Step Length Measurements Using the Received Signal Strength Indicator

Abstract

In this paper, portable transceivers with micro-controllers and radio frequency modules are developed to measure the received signal strength, path loss, and thus the distance between the human ankles for both indoor and outdoor environments. By comparing the experimental results and the theoretical model, a path loss model between transceivers attached to the subject’s ankles is derived. With the developed experimental path loss model, the step length can be measured relatively accurately, despite the imperfections of hardware devices, with the distance errors of a centimeter level. This paper, therefore, helps address the need for a distance measurement method that has fewer health concerns, is accurate, and is less affected by occlusions and confined spaces. Our findings possibly lay a foundation for some important applications, such as the measurement of gait speed and localization of the human body parts, in wireless body area networks.

Step Length Estimation Using the RSSI Method in Walking and Jogging Scenarios

“…Our previous work presented in [18] proposed an empirical path loss model to estimate the human step length in both indoor and outdoor scenarios under a static context rather than in a dynamic one. Therefore, this paper aimed to estimate human step length in daily activities.…”

“…Therefore, this paper aimed to estimate human step length in daily activities. In particular, a novel filtering technique is proposed in this paper, which was used along with the hardware transceivers and the empirical path loss model developed in our previous work [18] to estimate human step length correctly in both walking and jogging activities in both indoor and outdoor environments.…”

“…In this paper, we adopted the transceivers and the experimental path loss model between two human ankles developed in [18]. The experimental path loss PL OA between two transceivers attached to the ankles of the person under test can be described as a modified free-space path loss model with a correction factor ∆PL (cf.…”

“…The step length in this paper refers to the average distance between two ankles of the person under test when the person is walking or jogging at a normal and equal pace. Unlike our previous work in [18], which only considered a static environment, this paper undertook experiments in actual moving activities. In particular, in this paper, we propose a novel filtering technique to be applied along with the empirical path loss model proposed in [18] to estimate the step length in walking and jogging situations.…”

“…Unlike our previous work in [18], which only considered a static environment, this paper undertook experiments in actual moving activities. In particular, in this paper, we propose a novel filtering technique to be applied along with the empirical path loss model proposed in [18] to estimate the step length in walking and jogging situations.…”