Article,
Enabling Location-Based Services with a Combined Galileo/GPS Receiver Architecture
Proc. of the ION GNSS Conf., (2004)
Abstract
Several new requirements and challenges are introduced with the transition
of traditional navigation applications towards location based services.
The three most important ones are low cost, low energy consumption,
and high sensitivity. This paper introduces the HIGAPS receiver concept.
Aim of the first phase in the HIGAPS project is to develop the concept
for a combined Galileo/GPS receiver that is especially tailored for
location based services, E-911, and other consumer market applications.
After providing a brief overview of the receiver, the partitioning
into analog hardware, digital hardware, and software is outlined.
The architecture of the combined Galileo/GPS RF front-end is presented
in low-IF topology. The digital baseband presents a highly parallel
correlation architecture for combined Galileo/GPS reception, allowing
moderate times to fix for extended dwell times. Parallel digital
signal processing combined with aiding data allows single shot measurements
particularly designed for location based services. Differential correlation
where the current coherently integrated predetection sample is multiplied
with the conjugated complex of the previous predetection sample further
improves the reception sensitivity. The acquisition sensitivity thresholds
for differential correlation are compared versus conventional noncoherent
integration for white noise and strong interfering signals. After
summarizing multipath mitigation techniques, the multipath performance
of the Galileo L1 signal is evaluated through ray-tracing simulations.
The introduction of the navigation software and the simulation model
finalize the paper.
