A navigation system includes a receiver and a signal processor. The receiver is mounted on a second aircraft. The second aircraft is an acquisition target of location information. The receiver is configured to receive a navigation signal from each of three or more first aircrafts. The navigation signal includes the location information on a location of the corresponding first aircraft. The navigation signal is transmitted as a radio signal from a navigation apparatus mounted on each of the three or more first aircrafts. The signal processor is mounted on the second aircraft. The signal processor is configured to calculate a location of the second aircraft on the basis of the navigation signal.

A target device receives a plurality of pieces of first data, where each piece of the plurality of pieces of first data includes first ephemeris information and/or first almanac information. The target device identifies abnormal first data among the plurality of pieces of first data, where the plurality of pieces of first data include the abnormal first data, and the plurality of pieces of first data are obtained by the target device from a plurality of access network devices. A plurality of pieces of first ephemeris information and/or a plurality of pieces of first almanac information in the plurality of pieces of first data correspond to a first satellite. The target device may determine, by using the plurality of pieces of first ephemeris information and/or the plurality of pieces of first almanac information, that a piece of first ephemeris information and/or a piece of first almanac information is abnormal.

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.

The embodiments described herein provide ranging capabilities in RF-opaque environments, such as a jungle, that preclude the use of Global Positioning System (GPS) and/or laser ranging systems, utilizing transponders and Global Positioning System (GPS) receivers located on aerial vehicles. The aerial vehicles operate above the RF-opaque environment, and communicate with a ranging device within the RF-opaque environment on frequencies that propagate in the RF-opaque environment. The ranging device transmits RF signals to the transponders, which are received by the transponders and sent back to the ranging device on a different frequency. The aerial vehicles also provide their coordinates to the ranging device using their GPS receivers. The ranging device uses information about the transmitted and received RF signals and the GPS coordinates of the aerial vehicles to calculate a distance to a property line from the ranging device, and/or to calculate a coordinate location of the ranging device.

A preprocessing system includes a first port, where one end of the first port is coupled to a first switch, and the other end of the first port is suspended, where the first switch has a connecting end configured to couple to a first interface and is configured to connect a filter and the first interface, a second port configured to receive a first signal or a second signal, where the filter is configured to filter the first signal to obtain a first positioning signal and a second positioning signal, provide the first positioning signal for the first switch, and provide the second positioning signal for a second interface of a global navigation satellite system (GNSS) chip to adapt to a plurality of antenna configuration types and to achieve universality.

The present disclosure relates to a satellite system, and more particularly, to a satellite navigation system with high positioning accuracy. According to a low-orbit satellite, a satellite system including the same, and a control method thereof according to the present disclosure, a low-orbit satellite with high positioning accuracy is applied, but in order to reduce costs, the low-orbit satellite relays a signal from the existing high-orbit satellite and transmits the relayed signal to a signal receiving unit, thereby positioning of the receiving unit with high accuracy at low cost.

The embodiments described herein provide ranging capabilities in RF-opaque environments, such as a jungle, that preclude the use of Global Positioning System (GPS) and/or laser ranging systems, utilizing transponders and GPS receivers located on aerial vehicles. The aerial vehicles operate above the RF-opaque environment, and communicate with a ranging device within the RF-opaque environment on frequencies that propagate in the RF-opaque environment. The ranging device transmits RF signals to the transponders, which are received by the transponders and sent back to the ranging device. The aerial vehicles also provide their coordinates to the ranging device using their GPS receivers. The ranging device uses information about the transmitted and received RF signals and the GPS coordinates of the aerial vehicles to calculate a distance to a property line from the ranging device, and/or to calculate a coordinate location of the ranging device.

Satellite relaying for geolocation and mitigation of GNSS denial are provided, where a method comprises: receiving, by a processing device from a communication satellite along a communication path, a message initiated at a transmission time by a transmitting device, the communication path having a target device with an unknown distance to the communication satellite; determining, by the device, a reception time upon receiving the message; determining, by the device, a time of travel of the message associated with only traversal of a portion of the communication that is path between the communication satellite and the target device based on a difference between the transmission time and the reception time; calculating, by the device, a distance between the communication satellite and the target device based on the time of travel; and performing, by the device, one or more actions based on the distance between the communication satellite and the target device.

Satellite relaying for geolocation and mitigation of GNSS denial are provided, where a method comprises: receiving, by a processing device from a communication satellite along a communication path, a message initiated at a transmission time by a transmitting device, the communication path having a target device with an unknown distance to the communication satellite; determining, by the device, a reception time upon receiving the message; determining, by the device, a time of travel of the message associated with only traversal of a portion of the communication that is path between the communication satellite and the target device based on a difference between the transmission time and the reception time; calculating, by the device, a distance between the communication satellite and the target device based on the time of travel; and performing, by the device, one or more actions based on the distance between the communication satellite and the target device.

Satellite echoing for geolocation and mitigation of Global Navigation Satellite System (GNSS) denial are provided herein, where an example method comprises: transmitting, by a processing device, an echo message along a communication path having a communication satellite and a target device with an unknown distance to the communication satellite; receiving, by the processing device, a return of the echo message from the communication satellite over the communication path; determining, by the processing device, a time of travel of the echo message associated with only a single traversal of a portion of the communication path that is between the communication satellite and the target device; calculating, by the processing device, a distance between the communication satellite and the target device based on the time of travel; and performing, by the processing device, one or more actions based on the distance between the communication satellite and the target device.