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Вырез съемки RCD100

Аэросъемочные новости Leica Geosystems

X. Юбилейная международная научно-техническая конференция:

«От снимка к карте: цифровые фотограмметрические технологии»

Гаета 2010, Петер Шрайбер

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Permanent And Consequent Development of Leica Geosystems‘ Airborne Sensors

1. General developments

2. News to Airborne Digital Sensor, ADS80

3. News to Airborne Lidar System, ALS60

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1. General development: Leica IPAS Freebird

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IPAS Freebird – cut corners, not quality User benefits in airborne mission

Improves flight economy for sensor missions up to 25%

Allow sharper turns between the flight lines – does not require continuous lock of satellites

Deeply coupled GNSS-IMU technology saves time several minutes per turn

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GNSS-IMU processingThe basis for accurate image georeferencing

GrafNav

GNSS trajectory processing

Continuous lock of 5 or more satellites is

required

IPAS Pro

GNSS-IMU blending

IPAS TC

Tightly Coupled GNSS-IMU processing

using GNSS raw measurements

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IPAS Freebird – cut corners, not quality User benefits – data processing

Does not require the separate step of GNSS trajectory processing

GNSS-IMU post processing is simplified and faster

Precise Point Positioning – solutions without GNSS base station data

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2. News to ADS80 Airborne Digital Sensor

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Leica ADS80CCD layout in SH81 and SH82 focal plate

SH81 SH82

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Leica ADS80 Staggered Line Processing24000 Pixel Across Swath in Nadir

PAV80

ADS80

Productivity Increase of up to 100%

Effective 24000 pixels across track

Remember: UCX Pan/MS ratio 1:3

DMC Pan/MS ratio 1:4

ADS Pan/MS ratio 1:2

User Benefit:

• Fly twice as high with same GSD and image quality

• Huge productivity increase for orthophoto production

• Best pansharpening ratio on the market

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Application of staggered CCD line

High resolution resampling of

overlapping pixels

Final Image pixel raster

on ground

Sta

gg

ered

CC

D l

ine

GSD

1/2

GSD

Area of 1/2 GSD

For high panchromatic resolution with the ADS40 the area of 1/2 GSD is computed from 4 different recordings. That is, each recording takes place at 2 locations in each staggered CCD.To achieve this: The readout rate is at 1/2 GSD in flight direction

1/2 GSD offset across track is obtained with staggered CCD

CCD 1 1 2 2Recording 1 2 3 4

Location 1 2 1 2

CCD 2 1

Pixel

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ADS80 – Driving Productivity in Imaging24000 Pixel HighRes Mode!

1000m AGL, 10cm GSD 2000m AGL, 10cm GSD

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ADS80 - Driving Productivity in ImagingStandard and HighRes Mode brings Flexibility

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Example of staggered CCD line (2)

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MM40 Embedded IPAS20 with GNSS High data throughput of 130 MB/sec Radiometric resolution of

compressed data 10-bit and 12-bit, Recording interval ≥ 1 ms Data modes: ADS80 data format,

raw data, compressed

Leica ADS80 – Consistent Technical PerformanceControl Unit CU80 and MM80

Highly reliable flash disk technology

960 GB capacity per MM80 pair

Weight 2.5 kg

3. News to ALS60 Airborne Lidar System

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Typical LIDAR technology implementation

Develop lat/lon/el of points on ground based on:

Aircraft position (lat/lon/el)

Aircraft orientation (roll/pitch/heading)

Scan angle

Round-trip propagation time of laser pulse

Atmospherics

Raw data recorded in air (system) and on ground (DGPS base station)

Recorded data post-processed on ground

Waveform analysis concerns attributes of the range measurement

Time or distance

Intensity

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Footprint

Return waveform is generated by all reflective

surfaces within the

laser footprint

LIDAR waveformhow is it created?

Multiple return pulses are generated as the laser pulse hits various levels in the forest canopy, creating in total a complete return waveform

Waveform measurement is a natural extension of the conventional “discrete-return + intensity” measurement process

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Laser

Footp

rin

t

Start Pulse

Detector Signal

T1 ,

I 1 Tn

,

I n

Full Waveform Digitization (FWD) basic concept

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What is Full Waveform Digitization?capturing the complete return, not just the peaks

Conventional discrete return electronics capture only the exact time of the peaks of independently-recognized return pulses

Peak intensity is also measured

In FWD systems, the entire return signal is measured, allowing capture of subtle deviations in the shape of the reflected as compared to the shape of the outbound laser pulse

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Some points about FWD

Intensities must be digitized at <2 ns intervals to minimize aliasing, though 1 ns more common

1 ns in time represents 0.15 m in range (i.e., elevation)

Signal amplitude at each interval typically digitized at 8-bit resolution (i.e., one byte)

Therefore, 256 additional bytes of waveform data needed to digitize the return waveform from a 38.4 meter-tall object @ 1 ns intervals

Range data is still be measured independently to achieve typical 1.5 cm (i.e., 100 ps) range resolution

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Operating envelopemax waveform rate versus slant range

At pulse rates below 120 kHz, waveforms captured at laser pulse rate

At pulse rates above 120 kHz, waveforms capture for every other pulse, up to 200 kHz (150 kHz for ALS50-II)

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Thank You!

Спасибо!