Plans are in sight to shrink this to 0.320 grams for insect monitoring. The requirement for extreme precision in test subject location is for purposes of recapture and expanded examination.
Dinosaur system in current use- and animal has to be big as a dinosaur to carry their transmitter.
Their business model is about to change.
A local (Sydney) research group tracking small possums approached our radio club about their need for a system under 50grams that can run for a month or three while reporting position (and altitude) to sub-metre accuracy. The GPS systems they've been using fail on multiple fronts, and at $AU5000 each, are a substantial loss when they detach inside a hollow tree - often in a protected forest which cannot be cut to retrieve the Tx.
The range of movement is only a few hundred metres, so it doesn't need satellite Tx range. We discussed a number of options, including some of the AoA ones based on BLE, SX1280, as well as UWB impulse ranging devices, of which the Decawave TREK1000 seemed more viable than the highly protected and commercialised Ubisense or TDS systems.
The AoA systems cannot resolve accurately in the presence of multipath, which is a significant drawback given the forest environment. They just don't have a wide enough bandwidth to solve the geometry. The SX1280 systems might work ok for balloons but not in a forest.
Interesting papers:
A colleague did a system for small balloons many years ago, using RF cycle counting. It had no data super-imposed so could not re-acquire after LOS, but worked by correlating the differences in received cycle counts from multiple points and triangulating from that. I suppose you could superimpose a time code using PSK, to allow re-acquisition.
BTW the market opportunity here is for warehousing and site tracking such as in mining - the animal trackers are just for the feel-good marketing stories.
Clifford Heath.
I think you'll find modern GPS and communication techniques made feasible by more modern high performance technology have greatly simplified the implementation of such systems. Rohde & Schwartz has been handling the RF end which they sumarize here:
Icarus is cool, but GPS is nowhere near accurate enough for this, especially in altitude. These researchers need to know which branch a small animal is on, not just what tree or forest they're in.
The UWB base stations proposed would be just a suitcase-sized thing with something like the radio, an RPi and a battery. Sub-orbital, in any case, and a good deal cheaper.
CH
CH
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