# Presentation: 329905

## DPR Development Update

**Kinji Furukawa **
** **
**JAXA, GPM/DPR Project Team**
**4th International GPM Planning Meeting**
***15-17 June 2004; ***
***Marriott Hotel, Greenbelt, Maryland, USA***

***DPR Development Update***

## Objectives of DPR

- Three-dimensional observation of precipitation
- High sensitivity measurement for light rainfall and snowfall in high latitude, taking advantage of KaPR
- Accurate measurement using DSD (Drop Size Distribution) parameter derived from differential attenuation information observed by KuPR and KaPR
- Improvement of MWR’s precipitation estimation accuracy using the precipitation parameters (DSD, melting level, rain type, storm height, etc.)  observed by DPR

## Concept of precipitation measurement by the GPM core satellite

**Ku-band (14GHz) radar : ****KuPR**
**and **
**Ka-band (35GHz) radar : ****KaPR**

_***Concept of precipitation measurement by the GPM core satellite***_

- Flight direction

- Range resolution
- = 250m and 500m

- KuPR (13.6 GHz)
- swath width=245 km

- KaPR (35.5 GHz)
- swath width=120 km

- DPR

- GMI

- Microwave radiometer
- swath width =800km

- 5km

**407 km altitude, ****65 deg inclination**

## Topics of DPR Design Update Update from 25 June 2003 3rd GPM Workshop@ESTEC

- Beam Matching feasibility
- VPRF feasibility
- SCDP shearing
- Resource allocation
- Mechanical design
- Thermal design

## Concept of the DPR antenna scanning method

**KuPR: 245 km (49 beams)**

**KaPR: 120 km (24+25 beams)**

- In the interlacing scan area (  ), the KaPR can measure snow and light rain in a high-sensitivity mode with a double pulse width.

**1**

**49**

**1**

**13**

**12**

**37**

**38**

**49**

## Beam Matching feasibility

- After adjustment of CT and AT offset in the orbit, estimated
- error of Beam Matching is smaller than 1km spec.

## Min. Detect Rainfall Rate and VPRF 

**Min. Detect Rainfall Rate spec.**
**  ****KuPR:<0.5mm/h, KaPR:<0.2mm/h**

**Improvement ****of ****Tx Peak Power and RX NF are limited. Increasing of **
**independent sampling number is needed to satisfy the spec. **

**To increase the independent sampling number, high PRF is needed.  **
**Fixed PRF like TRMM PR can not satisfy the demand.**

**DPR adopts the VPRF technique to satisfy the Min. Detect Rain Rate **
**spec.**

## Practical Concept of VPRF 

|  | SCAN ANGLE [deg] and PRF [Hz] |  |  |  |
| --- | --- | --- | --- | --- |
| S/C Altitude | 0.0-8.52 | 8.52-12.07 | 12.07-14.91 | 14.91-17.04 |
| 396.0 | 4155.2 | 4104.1 | 4051.7 | 3998.6 |
| 396.5 | 4149.9 | 4098.9 | 4046.6 | 3993.5 |
| 397.0 | 4144.7 | 4093.8 | 4041.5 | 3988.5 |
|     :
    : |  |  |  |  |
| 419.5 | 3922.4 | 3874.2 | 3824.7 | 3774.6 |
| 420.0 | 3917.7 | 3869.6 | 3820.2 | 3770.1 |

**Example of VPRF table**

**The S/C Altitude (from earth reference ellipsoid: WGS84) calculated using GPS data will be obtained.**

**Input data**

**The VPRF table is written in ****a rewritable memory in SCDP.  An interval and a range of S/C altitude in the table is TBD.  Scan angle classification is also TBD.  Actual table will include start range bin and sampling number.**

## VPRF feasibility  

- PRF can be selected for all satellite altitudes and scan angles to
- satisfy the Min detect rain rate (KaPR:0.2mm/h).

- Satellite altitude (km)

- Scan angle (deg)

## Main Characteristics of DPR (Resource allocation)

| Item | KuPR | KaPR | TRMM PR |
| --- | --- | --- | --- |
| Antenna Type | Active Phased Array (128) | Active Phased Array (128) | Active Phased Array (128) |
| Frequency | 13.597 & 13.603 GHz | 35.547 & 35.553 GHz | 13.796 & 13.802 GHz |
| Swath Width | 245 km | 120 km | 215 km |
| Horizontal Reso | 5 km (at nadir) | 5 km (at nadir) | 4.3 km |
| Tx Pulse Width | 1.6 s (x2) | 1.6/3.2 s (x2) | 1.6 s (x2) |
| Range Reso | 250 m (1.67 s) | 250 m/500 m (1.67/3.34 s) | 250m |
| Observation Range | 18 km to -5 km (mirror image around nadir) | 18 km to -3 km (mirror image around nadir) | 15km to -5km (mirror image at nadir) |
| PRF | VPRF (4000 Hz250 Hz) | VPRF (4500 Hz250 Hz) | Fixed PRF (2776Hz) |
| Tx Peak Power | > 1000 W | > 140 W | > 500 W |
| Min Detect Ze
 (Rainfall Rate) | < 18 dBZ
( < 0.5 mm/hr ) | < 12 dBZ (at 500m reso)
( < 0.2 mm/hr ) | < 23 dBZ
( < 0.7 mm/hr ) |
| Measure Accuracy | within ±1 dB | within ±1 dB | within ±1 dB |
| Data Rate | < 112 Kbps | < 78 Kbps | < 93.5 Kbps |
| Weight | < 365.5 kg | < 299.5 kg | < 465 kg |
| Power Consumption | < 380 W | < 300 W | < 250 W |
| Size | 2.4×2.4×0.6 m | 1.44 ×1.07×0.7 m | 2.2×2.2×0.6 m |

*** Minimum detectable rainfall rate is defined by Ze=200 R****1.6**** (TRMM/PR: Ze=372.4 R****1.54 ****)**

## SCDP shearing

- SCDP A controls both KuPR and KaPR and processes data from
- them in normal operation.

## KuPR system block diagram

- Waveguide slot antenna

- 001

- 001

- 01

- Frequency Converter and Intermediate Frequency**(FCIF)**

- System Control    and Data Processing
**(SCDP)**

- TLM/CMD(1553B)

**Structure**

**Thermal control**

**Harness**

**TX/RX subsystem**

**Signal Processing subsystem**

**ANT subsystem**

- HYB

**Spacecraft Bus power system**

- SW

- CPS

- CPS

- T/R module

- T/R  UNIT

- DIV/COMB 2

- LNA

- PHS

- SSPA

- SW

- SW

- 008

- T/R module

- SSPA

- SW

- LNA

- SW

- PHS

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- Waveguide slot antenna

- 008

- SCDP ASCDP B

- DC

- (CMD)

- Waveguide slot antenna

- 121

- 121

- T/R module

- T/R  UNIT

- LNA

- PHS

- SSPA

- SW

- SW

- 128

- T/R module

- SSPA

- SW

- LNA

- SW

- PHS

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- Waveguide slot antenna

- 128

- SCDP ASCDP B

- DC

- (CMD)

- 01

- 16

- 16

- DIV/COMB 1

- DIV/COMB 2

- SSPA

- SSPA

- BPF

- SW  LNA

- BPF

- SW  LNA

- HYB

- TDA            A

- RDA           A

- TDA            B

- RDA           B

- A

- B

- +6V+4V
- +7V-8V
- +14V

- +6V+4V
- +7V-8V
- +14V

- SCDP A
- SCDP B
- (TLM/CMD)

- SCDP A
- SCDP B
- (TLM/CMD)

- TDA A
- TDA B

- RDA A
- RDA B
- (DC)

- TRU 01
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- TRU 16

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- DC/DC CONV

- A

- DC/DC CONV

- A

- TLM/CMD(1553B)

- System Control    and Data Processing
**(SCDP)**

- DC/DC CONV

- B

- Frequency Converter and Intermediate Frequency**(FCIF)**

- DC/DC CONV

- B

**KaPR SP subsystem**

- FCIF A
- FCIF B

- SCDP A

- +29V

- +29V

- +29V

- +29V

- TLM/CMD(1553B)

- TLM/CMD(1553B)

## KaPR system block diagram

- Waveguide slot antenna

- 001

- 001

- 01

- Frequency Converter and Intermediate Frequency**(FCIF)**

- System Control    and Data Processing
**(SCDP)**

- TLM/CMD(1553B)

**Structure**

**Thermal control**

**Harness**

**TX/RX subsystem**

**Signal Processing subsystem**

**ANT subsystem**

**Spacecraft Bus power system**

- SW

- CPS

- CPS

- T/R module

- T/R  UNIT

- LNA

- PHS

- SSPA

- SW

- 008

- T/R module

- SSPA

- SW

- LNA

- PHS

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- Waveguide slot antenna

- 008

- SCDP ASCDP B

- DC

- (CMD)

- Waveguide slot antenna

- 121

- 121

- T/R module

- T/R  UNIT

- LNA

- PHS

- SSPA

- SW

- 128

- T/R module

- SSPA

- SW

- LNA

- PHS

**:**
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- Waveguide slot antenna

- 128

- SCDP ASCDP B

- DC

- (CMD)

- 01

- 16

- 16

- SSPA

- SSPA

- BPF

- SW  LNA

- BPF

- SW  LNA

- HYB

- TDA            A

- RDA           A

- TDA            B

- RDA           B

- A

- B

- +6V+4V
- +7V-8V
- +14V

- +6V+4V
- +7V-8V
- +14V

- SCDP A
- SCDP B
- (TLM/CMD)

- SCDP A
- SCDP B
- (TLM/CMD)

- TDA A
- TDA B

- RDA A
- RDA B
- (DC)

- TRU 01
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- :
- TRU 16

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- DC/DC CONV

- A

- DC/DC CONV

- B

- TLM/CMD(1553B)

- System Control    and Data Processing
**(SCDP)**

- DC/DC CONV

- A

- Frequency Converter and Intermediate Frequency**(FCIF)**

- DC/DC CONV

- B

**KuPR SP subsystem**

- FCIF A
- FCIF B

- SCDP B

- +29V

- +29V

- +29V

- +29V

- TLM/CMD(1553B)

- TLM/CMD(1553B)

- HYB

- HYB

- 8 DIV/COMB

- 17

- 18

- 8 DIV/COMB

- 8 DIV/COMB

- 8 DIV/COMB

## Mechanical Design Update

- KuPR

- KaPR

- Mechanical layout and main structures specifications have been decided.
- The result of preliminary structural (Eigenvalue) analysis shows that
-    the 1st mode of natural frequency of KuPR and KaPR are over 30Hz.

## Thermal Design Update

**Both KuPR and KaPR have almost ****13 deg.C of temperature margins**** in the operation mode.**
**There is ****no need to add KaPR extra radiation panel**** as the result of preliminary thermal analysis.**

_***Thermal Design Update***_

**KuPR**

**KaPR**

## Design of KuPR T/R unit BBM

**T/R Module ****(X****2****) (****other 6 modules are thermal dummy****)**

- No Redundant
- Control Circuit

- (TX)

- (RX)

- Power    Phase data

- Main
- Control Circuit

- Control
- ON/OFF
- Power

_***Purpose of KuPR T/R unit BBM***_
- ・Verification of KuPR T/R unit design
-  (except for mechanical design).
- ・To establish test, evaluation and
-   manufacture procedure of T/R unit.

## Development of key devices in KuPR T/R module 

_***MMIC development***_
- MMIC designs of PHS, DPDT switch, MPA and LIM amplifier were completed.
- All MMIC masks were manufactured.
_***Power FET development***_
- Three types of Power FET were manufactured for trial, and the target performance were attained mostly.
- The highest power type FET is used for BBM.

## KaPR BBM & EM status update (NICT)

_***BBM development***_
- System design of the T/R system:completed
- Construction of the BBM of the T/R unit:completed
_***EM development***_
- Design of 32-element EM is underway.

## KaPR TR Unit Breadboard Model (BBM)

**KaPR is a radar with an active phased-array antenna with 128 elements.**

- The T/R part consists of 16 T/R units, and each T/R unit consists of 8 T/R modules. We adopt this design to realize a system that is small, light-weight, low power consumption, easy construction and high reliability.

- KaPR TR Unit BBM outlook

**SSPA**

**LNA**

**PHS**

**310mm**

**195mm**

**135mm**

**Approximately ****3.4kg**

- Inside view of the BBM of KaPR TR Unit

| SSPA | Frequency | 35.5-35.6GHz |
| --- | --- | --- |
|  | Peak Tx Power | 32.49 dBm |
|  | Pulse Width | 1.67s, 3.34s |
| LNA | Noise Figure | 5.80 dB |
|  | Gain | 26.64 dB |
| PHS | Number of bits | 5 bits |

## KaPR EM (32-element model)

## Summary

- Conceptual design work of DPR was completed by JAXA.
- KuPR (JAXA)
-   ・ Key devices in the T/R module were developed.
-   ・ Design of T/R unit BBM was completed and the
-    fabrication/test contract is starting.
- KaPR (NICT)
-   ・ Construction of T/R unit BBM was completed.
-   ・ EM design is in progress.