TAS Mk 23 is described by St. Norman in 1981's
Naval Radar as such (edited for brevity):
The Hughes Target Acquisition System (TAS) Mk 23 is designed to react automatically to incoming antiship cruise missiles, designating them to a Sea Sparrow illuminator (Mk 91 or Mk 115) and engaging them... in effect the TAS is an antiaircraft combat system (excluding missile fire control directors, which it controls) for a small ship; it can also be integrated into the fire control system of a larger unit. Its L-band pulse-doppler radar has no separate designation, but the system as a whole goes considerably beyond that visible element... Mk 23 was tested at sea aboard the frigate Downes in 1975... The TAS radar is designed for short-range operation in severe clutter and jamming; it requires high precision for good designation accuracy and, in turn, rapid lock-on of weapon fire control systems, as well as a low false-target rate, since the number of defensive weapons is quite limited. There is also a requirement for very fast switching on and off (in fact in milliseconds) to permit fleet operation in EMCON (RF Emission Control). The linear array antenna scans at 30rpm; it is mounted back-to-back with an IFF antenna on a stabilized platform: it is 14ft wide, for a horizontal beam width of about 3deg. Vertical beam-width is 75Β°, for gapless coverage of diving and sea-skimming approaching missiles. Total weight is 10,000 lb (2000 lb topside). There are four operating modes: normal, with an instrumented range of over 20nm, to employ point defense missiles; medium range, for radar surveillance, with an instrumented range of over 90nm (this also provides aircraft control capability)... Once a target has been detected, the IFF system determines whether it is friendly, and the associated UYK-20 computer determines whether it is a threat and when it can be engaged... In the frigate Downes the TAS radar has completely replaced the SPS-40 air search radar formerly installed.
SPS-58/65 was essentially a rapid-development emergency stopgap and radar for lower-value combatants. Described likewise:
L-band pulse-doppler air search target acquisition radar to work with the Point Defense Missile System. It was developed at high priority after the sinking of the Israeli destroyer Eilat by Egyptian 'Styx' missiles in 1967... Throughout the design the emphasis was on simplicity and low cost, in contrast to the Hughes Target Acquisition System. Construction is modular for maximum standardization, with two alternative antennas: a large stabilized, 16ft, horn-fed ellipse and a lightweight antenna, essentially SPS-10 with a dual feed permitting duplex operation. SPS-58 and -58B use the large antenna, the latter having no display but rather feeding directly into NTDS; -58A and -58C are analogous systems duplexing with SPS-10. There is also a new 9ft 6in planar array antenna. MTI is used to exclude clutter, and improvements in that direction continue to be made. Current production versions are designated SPS-65. Westinghouse.
NATO Sea Sparrow Missile is also referred to in the literature (and in US Navy service) as
IBPDMS (improved basic point-defense missile system, in contrast to the rather primitive and ad-hoc
BPDMS). It is notably deployed as the primary AAW armament of the Spruance class and all current USN carriers in
Mk 29 GMLS form, and in a great many Western frigates and destroyers in various box and VLS launchers. Note the compactness of the IPDMS launcher as compared to the ASROC-box-launcher-based
Mk 25 GMLS, which did not support RIM-7 wing folding.
Regarding the surface search set, I mean... it's not really a very attractive situation, is it? If nothing else, on a high-value combatant that by necessity will be operating in the littorals, I'd
really like to have a higher vantage point and clearer field of view for periscope detection. SSKs are going to be one of your most dangerous threats, I think. I'm not really sure how to improve the situation without incurring substantial costs (essentially, without removing and replacing the main GFCS). One idea might be to replace both of the dog-dish OE-82 SATCOM units with SPS-67, and relocate the SATCOM dishes to lower (but clear-overhead) vantage points. One might fit nicely right on the pilothouse where SPS-67 sits now. Maybe two more bracketed to either side of the stack? The current after SPS-67 (or whatever it is) could then be a SPS-65 or a TAS Mk 23.
This might help arrangement, by the way: SPS-67 has a 113" swung diameter, which means the antenna you're using is substantially oversize!