Part IV of the AWG-9 WCS Advanced series: a collection of suggestions and tips about the very base tool available to the RIO.
- PRF mention and P/PD/CW differences;
- Zero Doppler Filter;
- Radar clutter: Pulse Doppler;
- Recognizing a Notching Target;
- Pulse Radar mode;
- AN/APX-76 IFF Interrogator;
- ASPECT Switch;
- Television Camera Set;
- MRL – Manual Rapid Lock-on;
- Ground mapping;
- Manoeuvring and soft-locks;
- Vertical Scan Lockon;
The fourth part covers the MRL, Ground mapping, Manoeuvring and maintaining soft-lock, VSL.
As mentioned already, this is more a collection of tips and ideas rather than explanation. Details are, as usual, in the manual.
IX. MRL – Manual Rapid Lock-on
Close range mode, allows to use the HCU to manually set the antenna elevation and the azimuth. The range is limited to 5nm.
It’s use is unintuitive and usually ACM modes are faster and easier to employ.
Plate 8.1 shows an example of MRL employment.
Scenario: a target is set 2 miles in front of the F-14. Same speed, same altitude. By activating the MRL, the antenna switches to Supersearch in a vertical scan pattern.
The elevation of the MRL cues should be referenced by means of the EL indicator because the DDD displays Range vs AMZ. In the example, if the cues are superimposed to the target, the target mark disappears because by moving the MRL cuel lower, the antenna elevation decreases.
X. Ground mapping
The AWG-9 can be employed is an elemental ground mapping radar by means of Pulse mode. It can be successfully used to highlight the coastline and ground features that stand out from the horizon.
Ships can be detected from about 80nm and also be locked as a locked and targeted as shown in Plate 9.2. As any other target, the locked ship is visible both on the TCS and on the HUD of the pilot.
This can be used for different purposes such as recce of recover in case of TCN failure or other technical issues.
The Ground mapping features of the AWG-9 are a consequence of the Pulse radar mode not filtering ground returns. It is a very basic form of ground radar and works best over the sea surface to highlight the coastline.
Plate 9.1 shows a ship located a dozen miles from the F-14 and the outline of the coast. The map in the top-right corner is the F10 view of the situation whereas the bottom-left is the same view but distorted to resemble what is displayed on the DDD. The radar, in fact, distorts the view following a pattern similar to the MLC trace.
Despite not being a real ground mapping radar and suffering from excessive clutter when feet-dry, the Ground mapping can be useful to increment the spatial awareness in a degraded or zero-visibility conditions flight.
In a mountainous area, focusing on the peaks can spotted easily by adjusting the antenna elevation. Such peaks also offer an easily identifiable visual reference for the Pilot.
XI. Manoeuvring and soft-locks
NOTE: review post implementation of the TWS AUTO.
Whilst manoeuvring, the antenna of the F-14 pivots, causing the radar cone to miss the target hence the loss of the soft lock. This behaviour is not usually a problem but the RIO must take into consideration that, due to the WCS guidance peculiarities, the broken lock can induce the loss of a considerable amount of energy. Especially at longer distances, this can compromise the successful outcome of the launch.
The RIO can compensate by lowering the antenna or by switching to STT. The latter compensate automatically the elevation difference and angle.
The symptom is greater as the ΔALT = ALTF14 – ALTTGT increases. Therefore the RIO must, in primis be aware of causes the issue and, in secundis, be able to compensate if necessary.
Since STAB is off, the antenna is still using the horizon as the reference plane. The target can be illuminated again by dropping considerably the antenna elevation.
Plate 10.1 shows a sketch of the situation (please note that the angle is simply an approximation).
XII. Vertical Scan Lockon (VSL)
The RIO can control two variants of the VSL from the backseat: VSL High and VSL Low.
VSL modes starts a 5° wide circular pattern:
- VSL HI covers a vertical area between +15° and +55°;
- VSL LO covers a vertical area between -15° and +25°.
The VSL acquisition range is 5nm.
VSL can be operated by the Pilot or the RIO. The normal WVR usage is tasked to the Pilot. Depending on the contract, it can be operated by the RIO in certain conditions (loss of SA by the Pilot or explicit request).