Member Since: July 4, 2006

Country: United States

  • For high altitude, not all consumer grade GPS devices are the same. Most consumer grade GPS devices are designed to solve a 2d location problem on the surface of the earth, rather than a 3d location and then … dependent on the dynamics of the movement. I have successfully flown various GPS models of the uBlox GPS chipset on high altitude rockets over 60k' and the factory specs are to ~150k. The factory informally confirms that it will in fact report higher but that precision will degrade. The device WILL stop reporting at the ITAR speed limit of 515 m/s but will resume reporting when speed drops below that threshold. If you are below the speed limit, but continue to climb - unclear what the altitude limit really is. We have some flights planned for this summer that will likely test these limits. Intend to fly this modem as part of the avionics science package.

  • How is this board programmed on the Edison? Either in the Arduino environment or in a native Linux environment.

  • I have flown the uBlox chipset above 100k' and at Mach 3. When exceeding 515 m/s in velocity it stops reporting, and immediately begins reporting again when velocity is below 515 m/s.

    The uBlox factory specs these to 50 km altitude but tells me it will continue to report (though at diminished precision) at higher altitudes.

  • I just flew this on a rocket for the first time this past weekend using a uBlox for the GPS.

    The results look surprisingly good - certainly correlating well with the visual behaviour of the airframe as well as the other avionic data - acceleration and baro altitude used for recovery.

  • Yes. I fly them on rockets. Should be good to 50km.

  • An interesting module. Specs say it (along with uBlox devices) should work well for stratospheric balloons. It also has (again like the uBlox) a high dynamic mode, making it useful for rocket projects.

  • I fly high altitude rockets - and we have several common issues with HAB - measurement. Some thoughts from my experience:
    1. Your baro sensor does not have the range for high altitude. Your last measurement was about at the minimum pressure for the sensor. Check out the pressure range for these flights. There are other sensors available that have the range (and are appropriately temperature compensated) for this kind of flight.
    2. Most commercial GPS chipsets simply will not work about 60k' MSL. Most Trimble and uBlox chipsets can bet set in a “flight” or “air” mode that is appropriate for flight. Use what works.
    3. I have used the Digi radios that you used … and have gotten much better range in the air. Something tells me you have either a configuration or antenna problem. That being said, I would use an off the shelf HAM based APRS tracker as your primary recovery system … use the Digi as a higher performance secondary system.

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