ExH R&D

Since 2019 I have provided consulting services to small and large companies and start-ups. I have been working in the "New Space" area on payload computing since 2010, and in atmospheric remote sensing since 2013.I have acquired some expertise in the field of methane sensing by contributing to the design, implementation and development of private gas remote sensing payloads, as well as by contributing to public scientific research.I also provide prototyping and development services for embedded systems, in particular instrument payloads for small satellites. This includes firmware and hardware, as well as ground support equipment.
Portrait of Berke DURAKBerke DURAK, Ph.D

Remote Sensing — Instruments and Algorithms

Are you developing an atmospheric remote sensing instrument, maybe one based on absorption spectroscopy?Predicting the actual performance of a remote sensing system is a difficult multidisciplinary task that requires knowledge of many fields:
  • Inverse methods: Mathematical foundations, numerical methods, prior selection, bias and precision analysis
  • Radiative transfer: Spectroscopy, atmospheric physics, profile representation, surface modeling
  • Focal plane array modeling: Quantum efficiency, noise modeling, effects of readout electronics
  • Optics: Radiometry, distortions and aberrations, stray light
  • Space observation geometry: Orbital motion and manoeuvers, stability, terrain representation, refraction
This specialized knowledge can only properly be acquired through experience.Having provided services to multiple companies, including level 0 to Level 4 algorithms, I can help you with the following:
  • Instrument optical design, performance estimation and optimization
  • Design and implementation of complete end-to-end toolchains including retrieval algorithms, instrument and observation simulators
  • On-board calibration systems
  • Requirements, architecture and development for optical, electronical and software aspects
  • Focal plane array characterization and modeling
  • Optical modeling, including stray light, ghosting, polarization, spectral effects
  • Gas plume detection and quantification estimates
Recently, I have started studying muon-based remote sensing. This non-optical, density-based sensing modality is particularly useful in geophysical exploration. Here is an online tool (under development) for exploring muon sensing and comparing it to gravimetry, in the context of dense orebody exploration:
Muography vs. gravimetry evaluation tool
A collection of IASI spectra

Space Electronics — New Space

So you're launching your first small satellite...It is already difficult getting the first payload into orbit promptly. It then has to produce good data long enough to demonstrate your product.How confident are you that the components for your payload will survive in orbit? Is an on-board calibration system required? Have protection electronics been designed for the COTS elements? Are there backup modes or systems to guarantee a minimum level of functioning in case of typical payload and platform failures? Has the design been critically reviewed to eliminate unnecessary sub-systems? Suppose your suppliers fail to implement an interface on a critical long lead component for which there is no time to re-order a different unit. Or perhaps a strange EMI issue produces artefacts in your images. I will help you determine and resolve these kinds of issues and others that may arise.I have reviewed and improved existing designs and have provided initial and final implementations for the custom peripheral systems that you can't buy on the market, such as:
  • Recovery systems, boot loaders, software redundancy
  • Radiation-tolerant power and thermal supervision, control and protection circuits
  • Data link and protocol translators
  • Custom sensor and actuator electronics
Your team unavoidably changes as your company grows. As an independent external consultant I can ensure that the design knowledge of these specialized systems and solutions is properly transferred and maintainted.
Close-up of a payload board designed by ExH R&D

Topics

Remote Sensing

My experience covers mission and instrument design and all data levels.
  • To level 0: Acquisition modes, telemetry requirements, data compression
  • Level 0 to 1: Pixel, radiometric and geometric tracking and corrections
  • Level 1 to 2: Atmospheric column and surface reflectance parameter retrievals
  • Level 3 to 4: Emission rate estimates, detection thresholds, sensitivies and specificities

Instruments

  • GHGSat (GHGSat-D/Claire)
  • IASI (Metop)
  • TROPOMI (S5P)

Radiative Transfer and Atmospheric Spectroscopy

  • 4AOP
  • MODTRAN
  • RTTOV
  • Custom codes using
    • HITRAN
    • GEISA
    • Custom cross-section data

Forward and Inverse Methods

  • Optimal estimation routines
  • Noise and prior distributions, error analysis and modeling
  • Post-retrieval corrections (bias removal)
  • End-to-end OSSEs for design and optimization
  • Multi-instrument retrievals (L1/L1,L1/L2) and assimilation (L3/L3)

Codes for Instrument Optics

  • Simulation: Ray-based, sequential or FEM geometry, multiple reflections, spectral aspects
  • Stray light analysis and correction (diffuse and focused)
  • Analytic and detailed modeling of interferometers: Fabry-Perot, Fizeau
  • Pixel corrections: Flat-field, linearity, persistence, bad pixel detection
  • Detailed simulations of thin-film filters (inhomogeneities, thermal effects)

Software and Algorithms

Services

  • Algorithm Research, Design and Implementation
  • Software Development
  • Data Processing Services for Scientific Research
  • System Architecture and Code Review
  • Optimization, Testing and Debugging

Systems programming

  • General systems programming
  • Programming languages
    • Rust
    • C
    • Python
    • Fortran
    • Lua
    • OCaml
    • Javascript
    • etc.
  • Configurable, robust, high-performance data processing toolchains
  • Parallelized, vectorized, optimized and GPU-accelerated numerical codes
  • Auxiliary dataset API access and processing routines

Embedded Development

  • Linux kernel and userspace drivers
  • UEFI code, boot and upgrade managers, SecureBoot
  • Firmware development in C, nostd Rust, assembly (x86, ARM, RISC-V, 68k)
  • Generation of embedded Linux systems
  • Baremetal development: Boot and system initialization, device interfaces, task schedulers
  • Debugging and emulation setups

Electronics

Services

  • Electronics for prototypes and engineering or flight models
  • Circuit design, simulation and prototyping
    • Analog and digital
    • Microcontrollers, small FPGAs, OS level drivers
    • Hardened, fault-tolerant, radiation-aware design using discrete qualified components
  • Buses, Interconnections and Protocols
    • Protocol design and implementation
    • Capture, debugging and reverse-engineering
    • Single-ended, differential, protected and filtered interconnects
    • Test fixtures and fault injectors
  • Cooperation with domain experts for space layout, EMI or radiation tolerance
  • Layout, BOM optimization, procurement, fabhouse relations
  • Assembly, testing, rework and iterations
  • Test, documentation, knowledge transfer and follow-up

Examples

  • Payload daughter and interface boards
  • Microsecond software-adjustable latch-up protection circuits
  • Low-noise transimpedance photodiode amplifiers
  • Laser diode driver
  • Precision LED driver
  • GPS-disciplined multi-camera trigger and exposure synchronisation logic
  • Precision temperature control (< 5 mK) and monitoring
  • SPI-JTAG bridge for flash memory scrubbing & recovery

Publications

Atmospheric Science and Remote Sensing

  • Quantifying methane point sources from fine-scale satellite observations of atmospheric methane plumes
  • The GHGSat-D imaging spectrometer
  • GHGSat-D: Greenhouse gas plume imaging and quantification from space using a Fabry-Perot imaging spectrometer

Automata Theory

Software Engineering

  • Managing the complexity of large free and open source package-based software distributions
  • Improving the quality of GNU/Linux distributions
  • News from the EDOS project: improving the maintenance of free software distributions

Contact

E-mail : info@exhrd.ca

West Vancouver, BC, Canada