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    Using XBee’s for Wildlife Tracking / XBee 900 Range Test

    2010 - 04.24

    Using XBee 900’s for Wildlife Tracking

    Urban Range Test Setup

    We wanted to find out if XBee 900’s could be used as tracking system. Our first test took place at Washington Square Park. We used two XBee Pro 900 RPSMA. Monkey XBee was fitted with a Digi 2 dBi 7 inch omnidirectional antenna. The trackers XBee was also fitted with the same omnidirectional antenna. One person stayed with the trackers XBee at Washington Square Park, while the other person walked north on Fifth Avenue with the monkey XBee. We were able to get a range of .48 kilometers or 1/3 of a mile with the omnidirectional antennas. We then changed the trackers antenna to a 12 dBi Yagi directional antenna. Using the Yagi antenna increased our distance range marginally. We were able to get an additional .09 kilometers or 300 feet from the Yagi. An increased range was a secondary benefit for us.  We used the Yagi antenna mainly to locate the direction of the monkey.

    The second was at Central Park. We repeated the first test to see if the trees and foliage changed our results compared to the urban environment of Washington Square Park and Fifth Avenue.  The distance range was similar to urban test, the real issue is radio interference. We observed packet loss with the XBee’s. This issue is a characteristic of a highly sophisticated networking protocol.  Due to the high radio interference, packets were being resent causing a delay in trying to find the actual direction of the monkey collar.  XBee’s are great for getting you data reliably back and forth.  However, for our purpose we don’t care for data integrity.  We were instead trying to use the XBee’s as radio beacons.  Our conclusion was the XBee’s are not a suitable solution for replacing the current analog tracking system.

    Telemetry Receivers and Consumer Receivers

    2010 - 03.03

    Our group began looking into using consumer grade radio scanners (receivers). They are a lot cheaper then the current telemetry specific receivers. There are pro’s and con’s to each type of receiver. The consumer receivers are cheaper and can be purchased at any electronic store. They offer a lot of features, such as communication with a computer and GPS integration.

    The tradeoff of the consumer radio scanner is they do not have a high sensitivity for picking up faint radio signals. The specific animal tracking scanners (telemetry receiver) can receive the faintest of transmitter beeps. Having a sensitive radio allows the user to hear a signal from a weak transmitting transmitter. The sensitivity of a consumer radio scanner is around 0.4 microvolts. A telemetry receiver has a sensitivity around 0.007 microvolts.

    We tested the consumer radio scanner and a the telemetry receiver to see if there is a noticeably difference in sensitivity. We put both receivers next to each other and had a transmitter collar laying across both antennas. The collar had a very weak signal due to a low battery. The telemetry receiver was able to receive the pulse from the collar while the consumer receiver just heard static noise. The test didn’t have to go any further. It was clear that the consumer receivers would receive the transmitter collar’s signal when battery is fully charged, but overtime the consumer receiver could not detect the faint signal of the radio collar.

    Telemetry Radio Tests from Russell de la Torre on Vimeo.

    Research in Tracking Animals

    2010 - 03.03

    Animal Tracking Whitepaper – Princeton University

    Tiny transmitter tracking Bee’s