UWB Screening Attenuation Measurements of Cars. UWB stellt zwangsläufig gewachsene Strukturen in der Nutzung des Radiospektrums in Frage

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1 UWB eine neue (alte) vielversprechendetechnologie okkupiert Frequenzbereiche traditioneller Radio Services Konkurriert mit Technologien etablierter Services / Dienstleistern Kurzum: UWB stellt zwangsläufig gewachsene Strukturen in der Nutzung des Radiospektrums in Frage 1

2 ECC report 64 : maximum of PSD limits for UWB applications to protect existing radio services 2

3 TG3#16_21R0_UWB_screening-attenuation_measurements_of_cars.doc Contact Info: Dipl-Ing. Hartmut Dunger Phone: +49 (0) Dr.-Ing. Michael Mahler Phone: +49 (0)

4 The condition for the use of Ultra WideBand (UWB) technology is a harmonized regulation (CEPT ECC) and a harmonized standardization (ETSI) as for any other application using radio frequency resources. The existing CEPT ECC decisions regarding UWB, which are currently under work (year 2006), exclude the usage of UWB technology outdoor and inside vehicles. The following measurement campaign was requested by ECC TG3 and conducted by ETSI TG31C. It was managed by Bosch and participated by several companies mentioned later on. The measurements gives results as a basis for an compatibility analysis which can lead to a regulation covering all possible UWB applications in Europe including in-car operation. 4

5 Objectives Requested by European UWB Key Players (sensors and communication applications in the automotive industry) Three cars used: BMW with/without metallized windows and a Mercedes-Benz 10 UWB antenna positions measured Main outcome is the attenuation of UWB signal introduced by the car as a function of frequency ( GHz) Enforcement of an harmonized regulation of all possible UWB applications in Europe including in-vehicle operation 5

6 Antenna Coordinates The antenna pattern is plotted on a polar raster where the radius is the off-nadir angle θ and φ is the azimuth angle The gain values are given in dbi Antenna pattern measured over the upper hemisphere 6

7 Measurement setup o step in φ and θ 24 φ points 26 θ points = 624 point per half sphere 401 discrete frequencies in horizontal and vertical polarisition = measurement results per antenna position Measurement time duration per antenna position 4.75 h

8 Antenna Positions 8

9 Based on initial offline investigations and data sheets the broadband antenna developed by the Leibnitz-University Hannover, Institute for High Frequency Technology and Radio Systems has been chosen as the reference antenna. This antenna fulfils both requirements: covering the complete frequency range of interest with an acceptable matching. 9

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11 BMW with Metallized Windows Total Power H+V Pols (db) UWB Antenna inside the car UWB Antenna in Free Space ~10dB UWB-Ref-Ant-1-Hor UWB-Ref-Ant-1-Ver BMW-2-Metal-Pos-1 BMW-2-Metal-Pos-2 BMW-2-Metal-Pos-4 BMW-2-Metal-Pos-8 BMW-2-Metal-Pos-9 BMW-2-Metal-Pos-5 BMW-2-Metal-Pos Frequency (GHz) 11

12 BMW w/o Metallized Windows Total Power H+V Pols (db) UWB Antenna in Free Space UWB Antenna inside the car UWB-Ref-Ant-1-Hor UWB-Ref-Ant-1-Ver BMW-NoMetal-Pos-1 BMW-NoMetal-Pos-2 BMW-NoMetal-Pos-4 BMW-NoMetal-Pos-5 BMW-NoMetal-Pos-6 BMW-NoMetal-Pos-8 BMW-NoMetal-Pos-9 BMW-NoMetal-Pos Frequency (GHz) 12

13 Mercedes-Benz w/o Metallized Windows 0-10 UWB Antenna in Free Space UWB-Ref-Ant-1-Hor UWB-Ref-Ant-1-Ver M-B-NoMetal-Pos-1 M-B-NoMetal-Pos-8 M-B-NoMetal-Pos-9 M-B-NoMetal-Pos-6 Total Power H+V Pols (db) UWB Antenna inside the car Frequency (GHz) 13

14 Total Power vs. φ and θ (Pos 1) 14

15 Conclusion Positions which illuminate the passenger compartment: BMW-2 (with metal) BMW-1 (w/o metal) MB (w/o metal) db 8-14 db 4-9 db Positions with a LOS view of the RX antenna (positions 6 and 9): Pos BMW-2 (with metal) BMW-1 (w/o metal) MB (w/o metal) db 2 db 5 db 14 db 3 db Engine compartment positions show attenuations between 17 and 20 db 15

16 Conclusion Propagation inside passenger compartment characterized by multiple reflections and refractions Radiated field is Rayleigh distributed and no dominating LOS contribution exists Vehicle type has no significant impact on transmission loss Antenna position has no significant effect on the transmission loss (unless there is a LOS view) 16

17 UWB Sensor Applications inside cars (applications) Object Identification for Surveillance Distances between 0.30 to 2m driver monitoring (e.g. heartbeat for drowsiness detection) Facts: The National Highway Traffic Safety Administration conservatively estimates that 100,000 police-reported crashes are the direct result of driver fatigue each year. This results in an estimated 1,550 deaths, 71,000 injuries, and $12.5 billion in monetary losses. These figures may be the tip of the iceberg, since currently it is difficult to attribute crashes to sleepiness. Iiterature: with the key word sleepiness Accidents with a mental problems (of the driver) Drowsiness, inanttention and medical problems 38% 17

18 UWB Sensor Applications inside cars (applications) Object Identification for Surveillance Distances between 0.30 to 2m child / adult detection and classification airbag controlled deployment (no explosion) or blow control allows re-use and avoids costly replacement (distance and occupant detection (e.g. child seat)) critical situations / out of position Person in out of position, following injuries are possible: - Contusion of the backbone and the thorax - Interior injuries - strong injuries of the head and neck 18