Embodiment
The invention will be further described below in conjunction with drawings and Examples.
The present invention is three grades of multi-hop wireless sensor network systems, and it is made of a large amount of anisotropy magnetoresistive transducers (AMR sensor) terminal 3, some wireless relay terminals 2 and a wireless receiving terminal 1.The signal that anisotropy magnetoresistive transducer terminal 3 is responsible for front end obtains and handles, and passes through powered battery.Wireless relay terminal 2 is responsible for receiving the data that reported by anisotropy magnetoresistive transducer terminal 3, and gives wireless receiving terminal 1 with this data forwarding, by solar cell or accumulator or active power supply.Wireless receiving terminal 1 is responsible for the demonstration and the storage of system coordination, parking stall status information, by wired DC power system power supply.
The working method of above-mentioned three grades of multi-hop wireless sensor networks being made up of anisotropy magnetoresistive transducer terminal 3, wireless relay terminal 2 and wireless receiving terminal 1 is: anisotropy magnetoresistive transducer terminal 3 is behind electrifying startup, need to add network by near a wireless relay terminal 2 earlier, after successfully adding network, anisotropy magnetic resistance sensor terminal 3 enters standby detection operations state, and the data that needs report are sent to the wireless relay terminal 2 that this admits its adding network; Behind wireless relay terminal 2 electrifying startups, need to add earlier the network that wireless receiving terminal 1 is safeguarded, after success adds network, near wireless relay terminal 2 can be admitted anisotropy magnetoresistive transducer terminal 3 adds network, and the responsible data forwarding that all anisotropy magnetoresistive transducer terminals 3 of its admittance are reported is given wireless receiving terminal 1,255 anisotropy magnetoresistive transducers of each wireless relay terminal 2 maximum receivability terminal 3; Behind wireless receiving terminal 1 electrifying startup, set up one oneself to be the wireless network of administrative center, and begin to admit wireless relay terminal 2 and near anisotropy magnetoresistive transducer terminal 3 to add network, wireless receiving terminal 1 is collected the data that all terminals report, wireless receiving terminal 1 255 wireless relay terminals 2 of maximum receivabilities and 255 anisotropy magnetoresistive transducer terminals 3.
Anisotropy magnetoresistive transducer terminal 3 quantity are determined according to parking stall 4, each parking stall 4 is provided with an anisotropy magnetoresistive transducer and surveys terminal, the quantity of wireless relay terminal 2 and installation position are selected according to building structure, parking stall 4 layouts of practical matter, farthest to guarantee the connectedness and the real time of data transmission of Network Transmission under the minimum situation of use equipment.
Anisotropy magnetoresistive transducer terminal 3 among Fig. 1 comprises mutually vertical (X-axis, Y-axis, Z axle) the anisotropy magnetoresistive transducer of three tunnel among Fig. 2, three tunnel identical analogy signal processing units (module), control module (module) and radio frequency unit (module).The anisotropy magnetoresistive transducer is gathered the ground magnetic signal in real time, and exports the correspondent voltage signal and give analogy signal processing unit, and analogy signal processing unit is connected in control module, and control module and radio frequency transmission unit are connected to each other.
Every road analogy signal processing unit among Fig. 2 mainly comprises amplification module, every straight filtration module and voltage comparison module, amplification module is connected in every straight filtration module, be connected in voltage comparison module every straight filtration module, amplification module and voltage comparison module are connected in control module.
Amplification module is used for the ground magnetic signal that anisotropy magnetoresistive transducer unit collects is amplified fully, and the signal after this amplification is sent into the analog to digital converter of anisotropy magnetoresistive transducer terminal 3 control modules after the filtering of process filtration module.
Signal after straight filtration module is used for amplification module handled carries out Filtering Processing, rejects flip-flop wherein, the AC signal when picking up parking stall 4 states and changing.
Voltage comparison module is used for and will compares every the output of straight filtration module and given voltage, obtains the impulse level signal whether parking stall 4 states change, and the anisotropy magnetoresistive transducer information of waking up after control module amplifies three tunnel is gathered.
Control module is used for anisotropy magnetoresistive transducer information is gathered, after the impulse level signal that is produced by voltage comparator wakes control module up, anisotropy magnetoresistive transducer information after D/A converter module by control module is amplified three tunnel is gathered, and compare with original magnetic field of the earth size, through obtaining whether occupied status information of parking stall 4 after certain recognizer, if parking stall 4 states change, parking stall 4 status informations after then will changing are sent into radio frequency unit, send to wireless relay terminal 2 again; Radio frequency unit and wireless relay terminal 2 carry out exchanges data by the mode of radio communication.
Wireless relay terminal 2 among Fig. 1 comprises control module, the radio frequency unit that is connected with control module.Wireless receiving terminal 1 comprises control module, the radio frequency unit that is connected with control module and storage unit, and storage unit is used to store the reported data of receiving.
Between anisotropy magnetoresistive transducer terminal 3 and wireless relay terminal 2, wireless relay terminal 2 adopts data validation mechanism with the wireless transmission of wireless interface receiving end, the transmit leg of data needs to wait for to receive and sends out the acknowledgement frame that returns, to confirm that the take over party receives this Frame after sending Frame; If at the appointed time, transmit leg is not received the acknowledgement frame that the take over party returns, and transmit leg will be retransmitted this Frame, until the acknowledgement frame about this Frame of receiving that the take over party returns.
Between anisotropy magnetoresistive transducer terminal 3 and wireless relay terminal 2, the channel that wireless transmission between wireless relay terminal 2 and the wireless interface receiving end adopts band conflict to avoid intercepts that mechanism is effectively avoided because the collision conflict of shared wireless channel generation, before terminal sends data, renewal configuration or transmitting order to lower levels, terminal is intercepted the channel busy spare time earlier, if channel idle then sends immediately; If channel is then intercepted the channel busy spare time after random delay a period of time for busy again, if channel idle then sends immediately; If channel still for busy, is then intercepted the channel busy spare time after random delay a period of time again, when listening to channel idle, send.
The present invention is except using anisotropy magnetoresistive transducer terminal 3 to wireless relay terminal 2, by wireless relay terminal 2 outside the ul transmissions reported data of wireless receiving terminal 1, also use by wireless receiving terminal 1 to wireless relay terminal 2, send config update and the order of replacement background value to the downlink of anisotropy magnetoresistive transducer terminal 3 anisotropy magnetoresistive transducer terminal 3 by wireless relay terminal 2.
Wireless receiving terminal 1 upgrades decision threshold, background thresholding and the correlation parameter of anisotropy magnetoresistive transducer terminal 3, with the detection sensitivity and the radio frequency transmitted power of change sensor by sending order to anisotropy magnetoresistive transducer terminal 3; Wireless receiving terminal 1 also can issue the order of replacement background value to anisotropy magnetoresistive transducer terminal 3.
In the present invention comprehensive anti-interference processing method has been adopted in interference.This comprehensive anti-interference processing method comprises the low pass circuit filter method, closes the interruption method, intercepts channel idle method etc.The low pass circuit filter method is meant and adopts low-pass filtering to suppress the extraneous high-frequency interferencing signal that takes place on hardware circuit.Close the interruption method and be meant that control module was closed the interruption that the analogy signal processing unit voltage comparison module causes when terminal sent data to wireless relay terminal 2 behind vehicle stabilization (come to a complete stop or leave fully) at every turn.When anisotropy magnetoresistive transducer terminal 3 sends data at every turn, radiofrequency signal can produce bigger influence to circuit, interrupts by closing the mistake that causes when interruption that the analogy signal processing unit voltage comparison module causes can be avoided terminal wireless transmission data effectively.Intercept the channel idle method and be mainly used in the interference of getting rid of between the anisotropy magnetoresistive transducer terminal 3.Specifically refer to when the voltage comparison module output of one of them anisotropy magnetoresistive transducer terminal 3 causes interruption, be in busy condition if detect channel, prove that then this interruption is because other anisotropy magnetoresistive transducer terminal 3 radio frequencies that close on send due to the data, thinks invalid interruption.
The process of anisotropy magnetoresistive transducer terminal 3 concrete unloading lot detections 4 is among Fig. 3: because the ferromagnetic material that vehicle itself contains can exert an influence at the ground in zone magnetic signal to automobile storage, automobile storage is bent at the magnetic field of the earth in the zone magnetic line of force, vehicle sails into when rolling anisotropy magnetoresistive transducer induction region away from, ground magnetic signal in the anisotropy magnetoresistive transducer induction region is exerted an influence, anisotropy magnetoresistive transducer output ground magnetic signal changes the voltage signal that causes and changes, the amplification module of anisotropy magnetoresistive transducer terminal 3 analogy signal processing units amplifies voltage signal, the filtering of analogy signal processing unit is screened the signal that amplified every straight module, extracts the signal that contains information of vehicles.
When vehicle sails the induction region of anisotropy magnetoresistive transducer terminal 3 of the present invention into, the anisotropy magnetoresistive transducer is sensed the variation of ground magnetic signal, and compare with before background value, the variation of this signal is through after a series of signal Processing, can produce one in the voltage comparison module of anisotropy magnetoresistive transducer terminal 3 analogy signal processing units by the low pulse signal that uprises, control module is received the output that this pulse signal just begins to utilize the analog to digital converter that self has constantly to gather the analogy signal processing unit amplification module, thinks peripherally that until signal magnetic field stops sampling after stable after steadily.Whether adjudicate vehicle according to sampled value during this period of time and be parked on the parking stall 4, if judgement is a process for vehicle, then terminal reenters holding state; If judgement is parked on the parking stall 4 for vehicle, then anisotropy magnetoresistive transducer terminal 3 near the wireless relay terminal 2 of information sending to such as is used to self numbering, parking stall 4 wirelessly by radio frequency unit, after wireless relay terminal 2 is received, postback confirmation and give sensor terminal 3, and then give wireless receiving terminal 1 with this data forwarding, can send out confirmation after wireless receiving terminal 1 is received and give wireless relay terminal 2.Wireless receiving terminal 1 is designated the state of being used with corresponding parking stall 4 in display interface, and with relevant information real-time be kept at storage unit.
When vehicle sails out of the induction region of sensor terminal 3 of the present invention, the responsive variation of anisotropy magnetoresistive transducer to the ground magnetic signal, and compare with before background value, the variation of this signal can produce the pulse signal by high step-down in the voltage comparison module of anisotropy magnetoresistive transducer terminal 3 analogy signal processing units through a series of signal Processing, control module is received the output that this pulse signal just begins to utilize the analog to digital converter that self has constantly to gather amplification module, thinks peripherally that until signal magnetic field stops sampling after stable after steadily.Whether adjudicate vehicle according to sampled value during this period of time and sail out of on the parking stall 4, if judgement is not sailed out of for vehicle just moves on parking stall 4, then terminal reenters holding state; If judgement is sailed out of parking stall 4 for vehicle, near then terminal sends to information such as self numbering, 4 free time of parking stall wirelessly by radio frequency unit wireless relay terminal 2, postback confirmation after wireless relay terminal 2 is received and give sensor terminal 3, and then give wireless receiving terminal 1 with this data forwarding, can send out confirmation after wireless receiving terminal 1 is received and give wireless relay terminal 2.Wireless receiving terminal 1 is designated idle condition with corresponding parking stall 4 in display interface, and with relevant information real-time be kept at storage unit.
All terminals in the present invention use outside the device of various low-power consumption, have also adopted advanced power consumption control method, have farthest improved the power supply flying power of system.Anisotropy magnetoresistive transducer terminal 3 among the present invention only just is in normal mode of operation when vehicle moves, other times all are in dormant state.During dormant state, the control module of anisotropy magnetoresistive transducer terminal 3 is operated in the super low-power consumption state, and terminal is closed the power supply of all circuit except that analogy signal processing unit and control module minimum system circuit and supplied with.Radio frequency unit all is in the dormancy closed condition at ordinary times, reported data just after parking stall 4 states change only, and the energy consumption of anisotropy magnetoresistive transducer terminal 3 is very low, and quiescent current only is 1mA; After adding network, wireless relay terminal 2 is in dormant state, use the radio-frequency wakeup function, when anisotropy magnetoresistive transducer terminal 3 has data to send, wireless relay terminal 2 is waken up, enter into normal operating conditions, this working mechanism has effectively reduced the loss of wireless relay terminal 2, and quiescent current has only 10uA.
Behind anisotropy magnetoresistive transducer terminal 3 electrifying startups, at first carry out module initialization work, with wireless relay terminal 2 or the wireless receiving terminal 1 mutual network that adds, after network added successfully, terminal entered dormant state then.The interruption meeting that the voltage comparison module output of analogy signal processing unit causes when vehicle arrives (or leaving) wakes terminal up from dormant state, and the output of beginning control module collection amplification module, after vehicle leaves (or coming to a complete stop), to wireless relay terminal 2 or wireless receiving terminal 1 reported data, after confirming that the take over party receives data, just enter dormant state once more.
Each parking stall 4 among Fig. 4 is detected by an anisotropy magnetoresistive transducer terminal 3, and each wireless relay terminal 2 can be managed 255 anisotropy magnetoresistive transducer terminals 3 at most.During actual the use, can select the number and the installation position of wireless relay terminal 2 flexibly according to the factors such as building structure in parking stall 4 distributions, parking lot.During concrete the installation, anisotropy magnetoresistive transducer terminal 3 is layed in parking stall 4 postmedians, this terminal is fixed in the face of land by four swollen account screws.
The radio frequency unit frequency of operation of all terminals is 433MHz in the system, and bandwidth is 64MHz, message transmission rate and adjustable power, and peak transfer rate 500kbps, maximum transmission power 10dBm, the wireless transmission distance maximum that is embedded in the tomography of road surface can arrive 500m.
The English full name of anisotropy magnetoresistive transducer of the present invention is: anisotropicmagneto resistive abbreviates the AMR sensor as.