Using Multiple Sensor Triads for Enhancing the Navigation Solution of Portable and Wearable Devices

M. Omr, J. Georgy, A. Noureldin

Abstract:	A new age of technology is approaching very rapidly. A new age of wearable computing devices, such as smart glasses which is capable of overlaying a lot of information on user’s current view of the world, one example can be overlaying maps, street names, and directions to some destination while the user is driving or walking in streets; another example is smart watches with processing capabilities that enable them to run various number of applications, such as those computing the distance walked or covered during a running drill. Besides the general purpose computing unit most of these wearable devices include nowadays, one or more of MEMS inertial sensors triads, such as accelerometers, gyroscopes, and magnetometers triads. Some advantages of using MEMS technology is being small in size, light in weight, with low power consumption which facilitates including it in most of today’s portable devices where battery life is of big concern, and finally and most importantly being at low cost which helped it spread in most of recent smart phones and tablets. These sensors are mainly included for games or enabling a free-hand interaction between the user and the device, for example, when the user performs certain gesture, one or more of these sensors is used to capture this gesture and a corresponding command is executed in response. These sensors can be used also for navigation purposes, but due to the low accuracy offered by such grade of low-cost commercial MEMS sensors, the error drifts rapidly, and therefore, further enhancements by innovative algorithms are needed than using these sensors readings directly. Portable devices such as smart phones and tablets witness a great technological revolution as well. Portable devices sales are now overtaking those of traditional desktop computers. Using these Portable devices one can get local news and weather, be directed to the nearest point of interest like a restaurant, or reroute one’s way to work around traffic, and much more. All such kind of services can be provided due to the advancements taking place and the incorporation of Global Navigation Satellite Systems (GNSS) receivers and inertial sensors triads in most of modern portable devices. In addition to the above, the revolution in portable devices actually aided the emergence of APPlication acCESSORY or appcessory for short. Appcessories is a new term commonly used nowadays to describe an accessory for a portable device that is specific for certain application which can use Wi-Fi or Bluetooth for connection with its portable device and which represents another shift in portable devices technology. Many appcessories are available for most of today’s portable devices, such as, belt clips, and digital wristwatches connected to the portable device to monitor user physical activities for example and calculate how many calories user burnt out for certain time. Such appcessories include also one or more inertial sensors triads such as those found in wearable computing devices or portable devices mentioned above. The main challenge is that the low-cost MEMS sensors in current wearable computing devices, appcessories, or even portable devices such as latest smartphones are considered insufficient for reliable navigation purposes due to very high noise, large random drift rates, and especially for such mobile devices that can freely change orientation with respect to the person. Some prior solutions to overcome the sensors errors is better error modeling, however this is harder for portable navigation which also still have the hard problem of varying orientation with respect to the person. Given the fact that it is likely that a user will have multiple devices among the abovementioned groups (i.e. wearable computing devices, portable devices such as smartphones/tablets, and appcessories), the use of the sensors triads on the different available devices can be exploited to enhance the navigation solution through the use of multi-triads (e.g. multi-IMU’s). At least one device whether a wearable computing device such as glasses or portable device such as smartphone/tablet and which possesses enough computing power to run the proposed technique has to be present. The sensors in this device can be integrated with the sensors in one or more other devices whether wearable computing devices like a smart watch, portable devices such as for example a tablet, or appcessories like a belt clip or keychain to produce a higher accuracy navigation solution. This paper proposes a multiple sensors’ triads solution and the underlying techniques to benefit from this redundancy of sensors to get better navigation results. The proposed solution exploits the fact that that multiple of the abovementioned devices will be carried by the same user and wirelessly connected together. Benefiting from the multiple triads and integrating them boosts the final results outstandingly. The techniques presented in this paper show how integrating multiple sensors triads make the available low-cost sensors into navigation capable sensors. To sum up, a major factor that distinguishes the proposed solution from other traditional inertial navigation solutions is that it exploits the connection already present between most of today’s electronic gadgets carried by the same user most of the time, either wearable computing device, portable devices or appcessories and each other, and integrate all the information coming from these connected network of multiple sensors triads, and provide a final enhanced navigation solution which is reliable and accurate in the different environments indoors or outdoors in open sky or urban canyon, whether on foot or driving. A large number of datasets were collected for testing and verification. These datasets were collected by different users of different age, gender, and characteristics. The datasets were collected using two or more sensors triads in devices carried at different positions on users’ body such as on waist, on wrist, on head, on chest, handheld, in pocket, and on ear. The results were analyzed, and they clearly demonstrated that a much reliable and more accurate navigation solution can be obtained by integrating multiple sensors triads found in many devices carried by current electronic gadgets’ users.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	467 - 472
Cite this article:	Omr, M., Georgy, J., Noureldin, A., "Using Multiple Sensor Triads for Enhancing the Navigation Solution of Portable and Wearable Devices," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 467-472.
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