39 results about "Ballistic coefficient" patented technology

A low orbit optical imaging satellite has a long thin satellite body housing an optical telescope arrangement. A major part of the telescope arrangement has its optical axis roughly parallel to the direction of elongation and includes a mirror arrangement deployed to direct a line of sight of the optical telescope out sideways from the direction of elongation. The transverse dimensions of the satellite body are preferably minimized to be close to the optical aperture dimension of the optical telescope, thereby providing a high ballistic coefficient and high orbit lifetime for orbits in the low thermosphere.

The invention discloses a system state estimation method based on maximum likelihood criterion robust Kalman filtering. Under the situations that the system state and a measurement model are both nonlinear, non-Gaussian measurement noise occurs and there are large initial estimation errors, higher convergence speed, higher filtering accuracy and more stable filtering output can be obtained. Through verification and proving of positions, velocity and ballistic coefficient estimation errors, the higher convergence speed and the higher filtering precision are achieved. The method can be applied to spacecraft navigation, target tracking, fault detection, parameter estimation and other fields.

A projectile is improved aerodynamically by cutting grooves having parabolic transitions between the depth of the groove and the bearing surface. An ejectable tip is attached to the leading edge of the projectile to facilitate greater ballistic coefficient during flight and improved expansion upon impact at a soft target.

The invention discloses a small elliptic target reentry forecasting method under a sparse data condition. N circles of data collected in the past 5 days are processed, a numerical method is adopted tocarry out track determination on the single circle of data, the Kepler root number is adopted as a root number system, a semi-numerical method is adopted to carry out track integration, and a least square method is adopted to fit a ballistic coefficient of a reentry target. Compared with the prior art, the invention provides a reentry forecasting method combining the numerical method and the semi-numerical method for the characteristics of the sparse data and the small elliptic orbit. The problems that under the condition of sparse data, the multi-circle data joint orbit determination residual error is too large or not convergent, and the ballistic coefficient is difficult to determine through single-circle data orbit determination are effectively solved.

The invention discloses a system state estimation method based on a state augmentation iterated extended Kalman filter algorithm. The method adopts an accurate formula to calculate, measure and predicate a covariance matrix; and compared with an existing EKF and Modified IEKF algorithm, the method based on the state augmentation iterated extended Kalman filter algorithm can meet mutually-orthogonal relation between system state and measurement noise, and has faster convergence rate and higher filtering precision after calibration of position, velocity and ballistic coefficient estimation errors.

An aerial vehicle including a collapsible and inflatable vehicle body capable of being filled with a lighter than air gas so as to make the vehicle semi-buoyant or 100% buoyant at a predetermined altitude in an atmosphere above a solar system body. The vehicle body has a shape suitable to provide aerodynamic lift. The vehicle may include a propulsion device coupled to and extending from the vehicle body, where the device provides power to aerodynamically lift the vehicle above the 100% buoyant altitude to a higher altitude where the vehicle can maintain that altitude through the aerodynamic lift and vehicle buoyancy. The vehicle is configured to be deployed/inflated from a collapsed and stowed configuration to a deployed/inflated configuration in an orbit above the atmosphere of the solar system body, and is configured to enter the atmosphere in the inflated configuration and descend without propulsion.

The present disclosure pertains to a high ballistic coefficient wind sonde device and a method of determining wind speed and wind direction measurements relative to altitude with a high velocity wind sonde device. The device includes a streamlined body including a first end, a second end, a longitudinal axis, and an internal cavity. A tail extension includes a first end that is connected to the body second end and a second end, wherein the tail extends along the longitudinal axis of the streamlined body. At least one pair of oppositely extending fins are mounted to the tail adjacent its second end. An electronic assembly is located in the internal cavity for generating wind and altitude data. A transmitting antenna is mounted to at least one of the body and the tail for transmitting the wind and altitude data generated by the electronic assembly.

Embodiments of the invention include an elongate rifle bullet with a plurality of circumferential grooves having overmolded polymer therein defining embedded polymer rings. Embodiments of the invention include cartridges with propellant and such bullets. In one or more embodiments, the bullet has a body portion and a converging nose portion. The polymer rings have an outer surface that is flush with, that is, conforming to the outer surface of the body. The polymer may have be selected to have a favorable coefficient of friction with respect to the barrel. A feature and advantage of embodiments is that the metal to metal contact between the bullet and the barrel is reduced while not diminishing the ballistic coefficient of the bullet.

A rifle having a rifled barrel and a cartridge having a bullet having a diameter, a length, a ballistic coefficient (BC), and a muzzle velocity (V₁) greater than 1250 ft/sec are related to achieve accuracy at very long range in that the twist of the rifling is substantially equal to:

where: V₂ is the entry speed for the transonic, i.e. 1,250 ft/sec., and V₃ is V₁ minus V₂. A rifle barrel for receiving a bullet has rifling twist according to the relationship. A method uses the relationship to determine the rifling twist for a rifle barrel receiving a known bullet. Another method uses the relationship to design a cartridge for a known barrel rifling. The relationship is particularly applicable for bullets having a high BC, such as 0.325 or greater.

The invention discloses a space target meteorite forecasting method suitable for a space environment disturbance condition. The method specifically comprises the following steps: T1, counting ballistic coefficient results of the meteorite target under different space environment conditions in history, and establishing a ballistic coefficient corresponding table; T2, determining the orbit of the meteorite target, obtaining the position and the speed S0 of the space target at the end point of the data arc section; and T3, carrying out meteorite time and drop point prediction. The invention relates to the technical field of spaceflight measurement and control. According to the space target meteorite forecasting method suitable for a space environment disturbance condition, a reasonable ballistic coefficient can be selected according to disturbance conditions of a space environment at different forecasting moments; and the atmospheric resistance acceleration is calculated, so that the atmospheric resistance modeling error can be greatly reduced, the problem of low meteorite forecasting precision caused by relatively large atmospheric density modeling error in a space environment disturbance period can be solved, and the influence of the atmospheric density modeling error on meteorite forecasting in space environment disturbance is reduced.

The invention discloses a method for quickly analyzing the service life of a space target track based on a single-group TLE. The method specifically comprises the following steps: S1, calculating theorbit period first-order attenuation deltaT of a space target based on a single group of TLE, S2, calculating the atmospheric density reference height H, and S3, calculating the orbit service life L.The invention relates to the technical field of aerospace measurement and control. The invention discloses a method for quickly analyzing the service life of a space target track based on single-groupTLE. The track service life calculation precision is greatly improved; practical application requirements are met, the problems that the calculation error is too large when an SGP4 model is used during track life calculation, the difficulty of solving the ballistic coefficient through a single group of TLE is large, and the efficiency of a numerical integration method is low are effectively solved; the track service life calculation precision is basically less than 20%, and the analysis method is used for direct calculation, so that the calculation efficiency has obvious advantages compared with a numerical integration method, and the actual application requirements of large-batch space target track service life calculation are completely met.

The invention discloses a high-precision space target fall forecasting method based on a catalogue root sequence. The high-precision space target fall forecasting method specifically comprises the following steps: step 1, analyzing a catalogue element series as an actually measured orbit value; step 2, establishing an orbit perturbation model; step 3, calculating a ballistic coefficient; and step4, forecasting falling time and a falling point position. The invention relates to the technical field of spaceflight measurement and control. The high-precision space target fall forecasting method based on the catalogue root sequence can realize track extrapolation by using a half-value method, wherein the integral step length can be an integral multiple of the orbit period; the time is dozens of minutes or even dozens of hours; compared with a numerical method, the calculation efficiency is higher, and orbit integration is carried out by using the half-value method, so that the calculationefficiency is improved while the prediction precision is well guaranteed; and the calculation requirements of high precision and high efficiency under the condition of a large number of space targetscan be met at the same time, so that meteoric drop prediction can be carried out quickly and accurately.

This invention is a precision weapon that utilises solely as a projectile, a precision-ball made out of a suitable material namely solid C260 brass. It employs a smoothbore precision-barrel with a metal toothed rack/rail affixed along the northern hemisphere of the muzzle of the barrel that effectively converts some of the forward motion of the ball into rotational motion so that the ball is mechanically forced to rotate upwards/backwards at very high speed that can run into millions of rotations per minute, vastly improving it's ballistic coefficient and downrange accuracy. The weapon can be produced in a variety of existing types of firearms such as bolt-action, falling-block or semi-automatic, and can be chambered for a variety of calibers. A 5.5625 mm caliber bolt-action rimfire weapon for instance will provide a user with a weapon ideal for hunting small-game or for target shooting purposes.

The invention relates to an orbit parameter exception cleaning method based on extension minimization estimation. The orbit parameter exception cleaning method comprises the following specific steps of: selecting an orbit parameter exception cleaning method, an orbit parameter exception cleaning method and an orbit parameter exception cleaning method, the method comprises the following steps of: firstly, cleaning a corrected observation value: determining a threshold value for cleaning the corrected observation value by counting a release time interval of the observation value, or assigning a prior cleaning threshold value according to existing experience, and taking an orbital period as a unit; secondly, cleaning orbit parameters: based on polynomial regression and anomaly detection in a sliding window and detection of anomaly and space events outside the sliding window, completing observation value orbit element anomaly cleaning; If the target is close to the atmosphere reentry moment, all observation values containing negative ballistic coefficients are eliminated. The method can unify the orbital parameter exception cleaning process and effectively clean the orbital parameter exceptions of all targets in the spatial data cataloguing library.

A method of delivering over the air, shelled portions of fluids or granular substances containing effective ingredients, to a target, is provided herein. The method includes the following stages: selecting a type and a size of the shelled portions containing the required effective ingredients, based on mission parameters and physical data of a scene containing the target; conveying the shelled portions to a delivery point, based on the mission parameters and the physical data; and ballistically delivering the shelled portions towards the target, wherein the shelled portions comprise fluids or granular substances covered by shells that provide the shelled portions a ballistic coefficient that is significantly higher than a ballistic coefficient of similar portions without the shells.

The invention discloses a double-satellite and foundation combined reentry target forecasting method and device and electronic equipment. The method comprises the following steps: calculating initial orbit information of a reentry target based on a foundation; calculating a plurality of pairs of observation values of the reentry target based on double-satellite common view; wherein the double satellites are monitored and adjusted through a foundation, so that the double satellites track and observe a reentry trajectory of a reentry target; calculating a position trace point sequence of the reentry target according to the multiple pairs of observation values of the reentry target; performing orbit integration according to the position trace point sequence of the reentry target to calculate a corrected ballistic coefficient; and orbit extrapolation is carried out according to the initial orbit information and the corrected ballistic coefficient until a preset orbit height is reached, so that the reentry moment and the landing position of the reentry target can be determined. The method improves the prediction precision of the reentry time and the drop point position of the reentry target, achieves the accurate discrimination of the large-scale space reentry event, and reduces the range of a wreckage scattering region.

The invention relates to the technical field of aerospace, and relates to the technical field of aerospace. Aiming at the problem that in the prior art, the method for determining the safety condition of the large bottom separation is lack, the method comprehensively considers the ballistic coefficient of the outsole and the detector and the effect of the fire (by explosion) to push the two connected objects away, such as the two stages of the rocket, the anti-thermal outsole and the detector, the separation speed, the height, the separation phase, the angular velocity and the Mach number required by the large-bottom safe separation can be determined by step-by-step analysis on each separation condition, and the method is suitable for Mars detectors with different configurations.