A Baseband MLE for Snapshot GNSS Receiver Using Super-Long-Coherent Correlation in a Fractional Fourier Domain

Abstract

Accurate positioning with low-cost global navigation satellite system (GNSS)/ global positioning system (GPS) devices currently plays an important role in our daily lives. Examples include navigation for pedestrians via smartphones (Lachapelle & Gratton, 2019;Luo et al., 2019c;Ng et al., 2021) and wearable sensors (Faragher et al., 2018(Faragher et al., , 2019 and autonomous ground vehicles (Humphreys et al., 2020). These applications depend on low-cost antennas and hardware. There will be significant demand for consumer-level GNSS receivers in the next ten years (EUSPA EO and GNSS Market Report, 2022). GNSS signals are confronted with frequent interruptions and reflections in challenging environments. Thus, incoming GNSS signals are often weak and dynamic, which causes the traditional GNSS baseband architecture to be very fragile (Luo et al., 2018b;Ren & Petovello, 2017;Yan et al., 2017).

Development of a Custom GNSS Software Receiver Supporting Supercorrelation

“…Longer correlation allows a separation between the correct Line-Of-Sight (LOS) signal and multipath interference using the carrier frequency offset. The technique is similar to synthetic aperture processing [3][4][5], although it is specifically designed to overcome the challenges [6][7][8][9] provided by the low-quality oscillators found in smartphones and smartwatches and the highly non-linear motion dynamics that those devices can undergo in typical use. S-GNSS is ideal for urban environments with challenging multipath interference [10] and has shown benefits when integrated with 3D mapping [11] and inertial navigation systems [12].…”