Navigation enhancement method and system

1. A navigation augmentation method, comprising:

collecting, by a monitoring station of a ground operation and control system, first observation information of the navigation satellites and the LEO satellites, and sending the collected first observation information to a master control station of the ground operation and control system;

observing, by the LEO satellites, the navigation satellites to acquire second observation information, and sending the second observation information to the master control station through a communication network including an inter-satellite link and a satellite-to-ground link;

generating, by the master control station, augmentation information of the navigation satellites including the precise orbits and the precise clock biases of the navigation satellites, and the precise orbits and the precise clock biases of the LEO satellites, based on the first observation information and the second observation information, making arrangements to form the navigation augmentation information and LEO satellite navigation information, and sending the navigation augmentation information and the LEO satellite navigation information to an injection station of the ground operation and control system;

sending, by the injection station, the navigation augmentation information and the LEO satellite navigation information to the LEO satellites;

calculating and forecasting, by the LEO satellites, local clock biases, arranging the local clock biases to form navigation telegrams, generating navigation direct signals of the LEO satellites, after receiving the navigation augmentation information and the LEO satellite navigation information;

broadcasting, by Low Earth Orbit LEO satellites, navigation direct signals of the LEO satellites, navigation augmentation information and precise orbits and clock biases of the Low Earth Orbit satellites; and

performing precise positioning, speed measurement and timing by a user receiver according to navigation direct signals of navigation satellites, and the navigation direct signals of the LEO satellites, the navigation augmentation information and the precise orbits and clock biases of the Low Earth Orbit satellites broadcasted by the LEO satellites.

2. The method as claimed in claim 1 , wherein a LEO constellation comprises multiple LEO satellites distributed on multiple orbital planes, and the multiple LEO satellites broadcast navigation direct signals based on high-precision time-frequency references through specific frequency bands;

the navigation augmentation information further comprises at least one of the following: phase bias correction number of the navigation satellites, phase bias correction number of the LEO satellites, and ionospheric model parameter information.

3. The method as claimed in claim 1 , wherein the navigation satellites comprise: at least one of US Global Positioning System GPS, China Beidou, EU Galileo, and Russian Global Navigation Satellite System GLONASS satellite navigation systems.

4. The method as claimed in claim 1 , wherein observation data for precise positioning, speed measurement and timing by the user receiver includes at least one of the following: observation data of pseudo-range of the navigation satellites and the LEO satellites, observation data of carrier phase of the navigation satellites and the LEO satellites, and Doppler observation data of the navigation satellites and the LEO satellites.

5. The method as claimed in claim 1 , wherein when the user receiver performs precise positioning, speed measurement and timing according to the navigation direct signals of navigation satellites, the navigation direct signals of the LEO satellites, the navigation augmentation information and the precise orbits and clock biases of the LEO satellites, the processing mode of the user receiver comprises: a LEO satellite augmented ambiguity float solution mode or a LEO satellite augmented ambiguity fixed solution mode.

6. A navigation augmentation system, comprising:

a LEO constellation, which comprises multiple LEO satellites distributed on multiple orbital planes, and is configured to provide stable coverage of the world or specific service areas;

a ground operation and control system, which is configured to perform business calculation and processing, and control and manage satellites and constellations;

a user receiver, which is configured to receive navigation direct signals broadcasted respectively by navigation satellites and the LEO satellites, as well as navigation augmentation information broadcasted by the LEO satellites, and perform precise positioning, speed measurement and timing based on the navigation direct signals of the navigation satellites, the navigation direct signals of the LEO satellites and the navigation augmentation information broadcasted by the LEO satellites;

wherein the ground operation and control system comprises a master control station, an injection station, and a monitoring station; the master control station, the injection station, the monitoring station and the LEO satellites of the LEO constellation constitute a satellite-ground integrated system, and the working process of the satellite-ground integrated system is as follows:

the monitoring station collects observation information of the navigation satellites and the LEO satellites, and sends the collected observation information of the navigation satellites and the LEO satellites to the master control station;

the master control station, according to its own position information and the observation information of the navigation satellites and the LEO satellites, generates augmentation information of the navigation satellites including the precise orbits and the precise clock biases of the navigation satellites, and the precise orbits and the precise clock biases of the LEO satellites, and make arrangements to form navigation augmentation information and LEO satellite navigation information, and sends the navigation augmentation information and the LEO satellite navigation information to the injection station;

the injection station sends the navigation augmentation information and the LEO satellite navigation information to the LEO satellites;

the LEO satellites calculate and forecast local clock biases, and arrange the local clock biases to form navigation telegrams, generate the navigation direct signals and broadcast to users, after receiving the navigation augmentation information and the LEO satellite navigation information;

the user receiver receives and measures navigation satellite signals and LEO satellite signals, and analyzes the navigation augmentation information and the navigation telegrams of the LEO satellites, to perform high-precision positioning, speed measurement and timing solution.

7. The system as claimed in claim 6 , wherein the LEO satellites of the LEO constellation are configured with high-precision frequency references to receive, in real-time, navigation satellite observation information of global navigation satellite system GNSS, and generate and broadcast the navigation direct signals carrying the navigation augmentation information.

8. The system as claimed in claim 7 , wherein the system constructs an integrated inter-satellite and satellite-to-ground network to uniformly transmit multiple types of information.

9. The system as claimed in claim 8 , wherein the master control station comprises:

a first calculation unit, which is configured to calculate precise orbit and clock bias correction number of the navigation satellites according to the position information of the master control station itself, the collected on-satellite receiver data of the LEO satellites, and the observation information of the navigation satellites and the LEO satellites at the monitoring station;

a second calculation unit, which is configured to calculate system time reference according to its own position information, the collected on-satellite receiver data of the LEO satellites, and the observation information of the navigation satellites and the LEO satellites at the monitoring station, and calculate the precise orbits and the precise clock biases of the LEO satellites, and navigation satellite relative clock bias according to the system time reference;

an information arrangement unit, which is configured to respectively generate the navigation telegrams according to the precise orbit and clock bias correction number of the navigation satellites and the precise orbits and the precise clock biases of the LEO satellites, and send the navigation telegrams to the injection station to inject into the LEO satellites.