GPS (global positioning system) software receiver signal tracking method based on FPGA (field programmable gate array) and system of GPS software receiver signal tracking method

Abstract

Disclosed is a GPS (global positioning system) software receiver tracking method based on an FPGA (field programmable gate array). Inputted digital intermediate-frequency signals are transmitted into a code correlator after multiplying two channels I and Q of a carrier generator to obtain six channels of relevant results; in a carrier tracking loop, IP and QP in six channels of relevant outputs are transmitted into a phase decision device, frequency discrimination computation is carried out by a carrier frequency discriminator when phase deviation meets the condition that delta theta is larger than theta H, phase discrimination computation is carried out by a carrier phase discriminator if the phase deviation meets the condition that delta theta is smaller than theta H, a result is transmitted into the carrier generator after being filtered by a carrier loop filter so that carrier frequency is adjusted; and in a code tracking loop, IE, IL, QE and QL are taken to be transmitted into a code loop discriminator to be in phase discrimination computation, and results are transmitted into a CA (coarse acquisition) code generator after being filtered by a code loop filter so that phase ofCA codes is adjusted. The two loops are cross-coupled, the carrier frequency and the phase of the codes are synchronously tracked, accordingly, locally reproduced carriers and codes are aligned with signals, and navigation data bits are obtained after integral judgment for the IP is carried out by a posterior integral accumulation decision device.

Description

technical field [0001] The invention relates to a tracking technology of a GPS receiver, in particular to an FPGA-based GPS software receiver signal tracking method and system thereof, and belongs to the technical field of GPS software receiver baseband processing. Background technique [0002] At present, the world's major satellite navigation systems are developing vigorously, but the most mature and the largest market share is the GPS system. The GPS system is mainly composed of the space constellation part, the ground monitoring department and the user equipment department. Among them, the user sector has huge market prospects and commercial interests. Modern standard GPS software receivers use ASIC chips for baseband signal processing. If you want to upgrade or transform their performance, you need to redesign the ASIC chip, which is very expensive. With the progress of FPGA technology and manufacturing process in recent years, modern large-capacity and high-speed FPG...

AI Technical Summary

Problems solved by technology

[0004] The present invention utilizes the characteristics that FPGA can process data in real time, solves the real-time problems often encountered by tracking algorithms on PC platforms, and at the same time, in order to keep the GPS signal locked, a tracking loop is needed to further determine the carrier frequency and code phase and adjust the circuit in real time

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