Radar waves travel in different pattern from the ballistic path of bullets, they do not have to point at the same angle. And the angle difference can vary depending on target range.
Also there are sea skimming cruise missiles as well as high diving anti-ship missiles.
Lastly, is it not possible to have a redundant fire control system using either the fire control radar/optics attached on the CIWS itself, or utilising fire control function from other radars? This is useful if the fire control radar on the CWIS itself is damaged or malfunctioned.
Pakistani's Chinese made frigates have two CIWS with their radar and optical sensor removed, and located on different part of the ship.
The idea of having mini search radar and tracking radar --- two separate radars --- on the CIWS itself is for redundancy in case main radars are damaged.
AK-630 or H/PJ-13 design is based on CIWS with search and tracking radar located elsewhere. Also separate is the EO. In designs that use four AK-630 or H/PJ-13 design, there is a single radar and EO. In Sovremenny for example, you have four AK-630s at corners of the superstructure and each side of the superstructure, you have one MR-123 radar on each side. Refit changed that to Type 349 radar. In the 054 frigate, you got four H/PJ-13 but on top of the hanger you have a single Type 349 radar. Pre-refit 051B has the same arrangement.
Type 730B is similar to the AK-630/PJ-13 approach. The tracking radar and EO is separate with the search provided by the main search radar itself. In this case, the radar and EO is located between the CIWS.
Despite the number of CIWS, the targets you engage are limited to where these radars are pointed at. So let's say in the Sovremenny, you cannot engage four targets separately but two targets with two guns pointed at each target.
That is unless you have an EO that is separate and not attached to the radar and can operate independently from it. This allows the EO to engage different targets from the radar. For example in the refit Sovremenny they added two EO on each side along with the two radars. There are ships or boats that rely completely using EO for tracking with H/PJ-13, such as the Type 022 and the PLAN version of Zubr. Only the main search radar is provided.
Another possibility though not certainty, is that the main gunnery radar --- the one for the main gun --- can also serve to direct the CIWS, especially for ships that have a single gunnery radar on the rear. This is particularly of note with the Type 054A, whose main gunnery radar is the same Type 347G as the radars on the CIWS. In other ships, the main gunnery radar is the Type 344 which has EO and is similar in design to the 347G, only larger. I think its possible that the main gunnery radar can replace the Type 347G on the CIWS if the CIWS radar is damaged, and works also vice versa, the Type 347G on the CIWS can replace the main gunnery radar if the main gunnery radar itself is damaged. Note that the Type 347G is also the main gunnery radar on the 056/056A and the H/PJ-26 is used like a CIWS in the manner of the Oto Melara or the AK-176.
The Chinese approach to CIWS differs from other CIWS is that no dedicated search radar is provided on the CIWS, where a dedicated search radar is evident on the Goalkeeper (the rotating bar thingie) and on the Phalanx (the mini radar hidden on the cap on top of the body). Instead, the Type 364 surface search radar provides that function of queuing the CIWS towards the targets, then letting the tracking radars do the rest. On most PLAN ships that's the white dome on top of the main mast. This approach gives the SSR an extended radar horizon, and the same SSR can also use to queue the main gunnery radar and the HHQ-10 launchers.
In case if the tracking radars on the 730/1130 CIWS is broken, I would assume the EO installed on the CIWS would take over. If the Type 364 SSR is knocked out, which won't be that easy since it is protected by a dome, its possible the Type 347G radars have a built in search mode just in case. The EO can also do search by reverting to a wide angle lens; the EO allows for three different lens lengths and operates on a separate 3D axis from the rest of the CIWS, which is another departure from other CIWS designs.
In the case of the Type 055, the AESA panels on the integrated mast, likely X-band, serve to replace the Type 364, Type 344 and Type 366 radars in one set. It follows the same architecture as older PLAN vessels, only the radar is different. It may queue the CIWS, and it may have the potential to take it over. Along with this, there are holes towards the bottom of the pyramid mast that suggest these are for an EO system.
In that picture, is the ship testing the CIWS by using the X-band AESAs only? I noted that even the EO on the CIWS is deliberately turned around in the opposite direction so it won't be used. There is certainly the possibility, but whether PLAN checked the option in the order list for sure we don't know as a fact. I will put this on the list of mysteries for the 055 and for PLAN ships in general.
