Performance of EGNSS-based Timing in Various Threat Conditions

1 PPS UTC(k)

Time Interval Counter GNSS antenna

FREQ(k) 10 MHz

1 PPS Output

GNSS receiver

Observations Navigation Data RX Time Solution EGNOS Messages AGC Information RX clock error Jammer

Optional

Free-running local oscillator

10 MHz

Local Oscillator

Frequency Error

Frequency Counter

Splitter/

Combiner

GNSS antenna Variable Gain

GNSS Repeater

Time Interval Counter

FREQ(k) 10 MHz

1 PPS GNSS receiver

RX clock error Free-running

local oscillator

10 MHz

Local Oscillator Frequency Error Frequency Counter

1 PPS UTC(k) Long

cable

Observations Navigation Data RX Time Solution EGNOS Messages AGC Information

10⁰ 10¹ 10² 10³ 10⁴ averaging time (s)

10^-9 10^-8 10^-7

MTIE(s)

ITU mask SF GPS DF GPS SF Galileo DF Galileo SF GPS EGNOS

10⁰ 10¹ 10² 10³ 10⁴

averaging time (s) 10^-12

10^-11 10^-10 10^-9 10^-8 10^-7 10^-6

TDEV(s)

LO without GNSS ITU mask SF GPS DF GPS

SF Galileo DF Galileo SF GPS EGNOS

10

10

10

10

10

10

averaging time (s)

10

10

M T IE (s )

SF Galileo SF GPS

10

10

10

10

10

averaging time (s) 10

10

T D E V (s ) SF Galileo

SF GPS

0 1 2 3 4 5 6 7 8 9

time (s) 10⁴

-100 -80 -60 -40 -20 0 20

timeoffset(µs)

Based on GPS + EGNOS Based on GPS-only

0 1 2 3 4 5 6 7 8 9

Time (s) 10

-200 -100 0 100 200

T im e O ffs et (n s)

GNSS with KF - nominal values GNSS with KF - stronger smoothing GNSS with KF - increased GNSS weight ITU time offset mask

0 1 2 3 4 5 6 7 8 9

Time (s) 10

-10 -5 0 5

T im e O ff se t (n s)

10

10

10

10

10

10

averaging time (s) 10

10

10

10

M T IE (s )

Galileo DF - Nominal case Galileo DF with SF fall-back ITU mask

10

10

10

10

10

averaging time (s) 10

10

T D E V (s )

Galileo DF - Nominal case Galileo DF with SF fall-back ITU mask

0 500 1000 1500 2000 2500

time (s)

-50 0 50 100

tim e o ff se t (n s)

SF GPS SF GPS + EGNOS DF GPS SF Galileo DF Galileo