Understanding Smart Sensors - Nomads.usp

Transceivers, Transponders, and Telemetry 189combination of inclinometers, gyroscopes, inverse Loran, electronic odometers,and/or antilock brake system wheel-speed sensors. In addition, the cellularinfrastructure and/or radio beacons play an integral part in the vehicle navigationrequirements of ATMS, ATIS, APTS, ARTS, and CVO. The AVCS systemwill require sensors to determine distance between vehicles for smart cruisecontrol (automatic vehicle spacing) and closing distance (time to impact) forcollision avoidance systems. Figure 8.9 indicates the typical frequency ranges ofthe RF sensors.One configuration of a vehicle navigation and warning (VNAW) systemis shown in Figure 8.10. The smart inertial navigation system (SNS) containsthe computing that provides filter and integration for the GPS input as well asthe accelerometer and gyroscope inputs [21]. The output of the SNS is positioninformation for the VNAW system.Collision avoidance in an automotive ITS uses a 75-GHz three-beamradar unit to provide a time-to-impact warning. One system can track up to12 objects while measuring range angle and relative velocity [22]. The radarsystem also employs a video camera mounted near the inside mirror to providea 30-degree field of view. The camera detects lane markings, road edges, andobjects in the vehicle’s path.Near-obstacle detection systems (NODSs), for parking and blind-spotdetection, use Doppler radar operating at 10.5 to 24 GHz to sense objectsNear obstacle detectionBlind spot detectionCollision warning and avoidanceSpeed sensingAdaptive cruise controlPosition trackingNavigationPosition trackingVehicle identificationVehicle identificationDCKeylessentryKeylessentryTraffic managementIntelligent transportation system (ITS)Airbag armingAntitheftLight10 MHz 20 50 100 MHz 200 500 1 GHz 2 5 10 GHz 20 50 100 GHzExistingFrequencyDevelopingFigure 8.9 Frequencies of RF automotive sensing applications.