- AUVSI 2005, Baltimore USA

- UVS Tech 2004, Brussels Belgium

- UVS International 2004, Paris

EXECUTIVE SUMMARY

For the Unmanned Aerial Vehicles (UAV) community to gain access to the National Airspaces (NAS) everywhere in the world there is a generally agreed consensus that the UAVs shall provide the same level of safety as the piloted aircraft. It is also generally agreed that, as a corollary, the UAVs shall be equipped with means to Detect, See and Avoid (DSA) other aircraft flying in the NAS.

A review and description of the requirements that any DSA technology shall meet is analysed and justified. It depicts four areas of requirements to be met by DSA sensors:

  • Scan Envelope;
  • Time to Collision warning;
  • Threshold revisit rate;
  • Resolution;
  • Performance in adverse weather conditions.

Active and passive technologies, namely Laser Radar, Millimetre Wave Radar (35 GHz & 94 GHz) and Visible, IR and MMW imaging systems, are then reviewed against each of the requirements.

Findings can be summarized in the following table:

Sensor technology Scan envelope Time to Collision Revisit rate Resolution Adverse weather

Laser Radar

 Excellent Fair Poor Excellent Poor

35 GHz MMW radar

 Excellent Excellent Fair Excellent Fair

94 GHz MMW radar

 Excellent Fair Fair Excellent Fair

Visible Imaging

 Excellent Poor Excellent Fair Poor

IR Imaging

 Excellent Poor Excellent Fair Poor

Passive MMW imaging

 Excellent Poor Fair Poor Excellent

It can be concluded from the analyses presented here that the Millimetre Wave (MMW) Active Radar technology is the most promising as a DSA sensor for the UAVs.

A MMW Radar has been flight tested back in April 2003 in a project led by the NASA Environmental Research Aircraft and Sensor Technology (ERAST) group. Results presented showed that the 35 GHz Radar did the job but has to be improved to reflect the revisit rate requirement.

The design criteria for a maximally optimized MMW Radar system to be used as DSA for UAVs showed that, to meet the requirements, a solid state coherent 35GHz power source will be needed to allow higher sensitivity (leading to a faster revisit rate) and to pave the road towards a Low Probability of Intercept (LPI) strategy that could become a requirement for the tactical market.

This new radar sensor configuration would meet all requirements for DSA. Its estimated weight would be in the vicinity of 5 to 7 Kg with an aperture size of 11 inches.

The expected performances of a new design are presented. More compact, smaller weight, with better sensitivity and tracking features, the next generation of DSA radars at ICX Radar Systems has been shown to be both feasible and valuable.

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