This Ultrasonic scanner is made by Devantech that has a longer range than the SRF04.
This great sonar ranger from Devantech offers an amazing wide range from 3cm to 6m. Unlike the SRF04, the SRF08 is interfaced using the IIC/I2C bus. There is an additional photocell sensor on the front of this detector.
Beacons are mounted on walls or ceilings to measure distance to other beacons and “hedgehog” using ultrasonic pulses. They communicate with router wirelessly in ISM band. Powered by LiPo battery or USB. Indoor Positioning System (IPS)
LT2/F w/Arm "Bulldog" - Advanced Package with additional customization