Methods and apparatus for locating mobile devices using wireless signals in mixed mode

Methods, apparatus, systems and articles of manufacture are disclosed for locating mobile devices using wireless signals in mixed mode. A disclosed method includes generating an access point signal matrix based on signal strength values based on first signal data collected at a mobile device corresponding to first signals received from a plurality of access points for a first period of time, and based on second signal data collected at the plurality of access points corresponding to second signals received from the mobile device and the plurality of access points for a second period of time, determining a first group of contour perimeters corresponding to first ones of the signal strength values in the access point signal matrix that satisfy a first threshold, the first group of contour perimeters including an obstructed contour perimeter corresponding to second ones of the signal strength values in the access point signal matrix that do not satisfy the first threshold, determining a second group of contour perimeters by replacing the obstructed contour perimeter with a corrected contour perimeter, and determining a location of the mobile device based on the second group of contour perimeters including the corrected contour perimeter.