Refractivity retrieval via direct measurement of GNSS bending angle
AssigneeThe Boeing Company
InventorBrian J. Tillotson
Life of this patent
Estimating the term…
Abstract
A method and system for taking direct measurements of GNSS signal's arrival angle to remotely measure the atmospheric variables used for weather prediction. More specifically, an improved method and system for obtaining and processing accurate information regarding the weather and other atmospheric changes by measuring the total refractive bending angle of the GNSS signal. For mobile platforms on which receivers are mounted, phased array receivers are used to allow precise measurements of GNSS arrival angles. By measuring the refractive bending angle, more accurate and cost-efficient measurements of atmospheric changes are obtained, thereby resulting in more accurate predictions of the weather.
Claims28
A method of determining refractivity properties of the Earth's atmosphere comprising:
- providing a plurality of antenna elements configured to measure an actual arrival angle of a signal, the antenna elements separated by a predetermined vertical distance;
- providing a receiver device, the receiver device being coupled to each of the plurality of antenna elements and configured to compute a nominal arrival angle of the signal based on data transmitted from a source of the signal;
- receiving the signal at each of the plurality of antenna elements;
- measuring an actual arrival angle of the signal using the plurality of antenna elements;
- determining a difference between the nominal arrival angle of the signal and the actual arrival angle of the signal;
- calculating a refractive bending angle of the signal based on the determined difference between the actual and nominal arrival angles;
- and
- transforming the refractive bending angle of the signal into a profile of physical properties of the atmosphere.
A method of determining refractivity properties of the Earth's atmosphere comprising:
- providing a plurality of antenna elements configured to measure an actual arrival angle and actual arrival phase of a signal, the antenna elements mounted on a platform and separated by a predetermined vertical distance;
- providing a receiver device, the receiver device being coupled to each of the plurality of antenna elements and configured to calculate a nominal arrival angle and a nominal arrival phase of the signal based on data transmitted from a source of the signal;
- receiving the signal at each of the plurality of antenna elements;
- measuring an actual arrival angle of the signal;
- measuring an actual arrival phase of the signal for each antenna element of the plurality of antenna elements;
- determining a difference between the nominal arrival angle of the signal and the actual arrival angle of signal;
- determining a difference between the nominal arrival phase of the signal and the actual arrival phase of signal;
- calculating a refractive bending angle and an absolute phase shift of the signal based on the determined differences between the actual and nominal arrival angles of the signal and the actual and nominal arrival phases of the signal;
- and
- generating a profile of physical properties of the atmosphere based on a transformation of the refractive bending angle of the signal and the absolute phase shift of the signal.
A system for determining refractivity properties of the Earth's atmosphere comprising:
- a plurality of antenna elements configured to measure the arrival angle of a signal, the plurality of antenna elements mounted on a platform and separated by a predetermined vertical distance;
- a receiver unit, the receiver unit being coupled to each of the plurality of antenna elements;
- wherein the receiver unit being configured to:
- receive the signal detected by each of the plurality of antenna elements;
- compute a nominal arrival angle of the signal based on data transmitted from a source of the signal;
- measure an actual arrival phase of the signal for each antenna element of the plurality of antenna elements;
- compute an actual arrival angle from the arrival phases;
- determine a difference between the nominal arrival angle of the signal and the actual arrival angle of signal;
- calculate a refractive bending angle of the signal based on the determined differences between the actual and nominal arrival angles of the signal;
- and
- generate a profile of physical properties of the atmosphere based on a transformation of the refractive bending angle of the signal.
Dependencies are inferred from the claim text.