Processing satellite data for slant total electron content measurements
A method, system, and apparatus provide the ability to estimate ionospheric observables using space-borne observations. Space-borne global positioning system (GPS) data of ionospheric delay are obtained from a satellite. The space-borne GPS data are combined with ground-based GPS observations. The combination is utilized in a model to estimate a global three-dimensional (3D) electron density field.
1. A method for estimating ionospheric observables using space-borne observations, comprising:
obtaining space-borne global positioning system (GPS) data of ionospheric delay from a space-borne satellite receiver;
obtaining ground-based GPS observations;
combining the space-borne GPS data with the ground-based GPS observations; and
utilizing the combination in a model to estimate a global three-dimensional (3D) electron density field.
2. The method of claim 1 , wherein the space-borne GPS data is obtained via the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC).
3. The method of claim 1 , wherein the utilizing comprises phase leveling the space-borne GPS data.
4. The method of claim 3 , wherein the phase leveling comprises utilizing an unbiased level of a pseudorange code ionospheric observable to set a level of a carrier phase ionospheric observable.
5. The method of claim 1 , wherein the utilizing comprises estimating a bias of the space-borne satellite receiver and a second receiver.
6. The method of claim 5 , wherein the bias is estimated by taking cross correlations between multiple different ground based GPS measurements.
7. The method of claim 5 , wherein the estimating the bias for the second receiver comprises:
tabulating a smallest measurement of an arc that passes through a filtered region of the ionosphere;
averaging the smallest measurements over a course of a day; and
subtracting, from the average, a component for the ionosphere and plasmasphere contributions, to determine a daily bias for the second receiver.
8. The method of claim 7 , wherein the bias for the second receiver comprises a 10-day running average of the daily biases.
9. A system for estimating ionospheric observables using space-borne observations comprising:
(a) a processor having a memory;
(b) an application executing on the processor, wherein the application is configured to:
(1) obtain space-borne global positioning system (GPS) data of ionospheric delay from a space-borne satellite receiver;
(2) obtain ground-based GPS observations;
(3) combine the space-borne GPS data with the ground-based GPS observations; and
(4) utilize the combination in a model to estimate a global three-dimensional (3D) electron density field.
10. The system of claim 9 , wherein the space-borne GPS data is obtained via the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC).
11. The system of claim 9 , wherein the utilizing comprises phase leveling the space-borne GPS data.
12. The system of claim 11 , wherein the phase leveling comprises utilizing an unbiased level of a pseudorange code ionospheric observable to set a level of a carrier phase ionospheric observable.
13. The system of claim 9 , wherein the utilizing comprises estimating a bias of the space-borne satellite receiver and a second receiver.
14. The system of claim 13 , wherein the bias is estimated by taking cross correlations between multiple different ground based GPS measurements.
15. The system of claim 13 , wherein the estimating the bias for the second receiver comprises:
tabulating a smallest measurement of an arc that passes through a filtered region of the ionosphere;
averaging the smallest measurements over a course of a day; and
subtracting, from the average, a component for the ionosphere and plasmasphere contributions, to determine a daily bias for the second receiver.
16. The system of claim 15 , wherein the bias for the second receiver comprises a 10-day running average of the daily biases.