International Journal of Computer Applications (0975 – 8887) Volume 11– No.1, December 2010
Dynamic Data update for Intelligent Speed
Adaptation(ISA) System
B.Karthikeyan M. Tamileniyan
Embedded System Division Post Graduate Engineering Trainee School of Electronics Engineering AutomotiveInfotronics VIT University, Vellore
ABSTRACT
The Intelligent Speed Adaptation in vehicles using GPS technology is a method of speed adaptation in vehicles based on
its position on the highway. The position can be recognized using the GPS receiver. The main objective is to make the
system simple. The Toll gates on the highway are equipped with a transmitter that transmits a very small data to the receiver system in the vehicle. The received data carries a table of information with the latitude-longitude and its speed limit. As soon as the system receives the signal, the system starts operating; the system checks the latitude longitude data with the current position. When the system reaches the position, the controller informs the driver about the speed limit and also limits the speed of vehicle to the speed limit levels. Simultaneously the second data is taken from the received data and checks for next position and so on, till the last data. After the given data is executed, the next toll gate will be approaching for the speed limit patterns till the next tollgate. This system reduces usage of memory that is used for storing large map information, also reduces the cost of implementation in vehicles.
Key words: ZigBee, Dynamic Data, Speed Adaptation 1. INTRODUCTION
Intelligent Speed Adaptation (ISA), also known as Intelligent Speed Assistance, is any system that constantly monitors vehicle speed and the local speed limit on a road and implements an action when the vehicle is detected to be exceeding the speed limit. This can be done through an advisory system, where the driver is warned, or through an intervention system where the driving systems of the vehicle are controlled automatically to reduce the vehicle?s speed. Intelligent speed adaptation uses information about the road on which the vehicle travels to make decisions about what the safe
speed should be. This information can be obtained through use of a digital maps incorporating roadway coordinates as well as data on the speed zoning for that roadway at that location, through general speed zoning information for a defined
geographical area (e.g., an urban area which has a single defined speed limit), or through feature recognition technology that detects and interprets speed limit signage. The purpose of ISA is to assist the driver in keeping to the lawful speed limit at all times, particularly as they pass through different speed ?zones?. This is particularly useful when drivers are in unfamiliar areas or when they pass through areas where variable speed limits are used. Most drivers do not appreciate the extra risks involved in traveling just a few km/h over the speed limit. Most think that the risk of a casualty crash is doubled if traveling at least 25 km/h over the speed limit. Research has found that that, in urban areas, the risk of a casualty crash is doubled for each 5 km/h over the limit. So traveling at 70
km/h in a 60 km/h zone quadruples the risk of a crash in which someone is hospitalized. As a result, it is estimated that about 10% of casualties could be prevented if the large group of motorists who routinely travel at up to 10 km/h over the limit were encouraged to obey the speed limits. About 20% of casualties could be prevented if all vehicles complied with the speed limits. Savings in fatal crashes would be larger. There are many types of ISA systems of which GPS based ISA is the most recent and effective system. A GPS receiver is used with the ISA system to detect the vehicle?s current location on the earth as coordinates, and this coordinates are use to find its location by a preloaded map which contains the information about the roads and its various highway signals and speed limits. Event though this system is recent and effective, there are few limitations in this system and that is why this project is done to reduce to cost of the existing system, to improve the reliability and to make the system have updated information, dynamically.
1.2 Existing Speed Adaptation systems
There are number of Speed Adaptation systems proposed, at different times, but they are not effective and resulted in failures. Some important Speed Adaptation Systems are
1.2.1 RFid - Radio beacons
Roadside radio beacons, work by transmitting data to a receiver in the car. The beacons constantly transmit data, which the carmounted receiver picks up as it passes each beacon. This data could include local speed limits, school zones, variable speed limits, or traffic warnings. If sufficient numbers of beacons were used and were placed at regular intervals, they could calculate vehicle speed based on how many beacons the vehicle passed per second. Beacons could be placed in/on speed signs, telegraph poles, other roadside fixtures, or in the road itself. Mobile beacons could be deployed in order to override fixed beacons for use around accident scenes, during poor weather, or during special events. Beacons could be linked to a main computer so that quick changes could be made. This system can be used only for slow vehicles. Practically it cannot be used in the highway for vehicles with high speed. When vehicle moves with high speed on the road, the data will not be picked up by the car unit, and hence this system was not effective
1.2.2 Optical recognition systems
This system uses a camera mounted on the car to continuously capture the images on the road. The image is processed to find if there is any sign board present on the image, this is done by digital image processing to detect the shape of the signboard. Once the sign board is found, the other algorithm to find the pattern in the image in the signboard is used to extract the symbol and compare to recognize the sign board. According to the symbol recognized, information is given to the driver either by a LCD display on the dashboard or by buzzer alert or even control the vehicle automatically to strict to highway rules. It should be noted that all these process must be carried out within a fraction of second. It was suggested to keep the visual sign boards more away from the point. For eg. Now if the signboard is placed 50m away from the speed breaker, it was suggested to keep the signboard a 100m away so that the system has enough time to process and driver has enough time to control the vehicle. ? This system uses complex algorithm ? Uses much resources
? Some critical cases when the sign board is covered by tree branches, the system does not detect the sign board.
1.2.3 Dead reckoning
Dead reckoning (DR) uses a mechanical system linked to the vehicle?s driving assembly in order to predict the path taken by the vehicle. By measuring the rotation of the road wheels over time, a fairly precise estimation of the vehicle?s speed and distance traveled can be made. Dead reckoning requires the vehicle to begin at a known, fixed point. Then, by combining speed and distance data with factors such as the angle of the steering wheel and feedback from specialized sensors (e.g., accelerometers, flux gate compass, gyroscope) it can plot the path taken by the vehicle. By overlaying this path onto a digital map, the DR system knows approximately where the vehicle
is, what the local speed limit is, and the speed at which the vehicle is traveling. The system can then use
information provided by the digital map to warn of upcoming hazards or points of interest and to provide warnings if the speed limit is exceeded.
This system is much complicated with multiple sensors and possibility of deviation from actual position is high
1.2.4 GPS based systems
GPS is based on a network of satellites that constantly transmit radio signals. GPS receivers pick up these transmissions and compare the signals from several satellites in order to pinpoint the receiver?s location to within a few meters. This is done by comparing the time at which the signal was sent from the satellite to when it was picked up by the receiver. The GPS receiver module tracks its position and using the pre loaded map with speed zone database, the speed adaptation is done.
? Requires a large memory to store the complete map and speed zone databases.
? Emergency sign boards like “MEN AT WORK”, “TAKE DIVERSION” etc. are not updated to the system dynamically. 1.3 Need for a new system
? To over come the limitations of the other Speed adaptation systems.
? To reduce the memory requirement of conventional GPS speed adaptation techniques. ? To reduce the system cost
? To enhance the system performance to provide dynamic update of information.
2. SYSTEM DESCRIPTION 2.1 System Overview
The Intelligent Speed Adaptation system with Dynamic data update contains the basic control system for conventional GPS based ISA system with a GPS receiver to locate their vehicle?s geographic location and a wireless transceiver to receive the data which is a table of coordinates and speed limit.
2.1.1 Overall System Operation
The overall system contains the essential components of the ISA system with a wireless Transceiver. The tollgates in the highway have a Transceiver that is capable of communicating with the vehicle?s transceiver. The tollgate sends a data continuously around its coverage range. When the Vehicle which is equipped with the proposed system arrives near the tollgate, the data broadcasted by the tollgate is received in the vehicle module. This data is stored into the memory of the ISA system. The data sent is a table of information of coordinates and speed limit. That is, it contains the latitude and longitude value of a location and its corresponding speed limit or highway traffic symbols. As soon as the data is stored in the memory, The GPS receiver tracks it location and compares its coordinates with the table of coordinates received, as soon as the first value of coordinates and the current coordinates from GPS matches, the corresponding speed limit listed in the table is chosen as the speed limit from that point. The ISA system then alerts the driver by sound alert, displaying the speed limit and indicates the speed limit of the location.
2.2 Algorithm
Step 1: The Vehicle?s wireless device is ON as soon as the vehicle is started, and waits for the data to be received. Step 2: When Vehicle approaches the tollgate in the highway, and when it comes in to the tollgate?s wireless coverage area, the communication link is established
Step 3: Based on the communication link and direction,the data is sent to the vehicle?s wireless node. The data is stored into the memory stack.
Step 4: The stored data is the table of information based on geographic coordinates of the vehicle (longitude & latitude) and corresponding speed limits and highway signs are arranged in proper sequence.
Step 5: Stack data is compared with the received data, when received data is equal to the stack data, the
International Journal of Computer Applications
