Switched Monopulse Radar for Automotive Applications SLR. Tyco Electronics M/A-COM European Technology & Application Center Schweinfurt, Germany

Transcription

1 Switched Monopulse Radar for Automotive Applications SLR Tyco Electronics M/A-COM European Technology & Application Center Schweinfurt, Germany

2 Typical Applications Blind Spot Detection Improved ACC Functionality Pre-Crash Sensing Parking Aid Pedestrian Safety Closing Velocity Parking Lot Size Estimation Stop & Go Applications Reverse Back-up Aid

3 Sensor Objectives Radar Parameters Radar Principle: Pulse Radar Frequency: GHz Tx Power: <17dBm EIRP Bandwidth: 4 20 db points Pulse width: ns Pulse Repetition Frequency: ~3 MHz Detection Cycle Time: 40 ms Antenna Detection Characteristic: ± 8 Elevation 3dB limit ± 65 Azimuth 3dB limit Object Parameters Number of Objects: 10 Parameters Types: Range, Bearing, Velocity, Yaw Rate, Quality, Track ID Range Parameters Detection Range: 30m Range Performance: 20m (10sqrm target) Range (Object) Resolution: 15 cm Range Accuracy: 3 cm

4 Sensor Objectives (continued) Bearing Parameters Bearing Detection Principle: Switched Monopulse Bearing Detection Range: ± 40 Bearing Accuracy: ± 2 for Bearing Range ±5 ± 5 for Bearing Range ±5..25 ± 10 for Bearing Range ± Velocity Parameters Velocity Detection Principle: Range Rate Velocity Measurement Velocity Range: ± 100 km/h Velocity Accuracy: ± 1 km/h Velocity Resolution: 0.05 m/s Tracking Parameters Tracking Principle: Extended Kalman Filter Approximation Track Initiation: Retrospective Detector (4 in a row) Track Kill: 4 consecutive cycles with no detection

5 Principle of Operation Pulse Radar Correlation Minimum range: 15cm High Resolution Radar 24 GHz DRO Time Delay Comparision TX Antenna Maximum range: 20m (10sqm) Object Resolution: 15cm Time Normal RX Antenna Output Signal Correlation Correlation occurs when the pulse traveling time is equal to the internal delay. The resulting IF signal is related to the range of the detected object. Time Delay Comparison Pulse traveling time is compared with internal time delay

6 Block Diagram TX Antenna VCO TX Switch Power Splitter RX Switch Dual Channel LNA Switchable RX Antenna Control Circuitry PRF? IF Out Signal Processing

7 Sensor Bearing Capability Switchable antenna characteristics provide bearing information through signal processing based on the monopulse theory S/l og 10 5 Pattern log 10 0 Error Reference S/li n Pattern lin 0 o 0 db o o phi/deg phi/deg -60 o o 1 ASR 100 ASR AS R 0 phi/ de g Sum Pattern Delta Pattern phi/deg ASR Serr: Magnitude of delta pattern Sref: Magnitude of sum pattern

8 Typical Angle Accuracy Angle accuracy Meas Angle Real Angle Absolute Angle Error 20 Abs(Angle Error) Angle

9 System Impact of Sensor Bearing Capability Illustrated is a typical parking situation. In this case our test car is equipped with 4 sensors that are NOT capable of reporting bearing information on sensor level. The central processing unit of the radar network has difficulties to resolve the scenario and reports false targets due to ambiguities.

10 System Impact of Sensor Bearing Capability The screenshot beside shows the output of a SINGLE sensor in a similar scenario as illustrated on the slide before. In conjunction with other sensors of the network redundancy can be achieved leading to a more stable system.

11 Why Operating at 24GHz 5.8GHz: Integration of large antenna sizes into vehicle bumpers is not feasible Fractional BW for high resolution not realistic 24GHz: Integration of moderate antenna sizes into vehicle bumpers is feasible Acceptable attenuation of µwave propagation through bumper material Fractional BW for high resolution possible Availability of off-the-shelf components, mature production processes Economical hybrid design on softboard possible without MMIC s 64GHz / 79GHz: High attenuation of µwave propagation through bumper material no discrete packaged components available currently no affordable MMIC s available significant commercial and manufacturing technology deficiency issues Conclusion: 24GHz SRR is the key enabling technology on a short and medium term basis