Abstract: A system and method to enhance attitude estimation for transfer orbit maneuvers of a spinning satellite includes a transfer orbit earth sensor that can receive and convert an infrared radiance to an analog signal. The analog signal is provided to a hardware chord processor and an analog-to-digital converter. The hardware chord processor determines an earth chord length based on the analog signal. The analog signal is sampled in the analog-to-digital converter to provide a digital signal to a digital earth sensor pre-processor, which reshapes the digital signal to provide a pre-processed signal having nearly distinct peaks. A software chord processor is provided with the pre-processed signal. The software chord processor locates the peaks in the pre-processed signal and determines an earth chord length.