Tracking

This implements a basic tracking functionality for GNSS signals. The correlation is done in the interval of PRNs. Each call of the tracking function returns the current code phase, Doppler, the Carrier-to-Noise-Density-Ratio (CN0), data bits, number of data bits and the last correlator output.

Features

• Supports GPS L1 / L5 and Galileo E1B
• CN0 estimation
• Secondary code detection
• Bit detection
• Phased array tracking

Getting started

Install:

julia> ]
pkg> add Tracking

Usage

using Tracking
using Tracking: Hz, GPSL1
carrier_doppler = 1000Hz
code_phase = 50
sampling_frequency = 2.5e6Hz
prn = 1
state = TrackingState(GPSL1, carrier_doppler, code_phase)
results = track(signal, state, prn, sampling_frequency)
next_results = track(next_signal, get_state(results), prn, sampling_frequency)

If you'd like to track several signals at once (e.g. in the case of phased antenna arrays), you will have to specify the optional parameter num_ants::NumAnts{N} and pass a beamforming function to the track function:

state = TrackingState(GPSL1, carrier_doppler, code_phase, num_ants = NumAnts(4)) # 4 antenna channels
results = track(signal, state, prn, sampling_frequency, post_corr_filter = x -> x[1]) # Post corr filter is optional