Mobile sensors require periodic position measurements for navigation around the sensing region. Such information is often obtained using GPS or onboard sensors such as optical encoders. However, GPS is not reliable in all environments, and odometry accrues error over time. Although several localization techniques exist for wireless sensor networks, they are typically time consuming, resource intensive, and/or require expensive hardware, all of which are undesirable for lightweight mobile nodes. We propose a technique for obtaining angle-of-arrival information that uses the wheel encoder data from the mobile sensor, and the RF Doppler-shift observed by stationary nodes. These sensor data are used to determine the angular separation between stationary beacons, which can be used for navigation. Our experimental results demonstrate that using this technique, a robot is able to determine angular separation between four pairs of sensors in a 40 x 40 meter sensing region with an average error of 0.28 radian.