Timescale dissemination using global navigation satellite systems and applications thereof
A method and apparatus for dissemination of a timescale signal (T 2 ) from at least one server site to at least one client site is provided. The method comprises running, at each server site, a server Global Navigation Satellite System, GNSS, process ( 202 ( i )) configured to generate a server GNSS output raw data signal (R 7 (T 2 ); R 7 (T 2 ( i ))) based at least on one or more first satellite signals; generating a precise orbits and clocks signal (C 8 (T 2 ); C 10 (T 2 ); T 4 (Tppp−T 2 ); T 9 (Tppp−T 2 )) embedding said timescale signal (T 2 ) based on all server GNSS output signals (T 2 ( i ); T 7 (T 2 ( i ))) and broadcasting said precise orbits and clocks signal (C 8 (T 2 ); C 10 (T 2 ); T 4 (Tppp−T 2 ); T 9 (Tppp−T 2 )) via a telecom network ( 206 ); running, at each client site, a client Global Navigation Satellite System, GNSS, process ( 201 ( c )) configured to generate a client GNSS output raw data signal (R 5 (T 1 ( c ))) based on a client clock signal (T 1 ( c )) and based on one or more second satellite signals, running a client Precise Point Positioning, PPP, process ( 203 ( c )) configured to receive said client GNSS output raw data signal (R 5 (T 1 ( c ))) and said precise orbits and clocks signal (C 8 (T 2 ); C 10 (T 2 ); T 4 (Tppp−T 2 ); T 9 (Tppp−T 2 )) and to generate a difference signal (T 1 ( c )−T 2 ) between said client clock signal (T 1 ( c )) and timescale signal (T 2 ).
1 . A method of dissemination of a timescale signal from at least one server site to at least one client site, the method comprising:
running a plurality of server Global Navigation Satellite Systems (GNSS) processes at different locations, each GNSS process running configured to generate a server GNSS output raw-data signal based at least on one or more received first satellite signals;
receiving the GNSS output raw-data signals at the at least one server site;
generating, at the at least one server site, a precise orbits and clocks signal embedding the timescale signal based on the server GNSS raw-data signals;
broadcasting the precise orbits and clocks signal via a telecom network from the at least one server site to the at least one client site;
running, at the at least one client site, a client GNSS process configured to generate a client GNSS output raw-data signal based on a client clock signal and one or more second satellite signals; and
running, at the at least one client site, a client Precise Point Positioning (PPP) process configured to receive the client GNSS output raw-data signal and the precise orbits and clocks signal via the telecom network; and to generate a difference signal between the client clock signal and timescale signal.
2 . The method of claim 1 , wherein the client clock signal is generated at the client site.
3 . The method of claim 1 , wherein the precise orbits and clocks signal is generated based on an atomic clock signal.
4 . The method of according to claim 1 , wherein the precise orbits and clocks signal is generated based on clock information of a GNSS receiver clock or at least one satellite clock.
5 . The method according to claim 1 , wherein the client clock signal is produced by a disciplined oscillator based on the difference signal as a feedback signal.
6 . The method according to claim 1 , wherein the at least one server site comprises a plurality of globally distributed GNSS receivers.
7 . The method of claim 1 , further comprising:
generating, at a first client site, a first difference signal between a first client clock signal and the timescale signal;
generating, at a second client site, a second difference signal between a second client clock signal and the timescale signal; and
comparing the first difference signal with the second difference.
8 . The method of claim 1 , wherein generating the precise orbits and clocks signal further comprising:
running, at the at least one server site, a server PPP process configured to receive the server GNSS output raw-data signal and a PPP correction signal;
generating a server precise orbits and clocks timescale offset signal;
generating the precise orbits and clocks signal based on the server precise orbits and clocks timescale offset signal.
9 . A system comprising:
a plurality of server sites configured to:
run a plurality of server Global Navigation Satellite Systems (GNSS) processes, each GNSS process configured to generate a server GNSS output raw-data signal based at least on one or more received first satellite signals;
generate, at one or more server sites of the plurality of server sites, a precise orbits and clocks signal embedding a timescale signal based on the server GNSS raw-data signals; and
broadcast, from the one or more server sites to at least one client site, the precise orbits and clocks signal via a telecom network; and
at least on client site configured to:
run a client GNSS process configured to generate a client GNSS output raw-data signal based on a client clock signal and one or more second satellite signals; and
run a client Precise Point Positioning (PPP) process configured to receive the client GNSS output raw-data signal and the precise orbits and clocks signal via the telecom network; and to generate a difference signal between the client clock signal and timescale signal.
10 . The system of claim 9 , wherein the client clock signal is generated at the client site.
11 . The system of claim 9 , wherein the precise orbits and clocks signal is generated based on an atomic clock signal.
12 . The system of claim 9 , wherein the precise orbits and clocks signal is generated based on clock information of a GNSS receiver clock or at least one satellite clock.
13 . The system of claim 9 , wherein the client clock signal is produced by a disciplined oscillator based on the difference signal as a feedback signal.
14 . The system of claim 9 , wherein the at least one server site comprises a plurality of globally distributed GNSS receivers.
15 . The system of claim 9 , further comprising:
at a first client site generate a first difference signal between a first client clock signal and the timescale signal;
at a second client site: generate a second difference signal between a second client clock signal and the timescale signal; and
compare the first difference signal with the second difference.
16 . The system of claim 9 , wherein generating the precise orbits and clocks signal further comprising:
at the at least one server site:
run a server PPP process configured to receive the server GNSS output raw-data signal and a PPP correction signal;
generate a server precise orbits and clocks timescale offset signal; and
generate the precise orbits and clocks signal based on the server precise orbits and clocks timescale offset signal.
17 . A system comprising:
a plurality of server sites configured to:
run a plurality of server Global Navigation Satellite Systems (GNSS) processes, each GNSS process configured to generate a server GNSS output raw-data signal based at least on one or more received first satellite signals;
generate, at one or more server sites of the plurality of server sites, a precise orbits and clocks signal embedding a timescale signal based on the server GNSS raw-data signals; and
broadcast, from the one or more server sites to at least one client site, the precise orbits and clocks signal via a telecom network.
18 . The system of claim 17 , further comprising:
at least on client site configured to:
run a client GNSS process configured to generate a client GNSS output raw-data signal based on a client clock signal and one or more second satellite signals; and
run a client Precise Point Positioning (PPP) process configured to receive the client GNSS output raw-data signal and the precise orbits and clocks signal via the telecom network; and to generate a difference signal between the client clock signal and timescale signal.
19 . The system of claim 18 , wherein the client clock signal is generated at the client site.
20 . The system of claim 17 , wherein the precise orbits and clocks signal is generated based on an atomic clock signal.