Regenerative Legendre Sequence Ranging Codes for Deep Space Communications

Future deep space missions necessitate longer communication distances, deep space ranging will face more severe path loss. Consequently, high-precision ranging codes with longer one-way unambiguous distance are expected. This letter extends the composite logic to generate ranging codes from multiple subcodes and appropriate weights. By adjusting the composite logic, the desired ranging accuracy can be achieved. Additionally, 8 Legendre Sequence (LS) ranging codes are designed using generalized composite logic and Legendre sequences with good Pseudo-Noise (PN) performance. LS codes enhance the one-way unambiguous distance by 12.6 to 2375.8 times compared to T4B and T2B proposed by Consultative Committee for Space Data Systems (CCSDS) under the equivalent conditions, reducing ranging errors by 0.057 to 0.9417 meters. The DC components of the LS codes are lower than those of T4B and T2B. Simulation results demonstrate that newly designed ranging codes can achieve high-precision distance measurement as well as low DC component within longer one-way unambiguous distance. Furthermore, a methodology is proposed for the design of ranging codes that exhibit both extended one-way unambiguous distances and diminished acquisition time.