Abstract: Along with automobile consumption quantity’s increase, automobile’s localization security technology also becomes the market a big demand. GPS (global positioning system) and GSM (mobile communication) the technical development to realize the top level automobile localization< ?XML:NAMESPACE PREFIX = O /> burglary protection system to provide the possibility. In the article the DSP technology, the GPS technology and the GSM technology organic synthesis together, studies the possibility which the automobile localization burglary protection system’s architecture and realizes, to realize the automobile guidance, the localization good and security lays the foundation.
Key word: Automobile localization burglary protection system; DSP controller; GPS receive module; Wireless GSM connection module
0 outlines
Along with the people living standard’s enhancement, the automobile entered the family gradually, is getting higher and higher to the automobile security request. Although in the market automobile security is improving gradually, but these security mainly uses the call warning, the high-pressured electric shock and so on, follows the science and technology the development, the automobile steals the technology to be also getting higher and higher, causes the human to be virtually impossible to guard against. Automobile security, regardless of has the extremely important research value to the automobile manufacturer or the social insurance business, in view of the present worldwide scale in the automobile burglary’s trend of escalation, various automobiles factory unceasingly is improving the security technology, particularly along with microelectronic technology’s progress, the automobile security technology has turned toward the automation, the intellectualized direction to develop.
Has completed the GPS system officially since century’s end US and is operational, the GPS technology penetrated into human economic development each domain. The GPS market present had the suitable scale, is especially biggest by the vehicles localization guidance domain’s market share, the growth is quickest. The recently statistics indicated that in 2000 installed the GPS receiver’s vehicles guidance system’s sales volume to grow from 1996 500,000,000 US dollars to 3,000,000,000 US dollars, and this tendency will also continue. Under this kind of market’s enticement, various countries have launched the massive research to the vehicles guidance and the localization technology. At present our country automobile GPS localization guidance also occupies the beginning stage, special purpose vehicle’s GPS navigation aid and the application system already started to start, for example: Each Department concerned in the cash truck, the emergency car, the public transportation, the patrol car, has welcomed guests the vehicle, the prison van and so on special purpose vehicle to use GPS to monitor the entire process, the guidance and the direction.
The GSM form is the main service pattern which the present handset uses, holds 80% above shares in the market. Unify GPS and GSM, not only may carry on automobile’s global localization using the GPS technology, realizes the good guidance, moreover may use the GSM network widespread cover area and the short note function, enables the vehicle owner to have the prompt understanding to the automobile current condition, thus the whole enhances automobile’s guidance security performance.
1 system architecture design
Based on the DSP chip, automobile localization security functional system structure diagram as shown in Figure which by the GPS module, the GSM wireless communication module as well as the essential auxiliary circuit is composed 1. In Figure 1, DSP regarding GPS and the GSM module through the serial port control, G the SM module and DSP serial port connection, uses 8251 expands a serial port to supply the GPS module use. The examination control and the auxiliary circuit may use DSP directly the I/O mouth. TMS320LF240 DSP the chip I/O port has the multiplying function, therefore only need establish the information in the control register to cause I/O to take general I/O then.
Take DSP as controller’s system after the starting movement initialization, will be at does not stop receives the automobile positional information in the condition, simultaneously system also in waiting examination condition and receive user inquiry news interrupt. Once will have an interrupt to produce will shift to the corresponding interrupt processing subroutine. If system’s defended signal is invalid, then the control system does not carry on the above operation.
System after defended signal effective, the DSP main circulation processes the positional information which the GPS receiver receives. Each time has obtains the new telegram text to symbolize, then the transfer subroutine carries on telegram text processing, is mainly separates in the telegram text the useful information like latitude and longitude , the time and the verification and so on, and stores these data the storage space which assigns. Wireless communication module TC35T is also carries on the exchange of information through the serial port and DSP, is obtains in this serial port receive with the interrupt uses controller’s authority. If will have the unusual vehicle condition to have like in defended situation vehicle door opening, the engine start and so on also to send out the interrupt request to DSP. The interrupt which causes TC35T supposes in the software for the low priority, namely has the difference in the vehicle condition simultaneously to have the vehicle owner to inquire the news on own initiative, then the DSP controller cannot respond TC35T the interrupt request.
If the DSP controller receives the interrupt request, and judges examines is the engine start signal causes the interrupt (to be possible time delay certain time like 100 ms to examine again one time, was still effective only then determined that is effective for start signal, like this may prevent misoperation). The system will process the engine to start the interrupt servicing subroutine, soon transmits the short news (the engine is running) (also to be possible to establish transmission number of times) for the user. If the vehicle owner has not responded promptly, separates 5 min to be possible to send again one time, and sends out is separated 1 min, each time continues 30 s local alarm; The power failure, breaks the oil the signal to be effective (is immediately two indicating lamps lightens in this modelling), after 20 s, the band brake signal is also in effectively; Meanwhile positional information which receives the processing result and the current GPS receiver through wireless communication transmission for vehicle owner. When likewise, examines the left vehicle door, the right vehicle door to be destroyed the signal which or has the vibration, besides the transmission for vehicle owner’s short news content dissimilar other processing method is similar.
When user handset transmission examination condition (check status) short news request control system returns current condition, the control system will act according to the present system’s condition to make the different response: When has not been at the defended condition, the control system is in has not had the fortification (defen ses isnt’t set) the short news to give the user; When is under the defended condition, the system complete transmission mode complete (is ok) the short news will give the user. If the system already were destructed generally already to take the corresponding processing measure like first to lock the vehicle, then this time will transmit locks the vehicle (the engine is locked) the short news to give the user, and simultaneously will transmit further processing method the notice user. If the unlocking, needs user transmission certain password simultaneously to transmit the unlocking (unlock engine) the information to give the control system, can the effective unlocking. Other situations according to similar method processing.
2 system feasibility analysis
2.1DSP technology
DSP has the extremely high speed digital processing ability and the very big operand. Therefore, it can satisfy the highly effective real-time signal processing the request. This kind of new component’s characteristic is as follows:
(1) uses the Harvard (HARVARD) structure, the highly concurrent operation raises the operating speed greatly;
in (2) chip has disposed or a many hardware multiplier sum storage, can realize the single instruction while, to add the operation and the indexing operation;
in (3) chip has established the function very strong special instruction specially, may realize the instruction to overlap the movement;
in (4) chip has established many kinds of function very strong periphery component and the connection, causes its operating speed confidential to be very quickly more than PC time;
(5)DSP increased the hardware cyclic control, when after completing the circulation initialization. In the actual movement circulates no longer the consumption instruction cycle. Raised the digital signal processing operating speed greatly;
the (6)DSP cost is low, the selling price reduces year by year.
In the DSP domain, the Texas (TI) Corporation’s product and the necessary technology and the development kit present obtained the widespread application in the market. In the article uses TMS320LF240 is one of TMS320C24x series. TMS320LF24x is also called the DSP controller, is performance-to-price ratio high 16 fixed point DSPs which TI Corporation in 1997 promoted, was aims at controls and so on electrical machinery, invertor, robot, numerically-controlled machine tool to design specially.
Because the present research was still at the simulation stage, the examination vehicle condition’s signal is triggers by the switch, to the vehicle condition signal’s response is through whether to lighten the indicating lamp to judge, therefore outside the board electric circuit is relatively simple. The DSP controller is controls the GPS receive module and wireless communication module GSM through the serial port, but TMS320LF240 has a serial port, therefore needs to expand the serial port. Moreover the monitor condition is triggers the DSP control function through the interrupt, TMS320LF240 only then outside 3 may shield the interrupt source, therefore also needs to carry on the expansion to the external interrupt. Other port which uses may establish for the general I/O mouth.
2.2GPS basic principle
The US started from 1973 to prepare for construction global positioning system GPS, and was operational completely in 1994. Global positioning system (GPS) is composed of 3 sectors: GPS satellite constellation, ground control/surveillance network and user receiving apparatus. And the subscriber’s equipment is mainly a satellite signal receiver, has the different localization ability according to the different goal, the basic function receives the L1 carrier, separates the C/A telegraph code, carries on the simple the hypothesized distance localization, is also the type which the common vehicles localization uses. And what must pay attention: The GPS satellite has two kind of different carriers to come load bearing all telegraph codes and the news, the C/A code only accent sets in the L1 carrier, P yard distinguishes the accent to set in L1 and in the L2 carrier, and distinguishes is P1 and the P2 telegraph code. Generally user use’s GPS receive module’s function diagram as shown in Figure 2. Is mainly composed of the frequency receive processing electric circuit and the signal processor. Now to preserve certain positional information simultaneously to increase the program memory and the data-carrier storage in the near future, I/O connection including serial port and conventional data mouth and so on directly for user use.
2.3GSM short news service
The GSM system may provide two big services, namely basic service and supplement service. Basic service including telecommunication service and bearer service; Supplemented that the service not alone provides, is to the basic service supplement. GSM provides the telecommunication service has the telephone, the short news and the facsimile and so on. The short news service is in the GSM system only does not request the establishment end - end service way the service, even if the traveling carriage has been under the complete circuit correspondence situation also to be possible to enter the mean action news transmission, i.e. a news’s transmission constituted a correspondence.
Use TC35T the wireless GSM correspondence terminal is Siemens integrates the essential connection on wireless module TC35 to become. Makes the transmission receiving apparatus with the TC35T module, between uses the short news the transmission to realize on the vehicle owner and the vehicle controls the related automobile positional information and the monitor control information exchange. This way has the correspondence cost to be low, the frequency spectrum use factor is high, the system capacity is big, the service type are many, the security performance is good, antijamming ability is strong, connection quality merits and so on high, automated roaming, it uses the signaling channel transmission, does not use the digit dialing establishment connection, the information which must send adds on the destination address to transmit directly to the short news service center, issues the final two overnight stays again by the short news service center, is the present application widespread correspondence plan.
3 conclusions
In the article unifies the automobile localization and the security function the consideration, will not exist in equipment’s installment repeatedly, simultaneously security, the localization will also enhance to intellectualized this level comes up, simultaneously has also laid the foundation for the network development; Uses DSP and the TMS320LF240 series achievement controller, has many other controller no merit.
Reference
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