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VERY HIGH RATE TM DOWNLINK USING GMSK WITH SIMULTANEOUS PSEUDO NOISE RANGING

on 12 August 2019

ESA Open Invitation to Tender AO10006
Open Date: 02/08/2019
Closing Date: 27/09/2019 13:00:00

Status: ISSUED
Reference Nr.: 19.1ET.32
Prog. Ref.: Technology Developme
Budget Ref.: E/0901-01 - Technology Developme
Special Prov.: BE+DK+FR+DE+IT+NL+ES+SE+CH+GB+IE+AT+NO+FI+PT+GR+LU+CZ+RO+PL+EE+HU
Tender Type: C
Price Range: > 500 KEURO
Products: Ground Segment / Ground Station / Baseband equipment / Telemetry and Telecommand equipment, Tracking, Ranging and Doppler measurement equipment, CODECS, ... / Satellites & Probes / RF / Microwave Communication (Platform and Payloads) / Receivers / X-band, S-Band, Ka band, ¿ / Near Earth application, Deep space application, ... / Platform vs Payload
Technology Domains: RF Systems, Payloads and Technologies / TT&C and Payload Data Modulator (PDM) Systems/Subsystems / Deep-Space Transponders / Ground Station Systems and Networks / Ground Station System / TT&C, Radar and Optical Signal & Data Processing
Establishment: ESTEC
Directorate: Directorate of Tech, Eng. & Quality
Department: Electrical Department
Contract Officer: Erkelens-Sickinger, Franziska
Industrial Policy Measure: N/A - Not apply
Last Update Date: 02/08/2019
Update Reason: Tender issue

Future science mission (e.g., EnVision) will require very high TM downlink bitrates, up to 300 Msps, with possibly the simultaneoustransmission of a dual PN (pseudo noise) ranging in both X- and Ka-band to perform radio science experiments. As an example, in theframe of EnVision, it has been proposed the usage of OQPSK modulation to reach the high telemetry rates required in Ka band (from 16 Msps up to ~300 Msps). However, CCSDS (rec. 2.4.20B) only foresees GMSK modulation for Deep Space missions when symbol rates are greater than 20 Msps, because GMSK needs less bandwidth allocation compared to other modulation schemes like OQPSK. Furthermore, CCSDS foresees the simultaneous transmission of TM + PN ranging only when using GMSK as modulation scheme also in Ka band (CCSDS 401 - 2.4.22B P-1.0 in publication). GMSK modulation would therefore be recommended, even though at these rates it has not been used on ESAmissions yet. GMSK plus simultaneous PN ranging, with lower TM rates, has already been achieved for the Solar Orbiter X/X mission. However, at present the on board transponder and the ground station processors have limited capabilities in terms of respectively transmitting and receiving GMSK at very high symbol rates, reaching only 10 to 20 Msps. In addition, the combination of the very high rate GMSK telemetry with PN ranging at much lower chip rate value is not foreseen in the current CCSDS standard. As a consequence, to support future missions (as EnVision), requiring very high rate telemetry simultaneously with radio science experiment, it is necessary to increase the TRL level of this technology both for on-board and on-ground applications.For this purpose the needed steps are:- to analyze and prepare the technological readiness for using very high rate GMSK modulation on satellite transponders (Ka-band).- to study the possible combination in the downlink of the very high rate TM with a simultaneous pseudo noise ranging (PN RG) andestablish the end-to-end performances.- to implement the on-board modulator (TM GMSK + PN RG) and ground demodulator (TM GMSK + PNRG) at breadboard level for E2E test.A more detailed overview of the required activity will be:1. Analyze the technological limitations (mainly relevant to the processing speed) that constrain the achievable GMSK TM rate (at on-board level);2. Identify and trade off different solutions that overcomes the existing limitations (at on-board level);3. Analyze the impact of adding the lower PNchip rate range component to the very high rate GMSK signal (both at on-board level and at ground level);4. Analyze the end-to-endperformance of very high rate GMSK + PN ranging;5. Breadboard the proposed solutions;6. Test the proposed implementations standalone (in relevant environment e.g. temperature for the on-board breadboard); 7. Test the end to end performances using the on-board modulator and ground demodulator breadboards together.For the on-board modulator, it is of outmost importance to remark that any proposed solution shall be suitable for implementation in the current space qualified technology. A suitable roadmap for the implementation in the Flight Model shall be identified. It shall also be noted that the coherency of the ranging and carrier signal of the downlink signal to the uplink, has to be maintained. For the ground demodulator, the study shall analyze the potential benefits of using the new CCSDS recommendation for ranging cancellation. Ranging cancellation of the combined PN ranging and GMSK signal, allows forbetter TM performance and could be important in a scenario with large differences between the ranging and TM rates.The following criticalities shall be undertaken from the beginning: Assess the feasibility from analysis and/or/ simulation results; Define architectures suitable for implementation in the current space qualified technology (for the on-board part).The activity will accordingly foresee two phases: T0 to T0+1 year (1st milestone): a first phhase with the objective of confirming the feasibility, defining the architecture and describing the chosen implementation suitable to the current space qualified technology; T0+1 year to T0+18 months: an implementation phase (breadboard) that will include the environmental tests (for the on-board breadboard).

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