Solid-state Meteorological Radars in the C and X Bands

Transcription

1 Solid-state Meteorological Radars in the C and X Bands Dr. Masakazu Wada Toshiba Infrastructure Systems & Solution Corporation Japan 2017 Toshiba Corporation

2 Two Problems in interference between Weather radar and Wireless telecommunication technologies Incompatibility among each country s DFS standards Unmatched DFS standard for New-type weather radar 2017 Toshiba Corporation 1

3 Each country s DFS Technical Standard We can illegally use the wireless communication equipment in any countries, but the technical standard of each country is different. Europe (ETSI) US (FCC) Minimum Plus Percentage Minimum Radar PRI Number of Width of Number of Type [usec] Different PRFs [us] Successful Trials Detection See Note1 See Note1 1 Test A: 15 unique PRI values randomly selected from the list of 23 PRI values in Table 5a Test B: 15 unique PRI values randomly selected within the range of sec, with a minimum increment of 1 PRI values selected in Test A 60% % % % 30 Aggregate (Radar Types 1-4) 80% 120 Note 1: Short Pulse Radar Type 0 should be used for the detection bandwidth test, channel move time, and channel closing time tests. - Inefficiency for RLAN manufacturers - Risk for radar users Radar Type Plus Width [us] PRI [us] Number of Different PRFs Radar Type PPB (Pulse Per Burst) D Signal # Signal # Signal # Signal # Signal # /3 10 Signal # /3 15 Japan (MIC) Plus Width [us] PRI [us] Number of Different PRFs PPB (Pulse Per Burst) Type Type Unified standards 2017 Toshiba Corporation 2

4 Two Problems in interference between Weather radar and Wireless telecommunication technologies Incompatibility among each country s DFS standards Unmatched DFS standard for New-type weather radar 2017 Toshiba Corporation 3

5 Key technological development Types of Radars Evolution of Weather Radar Qualitative Estimates of Rainfall Quantitative Estimates of Rainfall Multi Parameter Radar Observation High-speed Observation Multi-point Joint Observation Primitive Radar (Analog Radar) Detection of presence or absence of rain Raingauge Radar Detection of amount of rainfall Doppler Radar Detection of wind Speed Dual Polarization Doppler Radar Electrically Steered Phased Array Antenna Dual Polarization Radar Hydrological classification (Rain, Snow, Hail) High-precision detection High speed observation of localized heavy rainfall, tornado Magnetron Analog Video Processing Digital Video Processing Klystron Digital I/Q Narrowband Filter Digital IF Solid-State Pulse Compression Digital Waveform Shaping Dual-Pol Phased Array Single-Pol Phased Array Digital RF Frequency Sharing 2017 Toshiba Corporation 4

6 SSWR(Solid-State Weather Radar) Transmitters Receiver, Signal Processor, Monitor & Control, Power Distributor (from left to right) Antenna (4.2mφ) Power Amp Unit (PA) GaN HEMT Already commercialized S-, C-, and X-band Solid-State Weather Radar 2017 Toshiba Corporation 5

7 Advantages of SSWR Accurate Observations Low Life-Cycle Costs Operational Continuity High quality dual polarization data No need for the replacement of highcost Klystron Power Amp. Unit can be made redundant Modules can be exchanged without suspending the system Downsizing Efficient Frequency Utilization Reduction of the size by a factor of half compared with a Klystron transmitter Less radio wave interference to the other systems Conform to ITU standards Power Amp Unit (PA) 2017 Toshiba Corporation 6

8 Accurate Observation Rain gauge vs Radar, NILIM (X-Band) Comparison between X-Band SSWR and rain gauges, 0 to 60km, 60min, MLIT, 2011 SSWR has high accuracy Toshiba Corporation 7

9 Operational Continuity Failure per radar = Num of total failure / *Num of radar Tx failure rate = Num of transmitter(tx) failure / Num of total failure Tx failure rate is lower for solid-state radar Year Mag/KLY SS years total Num of Radar Num of Total Failure Num of Tx Failure Failure per Radar [times] Tx Failure Rate [%] Num of Radar Num of Total Failure Num of Tx Failure Failure per Radar [times] Tx Failure Rate [%] * Num of radar : number of radar which is target of maintenance. Not all radar systems Toshiba delivered are counted. The number of SSWRs failure is less than MAG/KLY Radars Toshiba Corporation 8

10 Efficient Frequency Utilization The Spurious level of SSWRs is lower than MAG/KLY Radars. Reduction of vicinity spurious of transmission signal by the Solid-State radar The solid-state transmitter facilitates waveform shaping of transmission pulse by the use of semiconductors and enables reduction of vicinity spurious of transmission signals, allowing efficient utilization of frequency. Transmission spectrum (example) 60dB ITU-R Mask 5MHz Achieved 60dB suppression by 5MHz detuning Efficient Frequency Utilization is progressing Toshiba Corporation 9

11 Minimization of Channel Separation Width of Frequency Channel Assignment 1950 s ~ Magnetron 1990 s ~ Klystron 2000 s ~ Solid - state Magnetron Klystron Solid - state Channel Separation 20 MHz 10 MHz 5 MHz ITU-R standard Non-compliant Compliant Compliant 2017 Toshiba Corporation 10

12 Progress of Efficient Utilization of Frequency Efficient Utilization of Frequency (C-Band/5GHz) Reduce the bandwidth by one half while keeping the same number of channels (100MHz width 45MHz width) Reduce interference to the wireless LAN of the shared system and expand utilization 5250 MHz 100MHz MHz width Empty bandwidth can use for RLAN MHz 5250 MHz 45MHz MHz width MHz By adopting SSWR, the usable bandwidth of RLAN will become wider Toshiba Corporation 11

13 Receiving power from Radar transmitting power by Wireless LAN(dBm) Threshold of DFS SSWRs have lower peak power and longer pulse width than MAG/KLY radars dB B -62dBm (DFS Threshold in Technical Standard) kW (SSWR) 250kW (Electron Tube Radar) DFS threshold level should be lowered. Transmitting power (W) 2017 Toshiba Corporation 12

14 PAWR(Phased-Array Weather Radar) Active Phased Array Antenna Radar Processor Radar Controller Toshiba succeeded in development of X-Band Single-pol PAWR Toshiba Corporation 13

15 Scanning Strategy 2017 Toshiba Corporation 14

16 Observed Data (time interval 30sec, 300 times speed) PAWR can 3D observation by only itself Toshiba Corporation 15

17 Key technological development Generation of Wireless Communication Development of wireless communication and weather radar G Ex-OFDMA, NOMA, Massive MIMO 4G OFDMA (Orthogonal Frequency-Divisio Multiple Access), MIMO 2G TDMA (Time-Division Multiple Access) 1G FDMA (Frequency-Division Multiple Access ) 3G CDMA (Code-Division Multiple Access ) Electrically Steered Phased-Array Radar Active Phased-Array Antenna Dual-Polarization Doppler Radar Solid-state, Digital IF, Pulse compression Doppler Radar Dual-Polarization Radar Klystron, Digital I/Q Rain gauge Radar Magnetron, Digital Video Processing Weather radar technology is progressing as same as developing wireless communication technology Toshiba Corporation 16

18 Two Problems in interference between Weather radar and Wireless communication technologies Incompatibility among each country s DFS standards It should be described the same rule of DFS in ITU-R standards. Unmatched DFS standard for New-type weather radar DFS threshold level should be lowered. DFS standard should be reviewed regularly (every 4 years). Improving Efficiently Frequency Utilization of Weather radar increasing the Band for RLAN 2017 Toshiba Corporation 17

19 2017 Toshiba Corporation