The issues of radiometric calibration of optical-electronic equipment for remote sensing of the Earth in a wide range of spectral radiance have been studied. An alternative method for transmitting a spectral radiance unit from a reference source at the phase transition temperature of pure metals to optical-electronic equipment for remote sensing of the Earth in the infrared wavelength range above 2.5 μm is presented. The method is based on the stepwise transfer of a spectral radiance unit from a reference source through a precision model of a black body with a high level of emissivity and a wide temperature range identical to the temperature range of a wide-aperture black body model with a range of spectral radiance required for calibrating optical-electronic equipment for remote sensing of the Earth. A precision black body model PMBB-60m with an output aperture with a diameter of 30 mm was developed, studied and calibrated in the temperature range of 200–450 K. The calculated value of the effective emissivity of PMBB-60m with coating of the cavity by Aeroglaze Z306 paint is 0.9997. The composition and design of PMBB-60m are described. PMBB-60m can operate both in vacuum conditions and in conditions of inert gas or atmospheric pressure. The metrological characteristics of PMBB-60m , obtained by transferring a temperature unit from the State Standard of the zero digit of a temperature unit in the range from 0 to 3000 °C using a comparator, based on a precision pyrometer TRT II (Heitronics Infrarot Messtechnik GmbH, Germany) are presented. The correction to the PMBB-60m temperature readings in the temperature range of 223.15–450.15 K did not exceed 39 mK according to the results of calibration in the temperature range of 223.15–450.15 K. The results of calculating the expanded uncertainty in the temperature range of 223.15–450.15 K did not exceed 1 K. The values of instability of temperature maintenance PMBB-60m, measured in steps of 10 s for 15 minutes, did not exceed 15 mK in the considered temperature range. The results of calculation of the spectral effective emissivity of PMBB-60m, carried out using the STEEP3 program, are presented.

The article presents the structure of systems for radiometric calibration for the Earth remote sensing optoelectronic equipment in the infrared spectrum range. Analysis of existing facilities for radiometric calibration of the Earth remote sensing optoelectronic equipment in conditions of vacuum and low-background radiation was carried out. These facilities are based on using the black body models as radiation sources, including reference sources based on the phase transition of pure metals, for example gallium or indium. A large-aperture black body model LABB-380 with an aperture diameter of 380 mm in the temperature range of 223.15–423.15 K has been developed. LABB-380 is part of a high-vacuum low-background test rig currently being developed at the Scientific Research Institute of Optoelectronic Instrumentation for the radiometric calibration of the Earth remote sensing optoelectronic equipment. The results of calculating the normal effective emissivity of the LABB-380 surface in the above temperature range and the spectral range of 3–20 μm are presented. The metrological characteristics of LABB-380 obtained during the transmission of a temperature unit from the State Working Standard of the zero category of a temperature unit in the range from 0 to 3000 °C (Registration No. 3.1.ZZA.0020.2015) using a comparator based on the HETRONIXS precision pyrometer have been studied. According to the calibration results in the temperature range of 300.15–390.15 K, the instability of the LABB-380 radiation was 0.005 K, the extended temperature uncertainty was 0.66 K at the temperature of 300.15 K and 0.88 K at 390.15 K.

An improved monochromatic radiation source with spectral width 4 nm based on a supercontinuum laser and double monochromator is introduced into a unit based on an absolute cryogenic radiometer in order to increase the precision of measurement of spectral sensitivity in the range 0.9–1.6 μm. A feedback system that supports stabilization of the power of monochromatic radiation with standard deviation 0.025% is developed. The power of optical radiation in the plane of the detector and/or power of the absolute cryogenic radiometer varies from 0.1 to 1.5 mW. The spectral distribution of the power of the newly developed source in different operating regimes of the supercontinuum laser is presented.

The first-class State Working Standard of units of wavelength in the range from 1.25 to 20.00 μm and of units of wavenumber in the range from 500 to 8000 cm–1 developed at the All-Russia Research Institute of Optophysical Measurements on the basis of an infrared Fourier spectrometer is presented. The units of wavelength and units of wavenumber are transmitted to working standards in the course of a measurement (performed by an infrared Fourier spectrometer) of the positions of the radiation peaks from two laser sources incorporated into GET 170-2011, the State Primary Special Standard of the units of length and propagation time of a signal in an optical cable, mean power, attenuation, and wavelength for fiber-optic communication systems and information transmission systems. The working standard reproduces the spectral scale with the use of an interference pattern produced by a built-in He–Ne laser in the course of measurements of the spectral distribution of the strength of the internal source. Propagation of the wavelength scale in the range 1.25–20.00 μm and of the wavenumber scale in the range 500–8000 cm–1 is achieved through the introduction of corresponding correction factors to the results of measurements. An accuracy chart that establishes the traceability of an instrument used to measure wavelength and wavenumber to GET 170–2011 is developed and presented.

An improved monochromatic radiant source with spectral bandwidth of 4 nm based on supercontinuum laser and a double monochromator was included in absolute cryogenic radiometer-based facility to improve the accuracy of spectral responsivity measurement in the range 0.9–1.6 μm. The developed feedback system ensures stabilization of monochromatic radiant power with standard deviation up to 0.025 %. Radiant power that proceeds detector under test or absolute cryogenic radiometer varies from 0.1 to 1.5 mW in dependence of wavelength. The spectral power distribution of its monochromatic source for various operating mode is presented.

The 1st class Working Standard for units of wavelength in the range from 1.25 to 20.0 μm and wavenumber in the range from 500 to 8000 cm–1 developed in VNIIOFI based on Fourier-Transform Infrared Spectrometer is presented. Dissemination of wavelength and wavenumber units to the 1st class Working Standard is carrying out from FTIR-spectrometer measurements of two peaks of lasers from the State primary special standard of units of signal propagation length and duration in the optical fiber of the average power, attenuation and wavelength for optical fiber communication systems and information transmission GET 170-2011. Spectral scale realization by the Working Standard is carrying by interferogram of internal He–Ne-laser during spectral intensity measurements of internal source. Dissemination for units of wavelength in the range from 1.25 to 20.00 μm and wavenumber in the range from 500 to 8000 cm–1 is provided by corresponding correction factor to measurement results. The developed accuracy chart that set traceability for wavelength and wavenumber measurement instruments to GET 170-2011 is presented.

The principles of operation and the composition of instruments incorporated into GET 156–2015, the State Primary Standard of the unit of spectral regular transmittance, unit of spectral diffuse reflectance, and unit of spectral specular reflectance in the wavelength range from 0.2 to 20.0 μm are described. The instruments are designed for reproduction and transmission of the specular regular transmittance, spectral diffuse reflectance, and spectral specular reflectance in the wavelength range from 0.2 to 20.0 μm.

We present the composition of the State Primary Standard GET 156-2015 of units of the spectral coefficients of directional transmission, diffuse and specular reflections in the wavelength range from 0.2 to 20.0 μm. Metrological characteristics of the standard are given.

The new stage of the development of space-borne information systems is the creation of the Global Earth Observation System. For the full functioning of such a system, it is necessary to provide the uniformity of measurements of all national systems as members of the global system, with high-quality measurement data. This requires the implementation of a high level of ground (prelaunch) calibration of Earth remote sensing instruments. To solve these problems, there were created calibration facilities on the basis of large vacuum chambers with vacuum reference radiation sources, including sources on the basis of black bodies with a wide aperture of 500 mm in the spectral range from \(3~{\upmu }\hbox {m}\) to \(14~{\upmu }\hbox {m}\). Such a facility was created by FGUP “VNIIOFI” in cooperation with FGUP “TsNIIMash”. The ground calibration of Earth remote sensing instruments is being carried out by using blackbody models as radiation sources with known spectral radiance. Facility for ground calibration of remote sensing devices on spectral radiance is based on the usage of a large-aperture blackbody (LABB) with 500 mm diameter and working temperature range from 213 K to 423 K, as a radiation source. This calibration setup comprises a set of reference blackbodies, such as a blackbody on the phase transition of Gallium, a variable-temperature blackbody with temperature range from 213 K to 423 K, a reference blackbody cooled with liquid nitrogen, and IR Fourier spectrometer utilized as a comparator to perform LABB calibration on spectral radiance. The second important characteristic of LABB is the uniformity of spectral radiance across the radiating aperture of this blackbody. The paper describes the device for measuring the spatial homogeneity of the radiation power of the LABB’s radiating surface. This device is based on the use of two-color InSb-CdHgTe detector equipped with modulator and IR lens, which are mounted on a two-axis translation stage suitable for operation in vacuum and installed in the vacuum chamber against LABB. During the measurement of the radiation uniformity, the modulator sequentially sends probing radiation spot either from the LABB’s surface or from the thermostatic radiation source to the detector input. The principle of operation of the device is described. The results of measurements of the radiation power homogeneity across the LABB’s radiating aperture are presented in wide-temperature range.

The electronic system for the absolute radiometer MAR-1, which is a part of the national primary standard GET 86-2010 for the units of spectral radiance, spectral intensity, spectral irradiance, radiant intensity, and irradiance at wavelengths of 0.2–25.0 μm, is described, along with the results of a comparison of it with the World Radiation Standard.

Low- and mid-temperature blackbody models with operating temperatures in the range 80–1200 K are considered. These types of models function as components of verification systems for preflight calibrations of onboard optical radiometric space equipment operating in the infrared range of wavelengths. Radiation sources with tunable temperature and models based on fixed reference temperature points of the melting–solidification phase transitions of Ga and In are described.

This is a discussion of the characteristics of a cryogenic radiometer and monochromatic radiation source that form part of the National primary standard GET 213–2014 for the units of absolute and relative spectral sensitivity at wavelengths from 0.25 to 14.00 μm and are intended for calibration of photodetectors with respect to spectral sensitivity.

Preflight calibration of space-based observation systems (SOBS) is carried out by means of standard sources with known spectral radiance. There are no difficulties in preflight calibration of SOBS within the visible spectral range. The main problem here lies in achieving sufficiently high uniformity of spectral radiance across the radiating aperture of a large-area source. Standard blackbody radiance sources with the temperature that is measured and with the calculated emissivity are used for calibration of SOBS in the infrared (IR) spectral range. The emissivity of sources having an aperture as large as 500 mm cannot be calculated accurately enough, and they have to be measured. It is quite challenging to conduct the measurements in a vacuum chamber simulating the low earth orbit environment in a broad temperature range. A spectral radiance calibration facility for preflight calibration of SOBS which is based on using a large-area blackbody with a diameter of 500 mm and an operational temperature range from \(-60~^{\circ }\mathrm{C}\) to \(150~^{\circ }\mathrm{C}\) is presented. The facility includes a gallium fixed-point blackbody, a variable temperature blackbody with a temperature range from \(-60\,^{\circ }\mathrm{C}\) to \(150\,^{\circ }\mathrm{C}\), a reference liquid nitrogen-cooled blackbody located in the vacuum chamber, and a Fourier transform IR spectrometer (FT-IR) used as a comparator. Radiation from the different sources is fed, in sequence, into the comparator by means of a custom-made optomechanical system located in the vacuum chamber. Operation of the calibration facility is described. Characteristics and specifications of the sources are shown.

Metrological radiometric facilities for optoelectronic instruments calibration utilize in terms of standards as radiation detectors in a form of cryogenic radiometers (CR), so as radiation sources. However in practice, there are no CR working within IR spectral range. An alternative way of radiometric calibration in middle and far IR ranges is to develop a parametric series of standard radiation sources -blackbody (BB) models.The paper describes some of BBs developed at VNIIOFI for the last time [1] from cryogenic (80 K to 200 K), to low (about 200 K to 400 K) and medium (400 K to 700 K) temperature regions for calibration of the IR instruments under cryogenic-vacuum conditions. These BBs are presented by models of both types: variable-temperature and based on fixed points of Ga or In. BBs are characterized with high temperature uniformity and stability. Copper and aluminum alloys are used as the radiation cavity materials. The required value of emissivity epsilon(lambda) is achieved by using different black coatings. Low-temperature and cryogenic BBs are based on the principles of indirect multi-zone electric heating (with heat isolation from LN2 cooling loop, or by using an external liquid thermostat with circulating heat-transfer agent. The principles of operation, design and test results of BBs are described.

The consistency of the values of the spectral radiance of two standard vacuum absolutely black bodies (low and medium temperature) in the 80–170°C range, forming part of the equipment for measuring emissivity under vacuum, is considered. It is shown that, using this equipment, one can measure spectral radiance at low radiation temperatures (down to –100°C) in the 4.5–20 μm wavelength band. The characteristics of the inner coating of the sample enclosure, required in order to make the measurements in the far infrared band and compatible with the vacuum conditions and low temperatures, are presented.

The All-Russian Research Institute for Optical and Physical Measurements is currently carrying out a project on developing an integrated system for measurement assurance of Earth observations. The system should provide ground calibration of instruments and their control during space-borne observations. Such tasks require appropriate measurement facilities as well as regulatory documentation. In this paper we discuss the newly created radiometric facility, traceable to SI standard, for precise calibration of instruments for Earth observations, the project on precise monitoring of the stability of the instrument's in-flight performance and the development of national regulatory documentation in harmony with the international document 'Quality Assurance Framework for Earth Observation-QA4EO'.

Abstract: This paper reviews a wide list of precise blackbody (BB) sources developed at the All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI). These radiometric, photometric and radiation thermometry standards are for the entire UV-visible-IR spectrum, and cover the temperature range from 80 K to 3500 K [1, 2, 3]. Low temperature blackbodies with temperatures from cryogenic to 450 K were developed for space borne instruments calibration [4, 5, 6]. We present models of variable-temperature BBs, as well as those based on fixed-points of Ga, In and binary metal-metal eutectic alloys. BBs are characterized with high temperature uniformity and stability. For example, for the BB100-V1 model, these parameters account for 0.05 K to 0.1 K, and 0.1 % for the 1.5 μm to 15 μm wavelength region under cryo-vacuum conditions of medium background environment emulating the orbital working environment. Copper and aluminum alloys are used as the radiation cavity materials for the low-temperature and cryogenic BBs. Recent advances in high-temperature technology and a novel design made it possible to develop the Planckian sources with temperatures as high as 3500 K, high uniformity, and stable radiation characteristics [7, 8, 9]. These large-area blackbodies allow the creation of a new generation of radiometric and radiance temperature standards with low uncertainties. High-temperature, large aperture blackbodies of the BB3500 series allow the realization of projects requiring high-temperature fixed points based on metal-carbon eutectic and peritectic alloys.