A space timekeeping system, comprising a plurality of local area timekeeping systems, wherein each of the local area timekeeping systems comprises an information processing device, a proper time measuring device, and a pulsar pulse measuring device;
- the information processing device is configured to establish a wide area inertial coordinate system, which comprises all local area coordinate systems within a spatial range covered by a unified time;
- the proper time measuring device is configured to obtain a local proper time;
- and the information processing device is further configured to establish a local orbit parameter ephemeris by taking the local proper time as a time argument;
- the pulsar pulse measuring device is configured to observe a pulse profile of a pulsar according to the local proper time to obtain a pulse data sequence with the local proper time as the time argument;
- and the information processing device is further configured to determine a pulse local time according to the pulse data sequence with the local proper time as the time argument, wherein the pulse local time is a coordinate time at which the pulse of the pulsar arrives at a local position;
- and
- the information processing device is further configured to convert the pulse local time by using the local orbit parameter ephemeris so as to obtain a pulse origin time, wherein the pulse origin time is a coordinate time at which the pulse arrives at an origin of the wide area inertial coordinate system;
- wherein the proper time measuring device comprises a ground cesium atomic clock, and the pulsar pulse measuring device comprises a large-scale ground radio astronomical telescope or antennas for measuring X-rays on satellites;
- thus achieving time unification among the plurality of local area timekeeping systems;
- wherein the information processing device of each local area timekeeping system is further configured to:
- broadcast pulse serial number information to the plurality of local area timekeeping systems, so that each of the local area timekeeping systems corrects its own pulse origin time according to the pulse serial number information it receives, wherein the pulse serial number information contains serial number of the current pulse and the pulse origin time corresponding to the serial number of the pulse;
- and
- acquire the pulse serial number information sent by each of the local area timekeeping systems, and update its own pulse origin time according to multiple pieces of pulse serial number information;
- and
- wherein the observing the pulse profile of the pulsar according to the local proper time and determining the pulse local time comprises:
- observing the pulse profile of the pulsar, and obtaining a pulse data sequence with the local proper time as the time argument;
- converting the pulse data sequence with the local proper time as the time argument into a pulse data sequence with a local coordinate time as the time argument, according to the local orbit parameter ephemeris and the azimuth vector of the pulsar;
- and
- performing pulse profile superposition calculation or cross-correlation calculation on the pulse data sequence with the local coordinate time as the time argument to obtain the pulse local time;
- and
- wherein the converting the pulse local time by using the local orbit parameter ephemeris to obtain the pulse origin time comprises:
- obtaining the pulse origin time ton of the pulse with serial number n by using:
- ton=tn+dn/c, dn=({right arrow over (P)}·{right arrow over (a)});
- where tn is the pulse local time of the pulse with serial number n, dn is a distance from the local position at the moment tn to the origin of the wide area inertial coordinate system, {right arrow over (P)} is the local position vector, {right arrow over (a)} is the azimuth vector of the pulsar, and c is the velocity of light.