Zenith Aerospace is an aerospace company specializing in unmanned aerial and orbital vehicles. We are developing a space qualified software defined radio (SDR) payload utilizing a miniaturized atomic clock. This payload can be reprogrammed for a wide variety of different missions and can receive and transmit data over a huge range of frequencies (1 MHz to 8.1 GHz). We have identified use cases such as strategically disrupting adversarial RF transmissions, providing comms services and data transfer capabilities to deployed teams and augmenting position and timing services. While GPS is robust, the implication of failure would lead to the loss of trillions of dollars and potentially countless lives around the world. Operating without a backup for such a critical system is accepting unnecessary risk. Our ZPS constellation will provide the USAF with a reliable, dynamic, cost effective system to provide continual positioning and timing services. ZPS will create stability for military and commercial operations, minimize the impact and cost of a GPS failure, and increase the accuracy of current GPS receivers. This SBIR will fund the development of the first PNT SDR prototype with the goal of generating and transmitting a GPS-like signal in a form factor compatible with a CubeSat.