ADAS-E project
Project Title | Advanced earth observation Data Acquisition System Evolution | |
Project Acronym | ADAS-E | |
Contractor(s) | Alcatel Bell Space NV, Kongsberg Spacetec AS |
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Context |
Objectives | |
Architecture | |
Capabilities | |
Output |
Context | ![]() |
The versatility of an Earth Observation data acquisition station is highly determined by the performance characteristics of its demodulator section. The increasing diversity in the characteristics of the communication links used by advanced EO satellites require throughputs ranging from a few up to several hundreds Mbit/s, as well as the support of a wide spectrum of transmission schemes. Therefore a multi-mission demodulator is the basis to receive multiple satellite missions with the same ground station infrastructure.
A multi-mission demodulator/decoder can, thanks to the intervened technological evolution, be integrated with other functions, which could expand its capabilities into adjacent functions such as:
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Frequency conversion | |
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Data ingestion (with intermediate storage management) | |
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Front-end processing | |
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Modulation & coding (e.g.: for integrated equipment test) |
Objectives | ![]() |
The principle project objective is the extension of the ADAS equipment modulation and demodulation capabilities with:
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A 4DxTCM encoder for the 8PSK modulator function. This will allow for fullfledged real-time loopback testing of the demodulator 4x8PSK TCM modulation/coding scheme up to frame synchronisation level. | |
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Implementation of a programmable multi-purpose digital FIR filter as an extension to modulator and demodulator signal processing functionality. This FIR filter shall support: - Bandwidth efficient modulation schemes employing Square Root Raised Cosine (SRRC) baseband pulse shaping (a discrete number of roll-off factors shall be selectable). - For the demodulator, in case of expected severe Inter Symbol Interference (ISI) due to e.g. imperfect TX filters: Combined (nonadaptive) equalisation and matched RX filtering tailored to a given distortion specification (group delay versus frequency characteristics).The proposed channel filtering and equalization architecture will allow in a future evolution, baseband pulse shaping and equalisation as required for the linear QAM approximation to GMSK. |
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Study of the implementation of sub-optimal (but acceptable in terms of performance) demodulation of GMSK signals based on the linear QAM approximation to GMSK. Within the scope of this proposal, the GMSK work package shall consist of a technical requirements document and an architectural design document. These documents shall describe: - specifications of the GMSK transmitter and receiver that can be developed on the ADAS HW platform (performance degradation w.r.t. optimum theoretical receivers, minimum/maximum bit rate, selection of the bandwidth of the Gaussian filter, …) - how the GMSK functions can be implemented on the existing ADAS HW platform (definition of the extra VHDL building blocks required to do GMSK signal processing) The actual implementation, testing and demonstration of the GMSK functions on the ADAS are not part of this proposal. |
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The extension of the ADAS upper data rate limit by integrating in a single acquisition equipment a multi-carrier modulation and demodulation capability for up to 4 carriers (TBC depending on heat dissipation and power consumption), allowing the reception of satellite missions such as Pleiades, ESA Sentinel program, CBERS, HY, … etc. |
Architecture | ![]() |
The ADAS-E system is composed of several components (see diagram below).
The basic building blocks that are developed are:
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High Data Rate Demodulator (HDRD) | |
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High Data Rate Modulator (HDRM) | |
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X-Band DownConverter (XDBC) | |
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Data Ingest and Front End Processing (DIFEP) | |
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Monitoring & Control function and GUI |
Based on these building blocks different equipment configurations will be possible. The ADAS Host Computer is an Industrial PC (IPC), running the Linux operating system. It has an integrated front panel TFT screen and a drawer with a keyboard and pointing device (touchpad, trackball or other). The host computer contains the processor board (SBC - Single Board Computer) and the ADAS specific boards (XBDC, HDRD, HDRM, DIFEP). Either an internal disk, or an external SCSII disk array is used for storage of acquired and processed data.
Capabilities | ![]() |
The ADAS-E system has the following key capabilities:
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Supports a wide range of current and planned missions | |
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Processes telemetry from radio frequency (X-band) to Front End Processing (FEP: production of annotated raw data, VCDU, ISP) when in full configuration | |
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Recovers BPSK, QPSK, SQPSK, UQPSK, AQPSK signals (evolution to 8PSK) | |
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Supports a maximum input bit rate of 500 Mbit/sec (QPSK. 250 Mbit/sec I and Q channels) | |
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Saves telemetry data to disk in real time | |
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Distributes telemetry data over a network | |
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Supports loop-back testing | |
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Supports quicklook display |
Output | ![]() |
ADAS-E will provide ESA with an integrated earth observation data acquisisition system, able to Processes telemetry from radio frequency (X-band) to Front End Processing and supporting a wide range of current and future missions. The system will be validated in an ESA station using the CRYO, ALOS and ENVISAT missions.