We propose a new technique of remote wind measurements based on Doppler analysis of a CO₂ absorption line in the 1.605 µm overtone band measured in the direct Sun observation geometry. Heterodyne spectroradiometric measurements of the solar radiation passing through the atmosphere provide an unprecedented spectral resolution up to $\mathit{\lambda }/\mathit{\delta }\mathit{\lambda }\sim \mathrm{6}\times {\mathrm{10}}^{\mathrm{7}}$ , with a signal-to-noise ratio of more than 100. The shape of the individual rotational line profile provides an unambiguous relationship between the offset from the line center and the altitude at which the respective part of the line profile is formed. Therefore, an inverse problem may be posed in order to retrieve the vertical distribution of wind because with retrievals the vertical resolution is compromised by a spectral resolution and the signal-to-noise ratio of the measurements. A close coincidence between the measured and synthetic absorption line is reached, with retrieved wind profiles between the surface and 50 km being in good agreement with reanalysis models. This method may pose an alternative to widely employed lidar and radar techniques.

We present the project of a 2U CubeSat format spaceborne multichannel laser heterodyne spectroradiometer (MLHS) for studies of the Earth’s atmosphere upper layers in the near-infrared (NIR) spectral range (1258, 1528, and 1640 nm). A spaceborne MLHS operating in the solar occultation mode onboard CubeSat platform, is capable of simultaneous vertical profiling of CO₂, H₂O, CH₄, and O₂, as well as Doppler wind measurements, in the tangent heights range of 5–50 km. We considered the low Earth orbit for the MLHS deployment and analyzed the expected surface coverage and spatial resolution during one year of operations. A ground-based prototype of the MLHS for CO₂ and CH₄ molecular absorption measurements with an ultra-high spectral resolution of 0.0013 cm⁻¹ is presented along with the detailed description of its analytical characteristics and capabilities. Implementation of a multichannel configuration of the heterodyne receiver (four receivers per one spectral channel) provides a significant improvement of the signal-to-noise ratio with the reasonable exposure time typical for observations in the solar occultation mode. Finally, the capability of building up a tomographic picture of sounded gas concentration distributions provided by high spectral resolution is discussed.

We present a concept of the Martian multichannel diode laser spectrometer (M-DLS) instrument, a part of the science payload onboard Kazachok landing platform in the framework of the ExoMars mission second stage. The instrument, a laser spectrometer operating in the mid-IR spectral range, is aimed at long-term monitoring of isotopic ratios in main Martian volatiles—carbon dioxide and water vapor—in the near-surface atmosphere. The M-DLS spectrometer utilizes the integrated cavity output spectroscopy (ICOS) technique to enhance an effective optical path length and combines high sensitivity and measurement accuracy with relatively simple and robust design. Provided proper compensation of systematic errors by data post-processing, retrievals of main isotopic ratios with relative accuracy of 1% to 3% are expected during at least one Martian year.

We present E-CAHORS—a compact mid-infrared open-path diode-laser spectrometer designed for the simultaneous measurement of carbon dioxide, methane, and water vapor concentrations in the near-surface atmospheric layer. These measurements, combined with simultaneous data from a three-dimensional anemometer, can be used to determine fluxes using the eddy-covariance method. The instrument utilizes two interband cascade lasers operating at 2.78 µm and 3.24 µm within a novel four-pass M-shaped optical cell, which provides high signal power and long-term field operation without requiring active air sampling. Two detection techniques—tunable diode laser absorption spectroscopy (TDLAS) and a simplified wavelength modulation spectroscopy (sWMS)—were implemented and evaluated. Laboratory calibration demonstrated linear responses for all gases (R² ≈ 0.999) and detection precisions at 10 Hz of 311 ppb for CO₂, 8.87 ppb for CH₄, and 788 ppb for H₂O. Field tests conducted at a grassland site near Moscow showed strong correlations (R = 0.91 for CO₂ and H₂O, R = 0.74 for CH₄) with commercial LI-COR LI-7200 and LI-7700 analyzers. The TDLAS mode demonstrated lower noise and greater stability under outdoor conditions, while sWMS provided baseline-free spectra but was more sensitive to power fluctuations. E-CAHORS combines high precision, multi-species sensing capability with low power consumption (10 W) and a compact design (4.2 kg).

We present E-CAHORS $-$ a compact mid-infrared open-path diode-laser spectrometer designed for the simultaneous measurement of carbon dioxide, methane, and water vapor concentrations in the near-surface atmospheric layer. These measurements, combined with simultaneous data from a three-dimensional anemometer, can be used to determine fluxes using the eddy-covariance method. The instrument utilizes two interband cascade lasers operating at 2.78 $μ$m and 3.24 $μ$m within a novel four-pass M-shaped optical cell, which provides high signal power and long-term field operation without requiring active air sampling. Two detection techniques $-$ tunable diode laser absorption spectroscopy (TDLAS) and a simplified wavelength modulation spectroscopy (sWMS) $-$ were implemented and evaluated. Laboratory calibration demonstrated linear responses for all gases (R$^2$ $\approx$ 0.999) and detection precisions at 10 Hz of 311 ppb for CO$_2$, 8.87 ppb for CH$_4$, and 788 ppb for H$_2$O. Field tests conducted at a grassland site near Moscow showed strong correlations (R = 0.91 for CO$_2$ and H$_2$O, R = 0.67 for CH$_4$) with commercial LI-COR LI-7200 and LI-7700 analyzers. The TDLAS mode demonstrated lower noise and greater stability under outdoor conditions, while sWMS provided baseline-free spectra but was more sensitive to power fluctuations. E-CAHORS combines high precision, multi-species sensing capability with low power consumption (10 W) and a compact design (4.2 kg).

We present a concept of near-infrared FMCW lidar for real-time low-resolution imaging velocimetry and range finding of moving objects. One of the problems this instrument to challenge is the detection of unmanned aerial vehicles in an urban environment. The use of a lidar-based system is either in the detection of the object itself or of the wingtip vortices generated by rotating blades. A significant drawback of typical wind lidar is the long measurement time associated with the need to scan the area of ​​interest, therefore we propose an 8x2 matrix of receivers to reduce the total scan time. The main feature of the instrument is the use of commercially available components, including DFB lasers and single-mode fiber for the optical circuit, which can significantly reduce the cost of the device, as well as development time. Data processing and laser control are handled by the FPGA. The characteristics of the multichannel lidar are estimated based on ongoing testing of the single-channel prototype.AcknowledgementsThis work has been supported by the Russian Foundation for Basic Research grants #19-29-06104