Location may be determined in a way that does not primarily rely on jam-able or spoof-able techniques. For example, an apparatus may have multiple location-determining units, each unit having a different level of trust. One unit may have a first (e.g., highest) level of trust, a second such unit may have a second (e.g., medium) level of trust lower than the first level of trust, and a third such unit may have a third (e.g., lowest) level of trust lower than the first and second levels of trust. The apparatus may generally prefer to determine its location using the highest level of trust unit that is available at any given time.

An electronically steerable parasitic array radiator (ESPAR) antenna system that includes an ESPAR antenna, a GPS receiver, a GPS low-noise amplifier, a power detector module, and a central processing unit. The GPS receiver is connected to the ESPAR antenna as a separate component. The GPS low-noise amplifier strengthens a signal to propagate through the transmission line and operates in the L1 and L2 GPS bands. The power detector module provides additional amplification for noise quantification. The power detector receives an RF power level and converts the RF power level into a DC voltage output. The central processing unit includes memory that is capable of storing the DC voltage output from the power detector.

An electronically steerable parasitic array radiator (ESPAR) antenna system that includes an ESPAR antenna, a GPS receiver, a GPS low-noise amplifier, a power detector module, and a central processing unit. The GPS receiver is connected to the ESPAR antenna as a separate component. The GPS low-noise amplifier strengthens a signal to propagate through the transmission line and operates in the L1 and L2 GPS bands. The power detector module provides additional amplification for noise quantification. The power detector receives an RF power level and converts the RF power level into a DC voltage output. The central processing unit includes memory that is capable of storing the DC voltage output from the power detector.

A system includes at least one sensing unit, the sensing unit including a sensing element. The system includes at least one spatial Lorentz filter coupled to the sensing element. The spatial Lorentz filter (SLF) includes an input coupled to the sensing element and an analog to digital converter (ADC) providing a filtered output signal. The sensing unit is connected to a processor configured for determining velocity or position with respect to a magnetic field and/or a geographic position by processing SLF output signals.

An exemplary method includes a monitoring system identifying a time period during which a vehicle equipped with a tracking device travels at least a threshold distance, determining that the tracking device fails to acquire a desired signal for a predetermined amount of time during the time period, and, in response to determining that the tracking device fails to acquire the desired signal, determining that the tracking device is potentially being interfered with during the time period by a signal jamming device.

An exemplary method includes a monitoring system identifying a time period during which a vehicle equipped with a tracking device travels at least a threshold distance, determining that the tracking device fails to acquire a desired signal for a predetermined amount of time during the time period, and, in response to determining that the tracking device fails to acquire the desired signal, determining that the tracking device is potentially being interfered with during the time period by a signal jamming device.

A method of restoring navigational performance for a navigational system, the method comprising receiving by a first navigational system and a second navigational system a collection of data points to establish a real-time navigational route for the aircraft, comparing navigational performance values and/or drift ranges and establishing a new navigational route based on the collection of data points.

A system and method to distinguish spoofing signals from true GNSS signals is disclosed. One aspect of the present invention combines measuring GNSS carrier signals with measuring jitter in a vehicle's position via a low-cost inertial measurement unit (IMU) to distinguish spoofing signals from true GNSS signals. The present invention employs natural and/or artificial jitter of a vehicle, that, when combined with a tightly coupled inertial navigation system (INS), allows the receiver to distinguish the spoofing GNSS signal from the true GNSS signal. This spoofer survivability algorithm may be implemented, for example, in the software of a GNSS (or GPS) navigation system.

Existing networks of precisely surveyed GNSS receivers that are used for dGNSS or RTK positioning techniques can be used to measure GNSS time across a territory or region such as a country. The measured GNSS time base signals from each receiver are then fed back to a collating service, similar to the existing dGNSS/RTK systems, which also receives an accurate time base signal from a trusted third-party time base supplier which maintains a trusted time base. The collating service then compares the GNSS time signals from the network of GNSS receivers with the trusted time base and determines whether the GNSS time signals are accurate when compared to the trusted time base, and if they are not accurate, calculates the error. The collating service may provide the calculated error to users and the necessary correction that needs to be applied to measured GNSS time to obtain accurate UTC time.

Systems and methods for detecting spoofing attempts are disclosed. In one embodiment, a ground station system for detecting a Global Navigation Satellite System (GNSS) spoof signal includes a receiver configured to receive data collected by a detection satellite that (1) is on a first orbit that is lower than a second orbit used by a GNSS satellite and (2) includes: a first antenna positioned to receive signals originating from a planetary surface, and a second antenna positioned to receive signals originating from the GNSS satellite on a higher orbit than the first orbit of the detection satellite. The ground station further includes one or more processors configured to calculate, using the time of arrival of the signal received at the first antenna and the position of the detection satellite determined based on the signal received at the second antenna, a geolocation of a source of the signal originating from a planetary surface.