# L-band waterfall under jamming: the whole Global Navigation Satellite System (GNSS)
# L band as one power spectral density (PSD), frequency across, time down, while a
# scripted sequence of jammers switches on.
#
# The question a spectrum monitor or a receiver designer asks: what does the band look
# like while this happens, and which signals does each jammer actually take away? The
# navigation signals sit about 20 dB below the thermal noise floor, so the picture shows
# the floor and the jammers; the per-band carrier-to-noise density (C/N0) bars show what
# despreading recovers. Each jammer is scored against each band by its spectral
# separation coefficient (SSC), the overlap of the two spectra over the receiver band
# (Betz 2001; Kaplan & Hegarty, Understanding GPS/GNSS, 3rd ed., section 9.4), so a
# jammer only hurts the bands its spectrum reaches.
#
# Timeline (60 s, one row per second):
#   10 s  a swept (chirp) jammer, 16 MHz wide around L1, a 9 microsecond sawtooth, the
#         shape of a car-cigarette-lighter privacy device: 50 mW (-13 dBW) at 100 m.
#         It takes GPS L1 coarse/acquisition (C/A) and Galileo E1 away together.
#   30 s  a continuous-wave (CW) tone exactly on the L1 carrier, 10 mW at 1 km. On C/A
#         it lands on the peak of the binary phase-shift keying (BPSK) spectrum; on
#         Galileo E1 it lands in the null of the multiplexed binary offset carrier (MBOC)
#         spectrum, so E1 recovers when the chirp stops at 40 s while C/A stays lost.
#   45 s  flat 2 MHz noise on the L2 carrier, received at -135 dBW: GPS L2 civil (L2C)
#         is degraded but keeps tracking.
# GPS L5 and Galileo E5a, at 1176.45 MHz, are outside every jammer's spectrum.
#
# The [iq] section draws the model at 35 s as complex IQ samples (20.48 MHz around L1),
# writes them as a Signal Metadata Format (SigMF) recording and reads them back, and
# compares a Welch estimate with the model: a check of the synthesis, the SigMF codec and
# the estimator, not a measurement. A real recording can be compared instead with a
# [recording] section (meta_path = "capture.sigmf-meta"), native builds only.
#
# Assumptions: signal powers are the interface-specification minimum received powers
# (IS-GPS-200, IS-GPS-705, Galileo Open Service Signal-in-Space Interface Control
# Document); a 290 K antenna and a 2 dB receiver noise figure; free-space propagation
# to the jammers, 0 dBi receive gain toward them. MODELLED: the signal spectra are
# validated closed forms, but every jammer, power and timing here is a scenario input.
kind = "spectrum"
seed = 7
duration_s = 60.0
step_s = 1.0

[receiver]
noise_figure_db = 2.0
antenna_temp_k = 290.0
tracking_threshold_dbhz = 25.0

[grid]
f_min_mhz = 1160.0
f_max_mhz = 1590.0
n_freq = 430

[[jammers]]
name = "chirp privacy device"
waveform = "chirp"
centre_mhz = 1575.42
bandwidth_mhz = 16.0
sweep_period_us = 9.0
eirp_dbw = -13.0
range_m = 100.0
on_s = 10.0
off_s = 40.0

[[jammers]]
name = "CW tone on L1"
waveform = "cw"
centre_mhz = 1575.42
eirp_dbw = -20.0
range_m = 1000.0
on_s = 30.0

[[jammers]]
name = "L2 narrowband noise"
waveform = "narrowband"
centre_mhz = 1227.60
bandwidth_mhz = 2.0
received_power_dbw = -135.0
on_s = 45.0

[iq]
centre_mhz = 1575.42
sample_rate_mhz = 20.48
t_s = 35.0
log2_samples = 16
nfft = 1024
datatype = "cf32_le"