A collision alerting and avoidance system for use in an aerial vehicle is presented herein. The system comprises a one low profile antenna array disposed on the aerial vehicle. The array includes a plurality of horns; a polar horn, 45-degree horns, and equatorial horns. A transmitter/receiver probe is coupled to each horn. The transmitter/receiver probes are configured to transmit electromagnetic waves and to receive an echo signal reflected from a threat obstacle. A plurality of transmitter/receiver modules are coupled to each of the transmitter/receiver probes. The transmitter/receiver modules are configured to produce electromagnetic waves for transmission and to receive the echo signal. A processor coupled to the plurality of transmitter/receiver modules controls the transmission of electromagnetic waves from the horns and processes the echo signal to provide an output signal containing information regarding the obstacle.