ixGyro: Frequently Asked Questions (FAQ)
- Why do I need a device with gyroscope for a reliable attitude indication?
- Ok, I understand I should buy a smartphone with a gyro. Which device do you recommend?
- After mounting the device and starting ixGyro the artificial horizon is not in neutral position. How can I calibrate it?
- After starting ixGyro, the pitch and roll values tend to drift away from the neutral position. Why? What should I do?
- Why can ixGyro not be used in landscape orientation?
- Can I use ixGyro as an aviation instrument?
- Why is the Pro version so expensive compared to other apps?
Although the attitude can be determined also with the acceleration sensor if the device is in rest or in linear motion, the accelerometer becomes unusable as soon as the device is subject to trajectorial accelerations because of their interference with gravity. Thus a sensor like the gyroscope is needed that is able to measure rotation independent of acceleration. However, the problem with a gyroscope is that it cannot measure the attitude directly but only the rotation speed. Pitch and roll have to be calculated from that by integration which leads to numerical drift. Moreover, there is a physical drift due to the large bias of the low quality gyroscopes in today's smartphones. We have developed a new method to compensate for these drift effects, so our attitude indication is very stable and reliable if a gyroscope is available besides GPS and acceleration sensors.
Any device with Android 2.2 (or later) should do if it is equipped with a gyroscope, a magnetic compass, a GPS receiver and an accelerometer. Unfortunately, there are still not many devices out there on the market meeting these requirements, although the number is expected to increase rapidly in the future.
We have carried out extensive and successful tests with the following devices:
- Google Nexus S (Samsung Nexus S i9023)
- Samsung Galaxy Tab
- Samsung Galaxy S2
- Google/Samsung Galaxy Nexus
- HTC Evo 3D
The following devices should be working as well (although we didn't test them ourselves):
- Acer Iconia Tab A500
- Asus Eee Pad Transformer
- Motorola XOOM
- LG Optimus Pad
After mounting the device and starting ixGyro, the artificial horizon is not in neutral position. How can I calibrate it?
See the calibration instructions
After starting ixGyro, the pitch and roll values tend to drift away from the neutral position. Why? What should I do?
This effect is due to numerical and physical drift effects (see the explanation above). ixGyro compensates for drift by an autocalibration algorithm that takes some time to find the optimum parameters. After a few minutes, however, the attitude should be indicated correctly without offset. No intervention is needed from your side.
Important note: The sensor drift characteristics of some devices show strong temperature dependency. Although ixGyro will try to compensate for this by autocalibration you should try to avoid inaccuracies by not exposing the device to direct sunlight or other heat sources during operation.
We tried that, but it's hard to find a satisfying layout in landscape mode. The attitude indicator should take the full height in landscape mode, but then there is not enough horizontal space for the compass. So we decided to restrict the layout to portrait mode.
ixGyro is not an ICAO / FAA certified product, thus it is not intended to be used in real world aviation. If you use it as an additional source of information without deriving decisions from it there is probably nothing wrong with that. However, you will do this solely at your own risk because we cannot take any responsibility for this kind of use.
The development of ixGyro was very time-consuming. It took us several years to develop reliable algorithms that provide true-attitude indication based on the poor hardware of today's smartphones. There are cheaper apps out there in the market, but they don't provide true-attitude indicators (in fact, their artificial horizons are hardly more than a fake). Having that in mind, ixGyro Pro is not expensive. Actually, it is probably the cheapest true-attitude indicating solution available at all.