Search results
Results From The WOW.Com Content Network
A pseudo-noise code (PN code) or pseudo-random-noise code (PRN code) is one that has a spectrum similar to a random sequence of bits but is deterministically generated. The most commonly used sequences in direct-sequence spread spectrum systems are maximal length sequences , Gold codes , Kasami codes , and Barker codes .
There are two navigation message types: LNAV-L is used by satellites with PRN numbers 1 to 32 (called lower PRN numbers) and LNAV-U is used by satellites with PRN numbers 33 to 63 (called upper PRN numbers). [9] The two types use very similar formats. Subframes 1 to 3 are the same, [10] while subframes 4 and 5 are almost the same. Each message ...
Samples of three GPS satellites' orbits over a five-year period (2013 to 2018) USA-242 · USA-239 · USA-151 · Earth As of 22 January 2025, 83 Global Positioning System navigation satellites have been built: 31 are launched and operational, 3 are in reserve or testing, 43 are retired, 2 were lost during launch, and 1 prototype was never launched. 3 Block III satellites have completed ...
As minor planet discoveries are confirmed, they are given a permanent number by the IAU's Minor Planet Center (MPC), and the discoverers can then submit names for them, following the IAU's naming conventions. The list below concerns those minor planets in the specified number-range that have received names, and explains the meanings of those names.
Duplication of the same surface feature name on two or more bodies, and of the same name for satellites and minor planets, is discouraged. Duplications may be allowed when names are especially appropriate and the chances for confusion are very small. Individual names chosen for each body should be expressed in the language of origin.
BeiDou-1, first generation experimental satellite - BeiDou-1B 20 December 2000 16:20 Xichang, LC-2 Long March 3A: N/A GEO 80° E Retired December 2011: BeiDou-1, first generation experimental satellite - BeiDou-1C 24 May 2003 16:34 Xichang, LC-2 Long March 3A: N/A GEO 110.5° E Retired December 2012: BeiDou-1, first generation experimental ...
As minor planet discoveries are confirmed, they are given a permanent number by the IAU's Minor Planet Center (MPC), and the discoverers can then submit names for them, following the IAU's naming conventions. The list below concerns those minor planets in the specified number-range that have received names, and explains the meanings of those names.
True color image of the Earth from space. This image is a composite image collected over 16 days by the MODIS sensor on NASA’s Terra satellite. NASA Earth science satellite fleet as of September 2020, planned through 2023. Earth observation satellite missions developed by the ESA as of 2019.