SATELLITE PERFORMANCE MONITORING

• US 20090195444A1
• Filed: 01/28/2009
• Published: 08/06/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Miller, Mark J.
• Granted Patent: US 8,576,118 B2
• Time in Patent Office: Days
• US Class Current: 342/352
• CPC Class Codes: H04B 17/40 of relay systems
• CPC Class Codes: H04B 7/185 Space-based or airborne stations; Stations for satellite systemsH04B7/204 takes precedence
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Techniques for monitoring transmission performance of a satellite communications systems are provided, including techniques for measuring the primary contributors to the end-to-end SNR, including the uplink SNR, the downlink SNR, and the C/I for each link in the network. These individual measurements are used to estimate satellite effective isotropic radiated power (EIRP), satellite antenna gain-to-noise-temperature (G/T), and loss due to an Earth Terminal pointing error. The EIRP, satellite antenna G/T and loss due to Earth terminal pointing error may then be used to determine operating parameters for the satellite communications network that enable the network to operate more efficiently.

Claims

1. A method for monitoring the performance of a satellite communication system comprising:

measuring, at a gateway terminal, a total receive power of a signal received from a satellite under normal operating conditions;

measuring one of a signal only power and a signal to noise plus interference ratio (SINR) for a signal received from the satellite under normal operating conditions;

measuring a total thermal noise component of the signal received from the satellite;

measuring a downlink thermal noise component of the signal received from the satellite; and

calculating satellite communication system operating parameters using the total receive power, the signal only power or the SINR, the total thermal noise component, and the downlink thermal noise component measurements.

2. The method of claim 1, wherein the satellite communications system includes at least one gateway terminal and a plurality of user terminals, the method further comprising:

commanding the at least one gateway terminal and the plurality of user terminals to disable all transmissions prior to measuring the total thermal noise component of the signal received from the satellite; and

commanding the at least one gateway terminal and the plurality of user terminals to enable transmissions after measuring the total thermal noise component of the signal received from the satellite.

3. The method of claim 2 wherein an outage time used for measuring the total thermal noise component of the signal received from the satellite is built into a frame structure of the satellite communications system so that the outage time occurs at a regular interval.

4. The method of claim 2, further comprising:

scheduling an outage time for measuring the total thermal noise component of the signal received from the satellite, wherein the outage time is scheduled by a central control agent of the satellite broadcast system.

5. The method of claim 4 wherein scheduling an outage time for measuring the total thermal noise component of the signal received from the satellite further comprises:

commanding the at least one gateway terminal and the plurality of user terminals to disable all transmissions for an interval specified in a message.

6. The method of claim 2 wherein commanding the at least one gateway terminal to disable all transmissions prior to measuring the total thermal noise component of the signal received from the satellite further comprises:

calculating a path delay to the satellite from the at least one gateway terminal based on the location of the at least one gateway terminal and ephemeris data of the satellite; and

synchronously disabling the at least one gateway terminal with the disabling of the plurality of the user terminals using the path delay and an accurate time base of the at least one gateway terminal.

7. The method of claim 1, further comprising:

commanding the satellite to disable all transmissions prior to measuring the downlink thermal noise component; and

commanding the satellite to enable transmissions after measuring the downlink thermal noise component.

8. The method of claim 1 wherein the satellite communications system includes at least one gateway terminal and a plurality of user terminals, the method further comprising:

commanding the satellite, the at least one gateway terminal, and the plurality of user terminals to disable all transmissions prior to measuring the downlink thermal noise component; and

commanding the satellite, the at least one gateway terminal, and the plurality of user terminals to enable transmissions after measuring the downlink thermal noise component.

9. The method of claim 1, further comprising:

determining an estimated downlink thermal noise component instead of measuring the downlink thermal noise component; and

calculating satellite communication system operating parameters using the total receive power, the signal only power, the total thermal noise component, and estimated downlink thermal noise component measurements.

10. The method of claim 9 wherein determining an estimated downlink thermal noise component further comprises:

determining a ratio of a previously determined downlink thermal noise component to the total thermal noise component; and

calculating the estimated downlink thermal noise component by multiplying the ratio by the total thermal noise component.

11. The method of claim 9 wherein determining an estimated downlink thermal noise component further comprises:

measuring an out-of-band power level; and

calculating the estimated downlink thermal noise component by multiplying the out-of-band power level by a compensation factor.

12. The method of claim 9 wherein the satellite communications system includes at least one gateway terminal and a plurality of user terminals, the method further comprising:

determining the compensation factor before estimating the downlink thermal noise component, wherein determining the compensation factor further comprises;

commanding the satellite, the at least one gateway terminal, and the plurality of user terminals to disable all transmissions;

measuring an in-band power level;

measuring an out-of-band power level;

calculating the compensation factor using the in-band power level and the out-of-band power level; and

commanding the satellite, the at least one gateway terminal, and the plurality of user terminals to enable transmissions.

13. The method of claim 9 wherein the satellite communications system includes at least one gateway terminal and a plurality of user terminals, the method further comprising:

determining the compensation factor before estimating the downlink thermal noise component, wherein determining the compensation factor further comprises;

commanding the satellite to disable all transmissions;

measuring an in-band power level;

measuring an out-of-band power level;

calculating the compensation factor using the in-band power level and the out-of-band power level; and

commanding the satellite to enable transmissions.

14. The method of claim 1 wherein both the signal only power of the signal received from the satellite under normal operating conditions and the SINR for the signal received from the satellite under normal operating conditions are measured.