Tuesday, December 18, 2012

Fruit-Bat Tracking with Robin GPS Logger

I have recently received the results of an interesting experiment done with Robin, Cellguide's snapshot GPS tracker so I thought I should share it with the Community.

Figure 1: Yes, a fruit bat
Becuase of its size and weight Robin enables new applications of GPS technology, including wildlife tracking of course. Particularly of species on which was very difficult in the past.

Test Setup 
  • CellGuide Robin GPS Logger with 100mAh battery (2.2 grams): total weight 4.75 grams
  • Programmed to operate every day between 5pm to 5am
  • Total length of the experiment: 72 hours
  • Operating regime:
    • Fix every 3 seconds
    • Medium sensitivity (GPS snapshot length of 128ms)
The test was conducted by researches from Tel Aviv University. They packed Robin in a light weight plastic wrap along with a UHF beacon device, and attached everything to the bat using a special medical glue that only sticks for a few days.

Figure 2: A picture of the fruit bat with Robin on the back.
Figure 3: The test area.
During the first night, the bat visited three other trees along its path. On the second night, the bat took a bit of a different path but still quite similar to the one from the previous night and flew to the same tree. Then, pretty much as the two previous nights, the bat flew to his favorite tree again.

 Figure 4: From left to right: first, second, and third night

The Robin logger was found two weeks later inside the cave, using a UHF beacon device. A summary of the experiment is given below.

Figure 5: All nights on the same map.
Despite this experiment being simply very cool for a GPS passionate as I am, I shall probably mention here that I don't work for Cell-guide so for further information on the Robin GPS Logger please do contact the experts!


Friday, December 14, 2012

Full Galileo IOV

After a long wait, it was a pleasure this morning to record the full IOV constellation.

Figure 1: Orbitron prediction of Galileo visibility this morning.
The NV08C-CSM receiver with a R&D firmware could track all 4 IOV Galileo satellites, as well as another 21 SVs between GPS, Glonass, and EGNOS.

Figure 2: NVS Storegis recording NMEA with all 4 IOV satellites.
An excerpt of the log file:


I also turned on my SdrNav00 modified with a 26MHz oscillator and obtained the following:
Figure 3: SdrNav00 signal properties.
Figure 4: SdrNav00 signal power spectrum

Figure 5: Galileo acquisiton on E1b signal.

Galileo pseudoranges were logged by NV08C-CSM and by my SdrNav00, so the next step is to try PVT with the TUM orbits.