In 2015 October, I attended 中国第十一届信息无障碍论坛. There was a talk about Guangzhou public bus using BLE beacon technology to help user identify the bus.
This BLE beacon technology is quite new. Apple introduced iBeacon in 2013. One of the use is for Indoor Navigation. It's distinguished feature is it's ability to measure the precise distance between the beacon and it's receiver, notably user's iPhone.
What are the pros and cons of using it as an indoor Navigation system?
PROS
1. The system was specifically designed for this purpose.
2. It does not require complex system to set up although it does require a database system to provide a navigation map.
3. Scalability is flexible.
4. It can tell precisely the distance and the approximate direction by moving the reader around.
5. Both iPhone and Android are now capable of accessing BLE beacons.
CONS
1. The beacon is an active device that requires power supply in the form of battery or wired power line. Constant maintenance is required if battery is used.
2. Each device have a specific ID. In times of breakdown, maintenance will have a hard time detecting it unless the specific location is reported.
3. Cost is a great concern. In a typical building, a complete navigation system will require high numbers of beacons.
4. Proximity of beacon. The beacons cannot be placed too closely together. At any time only one can be accessed as it only tells the distance not direction. This could be overcomed by multiple scanning but it will slow down the speed of reading.
5. Implementation is also an issue. Unless the public is willing to invest in the beacon infrastructure, it will be limited. It will not be cost effective to provide for a small groups of clients. Small Enterprise will find it more costly to implement by themselves.
6. Unless hand phones can be cheap enough, user may not even have access to the technology.
Other devices like wifi/bluetooth hotspot or active RFID requires special reader devices that may have to integrate with hand phones. Proximity measurement virtually does not exist. Recently, I device a method of using RFID for navigation. If RFID is laid along a path with a known distance gap, A reader can read at least 2 or 3. While on the move, the reader can read more RFID and can tell which one is no longer in the list. By comparing with the last read RFID, You can actually tell which direction the reader is moving. This is provided a map of all the RFID are done. It like picking up sweets on the floor that is laid in a trail. This method does not require active RFID thus it is much cheaper to deploy and maintain.
Ultra sound emitters that sends out coded data requires higher power and may disturb guide dogs. I am not sure hand phones can receive ultra sound. Also in noisy environment. It will be difficult to implement.
Coded UV light communication will be directional but cannot determine proximity unless programmers can write codes to measure it. It also requires special hardware.
A new development is to use Augmented Reality. Apple have ARkit and Google have ARcore Unfortunately Google terminated the Tango project and replaced it with ARcore which does not do well detecting proximity unless OEM uses two camera technology and Google ARcore adds the "Measure" technology to make use of it. Other uses of this technology like heptic feedback is used to let VH "touch" objects but that is not the topic of discussion.
One of the main requirement of navigation is routing. It allows users to get to their destination from specific location. Routing requires waypoints. Thus it is important to get location info from waypoints. Besides beacons, there is actually a lack of such hardware. AR series uses camera to read the surrounding. If a known start point is determined, it does not require many waypoints. Unfortunately the technology is still new and lacks critical modules to determine precise proximity as currently it lack depth of field resolution capability.
Unless manufacturers and enterprises are willing to develope hardware that could determine direction and proximity and integrate with hand phone, it is still a long way for VH to fully navigate by themselves without assistance.
AR series technology is promising as it does not require hardware beacon devices to provide waypoints. If both Apple and Google are willing to use two camera devices to develop depth of field measurement, it will be good news to VH society. It is still feasible as we don't require precise measurement of objects. VH just need to use their cane to do more close proximity of distance.
One hardware I would like to introduce is the Raspberry PI computer. It is quite small (cigarette box size without battery and keyboard) with a complete Linux OS but it packs a punch. It has big range of sensors that can be used. Raspberry Pi Zero is a US$5 device that have USB Port. Just plug in a BLE USB dongle to provide bluetooth capability. All that is required is to make it a transmitter with unique ID. GitHub already have a Python script to simulate iBeacon funtionality. The standard Raspberry pi can be used as a navigation device. It costs just US$35. It does not have facility to compute proximity as provided by Apple or Google yet. The Zero series can be used with iPhone or Android already.
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