Method of characterizing the performance of a payload of a satellite in orbit and associated IOT system

Patent metadata

Field	Value
Publication number	US-10320495-B2
Application number	US-201615347560-A
Country	US
Kind code	B2
Filing date	Nov 9, 2016
Priority date	Nov 10, 2015
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

A method of characterizing the performance of the payload of a satellite in orbit is executed with the aid of a test ground station including first radio-frequency amplification means and a radio-frequency transmit ground antenna. The method includes a step of providing first amplification means that can be configured to generate at the input of the transmit ground antenna a wide-band test thermal noise the power spectral density of which can be adjusted to a test thermal noise reference power spectral density Dref so that the ratio of the test thermal noise spectral density received at the input of the transponder and that corresponds to it to the thermal noise floor spectral density generated by the satellite alone internally and the natural thermal noise of the Earth is greater than or equal to a first threshold Ds1 equal to 10 dB. An IOT system is configured to execute the method.

First claim

The invention claimed is:

1. A method of characterizing a performance of a payload of a satellite in orbit using a test ground station, comprising:
the test ground station including at least one first radio-frequency amplifier, and a radio-frequency transmit ground antenna with a first input port of the antenna connected to an output of the at least one first radio-frequency amplifier,
the payload of the satellite including a first receive satellite antenna for uplink, a second transmit satellite antenna for downlink, and a transponder connected between the first receive satellite antenna and the second transmit satellite antenna,
the transponder including a second radio-frequency input port connected to an output port of the receive satellite antenna, and at least one second amplifier being configured to amplify in an input portion of an uplink transponder or in the whole of transponder signals in a receive frequency band of the transponder, according to a linear amplification mode and with a fixed gain that can be remote-controlled and included in a gain range varying between a first lower gain Gmin and a second higher gain Gmax inclusive,
the method further comprises a supply step of:
generating a test thermal noise with the at least one first radio-frequency amplifier at the input of a transmit ground antenna, the test thermal noise having a bandwidth greater than or equal to the receive band of the transponder and a power spectral density of which is adjusted to a test thermal noise reference power spectral density Dref such that a ratio of the spectral density of the test thermal noise, received from the test ground station when the thermal noise spectral density that it transmits is equal to the reference spectral density Dref, and received at the input of the transponder, to a thermal noise floor spectral density generated by the satellite alone internally and natural thermal noise of the Earth at the input of the transponder is greater than or equal to a first threshold Ds1 equal to 10 dB.

2. The method according to claim 1 of characterizing performance of a payload,
in which a test bench remote from or integrated into the test ground station is configured to send and to receive, respectively, configuration telecommands and telemetry measurements from the satellite via a telecommand and telemetry measurement infrastructure, ending at a telecommand and telemetry measurement station visible from the satellite, and to send to and to receive from the test ground station commands of the at least one first amplifier and the test thermal noise retransmitted by the satellite with or without processing,
the method further comprising the steps:
configuring at least one of the attitude of the satellite and of the receive satellite antenna so that the receive antenna points toward the ground station according to a reference pointing angular position;
configuring the at least one second amplifier of the payload at a predetermined fixed gain that corresponds to a linear mode of operation over at least the input portion of the transponder corresponding to the uplink or to the whole of the transponder when the test thermal noise received from the ground station and at the input of the transponder corresponds to a test thermal noise spectral density transmitted by the ground station equal to the reference spectral density Dref;
configuring the at least one first amplifier of the test ground station to generate at the input of the transmit ground antenna a test thermal noise having a band covering the receive band of the transponder and the power spectral density of which is equal to the reference spectral density Dref, and to have the test thermal noise transmitted by the test ground station in this configuration of the at least one first amplifier; then
during a predetermined time period, acquiring at least one measurement representing the power received at the input of the transponder via at least one corresponding received power measurement:
either by the test ground station via the downlink when there exists an area of intersection of the coverage areas of the receive antenna and the transmit antenna of the satellite and the ground station is inside said intersection area;
or by corresponding telemetry measurements of the power picked up at a location of the transponder where the amplification is linear and where the corresponding gain is incidentally known.

3. The method according to claim 1 of characterizing the performance of a payload, wherein the bandwidth of the test thermal noise transmitted to the satellite is between 30 MHz and 3 GHz inclusive or between 3% and 10% inclusive of a central frequency of the transmit frequency band of the test ground station or the receive frequency band of the payload.

4. The method according to claim 1 of characterizing the performance of a payload, in which the transmit frequency band of the test ground station, respectively the receive band of the payload, is in bands L, S, C, X, Q, V, Ku and Ka,
wherein the frequency band L has a range of frequencies from 1 to 2 gigahertz (GHz),
wherein the frequency band S has a range of frequencies from 2 to 4 gigahertz (GHz),
wherein the frequency band C has a range of frequencies from 500 to 1000 MHz,
wherein the frequency band X has a range of frequencies from 7.0 to 11.2 GHz,
wherein the frequency band Q has a range of frequencies from 33 and 50 GHz,
wherein the frequency band V has a range of frequencies from 40 to 75 gigahertz (GHz),
wherein the frequency band Ku has a range of frequencies from 12 to 18 gigahertz (GHz), and
wherein the frequency band Ka has a range of frequencies from 26.5-40 gigahertz (GHz).

5. The method according to claim 1 for characterizing the performance of a payload, in which a first noise density ratio threshold Ds1 depends on the receive frequency band of the payload, the orbit of the satellite, the size of the transmit antenna of the test ground station and a G/T parameter of the payload of the satellite under test.

6. The method according to claim 1 for characterizing the performance of a payload, in which the characterization of the performance of the payload of the satellite in service orbit is included within the combination of:
the single-frequency or multi-frequency characterization of at least one or more radiation angular diagrams and of one or more radiation angular sections of the receive antenna of the satellite when the payload transponder is a transparent transponder or a regenerative transponder;
the linear gain response from the input port to the output port of the transponder when the transponder is a transparent transponder operating in a linear mode and when there exists an area of intersection of the coverage areas of the receive antenna and of the transmit antenna of the satellite and the ground station is in the said area of intersection;
the variation of the linear gain of the transponder as a function of frequency in the band of the transponder for a fixed gain of the transponder;
the measurement of a saturating flux or of a saturating flux density (SFD) of the transponder of the satellite and the measurement of the effective isotropic radiated power (EIRP) of the payload when the transponder is transparent;
the measurement of a G/T of the payload with or without visibility of the downlink from the ground station;
the characterization of the RF power withstanding at least one of the payload, the consumption, and the performance of the platform when the payload is loaded by the thermal noise received in a configuration close to the operational conditions, for example in accordance with a maximum traffic or a traffic variable in time.

7. The method according to claim 1 for characterizing the performance of a payload,

Assignees

• Thales Sa

Inventors

• TESSANDORI Stéphane-Olivier
• Bousquet Emmanuel
• DURAND Arnaud-Damien

Classifications

• H04B7/18515 Primary

  Transmission equipment in satellites or space-based relays · CPC title

• B64G1/1007

  Communications satellites · CPC title

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04B17/102 Primary

  Power radiated at antenna · CPC title