Optimering av ultraljudssändare- och mottagare avseende räckvidd, strålningsvinkel och energiförbrukning
Embedded Systems Lab at Umeå University is currently part of a research project with the purpose to examine the behavior of dairy cows inside a barn. Each cow needs to be tracked with a precision of 50 cm, and since GPS-technique has poor functionality at indoor environments, an indoor positioning system needs to be developed.Embedded Systems Lab has already developed an indoor positioning system using IR-light and radio, but since this system demands extensive infrastructure and is rather expensive, an alternate positioning system using ultrasonic pulses and radio is being examined.In this report the range, beam angle and current consumption of ultrasonic transmitters- and receivers are investigated. Three different driver stages for the transmitter is tested, and two amplifier solutions for the receiver. The report also describes how the length of the transmitted ultrasonic pulse affects the received signal, accessibility of a ?shadowed? signal, and the effect of different sound frequency.