Payload Developments
FOR EXTENDED RECONNAISSANCE to become a reality, intelligence data must be gathered, transmitted, processed and disseminated to the requisite users in a timely manner. Our UAVs are therefore being optimized as platforms for their mission payloads (themselves becoming smaller, lighter, and more reliable). These payloads currently comprise sensors, communication links, and in some cases information processing capabilities. Follow-on payloads will include such capabilities as signals intelligence (SIGINT), Measurements and Signatures Intelligence (MASINT), and advanced communications packages.
Like the photographic cameras they are replacing, imaging sensors may each include a range of capabilities and operating modes: - Electro-optical (EO) and infrared (IR) systems sense radiation in the visible through IR spectral bands and provide fine-resolution day-night imagery, primarily for point-target surveillance
- Synthetic aperture radar (SAR) systems operate from the Ku through UHF bands and provide all-weather imagery that is either wide-area coverage (strip-map mode) or point-target surveillance (spotlight mode).
Sensor operating modes and resolution capabilities, combined with varying platform slant ranges to the targets imaged, yield differing image quality. For optical sensors, this quality is represented by a number on the National Imagery Interpretability Rating Scale (NIIRS): the higher the number (from 1 to 9), the greater the detail for object recognition. For radar sensors, image quality is normally stated in meters (or feet) of resolution. In both cases, imaging quality is determined by its utility to the user: the information must be reliably identifiable to be operationally useful. Thus, both requirements and technologies drive toward NIIRS 5 - 6 for optical sensors, and well less than 1 meter for radar sensors. Platform positioning and sensor-to-target slant range conditions and operating modes are optimized to meet those criteria. A recent example of UAV imagery is shown on the next page. Additional promising sensor payload technologies and developments are summarized below.
UAV data links are used for flight control and for transmission of intelligence data. They may be line-of-sight (LOS) or they may use relays to extend their range beyond line-of-sight (BLOS). Relays, in turn, may be aircraft or satellites. All our UAVs have communicated via LOS links for close battle support, up to about 200 km beyond the forward line of own troops (FLOT). Hunter has also demonstrated its ability to operate BLOS (to 300+ km) by using another Hunter as airborne relay; thus, it can support additional, deep battle intelligence needs.
The endurance UAVs' deeper penetration beyond the FLOT will require the routine use of satellite communication (SATCOM) links. Predator is currently using a Ku-band SATCOM link to extend its mission capabilities.
We are working with the Defense Information Systems Agency (DISA) and the Services to ensure sufficient data link throughput to handle the increased quantities of information that will ensue from multiple UAVs imaging the battle area and conducting wide-area search operations. For example, to augment BLOS communications the DARO recently joined DISA in the Commercial Satellite Concept Initiative (CSCI) to buy satellite capacity in bulk.
Finally, a communications relay payload is being developed for UAVs so that their low-cost endurance can be used to support information distribution functions while freeing manned aircraft for other missions.