Disclosed is a method for achieving space-based autonomous navigation of global navigation satellite system (GNSS) satellites, and relates to the field of satellite navigation technologies. The method includes the following steps: optimizing a DRO, and establishing a dynamic model of an earth-moon space satellite orbit; establishing measurement links, by a low earth orbit (LEO) data relay satellite, with an earth-moon space DRO satellite and a GNSS respectively, and measuring an inter-satellite distance for modeling and linearization; adopting an extended Kalman filter (EKF) method to process inter-satellite measurement data, and autonomously determining a position and velocity of the global navigation satellite system without depending on the ground measurement and control support.

A method and a system for verifying integrity of GPS position information according to a disclosed embodiment is a method performed in an unmanned moving object including one or more processors and a memory for storing one or more programs executed by the one or more processors. The method includes an operation of performing an authentication process for a connected base station, by the unmanned moving object, an operation of measuring a position of the unmanned moving object by performing wireless communication with a plurality of authenticated base stations, and an operation of verifying the GPS position information by comparing a value of the measured position with a position value of the GPS position information received from a satellite.

A space based multi-band GPS/GNSS navigation system, including: a first RF card with a space grade application specific integrated circuit (ASIC) implementing two RF channels configured to receive and process two different received navigation signals; a space grade navigation processor configured to: execute processor instructions to process the two different received navigation signals to produce position, velocity, and time information; and process measurements using an Extended Kalman filter for enhanced performance at high altitude, including cis-lunar and lunar space.

The present disclosure relates generally to satellite communication systems, and, more particularly, to trilateration-based satellite location accuracy for improved satellite-based geolocation are provided. In one embodiment, a method comprises: determining, by a processing device, a location of each of a plurality of reference antennas with known locations; obtaining a plurality of distances between a communication satellite and the plurality of reference antennas, each distance of the plurality of distances corresponding to a respective reference antenna of the plurality of reference antennas, at least one distance of the plurality of distances based on an echo message communicated between a particular reference antenna of the plurality of reference antennas and the communication satellite; determining an accurate location of the communication satellite based on trilateration of the plurality of distances from the known locations of the plurality of reference antennas; and utilizing the accurate location of the communication satellite.

According to one or more embodiments herein, interferometry-based satellite location accuracy is provided. In one embodiment, a method comprises: determining, generally at a substantially given time, a reference satellite having a known accurate location within angular proximity of a communication satellite having a known general location; determining an accurate angular position of the communication satellite with relation to the reference satellite from the perspective of at least one ground station antenna of a known accurate location; determining an additional location reference measurement of the communication satellite; determining an accurate location of the communication satellite at the substantially given time based at least in part on the accurate angular position of the communication satellite with relation to the reference satellite from the perspective of the at least one ground station antenna and the additional location reference measurement of the communication satellite; and utilizing the accurate location of the communication satellite.

Satellite echoing for geolocation and mitigation of Global Navigation Satellite System (GNSS) denial are provided herein, where an example method comprises: transmitting an initiated message to a communication satellite along a communication path that has a target device with an unknown distance to the communication satellite; receiving a returned message from the communication satellite over the communication path in response to the initiated message; determining a local time difference between the transmission time and the reception time; calculating a distance between the communication satellite and the target device, the distance calculated based on a portion of the determined time difference associated with only a single traversal of a portion of the communication path that is between the communication satellite and the target device; and performing one or more actions based on the distance between the communication satellite and the target device.

According to one or more of the embodiments herein, systems and techniques for multi-system-based detection and mitigation of Global Navigation Satellite System (GNSS) spoofing are provided. In one embodiment, a method comprises: obtaining a first location of an object from a primary location determination hardware system; obtaining a second location of the object from a secondary location determination hardware system; determining a distance difference between the first location and the second location; determining whether the distance difference between the first location and the second location is acceptable based on a threshold distance; and initiating one or more mitigation actions in response to the distance difference between the first location and the second location being unacceptable.

According to one or more of the embodiments herein, systems and techniques for multi-subset-based detection and mitigation of Global Navigation Satellite System (GNSS) spoofing are provided. In one embodiment, a method comprises: determining data associated with a distance between an object and each of a plurality of satellites to produce a corresponding plurality of datums; creating a plurality of different subsets of the datums; determining a plurality of possible computed solutions for the object based on the subsets of datums; determining, in response to the plurality of possible computed solutions falling within an acceptable proximity of each other, a trusted computed solution for the object based on the plurality of datums; and initiating, in response to at least one the plurality of possible computed solutions not falling within the acceptable proximity of each other of the plurality of possible computed solutions, one or more mitigation actions.

According to one or more of the embodiments herein, systems and techniques for satellite relaying for geolocation and mitigation of Global Navigation Satellite System (GNSS) denial are provided. In one embodiment, a method comprises: receiving, at a processing device from a communication satellite along a communication path, a message initiated by a transmitting device and indicating a transmission time, the communication path having a target device with an unknown distance to the communication satellite; determining a reception time upon receiving the message, (the processing device and the transmitting device have synchronized clocks); determining a time difference between the transmission time and the reception time; calculating a distance between the communication satellite and the target device based on a portion of the determined time difference associated with only traversal of a portion of the communication path between the communication satellite and the target device; and performing action(s) based on the distance.

In one embodiment, a navigation system may include at least one self-describing fiducial with a communication element to communicate navigation state estimation aiding information comprising a geographic position of the self-describing fiducial with respect to one or more coordinate systems and a first navigating object to receive navigation information from an exterior system, receive navigation state estimation aiding information from the self-describing fiducial, and compare the navigation information received from the exterior system to the navigation state estimation aiding information to improve navigation parameters of the first navigating object.