Project Concept Descriptions
Table of Contents
- Communication using radio waves to exchange information between a reader and a tag. A read range from millimeters to meters depending on the frequency of the reader.
- Tags consist of an integrated circuit to process information/signals and an antenna. There are two types of tags that we would possibly use:
- Passive Tags: no power source and require external electromagnetic field to initiate signal transmission.
- Active Tags: contain battery and can transmit signals once an external source has been identified (expensive)
Idea for Project:Each room in building 9 will be tagged with passive tags.
Explanation: Didn't choose due to less accurate positioning. But this idea was a good starting point.
- Electromagnetic radiation with a wavelength between 0.7 and 300 micrometers.
- Can produce distance value when close enough to destination
Idea for project: Use IR to determine distance from different locations and base directions off of these values.
Explanation: Did not choose due to high instance for interference by other people in hallway. Need line of sight for this tactic to work.
Idea for project: Existing WiFi technology on the 2.4GHz spectrum can be used to triangulate the location of certain Wi-Fi aware devices using a concept similar to time-of-flight distance measurements. (Triangulation requires multiple Wi-Fi sources) Accuracy is typically within a few feet.
Explanation: While at first glance RIT's large Wi-Fi installation makes this an attractive choice, several limitations seem to exist. First and foremost, the 2.4GHz spectrum reflects off many surfaces. This means that while time-of-flight information is often thrown off balance, because reflections cause the signal travel distance to increase unpredictably. Most existing implementations of this concept are limited to a single open space, not an entire building with many rooms and hallways. This limitation could be overcome if each and every room and hallway we wished to navigate around contained multiple Wi-Fi sources. We deem this prohibitively expensive, and do not continue with this concept.
Idea for project: Traditional GPS systems are accurate to within ~3 meters. However using a localized antenna to assist triangulation with the necessary 4 GPS satellites, a system can measure distance accurately to within centimeters. This system could provide the accuracy required to navigate a building.
Explanation: The availability of GPS signals all over the world makes this the choice for a scalable implementation. However the cost of the hardware for this system is much too expensive. Also, the time required to design and test the software implementation is also too great for the scope of this project. Augmented GPS also does not allow for orientation to be determined, therefore we would also need a type of compass subsystem.
RFID & IR
Idea for project: Combination of RFID and IR (See above for description) to obtain better accuracy in direction and location.
Explanation: Did not choose due to inaccuracy with IR and likelihood of interference.
RFID and COMPASS
Idea for project:A drawback of an RFID implemented GPS system is the lack of knowledge of which direction the user is facing when they first begin to use the device. This information is important in determining the first step of the directions (keep straight ahead, turn to the left, turn to the right, turn around). Without it there is no way to know where the desired endpoint location is with respect to the direction the user is facing. By adding a compass to the design, the direction the user is facing can be determined. With this added information, it would be possible to provide the user with accurate directions to their final destination.
Explanation:This concept was the one that we ultimately chose to continue on with. It offered a combination of relatively low cost and high accuracy that none of the other concepts rivaled.
TWO RFID TAGS
Idea for project:In using RFID as a form of navigation, the precision of location identification is sub-par. An RFID tag can be read within a certain range of an RFID reader. Aside from knowing that the reader is within a specified range of a tag when that tag's ID number is read, not much else can be determined in respect to specifics of a location, such as where inside the tag range the reader is located. With the addition of a second RFID reader and tag set, with a different frequency and smaller read range than the first set, some precision can be added to the location identification. If the two different tags are located next to each other, two ranges are created, with one extending farther out than the other. If the reader passes through the larger range, the user has an idea of where they are. By then passing through the smaller range, the direction of travel can be found and a more location accurate location can be identified.
Explanation:RFID reader modules are fairly expensive. This concept requires two of them, and therefore was not chosen.
UltrasoundIdea for project: Use Ultrasound once in classroom to find the door again.
Explanation This was not chosen due to interference from surroundings (classmates) and difficulty generating directions from the readings.