APS006: The effect of channel characteristics on time-stamp
accuracy in DW1000 based systems
© DecaWave 2014 This document is confidential and contains information which is proprietary
to DecaWave Limited. No reproduction is permitted without prior express written permission of
the author
Table of Contents
LIST OF FIGURES ............................................................................................................................................... 2
LIST OF TABLES ................................................................................................................................................ 3
1 INTRODUCTION ........................................................................................................................................ 4
2 CHANNEL TYPES ....................................................................................................................................... 4
2.1 INTRODUCTION ........................................................................................................................................... 4
2.2 WHAT DO WE MEAN BY “RANGE” ................................................................................................................... 4
3 LOS OPERATION ....................................................................................................................................... 6
3.1 INTRODUCTION ........................................................................................................................................... 6
3.2 COMMUNICATIONS RANGE IN LOS CHANNELS ................................................................................................... 6
3.3 RANGING ACCURACY IN LOS CHANNELS ........................................................................................................... 7
3.3.1 Overview ......................................................................................................................................... 7
3.4 LOS OPERATION WITH MULTIPATH .................................................................................................................. 8
3.4.1 Introduction .................................................................................................................................... 8
3.4.2 Multipath due to ground-bounce .................................................................................................. 10
3.4.3 Multipath in indoor environments ................................................................................................ 11
4 NLOS OPERATION ................................................................................................................................... 12
4.1 INTRODUCTION ......................................................................................................................................... 12
4.2 REDUCTION IN RANGE DUE TO SIGNAL ATTENUATION ........................................................................................ 12
4.3 TOF ERRORS DUE TO REFRACTIVE INDEX DIFFERENCES ....................................................................................... 13
4.4 NLOS OPERATION WITH MULTIPATH ............................................................................................................. 14
4.4.1 Introduction .................................................................................................................................. 14
4.4.2 Analysis ......................................................................................................................................... 15
4.4.3 Mitigating strategies for operation in NLOS environments .......................................................... 17
5 REFERENCES ........................................................................................................................................... 18
5.1 LISTING .................................................................................................................................................... 18
6 DOCUMENT HISTORY ............................................................................................................................. 19
7 FURTHER INFORMATION ........................................................................................................................ 20
8 APPENDIX 1: ATTENUATION CHARACTERISTICS AND REFRACTIVE INDICES OF MATERIALS .................... 21
9 APPENDIX 2: FRESNEL ZONE ................................................................................................................... 22
List of Figures
FIGURE 1: LINE OF SIGHT CHANNEL ................................................................................................................................. 7
FIGURE 2: NARROWBAND SIGNAL IN THE PRESENCE OF MULTIPATH ....................................................................................... 9
FIGURE 3: ULTRA WIDEBAND SIGNAL IN THE PRESENCE OF MULTIPATH ................................................................................... 9
FIGURE 4: LOS CHANNEL WITH MULTIPATH .................................................................................................................... 10
FIGURE 5: MULTIPATH CAUSED BY REFLECTIONS FROM THE GROUND ................................................................................... 11
FIGURE 6: FADING DUE TO GROUND BOUNCE FOR TWO NODES EACH 1 M ABOVE THE GROUND ................................................. 11
FIGURE 7: RF PROPAGATION THROUGH AN OBSTRUCTION ................................................................................................. 12
FIGURE 8: EFFECT OF AN OBSTRUCTION ......................................................................................................................... 13
FIGURE 9: NLOS WITH MUILTIPATH .............................................................................................................................. 14
FIGURE 10: EXAMPLE CHANNEL IMPULSE RESPONSE OF A NLOS CHANNEL ............................................................................ 16
FIGURE 11: NLOS CHANNEL WHERE THE FIRST PATH IS NOT CORRECTLY DETECTED ................................................................. 16
