Team Prometheus Tracking Systems

This is actually my favorite and most worked on part of our mission and quite difficult to solve issue to get enough range for the guidance and telemetry required to get to space and on to orbit.
I'll be discussing optical, GPS and RSSI tracking as no one system alone can do the job on the amateur level with 100% signal lock required to properly control a rocket in flight.

Monroe

In the beginning we used the Argent Data Systems (Scott Miller) Tracker that was APRS at 144.39 Mhz 2 meter for tracking balloons and they worked fine. But we landed a sponsorship from Big Red Bee and started using the BeeLine high power 2 Meter units.

How much do they weigh? and what type/length antenna do you use?

Edited to add just looked at the pictures again is your antenna a length of wire close to a harmonic of the wavelength? 1/4 or 1/2?

These are used often with a 1/4 wave whip about 19 inches long. The better option is the dipole they use for the bionics microtrack. However we use a full twin lead J-Pole attached to the train line right up to the corner reflector for radar. Most of the weight is in the battery as these are 5 watt transmitters! We have hit a repeater nearly 500 miles away before with this radio. The beelines also hold the world amateur altitude and distance records. We made the beeline famous for balloon launches.
Greg at beeline also made us a special "Bee Sting" that would launch a rockoon at a predetermined altitude by triggering a mosfet you can ask Greg for the beesting and tell em we sent ya

I'm discussing our tracking systems from beginning to end with the optical tracking. Feel free to ask questions I sometimes forget details that could help other do the same without making the same mistakes we did.

Monroe

The units with the extra wire have the beesting that's not an antenna

Here is the dipole antenna http://www.byonics.com/mt-antennas

We also used the Beeline for rockoons in this case the beeline and the rocket ARE the payload for the balloon with the beeline tracker initiating the launch using the beesting for ignition. The beeline there has the yellow band and the antenna used here was the 1/4 whip that extends beyond the nosecone.

And that pretty much sums up APRS tracking for balloon or rocket payloads at this point we transitioned to telemetry and video and for that we built our first tracking antenna

Once having switched to full telemetry on the ground we started using 433 Mhz, 900 Mhz, 1.2 Ghz, 2.4 Ghz and 5.8 Ghz in addition to the 144.39 Mhz APRS so that's a lot of signal processing to do. We are also receiving GPS on 1.5 Ghz so transmitting with too much power or giving off harmonics does hamper GPS reception. So we had to fiddle around on frequency and power outputs depending on the mission. The first tracking antenna had an array of 3 helicals each at 15db gain at 433,900 and 2.4 Ghz.
Our ground station took the GPS location of the payload and pointed the antenna accordingly. I'll give the details on how that was accomplished in the Mission Control thread.
So next I'll post some photos of how we converted 2 automotive window motors into servos using H-Bridge controllers and a pot to function as standard servos to the software. Simple and effective for moving a heavy tracking antenna system as an Alt/Az mount. We also used the window regulator gears for the gear train. At first I used a lazy susan bearing for the Az axis but that sucked so I switched that to a front wheel hub assembly and wheel bearing from a front wheel drive Chrysler.

Here is a shot of the new base bearing.

From there we progressed to using Optictracker for optical tracking. In this photo the laser finder is installed but not the electronic focuser that has been added.

This was an early test of the optictracker software with me guiding it by joystick.



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Here is the first clip of the laser we use for alignment of the 2 cameras and can be used to illuminate a target.


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Cool!

It get's way cooler from here

Monroe

More to come!