo random spread spectrum code of satellite navigation receiver and capturing method thereof | |
| CN100539457C (en) | The double-folding capture searching method of long-period spread spectrum code | |
| CN101029923B (en) | Software receiver for indoor position and navigation technology of global positioning system | |
| CN105553507A (en) | Full coherence accumulation time-frequency domain parallel capturing method based on FFT | |
| CN104898136A (en) | Capturing method of Beidou second-generation B1 signals and system thereof | |
| CN105553506B (en) | A kind of quick capturing method and device of long code spread-spectrum signal | |
| CN102540217A (en) | System for rapidly acquiring GLONASS satellite signals in field programmable gate array (FPGA) | |
| CN106291619A (en) | A kind of aeronautical satellite inter-satellite link wireless long-period spread spectrum code signal high-performance catching method | |
| CN105717522A (en) | Second-generation BeiDou B1 frequency band weak signal capturing method | |
| CN102116866A (en) | Method and device for tracking global positioning system precision (GPS P) and/or Y code signal of full-cycle carrier | |
| Li et al. | Dual-folding based rapid search method for long PN-code acquisition | |
| CN103176189A (en) | Near-far effect suppressor for high-flexibility satellite navigation receiver and near-far effect suppressing method thereof | |
| CN103197328B (en) | High dynamic satellite receiver fast capture method based on 2 ms data storage | |
| CN103885071A (en) | Satellite signal capturing method and equipment | |
| CN108196274A (en) | Be applicable in BOC (n, n) signal without fuzziness catching method and device | |
| CN101520505A (en) | Adaptive coherent accumulation joint acquisition method under GNSS weak signal | |
| Kim et al. | Design of FFT-based TDCC for GNSS acquisition | |
| CN100553169C (en) | Short-period spreading code time frequency parallel searching method based on frequency folding | |
| Borio | Coherent side‐band BOC processing | |
| CN103163535A (en) | P code direct capturing method based on digital signal processor (DSP) | |
| CN103926604A (en) | Weak signal capturing method based on overlapping difference cycle coherent integration | |
| CN103760578B (en) | A kind of GNSS satellite navigation signal without fuzzy tracking method | |
| CN109581434A (en) | A kind of B2a signal acquisition methods and device | |
| CN102185628A (en) | Spread spectrum code phase capture equipment based on adaptive power accumulation and capture method thereof | |
| CN104993844B (en) | A kind of frequency domain search method and device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20130619 |