Seed Measurement by Radio Wave Spatial Filter

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The electric field intensity of radio waves generated and propagated from a broadcasting station show stochastically periodic spatial pattern due to the multi-pass fading phenomenon. This research aims at developing a new type of speedometer by applying the spatial filtering technique to the change in the electric filed intensity. Further here we consider use of radio waves from satellite for GPS and the fusion of GPS signal with local sensors in the vehicle.The research project was scheduled to investigate the following 4 items, i.e.,(1) investigation of multi-pass fading phenomenon as a spatial measure for spatial filter, (2) development of quick response tuner, (3) use of radio waves from satellite for GPS,and (4) fusion of GPS signal and signals from local vehicle sensors. We have the following results ;(1) As a spatial measure for the spatial filter, the low frequency change in the electric field intensity of radio wave causes error. Spatial difference by 2 antennae of the electric field intensities reduces the low frequency change and yields accurate speed measurement. More antennae than 2 leads to more accurate measurement.(2) Quick response tuner is required to detect the electric field intensity when detected driving vehicle. A tuner with less Q-value was newly developed by using log-amplifier. The tuner can detect the electric field intensity from a vehicle driving faster than 100km/h.(3) We tried to use the change in the intensity of radio waves from satellites for GPS.But we could not find if or if not it can be used, because the sampling interval of the receivers was too slow and essentially, the satellites are moving.(4) The positioning information and those from vehicle local sensors (speedometer and rate gyro) are fused and integrated by applying Kalman filtering technique. The accuracy of positioning is so good that no map information is required.