|| Interleaved Z4-Linear Sequences with Improved Correlation for Satellite Navigation
||P Vijay Kumar, Indian Institute of Science, India; Dileep Dharmappa, Sugandh Mishra, Indian Space Research Organization, India|
||D4-S3-T2: Sequences II
||Thursday, 15 July, 22:40 - 23:00
||Thursday, 15 July, 23:00 - 23:20
Global Navigation Satellite Systems (GNSS) typically use low-correlation sequences that have length related to the common clock frequency of 10.23 MHz. In particular, operations in the L1 frequency band, of two major GNSS systems, the Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS), employ spreading sequences having length 10230. In these two systems, the length 10230 is achieved by padding and truncating respectively, a family of Weil sequences having period that is a prime number, either 10223 or 10243. As is well known, either truncation or padding leads in general, to degradation in correlation performance. In the present paper, we adopt a different approach and present the design of a family of interleaved Z_4-linear sequences having period exactly equal to 10230. Closed-form expressions for the correlation properties of the sequence family are included. The balance and even-correlation performance of the new family equals or improves upon the performance of the GPS and BDS signal sets. In particular, the new family has maximum even cross-correlation value that is better by 4.4 dB, than that of the truncated or padded Weil sequences employed in these two systems. The sequence family also turns in comparable odd-correlation performance. The sequences can be generated using a simple, shift-register-based implementation presented here.