Impacts of vehicles on the outdoor search area of small wirelessly-controlled robots

This paper presents experimental results quantifying the vehicle-induced signal attenuation for small (lower than 50-centimeter high) wirelessly-controlled robots, which have been proposed for their potentials for post-disaster/attack casualty-search operations. Due to the robots´ small sizes, nearby vehicles that are prevalent especially in highly populated area could significantly attenuate robot communication signals. Via a linear regression of experimental results, a new mathematical expression predicting average vehicle-induced signal attenuation (in dB) as a linear function of a number of vehicles is derived. An example scenario about an outdoor casualty-search throughout a university campus by a small wirelessly-controlled robot that are capable of placing signal-relays to enlarge its operational area is provided. It is found that by taking into account of vehicle-induced signal attenuation, the robot could have sufficient wireless communication coverage to avoid failing to search for casualties in the crowded area where classroom buildings and office buildings are located.