This is the home page for my GPS-guided model rocket recovery project (last update September 2011).

The idea is to have the the rocket fly itself back to the launch pad using a steerable parachute and onboard GPS.

At this point I have the “Rev 4” PCB hardware and software working well. The navigation has worked a little bit on a couple of of test flights, but I’ve had problems with the parachute lines tangling and twisting – I got side-tracked for a whole year using a baseline for steering the parachute that was far too small – this was the main cause of the twisting. I’m making changes to solve those problems.

All the hardware schematics and almost all the software source code are posted here. Here is a quick rundown of the hardware specs:

  • CPU: Microchip PIC32 MCU (PIC32MX440, with the USB interface)
  • GPS: GlobalTop PA6B (updates at up to 10 Hz)
  • Telemetry: Microchip MRF24J40MB 100 mW IEEE 802.15.4 radio transceiver (2-way)
  • Altimeter: Freescale MP3H6115A pressure sensor (launch detect, electronic parachute ejection, beeps apogee altitude)
  • Hobby servo outputs: Up to 2 servos (to steer the parachute)
  • Power supply: 2 x LiIon cells, Microchip TC105 switching DC-DC converter
  • Outputs: 4 high-current outputs for parachute ejection and staging
  • Camera: Controls a still or video camera in-flight
  • Flight log: Stored in flash memory (lat/lon, speed, altitude, status…)
  • Ejection detection: Via CDS cell (light sensor)
  • 3 push-buttons, 3 LEDs
  • Piezo speaker output

Here is a quick guide to the project info on this site – see the “Rockets” category for other rocketry-related stuff:

  • Project intro from 2008 (aka Nevada Dave and the Rocket-Eating Trees). Includes slides describing my original ideas and goals for the project, and progress thru the first couple of hardware versions.
  • Flight test notes (pdf). Notes of every test flight from the beginning (mainly for my own reference). There’s lots of technical nitty-gritty here, but it has the most up-to-date info (from time to time I post news here on how things are going, but these notes get updated after every flight).

Similar & related projects

  • Pat Horton’s SPRS – I don’t know him, but Pat built & flew a working radio-controlled (not autonomous) “Steerable Parachute Recovery System” back in 2001. It was finding his web page that convinced me this project was possible, and got me interested in the NASA NPW5 parachute design that I’m still using.
  • Mike Passaretti – Mike’s goal is similar to mine – fully automated recovery using a steered parachute and autonomous GPS navigation. Mike seems like a very experienced engineer, and I think has a good approach, tho different in some ways from mine. He started his project in 2011; we’ve exchanged a few emails and swapped notes, and may end up collaborating or something. Have a look at his site.

If there are other people who should be listed here, please let me know and I’ll add them. I know similar systems have been working in the military for a long time, but I think the hobbyist community is just getting there now.