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May 19, 2011

Development of Pulse Detection IC for LIDAR on planetary lander

Takahide Mizuno, Kousuke Kawahara, Hirokazu Ikeda ISAS/JAXA, Japan

Contents

1. Background (Experience of Hayabusa) 2. Purpose of device development 3. Device outline 4. Results of evaluation 5. Summary

Background ~ Hayabusa Project ~

Technical demonstration spacecraft - Operation of Ion Engines - Earth Gravity Assist with Ion Engines - Rendezvous with Itokawa with Autonomous Navigation - Scientific Observation of Itokawa - Touch-down and Sample Collection - Return and Recovery of Capsule

· Launch date : May 9, 2003 · Touchdown date: November 19, 2005 · Re-entry date: June 13, 2010

Background ~ Hayabusa's LIDAR ~

Receiver Optics

Primary Optics Primary Optics (Receiving Optics) (Receiving Optics) Band pass Filter APD

Detector and Digital Controller

Gain Control Receiver Electronics AOCU RS422 Digital Counter CLK: 75MHz Digital Controller Transmitter Electronics

Items Range Accuracy Repetition Rate Laser Wave length Output Power Pulse Width TX Beam Width RX FOV RX Optics Weight Power Size

Specification 50m50km ±1m(@50m) 1Hz Q-SW, Nd:Cr:YAG 1064 nm 8 mJ 14 nsec 1.7 mrad1/e2 1 mrad Casegren 126 mmSiC 3.7kg Include: DC/DC, Radiator 17.0W (+LD Heater max5W) 240mm×228mm×250mm × × Radiator: 240mm×300mm ×

PreAmplifier

APD Pre-Amplifier

Diode Pumped Nd:YAG Laser Laser Beam Transmitting Optics Transmitting Optics Power Supply Hayabusa's LIDAR image

Laser Transmitter

Resolution 1m

Ranging result in touchdown sequence

Nov. 19 2005

Background ~ required dynamic range ~

· Dynamic range : more than 60 dB - In the case of a non-cooperative target, a receiving circuit is required a large dynamic range. If the required coverage is 50 km ~ 50 m, the received electrical charges is 0.002 pC ~ 2000 pC. - In addition to a large total dynamic range, every gain stage also needs to have about 10 dB dynamic range. Because, the receiving power of every shot will vary widely due to the fluctuations of a back scattering factor and irradiated spots.

Pt (Transmitting signal power) : 5 mJ D (Diameter of receiving-antenna) : 100 mm (System efficiency) : 70 % (Reflectance of a target) : 5 % YAG laser wave length : 1.064 um Transmitting pulse width : 10 ns The multiplication of APD : 100 The efficiency of APD : 40 %

Pr = Pt

D 2

32R

2

Contents

1. Background (Experience of Hayabusa) 2. Purpose of device development 3. Device outline 4. Results of evaluation 5. Summary

Purpose of device development

discrete parts

Receiver Optics

Primary Optics Primary Optics (Receiving Optics) (Receiving Optics) Band pass Filter APD

Detector and Digital Controller

Gain Control Receiver Electronics AOCU RS422 Digital Counter CLK: 75MHz Digital Controller Transmitter Electronics

SO C

System On Chip

PreAmplifier

APD Pre-Amplifier

Diode Pumped Nd:YAG Laser Laser Beam Transmitting Optics Transmitting Optics Power Supply

Laser Transmitter

Resolution 1m

· Reduction of circuit area · Reduction of size and weight · Reduction of development period · Reduction of digital clock frequency => Lower power consumption

Contents

1. Background (Experience of Hayabusa) 2. Purpose of device development 3. Device outline 4. Results of evaluation 5. Summary

Specifications

Main function of LIDARX03 · Gain adjustment ( for 60dB dynamic range ) · Timing detection ( for counter trigger ) · TAC ( for Low digital frequency ) Features of LIDARX03

Dynamic range Gain control Range resolution / time resolution Quality 0.002pC ~ 2000 p C (60dB) Digital ~ 10 cm / ~ nanoseconds SPACE CLASS2 (2012)

Process and package

Process Bare chip size Package CMOS 0.35m TSMC 3 mm x 3 mm Ceramic QFP (80 pins) 14 mm x 14 mm

Circuit structure

Integrator Divider

· Divider (coarse gain ADJ)

- Selects integrator channnels or - Split the electrical charges by capacitor - Coarse adjustment of gain.

· Integrator (fine gain ADJ)

- Adjusts its gain by means of changing feedback capacity. - The gain can be controlled by 4 bit-command. - Fine gain adjustment - Create a symmetry wave (leading wave).

leading wave

leading wave

Hit Pulse (Detection · TAC

Timing detector differential wave TAC

timing)

- Generates analog level for interpolation

· Timing detector

- Creates bipolar wave by differential circuit. - Detect zero cross timing of a differential wave - Sends a HIT Pulse as a timing of signal detection.

Contents

1. Background (Experience of Hayabusa) 2. Purpose of device development 3. Device outline 4. Evaluation results 5. Summary

Results ~ Typical output waveforms ~

Differential 100mV/div

250ns/div

zero cross point

HIT 2V/div

64ns

TAC slope 4mV/ns

TAC2 200mV/div

64ns

V2 V1

TAC1 200mV/div

Input charge dependence of HIT timing

Delay time from trigger

LONG MIDDLE SHORT

Divider (Coarse ADJ)

Integrator (Fine ADJ)

Flat area

60dB

Input charge dependence of signal level

Flat area

Input charge dependence of timing dispersion (1)

1ns 300ps

Temperature dependence of detection timing

CH1 0000 (others more or less similar)

Temp. monitor -1.63mV/deg C VEB (bipoler transistor)

+50 degC

-25 degC

Contents

1. Background (Experience of Hayabusa) 2. Purpose of device development 3. Device outline 4. Results of evaluation 5. Summary

Summary

The background, outline, evaluation results of this prototype IC (LIDARX03) are reported.

All main functions of LIDARX03 are confirmed. · Gain adjustment ( fine and coarse adjustment ) · Wide dynamic range ( about 60dB ) · Timing detection ( zero-cross timing detection ) · TAC (Time to Analogue Converter) circuit Environmental test has been done. · TID 60krad by nomal wafer (30krad/h) · Temperature range -25+50

Information

Microsoft PowerPoint - 05-14-04-Mizuno.ppt

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