GPS uses ECCs to see if an error occurs when the data sent from the satellite reaches the user. Each message structure uses ECCs such as Hamming Code, CRC, BCH Code, and LDPC Code. If the satellite contains all of the encoders, it has a negative impact to the area and power consumption. Therefore, in this paper, we propose a CRC-BCH unified encoder for GPS, which is efficient in terms of space and power consumption. Since both the CRC and BCH encoders use shift registers, the design was made using this part. To replace the existing encoder, the CRC-BCH encoder must have the same output. To validate this, we used individual CRC and BCH encoders and confirmed that the generated output was identical to the output of the proposed encoder. The proposed CRC-BCH unified encoder was synthesized at an operating frequency of 400 MHz using the CMOS 28nm process. The synthesis results showed that it used 16.67% less area and consumed 19.68% less power than the existing encoder. Therefore, the proposed CRC-BCH unified encoder offers advantages in terms of satellite weight and energy efficiency.