A Baofeng VHF/UHF radio is used a signal generator, which transmits via a Transmit/Recieve switch through an antenna. A RF detector is also connected to the T/R switch, which is connected to the MSO-19.
The radio controller is a 4N25 opto-isolator.
The T/R switch controller is a SN74HC04N (or similar) hex inverter.
Any Pi-compatible GPS and WiFi dongle will do.
The Raspberry Pi triggers the radio, T/R switch and MSO-19 via a buffered GPIO port once per second using a very simple python script.
In the United States, this project falls under FCC Part 97 Sec. 1 (b):
"Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art."