Systems and methods for determining radio frequency interference
First Claim
1. A method of determining radio frequency interference with communication links including a celestial body and an artificial geostationary satellite of the body, said interference originating from the body, said links being in a predetermined spectrum, comprising the steps of:
- (a) pointing a narrow beam antenna on the satellite toward a predetermined region of the body while only noise sources in the spectrum are radiated from the region toward the satellite;
(b) transmitting a calibrating electromagnetic wave of predetermined EIRP having a frequency in the spectrum from the region toward the satellite while the antenna is pointed toward the predetermined region;
(c) separately measuring the levels of electromagnetic energy received by the antenna in the spectrum during steps (a) and (b); and
(d) comparing the measured, received energy levels to determine the presence of radio frequency interference in the spectrum.
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Abstract
The presence, frequency and amplitude of radio frequency interference superimposed on communication links originating from a terrestrial region and including a relay in a geostationary spacecraft are determined by pointing a narrow beam antenna on the satellite at the terrestrial region. The level of noise radiated from the region, in a predetermined frequency band of interest, to the antenna is measured at a terrestrial station that is usually remote from the region. Many of the measurements are performed in each of a plurality of frequency bands across the spectrum. Calibrating radio signals having a plurality of predetermined EIRP'"'"'s (Effective Isotropic Radiated Power) and frequencies in the spectrum are transmitted from the region through the spacecraft narrow beam antenna back to the station. At the station, the levels of the received calibrating signals are separately measured for each of the frequency bands and EIRP'"'"'s. In response to comparisons of the measured amplitudes of like frequencies of the calibrating signals and noise, the presence, frequency and amplitude of sources of radio frequency interference originating from the region are determined.
56 Citations
17 Claims
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1. A method of determining radio frequency interference with communication links including a celestial body and an artificial geostationary satellite of the body, said interference originating from the body, said links being in a predetermined spectrum, comprising the steps of:
- (a) pointing a narrow beam antenna on the satellite toward a predetermined region of the body while only noise sources in the spectrum are radiated from the region toward the satellite;
(b) transmitting a calibrating electromagnetic wave of predetermined EIRP having a frequency in the spectrum from the region toward the satellite while the antenna is pointed toward the predetermined region;
(c) separately measuring the levels of electromagnetic energy received by the antenna in the spectrum during steps (a) and (b); and
(d) comparing the measured, received energy levels to determine the presence of radio frequency interference in the spectrum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14)
- (a) pointing a narrow beam antenna on the satellite toward a predetermined region of the body while only noise sources in the spectrum are radiated from the region toward the satellite;
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12. A system for determining radio frequency interference with communication links including a celestial body and an artifical geostationary satellite of the body, said interference originating from the body, said links being in a predetermined spectrum, comprising a relay station on the satellite said relay station including a narrow beam antenna pointing at a predetermined region of the body establishing an uplink for said interference, a second antenna on the body for establishing a communication downlink between the satellite and an Earth station on the body, and means located at the satellite for frequency translating signals and transmitting said signals between the narrow beam antenna and the second antenna;
- means located at the predetermined region for transmitting calibration signals with a predetermined region for transmitting calibration signals with a predetermined EIRP in the spectrum via another uplink toward the satellite, whereby the satellite relays the calibration signals back to the Earth station via said down link, said Earth station including means including the second antenna for receiving electromagnetic energy shifted in frequency by the relay station and coupled from the region to the Earth station via the satellite, circuit means at the Earth station for operating said receiving means while only RFI noise sources in the spectrum radiate from the region toward the narrow beam antenna via the interference uplink and only the calibration signals are in said another uplink and for operating the receiving means to be responsive to the calibration signals in the spectrum transmitted from the region through the narrow beam antenna and relayed through the satellite to the Earth station, said circuit means being responsive to the electromagnetic energies received by the Earth station for comparing the levels of the received energies while RFI noise sources and the calibration signals are transmitted from the region to the Earth station via the narrow beam antenna and the satellite to enable the presence of a source of radio frequency interference in the spectrum to be determined at the region.
- View Dependent Claims (15, 16, 17)
Specification