IMES for Mobile Users Social Implementation and Experiments based on Existing Cellular Phones for Seamless Positioning Dinesh Manandhar, Seiya Kawaguchi, Masayuki Uchida, Makoto Ishii, Hideyuki Torimoto GNSS Technologies Inc., Japan
Contents Introduction Background and Concept Experiments Various Locations Interference Analysis Conclusions 1
IMES stands for What is IMES? Indoor MEssaging System It transmits the position data itself in the Navigation Message 2
Background - 1 Japanese E911 legislations were enforced in April 2007 More than 100 Million cell-phones with GPS receiver in Japan in a couple of years Number of mobile phones in the world 3.3 billion by November 2007, Penetration Factor of 49% Source: http://en.wikipedia.org/wiki/mobile_phone#cite_note-9 http://www.chinapost.com.tw/business/global%20markets/2008/05/26/158188/mobile-phone.htm LBS market is expected to grow drastically Seamless positioning is one of the most important requirements for commercial applications. Several approaches RF ID, WiFi, UWB, Pseudolite, Repeater and so on.. And of Course ultimately IMES JAXA is developing QZSS in order to improve GPS availability, especially, in the urban canyon. proposing a new approach to expand this improvement from urban canyon to deep indoor environment, that we understand as value added use of QZSS 3
Concept of IMES - 2 Principle of Proposed IMES System 50% Discount On Ladies Shoes Warning Message Fire on 5 th Floor Weather: Sunny, 20 0 C Lat: 39.12345 RH 60% Long : 139.45678 Heigth: 45 Transmit ID and/or Position, Address Where am I? 5th Floor Mens Store Nihon-ya, Shinjuku 3-1-110 4
IMES Message Type #1, 4-Word Position Data 5
Experiments
IMES Control Software 7
Experiments Conducted at Various Locations Anechoic Chamber Building Entrance Office Room Building Entrance 8
Underground Parking Areas IMES Enabled Cell Phone Indoor Demonstration at Underground Parking 9
Observation using Mobile Phone IMES Enabled Phone GPS Antenna Standard GPS Phone IMES Enabled Phone Inside Pocket IMES Enabled Phone inside BAG 10
Public Facility Location Department Store, Shoe Section Railway Stations Department Store 11
IMES Output Position Data 12
0.20 m ~ 3.2 m Preliminary Interference Experiment This is the Worst case scenario, i.e., IMES transmitter is located just above a GPS antenna. IMES Signal 50cm Tx Power: 1. -64dBm Tx Power: 2. -70dBm Tx Power: 3. -76dBm IMES Tx. Antenna IMES & GPS Signal Rx1 Software Receiver Antenna & Commercial GPS Receiver 30m Rx2 Receiver antenna Reference Antenna GPS Only 13
0.6m 1.0m 2.4m 3.2m IMES Transmitter Signal Level (C/No) of Tracked Satellites Tx Power -64dBm IMES GPS Distance when First Position was Output Tx Power -70dBm IMES GPS Tx Power -76dBm IMES GPS GPS Receiver 14
Experiment Results Summary This is the Worst case scenario results, i.e., a IMES transmitter is located just above a GPS antenna. Transmit power Threshold Distance for TTFF -64dBm 240cm -70dBm 100cm -76dBm` 60cm 15
Summary We have conducted experiments using IMES in various locations: Anechoic Chamber To analyse the signal propagation behaviour Inside Buildings Office Rooms Building Lobby Building Entrance Underground Areas Inside Underground Parking Areas Inside Railway Stations Inside Department Stores These experiments have shown successful results for mobile phones as well as for standard GPS receivers. The interference analysis experiment has shown that there shall be minimum threshold distance between IMES transmitter and GPS receiver for GPS to work properly This threshold distance (0.6m to 2.4m) can be easily maintained based on location area. Further experiments and simulations will be conducted to define the rules for setting transmit power based on location area and application type 16
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Background - 2 There are other indoor navigation systems like A- GPS, E-GPS and Pseudolites etc But they have unstable accuracy The accuracy varies case by case from few meters to few hundreds of meters Difficulty in deep indoors During emergency, a search in 3-D space in 100m accuracy is not a good figure How to know that the victim is on the 15 th Floor, Room No 1510 precisely? 19
IMES Concept 1: Position Information Transmit Position Lat: 39.12345 Long : 139.45678 Heigth: 45 5th Floor Mens Store Nihon-ya, Shinjuku 3-1-110 Where am I? 20
Concept of IMES - 1 Outdoor Positioning Indoor Positioning Same handset can be both indoors and outdoors Server access for various info. Related to position and attributes, if necessary 21
Concept of IMES - 3 IMES can transmit its position in three dimensions and/or Tx. ID directly without performing any ranging between the transmitters and receiver other required information if necessary, e.g. location address, text message and so on. Signal is still compatible and interoperable with L1C signal from GPS/QZSS satellites for seamless positioning The same Receiver can acquire signals from satellites as well as indoor transmitters This means similar signal structure 22
Inside Railway Stations 23
TTFF at Different Tx Power 24