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Pulse-Doppler radar and Continuous-wave radar are required for high performance in this area because these exclude low-velocity reflections. This is a critical measure of performance for the Littoral zone and land-based radar. Prevailing winds of about 15 mile/hour cover most of the surface of the earth. This constantly stirs up debris into the ...
Track algorithm operation depends upon a track file, which contains historical track data, and a computer program that periodically updates the track file. [ 3 ] Sensors information (radar, sonar, and transponder data) is provided to the track algorithm using a polar coordinate system , and this is converted to cartesian coordinate system for ...
2024 YR 4 is an asteroid that is classified as an Apollo-type (Earth-crossing) near-Earth object, with an estimated diameter of 40 to 90 metres (130 to 300 ft).As of 22 February 2025, it has a rating of 1 on the Torino scale, with a 1-in-280 (0.36%) chance of impacting Earth on 22 December 2032, [7] and a rating of −1.11 on the Palermo scale, corresponding to an impact hazard 7.8% of the ...
A positive radial velocity indicates the distance between the objects is or was increasing; a negative radial velocity indicates the distance between the source and observer is or was decreasing. William Huggins ventured in 1868 to estimate the radial velocity of Sirius with respect to the Sun, based on observed redshift of the star's light. [6]
The minimum railway curve radius is the shortest allowable design radius for the centerline of railway tracks under a particular set of conditions. It has an important bearing on construction costs and operating costs and, in combination with superelevation (difference in elevation of the two rails) in the case of train tracks , determines the ...
As opposed to the year, month, and day format of the Gregorian calendar, the GPS date is expressed as a week number and a seconds-into-week number. The week number is transmitted as a ten- bit field in the C/A and P(Y) navigation messages, and so it becomes zero again every 1,024 weeks (19.6 years).
It is a unique ID number or code assigned to a package or parcel. The tracking number is typically printed on the shipping label as a bar code that can be scanned by anyone with a bar code reader or smartphone. In the United States, some of the carriers using tracking numbers include UPS, [1] FedEx, [2] and the United States Postal Service. [3]
Orbital position vector, orbital velocity vector, other orbital elements. In astrodynamics and celestial dynamics, the orbital state vectors (sometimes state vectors) of an orbit are Cartesian vectors of position and velocity that together with their time () uniquely determine the trajectory of the orbiting body in space.