01-08-2014, 01:07 PM
A Parking Guidance and Information System based on Wireless Sensor Network
A Parking Guidance.pdf (Size: 398.51 KB / Downloads: 13)
Abstract
t-This paper introduces a parking guidance and
information system based on wireless sensor system. This
system consists of parking space monitoring nodes, routing
nodes, sink node, parking guidance display and an information
and management center. The nodes transmit the information
through wireless sensor network by tree-like topological
structure with non-standard protocol we developed. After
analyzing and processing the data, the information and
management center would distribute the parking information
by LED screen and displays for the drivers. And the results of
the experiment show that the performance of the system can
satisfy the requirements of parking guidance
INTRODUCTION
Wireless sensor network (WSN) consists of a large
number of low cost sensor nodes which are deployed in the
sensing area. These nodes can form a multi-hop ad-hoc
network by wireless communication. They can sensor,
sample and process the information gathered from the
sensing area, and transmit it to the observer. WSN can be
applied to many fields such as environment monitoring,
intelligent transportation, smart home and so on [1].
During last two decades, the car ownership in China is
growing tremendously, the parking problem in big cities,
especially the mega-cities, has become one of the key
causes of the city traffic congestion. The Parking Guidance
and Information System (PGIS) is considered to be an
effective way to improve parking situation. Unfortunately,
there are only a few of the parking lots have applied the
PGIS whose way of transmitting information is usually
based on RS-485 bus. However, it is not so convenient for
the current parking lots to be equipped with the
cabled-based PGIS, because the reconstruction encumbers
the operation of the parking lots. Furthermore, most of the
nowadays parking lots only control the entrance and exit of
the parking lots, which can only know the whole number of
the available parking spaces in the parking lots, and ignore
the management of the parking spaces and the parking
guidance for drivers inside the parking lots. WSN for PGIS
is presented to solve this problem. WSN-based PGIS can b
SYSTEM ARCHITECTURE
There are three parts in our PGIS: sensor nodes, LED
display, and information and management center. In this
system, the information and management center is the key
part of PGIS, which control the whole system and is
installed in the monitoring room. The WSN in the parking
lot contains three kinds of sensor nodes, which are
monitoring nodes, routing nodes and sink node. In addition,
the LED displays are installed at the main turnoffs of the
roads and the LED screen is installed at the entrance of th
DESIGN OF THE NETWORK
Network architecture
Network communication plays an important role in
PGIS. It consists of the implementation of communication
software module and some important function modules such
as integrating embedded system, formatting the networks
and so on. As a result, the architecture of network
communication protocol is the function core of the whole
sensor networks [3].
The architecture of the system is shown in Fig.2. There
are two parts in the network, they are sensor nodes and
information and management center.
The design of ultrasonic sensor module
In order to get the information of the parking lots
effectively, the status of every parking space must be
detected effectively, reliably and stably. We need to employ
a right sensor to take the detection work, but the cost should
be considered. We will choose the sensor from three popular
sensors, they are ultrasonic sensor, infrared sensor and image
sensor. In references [4], the author made a detailed
comparison of these three kinds of sensor. For infrared
sensor, the process circuit is simple and the cost is low, but
the infrared reflection will be affected by the color of the
cars, thence the infrared sensor is not reliable enough. The
image sensor can detect the parking spaces more accurate, it
is reliable. But it is expensive and the process circuit is
complex. The ultrasonic sensor is cheap, its signal process is
simple, and it can detect the barriers from 2cm to 500cm by
echo stably. Moreover, it’s easy to design the hardware of
ultrasonic sensor, unite the ultrasonic transmitter and
receiver for convenient installation. Through detailed
comparison, we decide to employ ultrasonic sensor. The
schematic design of ultrasonic sensor is shown in Fig. 3.
Non-standard protocol
The function and performance of the wireless
communication protocol is the key factor of the application
of WSN. The network must be fulfilling the function of
resources allocation effectively, such as bandwidth
allocation, transmit power control and power management
etc [8]. To develop a non-standard wireless communication
protocol, we should to deal with the technical matters
involve physical layer and MAC layer. In our system, we
develop a non-standard wireless communication protocol
based on Nordic’s nRF24L01, which involve physical layer
and MAC layer mainly. The communication protocol
architecture is shown in Fig.7. And the details of access
mechanism are described in Table
CONCLUSION
This paper introduces a PGIS based WSN. We
developed three kinds of sensor nodes, which form a WSN
by tree-like topological network with non-standard protocol.
And the information and management center is introduced.
All of those constitute a PGIS. The experimental results
show that the PGIS we developed can satisfy the application.
This system can install in the parking lots convenient. So
that there is no need to change the existing parking system
greatly and little destructive effect; besides, it is compatible
with the existing wired networks. Therefore, this PGIS has
great market significance