【作者】 周兆丰；

【导师】 夏应清；

【作者基本信息】 华中师范大学 ， 电路与系统， 2007， 硕士

【摘要】 随着车辆的迅速增加，在大中城市特别是经济繁华的商业区附近，很多车辆因找不到停车场或因停车场管理效率低而导致交通严重堵塞。现有停车场大多采用人工收费方式进行管理，少量停车场则采用无源射频卡实现了自动化管理。但是无源射频卡系统不仅识别距离近，不能很大程度地提高收费效率，而且也不能利用其实现车辆信息的查询，特别是这样的管理系统没有车位检测的功能，不能实现泊车引导。目前无论是新建停车场还是对已有停车场的改造，无论是停车场管理者还是机动车司机都希望出现一种能实现不停车收费、实时车位检测及车辆的信息查询高效率和人性化的智能停车场管理系统。ZigBee技术是一种专注于低速率、低成本、低功耗、低复杂度和高安全性的新兴技术，其应用平台成本低廉而且用途非常广泛，因而近年备受关注，成为目前无线技术研究的一个新热点。为满足市场需求，本文设计了一种基于ZigBee网络的具有不停车收费(自动收费)、泊车引导、车位检测和车辆信息查询功能的智能停车场管理系统。整个系统由入口通道子系统、场内子系统、泊车引导子系统、出口通道子系统和控制中心五部分组成。各个子系统通过ZigBee网络进行通信，其中场内子系统由主控器、读写器和标签三部分组成，三者之间也是通过ZigBee网络进行通信的。本文主要完成了场内子系统的读写器和标签的设计，主要研究内容如下：(1)设计了超声波测距电路，实现了读写器的车位检测功能。(2)设计了低频唤醒电路，解决了接收端标签的功耗问题。低频唤醒电路由发射电路(读写器)和接收电路(标签)两部分组成，发射电路主要是由电流驱动器AS4420和串联谐振电路组成；接收电路主要由低频接收芯片ATA5283和并联谐振电路组成。(3)编写了标签端的程序，实现了低频唤醒确认码的识别和数据的发送，有效地解决了干扰问题。(4)经过对ZigBee协议栈的简化，优化了程序，大大减少了代码量，使得标签可以用低成本的单片机C8051F410来设计并同时提高了标签的效率和稳定性。最后，对系统低频磁场的覆盖范围和标签被唤醒时的方向性问题进行了测试，结论表明低频唤醒的效果良好，达到了市场的要求。更多还原

【Abstract】 With the quick increment of the vehicle, many vehicles cause the traffic jam because of the lack of parking space and the low efficiency of park management, especially in the prosperous business streets of the big cities. Though a few parks can realize automatic management using passive RF Card, many parks still adopt the manual mode. Because the passive RF Card has much shorter working distance, it can not improve the efficiency of charge. And the information of vehicles is not inquired by using this system, especially in which the parking guidance can not be implemented. So, a kind of intelligent park management system, which satisfies the function of no parking charge, real-time parking space detection and inquiry of the vehicle information, is expected to the market.Zigbee is a new technique, which has advantages of low rate, low cost, low power consumption, low complexity and good security. Therefore Zigbee technique is becoming a hotpot of the wireless communications field. In order to meet the demand of markets, this thesis designs a kind of intelligent park management system based on Zigbee network to realize the above functions.The system is composed of entrance sub-system, park sub-system, park guide sub-system, export sub-system, and control center. All the sub-systems can communicate with each other by Zigbee network. The park sub-system includes master、reader and tag, and they also communicate by Zigbee network.The thesis mainly finished the design of reader and tag in park sub-system, the research is as follows:1. We design the ultrasonic circuit for measuring distance and realize the function of park space detection.2. We design the low frequency wakeup circuit, which is composed of the transmitting circuit and the receiving circuit, to solve the power consumption problem of the tag. The transmitting circuit is mainly composed of AS4420 and the serial resonance circuit, and the receiving circuit is mainly composed of ATA5283 and the parallel resonance circuit.3. We finish the program of the tag, which can identify the code of the low frequency wakeup circuit and transmit the data, to resolve the interference efficiently.4. By simplifying the protocol stack, the program is optimized and the number of code is decreased. The tag can adopt a low cost MCU C8051F410, and the efficiency and stability of the tag is also improved.At the end, we finish two kinds of test, including the covering area of the low frequency magnetic field and the orientation problem when the tag is waked. Conclusions show that the effect of the low frequency wakeup is all right and it can meet the demand of markets更多还原