A Low-Ambiguity Signal Waveform for Pseudolite Positioning Systems Based on Chirp

Area of Science:

• Signal processing
• Navigation systems
• Wireless communication

Background:

• Signal modulation is critical for positioning system performance.
• Chirp compressions are effective in communication, radar, and indoor positioning due to high gain and interference resistance.
• Existing methods face challenges with interference and multipath fading.

Purpose of the Study:

• Introduce a novel modulation method, chirped pseudo-noise (ChPN), based on linear chirp.
• Analyze the mathematical model, auto-correlation function (ACF), and power spectrum density (PSD) of ChPN signals.
• Evaluate ChPN's performance in terms of tracking precision, multipath resistance, and ambiguity.

Main Methods:

• Developed a mathematical model for ChPN signals.
• Derived the ACF and PSD for ChPN signals.
• Conducted theoretical analysis and simulations to assess ChPN performance, comparing it with Binary Offset Carrier (BOC) signals.

Main Results:

• ChPN signals with larger sweep bandwidths offer better tracking precision and multipath resistance for a given main-lobe bandwidth (MLB).
• ChPN exhibits lower ACF side-peak ambiguity than BOC signals, though with slightly reduced tracking precision for the same MLB.
• ChPN demonstrates superior overall anti-multipath performance compared to BOC signals.

Conclusions:

• ChPN modulation provides a promising alternative for future positioning applications.
• Larger sweep bandwidths in ChPN signals generally enhance performance across various aspects.
• ChPN receivers can be implemented with minor modifications to existing BOC receivers, facilitating practical adoption.