New Product Announcement: GPS

[sakerjack]

At that cost you'd need a "LIFETIME WARRANTY" against everything to include loss...When is somebody gonna make affordable equipment for falconry? Not saying $995 isn't worth it, but at that price I hope they are not planning on selling to many of them... JMHO

Sorry but after watching the video Marshall radio will sell a S""t load of them. Well done!!

[thunderheartiii]

Sorry but after watching the video Marshall radio will sell a S""t load of them. Well done!!

I hope they do...

[sakerjack]

Hey Jim it is well past my budget for what I can afford to spend. So it will be RT and scout transmitters for me.

[Tony James]

Hey Jim it is well past my budget for what I can afford to spend. So it will be RT and scout transmitters for me.

Hi Ken,

as you know, I'm not the type to get excited by gadgets and new technology, but I can hardly contain myself with this.
I think the interesting possibilities, as well as the practical ones, are endless.
And the fact that this is available in a standard transmitter sized package is quite amazing.

Best wishes,

Tony.

[sakerjack]

Hi Ken,

as you know, I'm not the type to get excited by gadgets and new technology, but I can hardly contain myself with this.
I think the interesting possibilities, as well as the practical ones, are endless.
And the fact that this is available in a standard transmitter sized package is quite amazing.

Best wishes,

Tony.

Friggin agreed!!!

[rrcoati]

Can you use two at once?

[Captain Gizmo]

The Global Positioning System (GPS) is a location and navigation utility using a transmit only satellite constellation. This means that the user handset is a receive only device. The receiver listens to a set of 24 satellites (plus 12 "spares") in 55 deg. inclined orbits with 12 hour orbit times. Using the Time Difference Of Arrival (TDOA) of the signals from two satellites you can compute a line on the surface of the earth that meets that TDOA geometry. From a third satellite you compute another line. Where the two lines cross is where your receiver is located. From a fourth satellite you can compute altitude. The system is reliable as long as your receiver, in this case the locator tag on the hawk (Tag) has a clear view of the sky and can see a sufficient number of satellites. Inside a building, under a heavy forest canopy, and the old "she caught a rabbit inside a culvert" trick all block reception.

GPS is originally intended as a system to aid in killing people. It is robust and redundant. Military gear must be reliable. The military reserves the authority to scramble or "degrade" the signal. That authority has not been exercised to date.

Given a clear view of the sky acquiring the GPS position and altitude at the Tag is essentially trivial. The tough part is relaying that information from the Tag to the user. The two currently available methods are Cell Phone (GSM) and Direct Radio Link (DRL) to a dedicated user handset.

Uplink to a satellite is not available with current technology. The Argos satellite uplink used for wildlife studies (Island Girl) has a delay time of days to weeks and energy demands that make more than one report a day impractical. Argos air time is very expensive.

The advantage of GSM is location anywhere on the planet IF both the Tag and the user's cell phone have coverage. GSM is a TDMA phone protocol, which in North America means AT&T or T-Mobil. The state of Montana has zero TDMA phone service. The information goes via SMS or Text Message to your cell phone with the associated delay time for exchanging a pair of SMS packets. Requesting frequent updates burns the battery in a hurry.

DRL is best at real time (delay in seconds rather than minutes) and can support streaming data on a viable energy budget. For a given transmitter power data can travel 1/2 to 1/3 as far as a beep. DRL is better suited to the "convenience" mode but needs a Beep to back it up for longer range recovery mode. DRL has the same problems with dropping behind a hill as a Beep and the same solutions(get the receive antenna up high, use a Yagi). MRT is quoting 3 miles range down and dirty and 15 miles range line of sight.

So GSM is better at long range recovery (cell phone coverage allowing) and DRL is better at the convenience mode (radio propagation path allowing).
Use a back up Beep in both cases.

The Marshall and Martin systems are DRL, and require a dedicated receiver. In the case of the Marshal the receiver (Pocketlink) talks to your smart phone to give display function. The Martin appears to be an all in one receiver/display.
The ByMap and Ledesma systems are GSM and can use any TDMA smart phone as the user receiver/display.
The Microsensory Tag is both DRL and GSM. It requires a dedicated receiver/display in DRL mode.

[Captain Gizmo]

The Martin Systems says "up to 16 falcons at once".

Any GPS Tag system that is cell phone based is unlimited, each Tag has it's own phone number. Sending an SMS and Receiving an SMS from multiple phone numbers may take a bit of time.

For a Direct Radio Link (DRL) system (Marshall, Martin, and Microsensory) it is just a matter of software. The dedicated receiver could use either separate frequencies for each Tag or the Tags could each have a digital identifier on their data packets.

As to doing real time graphic displays with multiple tracks on screen, again it is all software.