Wireless radio consumes the highest power in many systems and must be activated wisely to save power especially in battery-powered systems. Hence, gathering insight into the spectrum activity is needed to control the wireless radio. In this work, classic full-band Fast Fourier Transform (FFT) and sequential digital spectrum scanning systems are presented with their high energy consumption and latency drawbacks. A context-aware, multi-layer-duty-cycled, multi-channel, ultra-low-power analog spectrum monitoring architecture is proposed as a solution to the drawbacks of the classic systems with the emphasis on Wi-Fi signal detection for a Basic Service Set Identifier (BSSID)-based geopositioning shipment tracking application. The proposed architecture provides more than 3 order of magnitude power saving in detection compared to the classic sequential spectrum scanning while maintaining the full functionality under vast variety of operating conditions.