Frequently Asked Questions |
General questions
Questions about the sensors
General questionsWhere can I find a more detailed documentation for your products?Please send us an email at This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we will send you a copy of the complete documentation of our products, including the communication protocol, the user manual and others. What are the default serial communication parameters?Default serial port parameters are:
Are your products upward and backward compatible?All IG products share the same communication protocol. An IG-20 can be plugged in place of an IG-500N, and will work correctly with the same software. Most of the features will not be available in the IG-20, but the device will be still functional. The inverse is also right: plugging an IG-500 in the place of an IG-20/30 without changing any line of code will be alright. What are the system requirements to use the Development Kit?The sbgCom library is available for the most popular operating systems: MS Windows, Mac OS X, and Linux. For now, the sbgCenter is only available on Windows platforms, but a version running on Mac and Linux is being developed. The sbgCenter requires some calculation power on the PC. We recommend a Pentium IV 1.5GHz or equivalent with accelerated graphics card and 512Mb of RAM as a minimum requirement. Higher configurations are always better to save long recordings, or to plot huge amounts of data. Can I connect my product to a specific design or a PDA?As long as your design contains a serial port, you can connect it to the IG product family. PDAs generally include such a port. In addition, our products accepts input supply down to 2.5V making them ideal for batteries powered applications. Are all the calculations performed on-board?Yes. You only have to retrieve the output values for calibrated sensors and orientation data, directly from the sensor. Is it possible to get the product without the box to enhance OEM integration?Yes. OEM versions are very easy to connect, with a single 2x3 ways 1.27mm pitch connector. No external wires are needed making OEM integration very simple and reliable even for IG-30G and IG-500N products that embed a GPS receiver. Questions about the sensorsAre the sensors calibrated over the full temperature range? What is the calibration procedure?Yes. We correct most errors due to MEMS sensors technology:
Performance will be optimal at any temperature in the specified temperature range. However, avoid too fast temperature changes that cannot be modeled. Best results are always achieved in stable temperature conditions. Can I tune some settings to improve results on a specific application?Yes. Our products are widely configurable. Low pass filters cutoff frequency can be configured for each sensor. The Extended Kalman Filter settings can also be finely tuned to achieve high performance in each situation. What is the effect of linear accelerations on the device output?Our IG family products uses the gravity vector as the local vertical reference. This gravity is measured by accelerometers, and cannot be differentiated from other sources of acceleration. Linear accelerations can affect performance in attitude estimation. The Kalman filter used in IG-500 devices is designed to be the least dependent on the gravity vector measured by accelerometers, and only long acceleration will affect quality of orientation. What is the effect of metals, magnets and high current power supplies in the vicinity of the magnetometers?The IG-30 and the IG-500 use the magnetic field to measure the local magnetic north. The Earth magnetic field is quite weak, and can be disturbed by other sources of magnetic field. Magnets of course, as well as ferromagnetic materials (anything that sticks to a magnet), and also power supplies that generate high current (several amperes) and their associated wires can distort the local magnetic field. The IG-30 and IG-500 have a built-in procedure to compensate for all these effects as long as the source of the magnetic distortion is fixed relatively to the device. External sources that move independently with respect to the device or sources that cannot be predicted cannot be compensated for and can generate error in attitude estimation. Placing the device at least at 2 – 3 meters from external sources of interference will make the error negligible. The IG-30 and IG-500 products can also be configured to ignore magnetic field in attitude computation or use other external heading sources such as GPS heading. At startup, I get some bias on gyroscopes and attitude has got a few degrees of error. What can I do to improve that?All MEMS gyroscopes can have some bias at startup, caused by the warm-up of the sensors, and a part of random walk. This bias generates some error in attitude estimation. Of course, our devices continuously perform an estimation of the gyro bias. Most of the time, a 1-2 min warm-up is sufficient to get good results, but we advise 15 min warm-up to get optimal performance. If the bias is too large at startup (more than 1.5 °/s), and you want to get faster startups, you can still perform a calibration of the gyro bias to get instantaneously a good attitude estimate. This only requires not moving the device during the calibration. Calibration result can be stored or not in the non volatile flash memory. |
