High-sensitive acquisition method of GPS signal based on iridium assistance

Abstract

Global positioning system (GPS) signal is severely attenuated in indoor, urban, and forest environments. To capture weak GPS signal, long-time coherent integration and non-coherent integration are used to increase signal to noise ratio (SNR). However, coherent integration time is constrained by Doppler frequency and navigation message, and the non-coherent integration has square loss. Assisted GPS (AGPS) can effectively prolong the coherent integration time, but it is costly and has poor performance in rural areas. An Iridium-assisted acquisition method is proposed here. The coherent integration time can be prolonged with Iridium-assisted values of code phase, Doppler frequency, and navigation message. This method can effectively improve the acquisition sensitivity and reduce the average acquisition time. The Monte–Carlo simulation results show that the capture sensitivity can reach 15 dB-Hz (CNR) with 200 ms coherent integration.

Keywords

• monte carlo methods
• global positioning system
• signal detection
• doppler effect
• assisted gps
• coherent integration time
• doppler frequency
• navigation message
• high-sensitive acquisition method
• iridium assistance
• gps signal
• global positioning system signal
• iridium-assisted acquisition method
• iridium-assisted values of code phase
• monte carlo simulation