Method and apparatus using transmit beam lobing for identifying an interfering mobile terminal

• US 20020146982A1
• Filed: 12/06/2001
• Published: 10/10/2002
• Est. Priority Date: 04/04/2001
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Parkman, David S., Chapelle, Michael de La, McLain, Christopher John
• Granted Patent: US 6,708,019 B2
• Time in Patent Office: Days
• US Class Current: 455/67.13
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

A method for rapidly monitoring and detecting a mobile terminal causing RF interference with one or more satellites orbiting in the vicinity of a target satellite, from a plurality of mobile terminals accessing the target satellite. Each mobile terminal performs a transmit lobing signal sequence and a ground-based component in the form of a Network Operation Center (NOC) analyzes the signals transmitted by each mobile platform. The NOC determines a ratio of energy-per-bit to noise spectral density (Eb/No) value for the signals transmitted by each mobile platform and compares these values to a predetermined Eb/No value. If the Eb/No values for a given mobile platform deviate by more than a predetermined magnitude from the predetermined Eb/No value, then the NOC identifies that given mobile platform as causing the unintended RF interference with the adjacent satellite(s).

Claims

1. A method for determining which one of a plurality of mobile terminals is causing an interfering event with one or more satellites orbiting in a vicinity of a transponded target satellite with which said mobile terminals are in communication with, said method comprising the steps of:

using a ground-based component to command each of said mobile terminals in communication with said transponded satellite to perform a transmit lobing sequence with a transmit antenna associated therewith by aiming its associated said transmit antenna at a plurality of positions off-axis of said target satellite and transmitting a plurality of signals thereto;

using said target transponder to relay said signals to said ground-based component;

using said ground-based component to determine a parameter of said signals transmitted to said target satellite for each one of said mobile terminals, said parameter representing at least one of signal strength or signal quality;

using said ground-based component to compare said parameter of said signals from each of said mobile platforms to a predetermined signal value to determine which one of said signal parameters deviates from said predetermined signal value by more than a predetermined amount; and

identifying said mobile terminal which has transmitted said signals generating a parameter which deviates from said predetermined signal value by more than said predetermined amount, as said mobile terminal which is causing said interfering event.

2. The method of claim 1, where said ground-based component comprises a Network Operations Center (NOC).

3. The method of claim 1, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in elevation from a known center of said target satellite.

4. The method of claim 1, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in azimuth from a known center of said target satellite.

5. The method of claim 1, wherein said mobile terminals perform said transmit lobing signal sequence in sequential fashion until each one of said terminals performed said transmit lobing signal sequence.

6. The method of claim 1, wherein said parameter comprises a ratio of energy-per-pit to noise spectral density (Eb/No).

7. A method for determining which one of a plurality of mobile terminals is causing an interfering event with one or more satellites orbiting in the vicinity of a transponded target satellite with which said mobile terminals are in communication with, said method comprising the steps of:

using a base station having a network operations center (NOC) to command a first one of said mobile terminals to perform a transmit lobing signal sequence with its associated said transmit antenna by aiming its said transmit antenna at a plurality of positions off-axis of said target satellite and transmitting a plurality of signals;

using said target satellite to receive said signals and to relay said signals to said NOC;

using said NOC to determine a parameter of said signals indicative of at least one of signal strength or signal quality;

using said NOC to determine if said parameter of said signals from said first mobile terminal deviates sufficiently from an expected value;

if said NOC determines that said signals from said first mobile platform do not deviate sufficiently from an expected value, then using said NOC to command each remaining one of said plurality of mobile terminals, one at a time in sequential fashion, to perform said transmit lobing sequence until one of said mobile terminals is determined by said NOC to be transmitting signals which generate a said parameter which deviates by a predetermined magnitude from an expected value, thereby indicating to said NOC that said one mobile terminal is causing said interfering event.

8. The method of claim 7, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in azimuth from a known center of said target satellite.

9. The method of claim 7, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in elevation from a know center of said target satellite.

10. The method of claim 7, wherein said parameter comprises a ratio of energy-per-pit to noise spectral density (Eb/No).

11. A method for determining which one of a plurality of mobile terminals is causing an interfering event with one or more satellites orbiting in a vicinity of a transponded target satellite with which said mobile terminals are in communication with, said method comprising the steps of:

using a base station having a ground-based component to command a first one of said mobile terminals to perform a transmit lobing signal sequence with its associated said transmit antenna by aiming its said transmit antenna at a plurality of positions off-axis of said target satellite and transmitting a plurality of signals;

using said target satellite to receive said signals and to relay said signals to said NOC;

using said ground-based component to evaluate said signals to determine a ratio of energy-per-bit to noise spectral density (Eb/No) value of each of said signals;

using said ground-based component to determine if any of said Eb/No values deviate more than a predetermined amount from an expected Eb/No value;

identifying said mobile terminal which has transmitted said signals having said Eb/No value which differs by more than said predetermined amount from said expected Eb/No value as being said mobile terminal which is causing said interfering event; and

using said ground-based component to inform said mobile terminal of a needed action to take to cease causing said interfering event.

12. The method of claim 11, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in azimuth from a known center of said target satellite.

13. The method of claim 11, wherein said transmit lobing signal sequence comprises having each said mobile terminal transmit two signals offset in elevation from a known center of said target satellite.

14. The method of claim 11, wherein said mobile terminals perform said transmit lobing signal sequence in sequential fashion until each of said mobile terminals has completed performing said sequence.