Summary of the invention
The objective of the invention is for a kind of position location satellite system of selection and corresponding device thereof that is applicable to bimodulus or multi-mode satellite locating device is provided; bimodulus navigational system as while compatible with GPS or the Big Dipper two generations satellite; thereby avoid single mode GPS or the Big Dipper two generations satellite positioning device a little less than satellite-signal; frequency band signals disturbs big; the satellite-signal health degree is bad; satellite-signal is closed; satellite constellation distributes and to cause normally locating under the situation such as bad and can't navigate, and makes the district system that can not normally navigate in the gps satellite navigational system automatically switch to the Big Dipper two generations satellite navigation pattern.The district system that can not normally navigate in the Big Dipper two generations satellite navigation system automatically switches to the gps system navigation mode, and can both extraordinary work under various scenes.
The present invention is achieved in that a kind of mode selecting method that is used for bimodulus or multimode positioning satellite signal receiving trap, and this method comprises, starts described satellite signal receiving apparatus; Read the last mode of operation of described device; Read the last working date under this pattern; Enter this mode of operation.
Further, described method also comprises, judges whether described device is to use for the first time, if use for the first time, system enters each mode of operation successively and obtains the operational data of each pattern.
Further, described method also comprises, assesses the satellite signal quality of each mode of operation, and the mode of operation of selecting satellite signal quality the best is as last mode of operation and storage.
Further, described method comprises that also except that the RF front-end module maintenance operate as normal of work at present pattern, the RF front-end module that switches other mode of operation is a dormant state.
Further, described method comprises that also before device was closed, system stored the work at present pattern as last mode of operation, and the employed operational data of present mode is stored as this pattern last working date.
Further, described pattern has comprised Big Dipper pattern.
In addition; the present invention also provides a kind of bimodulus or multimode positioning satellite signal receiving trap; described device comprises, is used for the radio frequency unit that bimodulus or multimode receive, baseband signal processing unit; in baseband signal processing unit, also comprised a satellite-signal evaluation module; main control unit, mode switch element and storage unit, the last working date of each pattern of storage on the described storer; when system start-up, utilize last working date control model switch unit to switch.
Further, described device also comprises the judging unit of starting shooting for the first time, if start for the first time, system carries out the flow process of starting shooting for the first time.
After adopting technical scheme of the present invention, solve the problem that automaticallyes switch between bimodulus or the multimode system, improved the efficient of between bimodulus under the different scenes or multimode system, switching, and can improve the stability that system locatees first.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
System architecture of the present invention as shown in Figure 1.Its ultimate principle is that system is handled the satellite-signal that is received by antenna by the RF radio-frequency module, and the data that have satellite information that will deal are then given baseband chip and carried out algorithm process.The whole system operation pattern is controlled by a processor.
System is by two-way RF radio-frequency front-end, and promptly GPS RF front-end module 2 and 4, one baseband chips 6 of the Big Dipper two generations RF front-end module and a main control microprocessor 7 constitute.Wherein baseband chip inside has also comprised a satellite-signal evaluation module 9.Satellite-signal evaluation module assessment and judgement have following method: the carrier-to-noise ratio C/N0 that at first is the satellite-signal that will be used for locating averages, if mean value is less than the thresholding mean value 23 that can catch satellite, just judge that the satellite signal quality under the work at present pattern is not good, system needs switching working mode.As shown in table 1 such as present case:
The satellite numbering |
C/N0 |
2 |
50 |
8 |
43 |
12 |
38 |
15 |
34 |
22 |
35 |
24 |
20 |
Table 1
In table 1, the satellite that is used for locating is respectively No. 2, No. 8, No. 12, No. 15, No. 22, and their C/N0 mean value is 40, and greater than threshold value 23, so the current satellite signal quality of satellite-signal evaluation module 9 judgements is good, and system does not need to switch.But when following situation occurring, as shown in table 2:
The satellite numbering |
C/N0 |
2 |
45 |
8 |
30 |
12 |
21 |
15 |
22 |
22 |
16 |
24 |
15 |
Table 2
The satellite that is used for locating in table 2 is respectively No. 2, No. 8, No. 12, No. 15, No. 22, No. 24, their C/N0 mean value is 24.8, less than threshold value 23, so the current satellite signal quality of satellite-signal evaluation module 9 judgements is not good, and system needs the switch operating state.
The signal frequency of the GPS navigation satellite that the present invention uses is 1575.42MHz, the signal frequency of the Big Dipper two generations Navsat is 1561.098MHz, native system receives GPS and the Big Dipper two generations satellite-signal in the sky by the compatible type antenna 1 of external received GPS and the Big Dipper two generations satellite-signal, and offers the two-way RF front-end module.The output frequency of crystal oscillator 3 is 16.367667MHz, provides sampling clock to GPS radio-frequency front-end 2, and the output frequency of crystal oscillator 5 is 16.301MHz, provides sampling clock to the Big Dipper two generations RF front-end module 4.
The receiving side signal formula of system default is the GPS navigation satellite-signal, provides sampling clock by crystal oscillator 3.When system works in GPS pattern following time, system can be set to low-power consumption mode with root module 4 before the Big Dipper two generations radio frequency automatically, makes two paths of signals not produce the phase mutual interference.
With the gps signal is example, and satellite-signal is given baseband chip by data-interface after handling through radio-frequency module.In these data, comprised satellite-signal intensity, information such as noise intensity, assess and judge that baseband chip is identical with the assessment and the determination methods of gps satellite signal with determination methods to the assessment of the Big Dipper two generations satellite-signal by 9 pairs of gps satellite signals that receive of satellite-signal evaluation module of baseband chip inside.When the satellite-signal evaluation module judges that the satellite-signal that receives is not suitable for being used for locating, CPU in the baseband chip will send a control signal, main control microprocessor 7 receives after this signal, send signal to GPS radio-frequency module that is moving and the Big Dipper two generations radio-frequency module Enable Pin that is in low-power consumption mode respectively simultaneously, allow the GPS radio-frequency module enter low-power consumption mode, allow the Big Dipper two generations radio-frequency module enter normal mode of operation, provide sampling clock by 16.311MHzTCXO crystal oscillator 5.Simultaneously, baseband chip receives the control signal that is sended over by microprocessor, enters the Big Dipper two generations satellite system navigation mode of operation.So just finished the automatic switchover of two satellite systems.In like manner, if under the Big Dipper two generations satellite system navigation mode of operation, when the satellite-signal evaluation module in the baseband chip 9 judges that the satellite-signal that receives is not suitable for being used for locating, CPU in the baseband chip will send a control signal, allow system works under the GPS pattern, allow the Big Dipper two generations radio-frequency module enter low-power consumption mode.
Fig. 2 is satellite mode switching flow figure of the present invention, and its principle is to carry out navigational satellite system according to satellite signal quality to switch.
Being in gps satellite navigation mode of operation with system is example, and the course of work of system is as follows:
Step 11 is by the antenna receiving satellite signal;
Step 12 is given the GPS radio-frequency module with the signal that receives and is carried out the gps signal processing;
Step 14, baseband chip are carried out the algorithm process of normal condition again;
Step 15, the assessment satellite signal quality;
Step 16 judges whether the satellite-signal that receives can be used for normally locating.If system is in the more weak place of gps signal, satellite-signal evaluation module 9 judges that current satellite-signal is not suitable for being used for locating, and baseband portion is caught and followed the tracks of satellite accurately with regard to being difficult to; If current satellite signal quality is bad, then need to switch; After 9 pairs of satellite-signals that receive of satellite-signal evaluation module are assessed and are judged, think that the satellite-signal under the current state is fit to be used for locate, baseband chip keeps normal operating conditions, the CPU of baseband chip inside carries out the action of normal data processing and algorithm, then continues the current GPS mode of operation.
Step 17, if current satellite signal quality is bad, baseband chip 6 produces and sends to the control signal of main control microprocessor 7, and stops to export the NMEA sign indicating number simultaneously;
Step 18, the control signal of sending according to baseband chip 6, main control microprocessor 7 sends the enable signal that can control GPS radio frequency module mode of operation for the GPS radio-frequency front-end 2 and the crystal oscillator 3 of working, allow GPS radio frequency module enter low-power consumption mode, send a signal that allows this module enter normal mode of operation for again simultaneously the Big Dipper two generations radio-frequency front-end 4 and crystal oscillator 5 Enable Pins that are in low-power consumption mode, and control baseband chip 6 mode of operations, allow baseband chip 6 switching working modes enter the Big Dipper two generations satellite system navigation mode of operation.
Step 19, the signal that baseband chip 6 sends according to main control microprocessor 7, switching working mode is to the Big Dipper two foundry operation modes.
Step 20, after system's operate as normal, record work at present pattern, data such as the satellite that is used to locate numbering, carrier-to-noise ratio C/N0 are recorded and are kept in the middle of the FLASH storer 20.
After system entered the Big Dipper two generations satellite system navigation mode of operation, principle of work was basic identical with gps satellite system navigation mode of operation.If the satellite-signal evaluation module of baseband portion 9 judges when satellite signal quality is bad under the current state that just be difficult to catch and tracking satellite, baseband chip transmits control signal to main control microprocessor, and stop the output of NMEA data.Main control microprocessor sends signal respectively for simultaneously two generations of the Big Dipper and GPS radio-frequency module Enable Pin according to the control signal that receives, and makes the Big Dipper two generations radio-frequency module enter low-power consumption mode, makes the GPS module enter normal mode of operation.Simultaneously, control baseband chip mode of operation allows baseband chip enter gps satellite system navigation mode of operation.So just realized the automatic switchover of system by the Big Dipper two generations satellite navigation system and gps satellite system navigation mode of operation.
FLASH storer 8 is controlled by main control microprocessor 7, when navigation mode need be switched in system, can call the data of preserving in the FLASH storer.For dual system shown in Figure 1, in order to allow system better work, system can write down following data:
Data A: last satellite navigation pattern, be current use be the Big Dipper or GPS navigation pattern;
Data B: the result of satellite-signal evaluation module 9 assessments of last each pattern and the satellite that is used to separately locate are numbered, almanac data, or the like.
The above-mentioned data of system log (SYSLOG) are used for start next time to FLASH storer 8, and the system of being convenient to finishes location first fast.If the last time is the GPS pattern, just start the GPS pattern next time when starting shooting, and call related data and finish location first, and according to flow performing signal Processing shown in Figure 2.If gps signal is weak so that can't finish the location, system will switch to the Big Dipper two generations pattern, and the data of calling the last Big Dipper two generations satnav of storage are finished location first.
In order to preserve above-mentioned data, before system closing, system can write current data automatically, and when started shooting next time like this, the current data that writes was exactly last data.Start like this, each time all can enter last mode of operation and utilize last data to finish this and locate first.
Which kind of pattern should but if start for the first time, system switch to? in order to make system works more reliable, Fig. 3 is start shooting for the first time workflow of Data Update of native system.
Step 31 at first, system start-up.
Step 32 then, after system started shooting for the first time, owing to there are not the data of GPS and the Big Dipper two generations satellite in the system, promptly the zone of the above-mentioned data of storage all be 0xFF in the system, system judges that it is start use for the first time.
Step 33, system switch to the GPS pattern, and finish first the location, obtain the satellite data that is used to locate, and satellite-signal evaluation module 9 is finished the quality evaluation to gps satellite signal, if signal can not satisfy positioning requirements in a period of time, and data B too.
Step 34, system switch to the Big Dipper two foundry operation modes, and finish location first, obtain the satellite data that is used to locate, satellite-signal evaluation module 9 is finished the quality evaluation to gps satellite signal, if signal can not satisfy positioning requirements in a period of time, and data B too.
Step 35 is preserved the data that step 33 and step 34 obtain.Wherein the last satellite navigation mode data of data A is best through satellite-signal evaluation module 9 assessment back signal qualitys in GPS and the Big Dipper two generations signal.The satellite-signal of last each pattern of data B is numbered through satellite-signal evaluation module 9 assessment back signal qualitys satellite best and that be used to separately locate, and almanac data is for finishing the relevant information of the acquisition when locating first separately.So just upgraded data A and the data B in the system.
Step 36 continues to carry out other initialization tasks.
Like this, if next system will carry out positioning service, system selects system stronger in GPS and the Big Dipper two generations signal as the work at present pattern.
Because system's primary positioning time is about 36 seconds.So the process of whole Data Update can be finished in 3 minutes substantially.
In addition, judging that the method whether system starts shooting for the first time can also be to open up a counting unit on the FLASH storer, is 0 when just beginning, every use once increases once, be 0 and do not overflow if detect counting, then think start for the first time, and carry out the flow process of starting shooting the above-mentioned first time.
Need to prove, native system only as an example with GPS and the Big Dipper two generations navigational satellite system, if the system integration other navigational satellite system such as GLONASS or Galileo, its ultimate principle is also the same with the present invention, also within protection scope of the present invention.In addition, signal carrier-to-noise ratio threshold value of the present invention is located at 23, also has in the practical application to be lower than 23 and can to locate, and need look concrete system and determine.Also have, technology of the present invention is not only applicable to satellite positioning navigation, and is applicable to the satellite time service.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.