TxBx2

Status

Completed
Status date

2017-01-24
Activity Code

5D.025

Objectives

The main objective for the program was to develop and qualify the Second Generation Telemetry and Beacon Transmitters at Norspace. The starting point for the activity was the already established first generations of the beacon and telemetry transmitter. The objective for this development contained various elements in order to extend the transmitter functionality to meet a wider variety of customers’ requirements.

Development of new output section for Ka-band
Development of digital telemetry interface
Development of 35 V DC/DC for beacons and telemetry transmitter.
Development of a frequency flexible telemetry transmitter.
Upgrade of the output sections for C- and Ku-band. This as the key output amplifiers became obsolete. For this upgrade a full custom development of MMIC amplifiers for C- and Ku-band was performed.

The new elements were qualified in EQM units in various test campaigns. This program included 3 complete EQM qualification campaigns.

ACHIEVEMENT

Through the Artes-34 R&D project “2nd Generation Telemetry and Beacon Transmitter (“TxBx2”) with ESA, Kongsberg Norspace has developed and successfully qualified a frequency agile telemetry transmitter. The EQM was qualified at Ku-band output. In addition, the program included qualification of C- and Ku-band beacon transmitters. The program has also prepared the necessary modules for adaption to Ka-band operation. Interfaces to accept either analogue or digital telemetry signals were prepared as part of the program. With this development contract Kongsberg Norspace has extended the portfolio of beacon and telemetry transmitters to meet a variety of customer demands. The modular design allows delivery of beacons or transmitters at C-, Ku- or Ka-band and with 35 V, 50 V or 100 V power interface DC/DC converters. The telemetry transmitters can be delivered with digital or analogue telemetry interface. With the developed in orbit flexible frequency setting, the transmitters can programmed to a desired output frequency over a wide bandwidth. This is very attractive and opens for a new way of in-orbit satellite fleet management. Also with the increased use of electrical orbit raising, the need to resolve interferer issues during the LEOP phase has increased. Here the frequency flexibility of the 2nd Generation telemetry transmitter will contribute as a powerful tool to assure interference free communication between the spacecraft and the earth stations.

Challenges

A key challenge in this development was to develop a modular design that would work for a variety of requirements for telemetry and beacon transmitters. The design is based on a modular approach that allow the units to operate at C-, Ku- and Ka-band just by replacing the output section elements. Furthermore by adding the CAN BUS interface for flexible output frequency setting of the transmitter, the unit is prepared for in-orbit flexible frequency setting. In addition to this, the telemetry transmitter can be configured with either digital or analog telemetry interface.

Benefits

A main new feature of the second generation telemetry transmitter is the in orbit programmable transmit frequency. This opens for improved possibilities for solving interference issues during deployment and on-station operation. In particular this is an advantage for Electrical Orbit Raising. In addition, this contributes to efficient satellite fleet management and more flexible use of satellites in new positions during their lifetime.

The product range is also extended to meet a wider range of customers through this development. The operation at C- and Ku-band is secured though the updated output stages.

Features

Telemetry Transmitter

The main functions of the telemetry transmitter are:

Carrier generation
Telemetry data and ranging data interfaces
Phase modulation of the carrier and
Medium power amplification and filtering

The Telemetry transmitter is designed for transmission of C-, Ku- and Ka-band signals. The telemetry transmitter can be configured for single, dual or on-board selectable output frequency.

Main Characteristics:

Ka-band: 18.8 to 23 GHz
Ku-band: 10.7 to 12.75 GHz
C-band: 3.4 to 4.25 GHz
Frequency agility interface; In-orbit programmable via CAN BUS or HLC for dual frequency.
Output power BOL: + 28dBm (typical)
Modulation inputs: Up to six analogue modulation inputs (RNG or TM), or two digital telemetry inputs plus two analogue ranging inputs.
Modulation index: Linear up to 2.0 rad-peak aggregate for up to three simultaneous inputs. Automatic Level Control (ALC) of the modulation index available.

The Transmitter is also qualified in Beacon (Bx) configuration, which includes the same main elements as the TLM transmitter with the exception of the modulation blocks (video interface circuitry and phase modulator).

System Architecture

The telemetry transmitter is design with an OCXO or TCXO as reference frequency. A programmable fractional synthesizer is used to generate L-band frequency. A digital or analogue video interface board receives the RG and TLM input. The phase modulation of the carrier is performed at L-band. The modulated signal is then multiplied in frequency in several steps to reach the desired output frequency. The output sections also include filtering and ALC functions to assure output power stability over life.
The unit output frequency can be changed in orbit via a CAN BUS interface.

Plan

The following development plan has been followed during the program:

PDR – Preliminary Design Review

This milestone concluded the initial work with the unit optimization and critical design

CDR– Critical Design Review

This milestone concluded the detailed design and development as well as the supporting performance and reliability analysis. This also gave the starting point for the manufacturing of the EQM

EQM TRB – Test Review Board / Final Review

After the completion of the EQM test campaign, the TRB was successfully held.

Two change notices were issued and approved in the program:

CCN01: This change included the development of a C-band and a Ku-band MMIC amplifier for the C and Ku-band output stages.
CCN02: This change optimised the definition of the EQMs to be developed in the program. In addition this CCN took into account the development of the flexible interface for frequency setting.

Current status

The program is now completed.