Global Navigation Satellite Systems (GNSS) employ low-correlation sequences, termed as spreading codes, to distinguish between the signals transmitted by the different satellites. The spreading codes commonly employed have period that is a multiple of 1023, as the fundamental frequency associated with the navigation signals generated onboard all of these systems is 10.23 MHz, derived using highly-stable atomic clocks. The principal contribution of the paper is the construction of a family${\mathcal{ J}}_{{\text {NAV}}}$, of low-correlation, binary sequences having period 10230, derived by interleaving a selected set of$5 {\textstyle \mathbb {Z}_{4}}$-Linear sequences of period 2046 followed by flipping or complementing, a subset of the interleaved sequences. Sequence selection is based on the value of an exponential sum over a Galois ring and interleaving is carried out using the Chinese Remainder Theorem. The period 10230 is of particular interest, as it is the period of the spreading codes employed by major GNSS currently in operation. The${\mathcal{ J}}_{{\text {NAV}}}$spreading code family turns in competitive performance when compared to existing designs including a 4.5 dB improvement in worst-case, even-correlation properties. Additional techniques are employed to ensure that Family${\mathcal{ J}}_{{\text {NAV}}}$has other desirable attributes of a GNSS spreading code such as low values of odd-correlation, an orthogonality property and a simple, shift-register-based implementation. The construction is shown to be a special instance of a general select, interleave and flip approach to construction that generates families of balanced, low-correlation interleaved${\textstyle \mathbb {Z}_{4}}$-linear sequences having period$10(2^{m}-1)$for$m=2 \pmod {4}$and$14(2^{m}-1)$for$m=2,4 \pmod {6}$. By replacing the constituent${\textstyle \mathbb {Z}_{4}}$-linear sequences with Family${\mathcal{ A}}$quaternary sequences, the same approach can be used to construct two low-correlation, interleaved quaternary sequence families having period$5(2^{m}-1)$with$m=2 \pmod {4}$and$7(2^{m}-1)$with$m=2,4 \pmod {6}$, respectively.

Global Navigation Satellite Systems (GNSSs) 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 a 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 (IZ4) 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 corresponding performance of the GPS and BDS signal sets. In particular, the new IZ4 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.