TECHNICAL FIELD

The present disclosure relates generally to satellite communication systems, and, more particularly, to trilateration-based satellite location accuracy for improved satellite-based geolocation.

BACKGROUND

Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS) (also referred to as “global positioning satellites”) in the United States, are systems wherein a mobile device is a passive device which receives signals from GNSS satellites and determines its own location based on the information encoded in the received signals as well as the time difference between the received signals. One of the benefits of this system is the fact that the mobile device does not need to transmit any signals and as such it does not have any radio footprint that may identify its location. Additionally, the fact that the mobile device does not need to transmit any radio signal saves battery power and extends the operation time of the device.

One of the biggest shortcomings of GNSS systems is the ease with which they can be jammed (blocked) or spoofed (making a receiver believe it is in a different location than it actually is). GNSS jamming devices are readily available for personal privacy use, and on a larger scale, GNSS jammers can be, and frequently are, used as part of electronic warfare to eliminate or misguide an adversary's personnel navigation and sophisticated weaponry systems. Additionally, while GNSS spoofing devices are generally more sophisticated, they are still known to exist and to be in use.

Generally, GNSS is easy to jam because it relies on a weak signal transmitted from satellites over a narrow frequency band. Additionally, given the fact that the GNSS signal is generated by predefined hardware in satellites makes it practically impossible to modify the system in order to make it more robust.

Numerous worldwide commercial operations heavily rely on the operations of the GNSS system. A 2017 London Economics report concluded that a five day GNSS outage would cost the nation at least $1.3B per day.

The US army is experimenting with a solution based on deploying GPS “satellites” or stations on or near the ground. The ground-based GPS stations provide full control over the locations and power of the transmissions. Such a system can ensure that transmissions reach places that space borne GPS signals normally struggles with, such as deep urban canyons, forests, and valleys. Though the transmit power of such a system may be increased to make the signal much harder to jam than space-borne GPS satellite signals, the challenge with these GPS ground stations (or pseudo-satellites) is determining their location accurately in an environment that is prone to jamming and susceptible to spoofing of the space borne GPS.

Similarly, another suggested solution to this problem is based on low elevation orbiting satellites (LEO) which are 25 times closer to earth than the GPS satellites, and as such the signal received from these satellites is 1000 times stronger than signals received from the GPS satellites. Additionally, the signal from these satellites is encrypted. Therefore, it is proposed that jamming or spoofing these signals is more challenging. However, one problem associated with this solution is that a low flying drone or other devices can still jam the specific frequencies used by this system and block the frequency band used by this solution.

To address the severity of this situation and the lack of current solutions, the United States Department of Defense issued a memorandum on Dec. 16, 2019 to the Defense Science Board Task Force on Position, Navigation, and Timing Control (PNTC) establishing a taskforce to study and recommend an architecture which provides a more resilient position, navigation, and timing (PNT) services (alternatively, precision navigation and timekeeping (PNT)) for both commercial and military purposes.

SUMMARY

According to one or more of the embodiments herein, systems and techniques are provided for a viable alternative to a traditional Global Navigation Satellite System (GNSS), as well as for detection and mitigation of GNSS denial (jamming and/or spoofing). In particular, certain aspects of the techniques herein may be used in conjunction with providing a robust positioning and navigation system that is not prone to jamming or spoofing, and is easy to modify through software methodology (i.e., without modifications to satellite hardware systems). Unlike existing GNSS systems, where the mobile device acts as a passive receiver, a system in accordance with certain techniques herein may use a mobile device's satellite transmission and reception capabilities to determine a position of the mobile device, without being dependent on receiving signals from traditional GNSS satellites. Also, a system in accordance with the present disclosure can operate as a standalone system or as a companion system to the conventional GNSS system. Further embodiments described herein may also be used to increase the accuracy of the satellite-based geolocation techniques herein, accordingly.

Specifically, the current application is directed to satellite communication systems, and, more particularly, to trilateration-based satellite location accuracy for improved satellite-based geolocation. In one particular embodiment, an illustrative method according to one or more embodiments of the present disclosure may comprise: determining, by a processing device, a location of each of a plurality of reference antennas with known locations; obtaining, by the processing device, 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, by the processing device, 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, by the processing device, the accurate location of the communication satellite.

Other embodiments of the present disclosure may be discussed in the detailed description below, and the summary above is not meant to be limiting to the scope of the invention herein.

