14 results about "Nadir" patented technology

A right-hand circularly-polarized patch antenna comprising a ground plane and a patch connected to each other with one or more wires for which the wire shape and location of the end points are selected such that they do not cause an antenna mismatch, and the electrical current carried in the wires produces an extra electromagnetic field subtracted from the patch field in the nadir direction.

The present invention relates to a gross primary productivity calculation system using deep learning, and a calculation method using same, wherein gross primary productivity can be estimated on the basis of Sentinel-2 reflectance and photosynthetically active radiation (PAR). In particular, by applying a deep learning model that does not require other weather variables and uses only "Nadir BRDF-adjusted reflectance (NBAR)" of Sentinel-2 and the PAR as input data, accuracy similar to or higher than that of existing models can be achieved, even though the gross primary productivity is derived using deep learning with significantly simplified input data.

The invention provides a bottom point adjusting device (10). A liquid volume (60) through which a central longitudinal axis (Z) passes and which comprises a first portion (20) and a second portion (30), respectively having perforations (27, 37) in the direction of the central longitudinal axis (Z), a radially outer diaphragm-folded balloon (40) extending from the first portion (20) to the second portion (30) radially outside the liquid volume (60), and a diaphragm-folded balloon (40) extending from the first portion (20) to the second portion (30) radially inside the liquid volume (60) a radially inner diaphragm fold bladder (50), wherein the radially inner diaphragm fold bladder (50) forms a radially inner seal of the liquid volume (60).

The present invention concerns a rideshare satellite (1) comprising a satellite's body (10) including a nadir face (101) and a zenith face (102) opposed one to another. The satellite comprises a mechanical structure within the satellite's body (10). The mechanical structure comprises a structural hollow core element (20) extending from the zenith face (102) within the satellite's body. An extremity of the hollow core element (20) forms a fixation ring (201) on the zenith face (102) configured to be fixed to a payload adapter (A) of a spacecraft (S) when the rideshare satellite (1) is launched. The invention also concerns a launching method and a payload adapter.

A method for the transmission of a region-specific piece of information from at least one non-geostationary satellite to at least one ground-based device, the method being carried out by the non-geostationary satellite and including emitting at least one signal periodically towards the Earth, the signal including the region-specific piece of information and an elevation criterion, the region-specific piece of information being specific to a region around the nadir of the non-geostationary satellite, the elevation criterion being relative to the region around the nadir of the non-geostationary satellite.

This invention discloses a Bayesian inversion extraction method for the equilibrium signal of wide-span altimeter data. The method involves acquiring and preprocessing sea surface height anomaly sequences from radar interferometers and nadir altimeters. A normalized sine square window function is applied for windowing, and multidimensional spatial averaging is used to estimate the one-dimensional wavenumber power spectrum. A piecewise power law-based equilibrium signal spectrum model and a noise spectrum model constrained by dynamic sea state are constructed, and the set of spectral parameters is extracted through logarithmic domain weighted least squares fitting. A set of spatial covariance matrices is constructed using cosine integral transform and Abelian forward and inverse transforms. A graphics processor is scheduled to perform batch matrix decomposition and singular fault-tolerant regularized inversion to solve for the posterior mean vector and posterior covariance matrix of the target equilibrium signal. Window fusion and index mapping are applied to fill the gaps in nadir observations. Geostrophic dynamics parameters are calculated, uncertainty quantification is performed based on the linear error propagation law, and the knowledge base is updated based on the exponential moving average algorithm. This invention achieves suppression of observation noise and physical filling of observation gaps, improving the adaptability of the inversion system to environmental changes while preserving non-Gaussian dynamic characteristics.

Systems, methods, and computer-readable media for vessel identification are provided. The system includes a data storage device storing: a database of optical oblique images each containing a known candidate vessel having a known unique vessel identifier; and an optical nadir satellite image containing an unknown vessel. The system further includes a processor configured to execute a nadir-oblique image matcher configured to: compare, via a neural network, the nadir image to oblique images in the database including determining a similarity score between the nadir image and a respective oblique image; output, via the neural network, a ranked list of the oblique images based on the determined similarity scores; and assign a known unique vessel identifier to the nadir image based on the ranked list.

The invention provides a near space aircraft refraction starlight guidance, optical axis maneuvering and intersection positioning method. Firstly, a starlight path differential equation in a near space is deduced, and then a starlight refraction distribution model under a refracted starlight coordinate system is established by using a numerical integration method. On the basis, determining the nadir distance pointed by the optimal optical axis of the star sensor according to the selected optimal refraction observation interval and the altitude of the aircraft as a guidance law, and deriving an optical axis longitudinal rotation angle as an optical axis maneuvering control instruction according to an attitude angle and an optical axis transverse rotation angle; an intersection point of an isorefraction line and an isoaltitude line of a single refraction star and an intersection point of a normal vector of refraction surfaces of two refraction stars and the isorefraction line are respectively utilized; positioning is achieved through four methods including the intersection point of the geocentric vector of the circle center of the inscribed circle of the spherical triangle intercepted by the refraction surfaces of the three refraction stars on the celestial sphere and the isorefraction line and the intersection point of the feature vector corresponding to the minimum feature value of the matrix constructed by the normal vectors of the refraction surfaces of the at least three refraction stars and the isorefraction line.

This application discloses a sub-Sun-level drought monitoring method and system based on gravity satellites, relating to the field of surveying and mapping science and technology. It achieves efficient monitoring through a triple technical architecture: First, it employs a line-of-sight gravity difference algorithm, subtracting the integral reference orbit from the gravity satellite payload ranging data. Based on numerical difference, it obtains the distance acceleration residual, then calculates the line-of-sight gravity difference using a transfer function. The sub-Sun-level mass block of the nadir trajectory is divided into arcs of 2700 epochs (13500 seconds). Combined with Fibonacci point discrete integrals and Tikhonov regularized inversion, it obtains the sub-Sun-level mass change along the orbit. Second, it constructs standardized drought monitoring factors based on the mass change sequence, classifying mild, moderate, and severe drought levels using standard deviation as a threshold. Third, it extracts temporal and spatial features, fuses these features using a fully connected layer, and outputs the drought anomaly probability. The judgment threshold for the anomaly probability is dynamically adjusted, and real-time three-dimensional visualization is achieved through a 5G-A network, improving the accuracy of drought identification.

The invention provides a calibration test system and method for a satellite-borne nadir hyperspectral imaging load, and belongs to the technical field of hyperspectral imaging load test.The calibration test method mainly comprises the steps that (1) installation and debugging of the calibration test system are completed in an ultra-clean room, and the load is installed to a theoretical position; (2) selecting a calibration light source according to a load wave band and a view field range, and sequentially completing spectrum calibration and radiation calibration through the calibration test system; (3) installing a sample gas pool assembly in the calibration test system to complete the sample gas test of the load; and a debugging light path is established, and the spatial resolution test of the load is completed. Through the technical scheme provided by the invention, on the basis of meeting the calibration test requirement and precision, the calibration test process can be simplified, the calibration test efficiency is improved, and the method is suitable for the calibration test of the hyperspectral imaging load of the same type.

Computer systems and methods for maritime surveillance and identification of unknown vessels are provided. The system includes at least one data storage device storing: a database of known optical nadir satellite images each containing a known candidate vessel having a known unique vessel identifier; and an unknown optical nadir satellite image containing an unknown vessel. The system also includes at least one processor configured to execute a nadir-nadir image matcher configured to: compare, via a neural network, the unknown nadir image to a plurality of known nadir images in the database, the comparing including determining a similarity score indicating a similarity level between the unknown nadir image and a respective known nadir image; output, via the neural network, a ranked list of the known nadir images based on the determined similarity scores; and assign a known unique vessel identifier to the unknown nadir image based on the ranked list.

This invention discloses a method for obtaining satellite laser timing pointing. By using the six root numbers of the satellite orbit, the nadir trajectory and foot point trajectory of the satellite are obtained. Combined with the elevation database, the continuous laser pointing of the satellite is calculated, which greatly simplifies the laser pointing calculation process and improves the simulation calculation speed. The input used in this invention does not involve complex parameters such as laser attitude angle. Only TLE ephemeris and elevation data need to be input. The requirements for the function configuration of the scene simulation software are not high, and the calculation cost is low.

The invention relates to a method, a system and equipment for measuring an incident light compensation angle of a downlink light sensor. The method comprises the following steps: acquiring attitude information of an aircraft 1, time service of a global satellite navigation system and latitude and longitude coordinates of the aircraft 1; acquiring attitude information of the stability augmentation holder 2; the stability augmentation holder 2 is arranged in a yaw axis following mode and is used for realizing that the visual axis of the imaging spectrometer is in the nadir direction; according to the attitude information of the aircraft 1 and the attitude information of the stability augmentation holder 2, angle compensation values of a downlink light irradiance measurement sensor in the rolling and pitching directions are calculated; the downlink light irradiance measurement sensor is provided with a transverse rolling and pitching two-dimensional adjusting mechanism, and the optical axis of the downlink light irradiance measurement sensor points to the zenith according to the angle compensation values in the transverse rolling and pitching directions and the transverse rolling and pitching two-dimensional adjusting mechanism; a sunlight direct incidence angle is calculated according to latitude and longitude coordinates of the aircraft 1 and time service of a global satellite navigation system. According to the invention, more accurate measurement of the sunlight direct incidence angle is realized.

This invention discloses a method for analyzing and simulating spaceborne SAR coverage performance, used for accurate and efficient analysis of spaceborne SAR coverage indicators and visualization. The method comprises two parts: First, by combining antenna pointing and real-time satellite position, a nadir trajectory map is generated. The intersection of the beam and the Earth ellipsoid is solved using a vector triangle coverage model to visualize the beam coverage area. Second, after coordinate transformation of the target position, the relative radius vector between the satellite and the target is calculated. Target visibility is determined through multi-dimensional coordinate system transformation, and then the single illumination time and revisit time are calculated. This invention uses an accurate Earth ellipsoid model as a benchmark, integrating satellite orbital dynamics, precise coordinate transformation under multi-factor perturbations, and TLE parameter analysis to ensure high-precision analysis. Its process is clear, core steps can be efficiently implemented using mature algorithms, and it features both visualization output and high customizability. It can adapt to different SAR system parameters and scenarios, achieving targeted performance evaluation and optimization, demonstrating outstanding efficiency and practicality.