Systems and methods for GNSS interference monitoring
Systems and methods for GNSS interference monitoring are provided. In certain embodiments, a system includes at least one GNSS receiver configured to receive a plurality of signals from a plurality of satellites and provide measurements from the plurality of satellites; and a processor coupled to the at least one GNSS receiver. Further, the processor is configured to calculate a detection parameter that comprises at least one of a composite detection parameter based on a short-term average and a long-term average of carrier-to-noise measurements for the plurality of signals; and a transient detection parameter based on an average difference for the plurality of satellites between the short-term average and long-term average of the carrier-to-noise measurements for each satellite in the plurality of satellites. The processor is also configured to determine a state of the plurality of signals based on a comparison of the composite detection parameter against a comparison threshold.
1 . A system comprising:
at least one global navigation satellite system (GNSS) receiver configured to receive one or more signals from a plurality of satellites and provide carrier-to-noise measurements for the one or more signals; and
at least one processor coupled to the at least one GNSS receiver, wherein the at least one processor is configured to:
calculate a detection parameter, wherein the detection parameter comprises at least one of:
a composite detection parameter based on a difference between a short-term average of the carrier-to-noise measurements for the one or more signals and a long-term average of the carrier-to-noise measurements for the one or more signals; and
a transient detection parameter based on an average difference for the plurality of satellites being an average of respective differences between a short-term average of the carrier-to-noise measurements for each respective satellite in the plurality of satellites and a long-term average of the carrier-to-noise measurements for each respective satellite in the plurality of satellites; and
determine a state of the one or more signals based on a comparison of the detection parameter against a comparison threshold.
2 . The system of claim 1 , further comprising one or more motion sensors configured to provide motion measurements of an object to the at least one processor;
wherein the at least one processor is further configured to:
determine whether the object is experiencing a maneuver based on the motion measurements received from the one or more motion sensors; and
suspend the calculation of the detection parameter and determination of the state when the motion measurements indicate that the object is experiencing the maneuver.
3 . The system of claim 1 , wherein the at least one processor is configured to detect whether the at least one GNSS receiver is experiencing significant signal loss based on a number of available satellite measurements received by the at least one GNSS receiver.
4 . The system of claim 1 , wherein the long-term average is a filtered average of the carrier-to-noise measurements calculated using a time constant.
5 . The system of claim 1 , wherein the short-term average is an average of a number of most recently received carrier-to-noise measurements.
6 . The system of claim 1 , wherein the short-term average is a filtered average of the carrier-to-noise measurements calculated using a short-term time constant that is shorter than a long-term time constant used to calculate the long-term average.
7 . The system of claim 1 , wherein the at least one processor is configured to exclude carrier-to-noise measurement outliers when calculating at least one of the long-term average and the short-term average.
8 . The system of claim 1 , wherein the at least one processor is configured to determine whether the one or more signals from the at least one GNSS receiver is in a low-power state, a high-power state, or a normal-power state.
9 . The system of claim 8 , wherein the at least one processor executes logic for controlling at least one of transitions between the low-power state and the normal-power state and transitions between the high-power state and the normal-power state.
10 . The system of claim 1 , wherein the carrier-to-noise measurements are adjusted based on expected values as a function of satellite elevation angle.
11 . The system of claim 1 , wherein the at least one processor provides the state of the one or more signals as an output to a connected system.
12 . A method comprising:
receiving one or more global navigation satellite system (GNSS) signals from a plurality of satellites and carrier-to-noise measurements for the one or more GNSS signals by a receiver mounted on a vehicle;
receiving navigation information for the vehicle from one or more sensors;
determining when the vehicle is experiencing a maneuver based on the navigation information;
updating an interference detection parameter for the one or more GNSS signals when the vehicle is determined to not be experiencing the maneuver; and
identifying a state of the one or more GNSS signals based on the interference detection parameter, comprising:
updating the interference detection parameter based on a difference between a short-term average and a long-term average of the carrier-to-noise measurements for the one or more GNSS signals; and
comparing the interference detection parameter against at least one of a low power threshold and a high power threshold.
13 . The method of claim 12 , wherein the long-term average is a filtered average of the carrier-to-noise measurements calculated using a time constant.
14 . The method of claim 12 , wherein the short-term average is an average of a number of most recently received carrier-to-noise measurements.
15 . The method of claim 14 , wherein the short-term average is a filtered average of the carrier-to-noise measurements calculated using a short-term time constant that is shorter than a long-term time constant used to calculate the long-term average.
16 . The method of claim 12 , wherein updating the interference detection parameter further comprises calculating a transient detection measure.
17 . The method of claim 12 , further comprising detecting significant signal loss based on a number of available satellite measurements.
18 . The method of claim 12 , wherein identifying the state of the one or more GNSS signals comprises determining whether the one or more GNSS signals is in a low-power state, a high-power state, or a normal-power state.
19 . A system comprising:
at least one global navigation satellite system receiver mounted on a vehicle configured to receive one or more signals from a plurality of satellites and provide carrier-to-noise measurements for the one or more signals;
one or more sensors that provide navigation information for the vehicle; and
a hardware processor coupled to the at least one global navigation satellite system receiver and the one or more sensors, wherein the hardware processor executes an excessive interference monitor that comprises:
a composite monitor section that updates a composite detection parameter based on a difference between a short-term average of the carrier-to-noise measurements for the one or more signals and a long-term average of the carrier-to-noise measurements for the one or more signals, wherein the composite monitor section suspends updating the composite detection parameter in response to a determination that the vehicle is experiencing a maneuver based on the navigation information;
a state determination section that determines a state of the one or more signals based on a comparison of the composite detection parameter received from the composite monitor section against at least one of a low-power threshold and a high-power threshold; and
an output section that provides information related to the state of the one or more signals for use by the vehicle.