Editing SAMPSON (section)

==Operation==
[[File:HMS Daring SAMPSON is a multi-function AESA radar.jpg|thumb|The mainmast of {{HMS|Daring|D32|6}} showing the SAMPSON multi-function AESA radar]]
Conventional radars, consisting of a rotating transmitter and sensor, have limited power, are vulnerable to [[Radar jamming and deception|enemy jamming]], and perform only one function—with separate units therefore required for surveillance, tracking, and targeting.

As an active array, SAMPSON uses software to shape and direct its beam, allowing several functions to be carried out at once and, through adaptive waveform control, is virtually immune to enemy jamming. Active arrays have both longer range and higher accuracy than conventional radars. The beam-directing software uses sophisticated algorithms to schedule searches so that the potentially hundreds of active tracks are maintained with maximum accuracy.<ref name="Tessella Case Study">{{cite web |url=http://tessella.com/case-studies/sampson-radar-tracking-algorithms/ |title=Tessella Case Study |access-date=2013-11-29 |archive-date=2013-12-03 |archive-url=https://web.archive.org/web/20131203084149/http://tessella.com/case-studies/sampson-radar-tracking-algorithms/ |url-status=dead }}</ref>

The SAMPSON uses two planar arrays to provide coverage over only part of the sky; complete coverage is provided by rotating the arrays, similar to the way conventional radar systems operate. This is in contrast to the US [[AN/SPY-1]] (as used on the {{sclass|Ticonderoga|cruiser|1}} and Flight I–IIA {{sclass|Arleigh Burke|destroyer|1}}) and [[AN/SPY-6]] (as used on the Flight III ''Arleigh Burke''-class destroyer) or the Dutch [[Active Phased Array Radar|APAR]] system (as used on the Royal Netherlands Navy's {{sclass|De Zeven Provinciën|frigate|1}}, the German Navy's {{sclass|Sachsen|frigate|1}}, and the Royal Danish Navy's {{sclass|Iver Huitfeldt|frigate|1}}), which use multiple arrays fixed in place to provide continuous coverage of the entire sky.

Although the SAMPSON radar does not provide continuous 360-degree coverage, it rotates at 30 revolutions per minute, and with two back-to-back arrays, no part of the sky lacks coverage for more than half a second on average (the precise time varies as the beams can also be swept back and forth electronically). In addition, the use of a smaller number of arrays allows the system to be much lighter, allowing placement of the arrays at the top of a prominent mast rather than on the side of the superstructure as in the Dutch or US ships. Placing any radar emitter at a higher altitude extends the horizon distance, improving performance against low-level or [[sea-skimming]] targets; SAMPSON is at approximately double the height above the waterline than the arrays of equivalent ships in foreign navies. Although precise details of the SAMPSON's performance in this regard are unlikely to enter the public domain, such factors may mitigate the disadvantages of fewer arrays.

Some tasks are difficult to combine: for example, (long-range) volume search consumes substantial radar resources, leaving little room for other tasks like targeting. Combining volume search with other tasks also results either in slow search rates or in low overall quality per task. Driving parameters in radar performance is time-on-target or observation time per beam. This led to the Royal Navy selecting the [[S1850M|S1850M long-range radar]] to complement SAMPSON on the Type 45 destroyers. This also resulted in the NATO Anti-Air Warfare System study (NAAWS) defining the preferred AAW system as consisting of a complementary Volume Search Radar and MFR. This gives the added advantage that the two systems can use two different radar frequencies; one being a good choice for long-range search, the other a good choice for an MFR (physics makes both tasks difficult to combine).<ref name="bare_url" />{{dead link|date=August 2017}}

The first Type 45, {{HMS|Daring|D32|6}}, was launched on February 1, 2006. The ship was fitted with SAMPSON and S1850M radars in 2007 and was commissioned on 23 July 2009.

=== Modes ===
*Long and medium-range search
*Surface picture search
*High-speed horizon search
*High-angle search and track
*Multiple target tracking and multiple channel fire control; 1000 targets can be tracked