Missile Warning Systems
By Ollie Holt
Table 1: Comparison of Active and Passive Missile Warning Technologies Attribute
Time to Go (TTG)
ED l ast looked at missile warning systems in the May 2008 issue. In that survey, two responses were from suppliers of active RF – pulse Doppler (RF-PD) missile warners and the rest were from suppliers of passive UV or IR missile warners. The current survey saw a similar response, with two active systems and the rest being passive. The survey results also indicate a trend toward staring two-color
The Journal of Electronic Defense | May 2010
Active (RF-PD) radars can determine the distance and speed of incoming missiles.
Passive (IR) cannot provide range information. Passive (UV) can only provide course range as a function of plume intensity. By using the launch point and stored terrain data with IR or UV sensors, some TTG information can be developed. Passive (IR) can potentially detect missile kinematic heating along with the missile motor. Passive (UV) typically requires the missile motor to be burning. IR offers better post-burn-out performance than UV.
Missile Motor Burn
Active (RF-PD) Does not require the motor to be burning for declaration.
Active sensors do not use missile motor plume detection, while a passive sensor requires the missile motor plume but in some cases can also detect kinematic heating of the missile structure post motor burn out. Field of View Passive (UV) requires a less complex set of sensors to provide 360-degree coverage. Passive (IR) is similar to UV, but requires a slightly more complex sensor scheme. All sensor types require a sensor in each quadrant to provide full spatial coverage. Angle of Arrival Passive (UV) provides very good angle-of-arrival information. Passive (IR) angle of arrival performance is a function of the size of the IR array. The larger the array, the better the angle of arrival performance. Weather Conditions Active (RF-PD) less sensitive to weather conditions. Passive (UV) sensitive to weather conditions but not sensitive to sun glint. Passive (IR) sensitive to weather conditions and to false alarms caused by sun glint. Also sensitive to manmade IR clutter. Active (RF-PD) complex transmitter, antenna and receiver system if AOA required. A low complexity conﬁguration could be created with low cost communications components but with reduced performance. Active (RF-PD) will provide quadrant, but to provide better resolution it needs a more complex antenna array. Active (RF-PD) requires an antenna in each quadrant to provide 360-degree coverage.
Passive (UV) low complexity. Also the lowest life-cycle cost system. Passive (IR) complex processing to prevent false alarms and the sensor needs cooling. (Some new technologies are moving away from the cooling requirement.)
The passive sensor hardware is relatively simple but the processing is complex to reduce false alarms. While the active system requires antennas and a coherent transmitter and receiver hardware system with the complex processing. False-Alarm Rate (FAR) Active (RF-PD) dependent on altitude, radar cross section of the missile and other RF signals in the environment. Passive (IR) higher FAR at lower altitudes then UV because of the clutter sources. Requires complex processing to reduce FAR. Passive (UV) lower FAR then IR but still has complex processing to remove false alarms.
An integrated RF-PD and a passive IR or UV system would provide lower FAR. Declaration Range Passive (IR) atmospheric transmission of IR radiation is better than that of UV. Better performance at higher elevations. Active (RF-PD) is a function of transmitter power and the radar cross section of the missile. Passive (UV) lower atmospheric transmission of UV radiation.
Table of Contents for the Digital Edition of JED - May 2010