CN105988126A - Multi-mode satellite navigation module applied in field of agricultural internet of things - Google Patents
Multi-mode satellite navigation module applied in field of agricultural internet of things Download PDFInfo
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- CN105988126A CN105988126A CN201410788295.3A CN201410788295A CN105988126A CN 105988126 A CN105988126 A CN 105988126A CN 201410788295 A CN201410788295 A CN 201410788295A CN 105988126 A CN105988126 A CN 105988126A
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Abstract
The present invention relates to a satellite navigation module applied in the field of agricultural internet of things. The satellite navigation module comprises an antenna, a radio frequency (RF) module, a baseband signal processing module, an application information processing module and a power supply module. The RF module is respectively connected with the antenna and the baseband signal processing module. The baseband signal processing module and the application information processing module are realized in the same FPGA. The power supply module supplies power to the entire satellite navigation module. The satellite navigation module is compatible with a GPS navigation system and a BD navigation system at the same time, and enables three positioning modes. Meanwhile, based on the rapid pseudo-code acquisition technique and the multi-order loop tracking carrier technique, the high-precision positioning and navigation requirements of high-speed and high-acceleration carriers are fully met. Therefore, the continuity, the reliability, the navigation accuracy and the availability of the system are effectively improved. Applied in the field of agricultural internet of things, the satellite navigation module can accurately position agricultural information resources.
Description
Technical field
The present invention relates to a kind of satellite navigation module, particularly relate to a kind of multimodal satellite navigation module being applied to agricultural Internet of Things field.
Background technology
Traditional agriculture production model is far from the requirement of adaptation agricultural sustainable development, and utilizing modern information technologies to change mode of agriculture becomes the popular tendency of Current Agricultural Development.Technology of Internet of things is generation information technology; in fields such as utilization of agricultural resources utilization, monitoring agricultural environment, agricultural production, agricultural product security supervision extensively apply, to improving resource utilization, the aspect such as environmental conservation, abridged edition increase income, product quality played important function.
In agricultural Internet of Things application, need agricultural information resources is positioned accurately, and use traditional method to be difficult to.Satellite Navigation Technique has and is accurately positioned and time service function, and the GPS system of the U.S. and the triones navigation system of China have had certain application and development in agriculture field.But, the navigation system of single standard can not show a candle to multimode compatibility satellite navigation system at aspects such as the seriality of system, reliability, navigation accuracy, availabilities, additionally there is serious fix drift problem when location navigation, it is difficult to realize, the precise positioning of high acceleration object dynamic to height and navigation.
Summary of the invention
Present invention aim at the problem for above-mentioned existence, it is provided that a kind of multimodal satellite navigation module being applied to agricultural Internet of Things field, compatible with GPS and two kinds of navigation system of BD simultaneously, fully adapt at high speed, the hi-Fix of high acceleration carrier and navigation needs.
The technical scheme is that the multimodal satellite navigation module being applied to agricultural Internet of Things field, including antenna, radio-frequency module, baseband signal processing module, message processing module and power module, wherein, described antenna is GPS/BD dual-band antenna, has been used for the reception of GPS and BD satellite-signal；Described radio-frequency module is connected with baseband signal processing module, be used for the pre-amplification of signal, conversion radio frequency signal be converted to standard intermediate-freuqncy signal and provide clock signal；Described baseband signal processing module and application message processing module realize in same FPGA, mainly complete Code acquisition, passage correlator, the measurement of observation vector, navigation message demodulation；Described application message processing module has been mainly used in the observation information to baseband signal processing module and satellite message information carries out data conversion and fusion, it is achieved the resolving to real-time navigation information；Described power module is for providing power supply for whole receiver system.
Described radio-frequency module includes BD radio-frequency module and GPS radio frequency module, and BD radio-frequency module is used for exporting IF-B3 signal and 10MHz clock signal, and GPS radio frequency module is used for exporting IF-L1 signal and 10MHz external clock signal.
Described baseband signal processing module includes 24 independent digital received passages, follows the tracks of multi-satellite signal simultaneously, and each passage mainly completes Code acquisition, loop tracks, despread-and-demodulation and distance measurement function.
Described Code acquisition uses digital matched filter+FFT fast Capture Technique, and Code acquisition substantially workflow is as follows:
First docking is collected mail and number is carried out down coversion, and carry out 3 average, obtain homophase and quadrature branch baseband signal, then pass through digital matched filter；Digital matched filter includes 24 partial matched filters, and each partial matched filter about provides the coherent integration time of 0.0833ms, and homophase and digital orthogonal baseband signal are processed by timesharing, uses channel multiplexing technology to save FPGA resource；The output of 24 partial matched filters is sent to FFT unit and is carried out spectrum analysis, completes carrier search；The result of FFT unit is sent to no-coherence cumulating unit and accumulates；After no-coherence cumulating reaches stipulated number (1-3 time), carry out detection judgement.
Described loop tracks function mainly includes that correlator, carrier loop control, pseudo-code loop controls and carrier-to-noise ratio is estimated.
All there are 6 independent road integrated signal output and the outputs of 2 drive test amount signals on the every road of described correlator, shares a sampling clock and a measurement sampling clock；Wherein, correlator spacing can configure, and code generator produces or stores the pseudo noise code in all known satellite navigation system, it is ensured that the versatility of tracking channel.
Described carrier loop controls and pseudo-code loop has controlled the estimation to carrier frequency/phase place and pseudo-code phase, it is achieved carrier wave and the precise synchronization of pseudo-code, and the method estimated by carrier-to-noise ratio judges the lock-out state of loop.
Described carrier loop controls, and mainly includes FLL FLL, phase-locked loop pll, normalized dot product descriminator and normalized subtracts after-power device phase discriminator in advance；Described FLL parameter designing is: chooses FLL integration lengths 1ms, determines loop bandwidth by emulation；Described pll parameter is designed as: chooses PLL integration lengths 1ms, determines loop bandwidth by emulation；The gain of described normalized dot product descriminator is 2；The described normalized gain subtracting after-power descriminator in advance is 4.
Beneficial effects of the present invention:
Being applied to the multimodal satellite navigation module in agricultural Internet of Things field, compatible with GPS and two kinds of navigation system of BD, support three kinds of station-keeping modes simultaneously, and station-keeping mode can automatically switch, it is possible to is manually arranged to any station-keeping mode.By using Rapid capture of false code and multistage loop tracks ZAP, can fully adapt to high speed, the hi-Fix of high acceleration carrier and navigation needs, it is effectively improved the seriality of system, reliability, navigation accuracy and availability, in agricultural Internet of Things application, can realize agricultural information resources is positioned accurately.
Accompanying drawing explanation
Fig. 1 is the multimodal satellite navigation module composition frame chart being applied to agricultural Internet of Things field；
Fig. 2 is composition and the theory diagram of radio-frequency module；
Fig. 3 is digital received passage composition and theory diagram；
Fig. 4 is digital matched filter structured flowchart；
Fig. 5 is correlator and NCO structured flowchart；
Fig. 6 is FLL loop bandwidth and thermal noise graph of a relation；
Fig. 7 is FLL loop bandwidth and dynamic stress graph of a relation；
Fig. 8 is PLL loop bandwidth and thermal noise graph of a relation；
Fig. 9 is PLL loop bandwidth and dynamic stress graph of a relation；
Figure 10 is normalization dot product phase discriminator performance diagram；
Figure 11 is that normalization subtracts stagnant phase discriminator characteristic curve in advance；
Figure 12 is second order DLL pseudo-code loop filter structure figure；
Figure 13 is FLL frequency discrimination result；
Figure 14 is PLL identified result；
Figure 15 is DLL pseudo-code identified result.
Detailed description of the invention
Below in conjunction with the accompanying drawings highly preferred embodiment of the present invention is further described:
As it is shown in figure 1, the multimodal satellite navigation module being applied to agricultural Internet of Things field mainly includes antenna, radio-frequency module, baseband signal processing module, application message processing module and power module.Wherein, described antenna is GPS/BD dual-band antenna, has been used for the reception of GPS and BD satellite-signal；Described radio-frequency module is connected with baseband signal processing module, be used for the pre-amplification of signal, conversion radio frequency signal be converted to standard intermediate-freuqncy signal and provide clock signal；Described baseband signal processing module and application message processing module realize in same FPGA, mainly complete Code acquisition, passage correlator, the measurement of observation vector, navigation message demodulation；Described application message processing module has been mainly used in the observation information to baseband signal processing module and satellite message information carries out data conversion and fusion, it is achieved the resolving to real-time navigation information；Described power module is for providing power supply for whole receiver system.
The operation principle of the multimodal satellite navigation module being applied to agricultural Internet of Things field is: received the radio signal launched from space segment BD and gps satellite by Anneta module, GPS/BD satellite-signal is through radio-frequency module and baseband signal processing module, the extract real-time solving mediation observed quantity of complete pair signals, then satellite information and observation information transmission are completed the positional information to the Current observation moment to application message processing module, velocity information and the resolving of punctual information and integrity monitoring, and the inertial navigation information carrying out acquisition and tracking level merges, the inertial navigation information of original observed quantity level and position and speed level merges, the power supply of whole receiver system has been unified by power module.
Radio-frequency module mainly undertakes the reception task of BD signal and gps signal, and provides relevant clock signal simultaneously.The composition of radio-frequency module and theory diagram are as shown in Figure 2, BD B1 that antenna is sent here and GPS L1 two-way weak satellite signal amplify through each self-corresponding low-noise amplifier and are re-fed into the radio-frequency module of correspondence after long cable transmission, signal amplifying through mixing, AGC in radio-frequency module, baseband filtering exporting to baseband signal processing module after being amplified to+4dBm level.
Baseband signal processing module includes 24 independent reception passages, follows the tracks of multi-satellite signal simultaneously, and each passage completes pseudo-code or capture, tracking, despread-and-demodulation and the range finding of GPS CA code of BD.
Digital processing receives passage design
Digital processing receive passage design principle as it is shown on figure 3, digital channel to be designed to 24 tunnels, tracking continuous to multi-satellite simultaneously, it is important to the extraction of fast Acquisition, accurate tracking and the observed quantity of the short code (C code) being modulated on I branch road.
Code acquisition designs
For improving acquisition speed, the capture for code uses matched filtering+FFT fast Capture Technique, it is possible to achieve receives signal and local code Sequentially continuous related operation, and completes frequency discriminating simultaneously.Digital matched filter structure is as shown in Figure 4.First docking collections of letters down coversion, and carry out 3 averagely, obtain homophase and quadrature branch baseband signal, then passed through matched filtering device.Whole matched filtering device comprises 24 partial matched filter CMFn(n=1 to 24), each CMFn about provides the coherent integration time of 0.0833ms, and homophase and digital orthogonal baseband signal are processed by timesharing, save resource by the method for multiplexing；The output of 24 partial matched filters is then sent to FFT unit and is carried out spectrum analysis, completes carrier search；The result of FFT send no-coherence cumulating unit to accumulate again.After no-coherence cumulating reaches stipulated number (1-3 time), finally carry out detection judgement.
Loop tracks designs
Loop tracks function mainly includes that correlator, carrier wave and pseudo-code loop control, carrier-to-noise ratio estimates and coupling collar circuit-switched data produces measurement data.The function of correlator includes carrier wave demodulation and pseudo-code two processes of despreading, solves the signal after harmonic solution expands and is exported by integration remover (being equivalent to low pass filter), and what Fig. 5 illustrated a road correlator realizes structure.Every road correlator has 6 independent road integrated signal output and the outputs of 2 drive test amount signals, and all of correlator branch road all shares a sampling clock and a measurement sampling clock.Wherein correlator spacing can configure, and code generator/code table produces or stores the pseudo noise code in all known satellite navigation system, it is ensured that the versatility of tracking channel.Carrier wave and pseudo-code loop have controlled the estimation to carrier frequency/phase place and pseudo-code phase, to realize the precise synchronization of carrier wave and pseudo-code, and are judged the lock-out state of loop by carrier-to-noise ratio method of estimation.
Carrier loop filter construction designs
Carrier loop wave filter mainly includes FLL FLL, phase-locked loop pll, normalized dot product descriminator and normalized subtracts after-power device phase discriminator in advance.
FLL parameter designing
Choosing FLL integration lengths is 1ms, determines loop bandwidth by emulation, to meet system dynamics index request.Simulation result is as shown in Figure 6,7.
Pll parameter designs
Choosing PLL integration lengths is 1ms, determines loop bandwidth by emulation, to meet system dynamics index request.Simulation result is as shown in Figure 8,9.
DLL phase demodulation algorithm
Normalized dot product descriminator: normalization dot product phase discriminator characteristic is as shown in Figure 10.Normalization dot product phase discriminator is 2 at the slope of zero point, and therefore the gain of normalization dot product phase discriminator is 2.The normalized after-power descriminator that subtracts in advance: normalization subtracts after-power phase discriminator characteristic as shown in figure 11 in advance.It is 4 that normalization subtracts after-power phase discriminator in advance at the slope of zero point, and therefore normalization subtracts the gain of delayed phase discriminator in advance is 4.The normalized after-power phase discriminator that subtracts in advance has the advantage being suitable to narrow relevant spacing, and its gain is relatively big and discriminator sensitivity is higher, but linear pulling scope is smaller than dot product descriminator, it is adaptable to the precision tracking in later stage.
Pseudo-code loop filter structure designs
The design uses second-order loop filter structure, as shown in figure 12.Use photocarrier method method to eliminate most code Doppler frequency, reduce pseudo-code phase and follow the tracks of the exponent number of ring, simplify pseudo-code phase and follow the tracks of ring design.
Loop tracks simulation result
Simulated environment: initial velocity: 1000m/s；Acceleration: 20g/s, as shown in Figure 13, Figure 14, Figure 15.
Application message processing module has been mainly used in GPS and the BD observation information to baseband signal processing module and satellite message information carries out data conversion and fusion, it is achieved the resolving to real-time navigation information.Major function includes many constellation data fusion treatment and passage configuration.
Many constellation data fusion treatment
The correct collection in the main complete paired data source of many constellation data fusion treatment, general character is extracted and unified drift correction；Unified many constellations satellite time system and coordinate system.The information such as required original observed quantity and navigation message are given by signal processing module.The two is interacted by serial ports, uses order-response modes, i.e. message processing module to provide data request command, and signal processing module, according to order, sends the data of response by serial ports.In order to provide the information of correspondence in the request of data moment, signal processing module needs first to cache observed quantity and navigation message.
Passage configures
12 channel allocations are to GPS, and 12 channel allocations are to BD.Channel allocation is completed to calculate by message processing module, by transmission order, is preset to signal processing module.
The present invention is not limited to embodiment discussed above.Description to detailed description of the invention is intended to describe and the technical scheme that the present invention relates to being described above.Obvious conversion based on present invention enlightenment or replacement should also be as being considered within protection scope of the present invention.Above detailed description of the invention is used for disclosing the optimal implementation of the present invention, so that those of ordinary skill in the art can apply the numerous embodiments of the present invention and multiple alternative to reach the purpose of the present invention.
Claims (8)
1. it is applied to the multimodal satellite navigation module in agricultural Internet of Things field, it is characterised in that: include antenna, radio-frequency module, baseband signal processing module, application message processing module and power module,
Described antenna is GPS/BD dual-band antenna, has been used for the reception of GPS and BD satellite-signal；
Described radio-frequency module is connected with baseband signal processing module, be used for the pre-amplification of signal, conversion radio frequency signal be converted to standard intermediate-freuqncy signal and provide clock signal；
Described baseband signal processing module and application message processing module realize in same FPGA, mainly complete Code acquisition, passage correlator, the measurement of observation vector, navigation message demodulation；
Described application message processing module has been mainly used in the satellite message information of GPS and the BD observation information to baseband signal processing module and GPS and BD and has carried out data conversion and fusion, it is achieved the resolving to real-time navigation information；
Described power module is for providing power supply for whole receiver system.
The multimodal satellite navigation module being applied to agricultural Internet of Things field the most according to claim 1, it is characterised in that described radio-frequency module includes BD radio-frequency module and GPS radio frequency module；Described BD radio-frequency module is used for exporting IF-B3 signal and 10MHz clock signal；Described GPS radio frequency module is used for exporting IF-L1 signal and 10MHz external clock signal.
The multimodal satellite navigation module being applied to agricultural Internet of Things field the most according to claim 1, it is characterised in that described baseband signal processing module includes 24 independent digital received passages；Described digital received passage follows the tracks of multi-satellite signal simultaneously, and each passage mainly completes Code acquisition, loop tracks, despread-and-demodulation and distance measurement function.
The satellite navigation module being applied to agricultural Internet of Things field the most according to claim 3, it is characterised in that described Code acquisition uses digital matched filter+FFT fast Capture Technique, and Code acquisition substantially workflow is as follows:
First docking is collected mail and number is carried out down coversion, and carry out 3 average, obtain homophase and quadrature branch baseband signal, then pass through digital matched filter；
Described digital matched filter includes 24 partial matched filters, and each partial matched filter about provides the coherent integration time of 0.0833ms, and homophase and digital orthogonal baseband signal are processed by timesharing, uses channel multiplexing technology to save FPGA resource；
The output of described 24 partial matched filters is sent to FFT unit and is carried out spectrum analysis, completes carrier search；
The result of described FFT unit is sent to no-coherence cumulating unit and accumulates；
After described no-coherence cumulating reaches stipulated number (1-3 time), carry out detection judgement.
The satellite navigation module being applied to agricultural Internet of Things field the most according to claim 3, it is characterised in that described loop tracks function mainly includes that correlator, carrier loop control, pseudo-code loop controls and carrier-to-noise ratio is estimated.
The satellite navigation module being applied to agriculture Internet of Things field the most according to claim 5, it is characterised in that all there are 6 independent road integrated signals output and the outputs of 2 drive test amount signals on the every road of described correlator, shares a sampling clock and a measurement sampling clock；Wherein, correlator spacing can configure, and code generator produces or stores the pseudo noise code in all known satellite navigation system, it is ensured that the versatility of tracking channel.
The satellite navigation module being applied to agricultural Internet of Things field the most according to claim 5, it is characterized in that, described carrier loop controls and pseudo-code loop has controlled the estimation to carrier frequency/phase place and pseudo-code phase, realize the precise synchronization of carrier wave and pseudo-code, and the method estimated by carrier-to-noise ratio judges the lock-out state of loop.
The satellite navigation module being applied to agricultural Internet of Things field the most according to claim 7, it is characterized in that, described carrier loop controls, and mainly includes FLL FLL, phase-locked loop pll, normalized dot product descriminator and normalized subtracts after-power device phase discriminator in advance；Described FLL parameter designing is: chooses FLL integration lengths 1ms, determines loop bandwidth by emulation；
Described pll parameter is designed as: chooses PLL integration lengths 1ms, determines loop bandwidth by emulation；The gain of described normalized dot product descriminator is 2；The described normalized gain subtracting after-power descriminator in advance is 4.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108594276A (en) * | 2018-05-02 | 2018-09-28 | 北京七维航测科技股份有限公司 | Positioning and orientation system |
| WO2019000425A1 (en) * | 2017-06-30 | 2019-01-03 | 深圳市大疆创新科技有限公司 | Satellite signal processing apparatus and unmanned aerial vehicle |
| CN110376616A (en) * | 2019-08-22 | 2019-10-25 | 江西渥泰环保科技有限公司 | GNSS and the reception of Internet of Things wide area signal and its data processing method |
| CN113109847A (en) * | 2021-03-04 | 2021-07-13 | 北京北方联星科技有限公司 | Satellite navigation signal capturing method for reducing storage space consumption |
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2015
- 2015-02-15 CN CN201410788295.3A patent/CN105988126A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019000425A1 (en) * | 2017-06-30 | 2019-01-03 | 深圳市大疆创新科技有限公司 | Satellite signal processing apparatus and unmanned aerial vehicle |
| CN108594276A (en) * | 2018-05-02 | 2018-09-28 | 北京七维航测科技股份有限公司 | Positioning and orientation system |
| CN110376616A (en) * | 2019-08-22 | 2019-10-25 | 江西渥泰环保科技有限公司 | GNSS and the reception of Internet of Things wide area signal and its data processing method |
| CN110376616B (en) * | 2019-08-22 | 2022-02-11 | 江西渥泰环保科技有限公司 | GNSS and Internet of things wide area signal receiving and data processing method |
| CN113109847A (en) * | 2021-03-04 | 2021-07-13 | 北京北方联星科技有限公司 | Satellite navigation signal capturing method for reducing storage space consumption |
| CN113109847B (en) * | 2021-03-04 | 2023-08-01 | 北京北方联星科技有限公司 | Satellite navigation signal capturing method capable of reducing storage space consumption |
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