Computational Efficiency Improvement for Unaided Weak GPS Signal Acquisition

Abstract

Acquisition of unaided weak Global Positioning System (GPS) signals requires long coherent integration time and thus all the possible navigation data bit combination paths have to be searched. In this paper, to improve the computational efficiency, the Improved Fast Modified Double-Block Zero Padding (IFMDBZP) algorithm using the Optimal Path Search Method (OPSM) is proposed instead of the FMDBZP algorithm using the All Paths Search Method (APSM). The proposed method consists of unlikely data bit combination path elimination by applying the Viterbi algorithm during each coherent integration step to improve the FMDBZP algorithm. The analyses show that the proposed OPSM can reduce the computation calculations and save memory space without suffering any loss compared to the APSM. And the longer the coherent integration time is, the more benefit one can gain from the proposed method. The simulation results also show that the IFMDPZP algorithm using the proposed OPSM has the same acquisition performance as the APSM.K E Y WO R D S 1. GPS. 2. Acquisition. 3. Weak Signal. 4. Viterbi Algorithm.

Two-step compressed acquisition method for Doppler frequency and Doppler rate estimation in high-dynamic and weak signal environments

“…1, , , and represent , , and in the presence of noise, respectively. Then, based on (17), the integration process can be performed and can be obtained. If and , it proves that the signal is absent, or acquisition fails.…”

“…For acquisition in the high-dynamic and weak signal environments [16,17], four-dimension detection of bit transition [18,19], Doppler frequency [20], Doppler rate, and code phase is needed [21], which costs more computational burdens compared with the two-dimension acquisition. Frequency parameters estimation includes Doppler frequency and Doppler rate estimation.…”

Efficient BeiDou DBZP‐based weak signal acquisition scheme for software‐defined receiver

“…IFMDBZP, the optimal path search method based on the Viterbi algorithm theory, is proposed to instead of the all paths search method for the FMDBZP. It consists of unlikely data bit combination path elimination during each coherent integration step to improve the algorithm, which has obvious improvements in computational efficiency [25].…”

Weak GPS signal acquisition method based on DBZP

“…However, FMDBZP still needs to calculate each possible data bit combination, resulting in large memory requirements. A method based on the Viterbi algorithm theory [6], the optimal path search method (OPSM) for the improved FMDBZP algorithm (IFMDBZP), reduces the computational operations and saves memory space. Nevertheless, the memory and searching costs are still high overhead GPS receivers.…”