ESA

Remote Sensing Laboratory

The Remote Sensing Laboratory is a set of facilities supporting research related to a broad range of systems for both the space and the ground segments

The Remote Sensing Laboratory evaluates and tests designs for radio-based remote sensing systems such as synthetic aperture radar (SAR), radar altimeters and radiometers. It also performs R&D related to telecommunications and navigation systems and applications, including both the ground and space segments. This lab offers a collection of software tools for the analysis and simulation of various kinds of passive and active remote sensing instruments. 

Possible activities cover the Design optimisation, evaluation, simulation and trade-off of active and passive RF Earth Observation sensors (i.e. advanced SAR, Radar Altimeters, Microwave Radiometers, Radars for Ocean Currents and Winds, GNSS-R instruments, GnSS, Radio Occultation). 

The Remote Sensing Lab also supports testing activities of SAR/Radar related hardware, i.e. T/R modules, antenna panels and subpanels, central electronics and others.

For general enquires regarding this TEC location please refer to the assigned contacts:

Remote Sensing and Payload Engineering

Laboratory Manager

Propagation & Wave Interaction Facility

Facility Manager

Evaluating and testing designs for radio-based remote sensing systems & 

performing R&D related to telecommunications systems and applications

PROPAGATION & WAVE INTERACTION FACILITY

Propagation & Wave Interaction Facility

This facility encompasses the instrumentation, databases and supporting software that are used to perform the analysis of the contribution of natural environment to the electromagnetic signals used for telecom, navigation and remote sensing as well as to assess their impact on end-to-end mission performance. 

Instruments & technical parameters

This facility includes:

Models of wave interaction and wave propagation models;

End-to-end performance assessment tools; 

Ground-based instrumentation (on-site and off-site); 

Electronic datasets (experimental data, spaceborne observations, results of simulations, third-party databases, ...);

Supporting computational infrastructure.

Propagation & Wave Interaction provides:

Capability to analyse and model many types of signals e.g.:

  1. Propagation impairments on telecom signals;
  2. Optical and RF remote sensing signatures (passive, active);
  3. Environment contribution to position accuracy;

End-to-end system and performance analysis;

Support to mitigation solutions;

Support to vicarious calibration techniques.

Examples of available resources:

Software models of RF and optical propagation and interaction with natural environment (atmosphere, land and ocean surfaces);

Ground based RF radiometers for atmosphere monitoring;

Ground based navigation equipment for ionosphere and environmental monitoring;

End-to-end performance models;

Data processing tools.

Tx/Rx Multi-Channel RF system

This powerful Tx/Rx multi-channel system can emulate a Digital Processor or multiple RF chains of an active antenna, an arbitrary waveform Generator or a TX/RX Digital Beam former. It can be also used for efficient testing and characterisation of active antennas / phased arrays. Since it can host a SW development environment, prototyping of Digital Signal Processing functions (i.e. digital filtering, digital up/down conversion, pulse compression, etc…) can be performed directly on the programmable boards.  

The TX/RX multi-channel system is based on a distributed HW platform. The design consists of one chassis hosting multiple programmable RF boards. 

The system is composed of several separate TX/RX channels, fully synchronized, in order to simulate, for example, a phased array system in both TX/RX sides. Each board, being based on FPGAs and ADCs/DACs, generate analog inputs/outputs and can be used for antenna testing (or any other RF testing) and for performance verification of digital functions. 

The system already hosts an application SW in LabView and I/F command/control code in Matlab.

Wavemill

Wavemill End-to-End Simulator – WE2ES for interferometric radar altimeters. 

It combines a state-of-the-art ocean model, ocean scattering module and radar instrument characteristics for performance assessment and design of wide-swath ocean altimeters and ocean current retrieval by along-track interferometry:

  1. Simulates complete Wavemill-type instrument;
  2. Includes geometry, sea state, sea scattering, propagation, instrument configuration, raw data generation, SAR processing, interferometric processing and surface current retrieval;
  3. Used to support OSCM, OSCAR missions.
GNSS-R & OceanPal

 GNSS-R simulator and OceanPal instrument for examining the end-to-end performance of GNSS reflectometry techniques, including PARIS. 

A tool for examining the end-to-end performance of GNSS reflectometry techniques, including PARIS and typical GNSS-R missions.

SAR Instrument Modelling Software

IMS

IMS is a tool for SAR performance assessment and design SAR digital calibration transponder.

The IMS tool has the aim to support high-level design of future SAR systems. Since a SAR cannot be fully tested prior to launch, due to the need for relative motion between the sensor and the target, the performance of the end product, namely the image quality, must be modelled. A similar approach is necessary in the design process. The IMS model considers only a subset of the total in-orbit performance requirements, based on those considered to be the most important. 

The software is capable of assessing the performance of future SAR in the following operating modes (techniques):

  1. Conventional SAR
  2. Scan SAR
  3. Spotlight SAR

The IMS allows the simulation of Active array/front-end simulators and in particular IMS is capable of generating elevation gain pattern templates that can be updated by the user. These templates can then be used in the synthesis of appropriate elevation beam patterns.

Instruments & technical parameters

The IMS is able to calculate the following performance parameters :

Impulse response function : in range and azimuth (and determined at the near edge of the swath):

  1. Spatial resolution (ρ)
  2. Peak sidelobe ratio (PSLR)
  3. Spurious sidelobe ratio (SSLR)
  4. Integrated sidelobe ratio (ISLR)

Radiometric Analysis: Modelled using the following output parameters (and determined at a selected spacing across the swath):

  1. Radiometric resolution (γ)
  2. Noise equivalent sigma zero (NEσ0)
  3. Instrument (video) signal-to-noise ratio (VSNR)
  4. Complex coherence
  5. Radiometric stability (RS)

Ambiguity Suppression: Modelled using the following output parameters (and determined at a selected spacing across the swath):

  1. Point target ambiguity ratios for range, azimuth and offcut ambiguities
  2. Distributed target ambiguity ratio for range, azimuth and offcut ambiguities

Doppler Analysis: Modelled using the following parameters (and determined at each edge of the swath):

  1. Calculation of Doppler parameters, including effect of pointing errors
  2. Calculation of range walk parameters
  3. Determination of data rates

Dynamic range: Modelled using the following output parameters:

  1. The instrument dynamic range
  2. The total number of quantisation bits (required in achieving the desired quantisation error)
StarGym

StarGym is a state-of-the-art advanced simulator of GNSS-R spaceborne instruments. It allows to simulate realistically a complete end-to-end observation GNSS-R chain, including realistic modelling of the instrument and signal processing functions. It includes a performance assessment module able to extract main performance parameters.

Instruments & technical parameters:

  • End-to-end GNSS reflectometry simulator
  • Includes sea-surface generator, atmospheric and ionospheric propagation, instrument characteristics, delay-Doppler map processor 
  • Outputs SSH, MSS

Operates in different modes:

  • Waveform
  • Bitstream
  • Interferometric
Synthetic Aperture Interferometric Radiometer Performance Simulator – SAIRPS

The SAIRPS is an advanced stat-of-the-art simulator of synthetic aperture interformatric radiometers for earth observation and scientific missions. It allows to assess new instrument architectures and the end-to-end performance of next generation instruments such as SMOS mission and similar. The simulator allows to simulate observations from different orbits (e.g. LEO, GEO).

Instruments & technical parameters:

  • Estimates performance of SMOS-like radiometers
  • Covers different modes of operation
  • Snapshot
  • Monte-Carlo
  • Time EvolutionLinux based
Performance Estimation for Ultra-wide-band SAR Over Rocky Terrains
  • Simulates the operation of a stepped-frequency radar over rocky terrains
  • Includes dry rocky-terrain scattering models and SAR processing
  • Developed by IPAG to support the Asteroid Impact Mission HFR instrument
  • Potential for use to simulate UWB-SAR over terrestrial (rocky) deserts
  • Additional software including OASIS, and Multi-channel Ka-band SARs for GMTI Performance Model.

Raw-data Multi-Channel SAR simulator

Raw-data Multi-Channel SAR simulator

The McE2E is an E2E tool aiming the modelling of the global response of representative multi-channel SAR systems at L1. In particular, the simulator allows for the assessment of the system impulse response, its geometric and radiometric accuracy, sensitivity and ambiguity rejection characteristics over the imaged swath and along the orbit. 

The simulator is capable of simulating and processing raw data acquired with a multi-channel SAR system operating at a configurable wavelength in both single and multi-swath imaging modes with a constant PRF. The simulator incorporates a configurable data compression (e.g., BAQ) stage. 

It is capable of simulating antennas with an arbitrary number of elevation and azimuth channels and on-board and on-ground beamforming capabilities on transmit and receive. The element patterns for transmit and receive are both configurable by the user with the use of external files .McE2E also accepts the use of mechanic and electronic roll steering parameters. 

The MCE2E accepts a fully polarimetric backscattering law configurable with the use of an external file, as well as the computation of range ambiguity ratios in co-pol and cross-pol modes. The simulator accepts the configuration of receiver noise characteristics. 

It accepts as input the location of the scene, the duration of the acquisition, the timing and range of incident angles of the acquisition, as well as range and azimuth resolutions. 

Instruments & technical parameters

The simulator can be configured via an XML file and generates simulation data and plots captured in a performance evaluation report, in PDF format, containing the aforementioned information. 

The basic modules of the simulator consist of:

Raw data simulator tailored to a configurable multi-channel instrument and wide-swath observation mode including relevant error sources 

Prototype processor, with a range-Doppler kernel, tailored to the multi-channel, wide-swath nature of the system 

Performance evaluation module capable of deriving the relevant performance figures and statistics according to user inputs

The performance report contains the following output information: 

The Imaged scene and geometry, which allows for the cross-check of swath and burst overlap

Element patterns, transmit and receive antenna patterns before beamforming, and ScORe patterns, allowing the cross-check with system design reports or tools 

System impulse response for the different locations within the swaths and along the orbit with the relative performances (resolution, ISLR, PSLR)

Analysis of geolocation accuracy

Sensitivity

Ambiguity ratios

Analysis of radiometric accuracy and scalloping

Analysis of interferometric phase errors in the SLCs

Data rate

SAR Performance Toolbox

SAR Performance Toolbox

The SAR Performance Toolbox (SPT) is a performance simulator tool for Synthetic Aperture Radars that implements advanced operative modes and innovative observation concepts.

 

Instruments & technical parameters

The SPT aims to the simulation of state-of-the art SAR acquisition modes:

Stripmap

ScanSAR

TopSAR

For Single/dual/quad pol acquisitions.

Processing and acquisition techniques

Making use of the DBF it implements the simulation of the following processing and acquisition techniques:

Azimuth DBF (HRWS)

Elevation DBF (SCORE) with added frequency dispersive beams capability

Additional capabilities

Additional capabilities consist in being able of simulating:

Multistatic SAR configuration, in along-track formation flight for cooperative acquisition, with 1 TX payload and multiple receiver payload, whose swath is different or equal for the various Rx’s

Frequency Scanning technique: implementation of fully or partially controlled dispersive beamforming

The SPT is able to generate antenna patterns and treat them in a 2 1D (Phased Array antenna) or 2D (Reflector antenna)

The SAR Performance Toolbox shall compute:

Radiometric Performances

Ambiguity performances

Doppler performances

Interferometric analysis

 

The design of the tool is intended to be modular and extendable, foreseeing the enhancement with additional modules in future releases

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Salvatore D'Addio

Laboratory manager