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Slide Text Space SUBMIT ALL submit all SUBMIT submit Submit Unmute volume principles of meteorological doppler radar range unfolding instructor: andy wood review lesson take your time and review the lesson content provided in this presentation. review lesson technical problems? if you encounter any technical problems with this lesson, please contact the rac team directly by e-mail at: nws.wdtd.rachelp@noaa.gov technical problems? complete the quiz at the end of this lesson, there is an embedded quiz. complete this quiz by selecting the best answer for each question. you need to correctly answer 70% of the quiz questions to receive completion credit in the lms. complete the quiz course completion review lesson review lesson complete the quiz technical problems? technical problems? introduction in order for nws forecasters to receive credit for this course in the nws learning center, you will need to take the following steps rac principles roadmap objective identify the purpose, strengths and limitations of the following range unfolding algorithms: legacy range unfolding sz-2 range unfolding rf on velocity & spectrum width cd rmax range folding rarely on reflectivity no rf assigned to z products (purple means very high dbz!) multiple tripping rare on z products: cs scan uses low prfs rmax typically ~250 nm legacy range unfolding algorithm in action since wsr-88d original deployment assigns v & sw to proper range may be beyond cd rmax run at rda signal processor for several vcps: vcps 12, 31, & 32 the legacy unfolding algorithm two examples provided: without echo overlay with echo overlay use “in slide animations” (replay as needed) manually advance slides no echo overlay example – step 1 rda 20 nm 90 nm 250 nm rmax a b cs mode no echo overlay example – step 2 rda 20 nm 90 nm a b cs mode 60 nm rmax 30 nm computing apparent range b no echo overlay example – step 3 rda 20 nm 80 nm cs mode 60 nm rmax a b computing possible ranges 80 nm a b 120 nm 140 nm a b 180 nm 200 nm a b no echo overlay example – step 4 rda 20 nm 90 nm a b 60 nm rmax cd mode no echo overlay example – step 5 rda 20 30 60 nm rmax cd mode rda 20 90 cs mode 250 nm rmax a b was there something at this range? yes! comparing cd and cs data a b no echo overlay example – step 6 rda 20 30 60 nm rmax cd mode rda 20 90 cs mode 250 nm rmax a b how about this range? no! comparing cd and cs data a b no echo overlay example – step 7 rda 20 30 60 nm rmax cd mode rda 20 90 cs mode 250 nm rmax a b how about possible ranges? yes! comparing cd and cs data a b b assigning final ranges for velocity and spectrum width this radial has beenrange unfolded! echo overlay example – step 1 rda 20 nm 90 nm 250 nm rmax a b cs mode echo overlay example – step 2 rda 20 nm 90 nm a b cs mode 70 nm rmax 20 nm computing apparent range a/b uh oh! overlay! echo overlay example – step 3 rda 20 nm 90 nm cs mode 70 nm rmax a/b computing possible ranges 90 nm a/b 140 nm 160 nm a/b 210 nm 230 nm a/b echo overlay example – step 4 rda power low power high a b power known 70 nm rmax db = 10 log phigh plow tover (5db) exceeded? yes! echo “b”: assigned v & sw echo “a”: assigned rf echo overlay example – step 5 rda 20 nm 90 nm a a/b 70 nm rmax cd mode echo overlay example – step 6 rda 20 nm 90 nm a/b 70 nm rmax cd mode rda 20 nm 90 nm cs mode 250 nm rmax a b did this echo have the higher power? no comparing cd and cs data echo overlay example – step 7 rda 20 nm 90 nm a/b 70 nm rmax cd mode rda 20 nm 90 nm cs mode 250 nm rmax a b how about this possible range? yes! comparing cd and cs data echo overlay example – step 8 rda 20 nm 90 nm a/b rf 70 nm rmax cd mode rda 20 nm 90 nm cs mode 250 nm rmax a b assigning final ranges for velocity and spectrum width this radial has been range unfolded! more on when echoes are overlaid a and b will have same apparent range: pulses returning from both targets at same time is base data representative of either target? tover met? range unfolding algorithm: echoes are overlaid if power ratio exceeds tover (5 db) v & sw assigned to echo with higher power other echo assigned rf if power ratio does not exceed tover both echoes assigned rf tover met? distribution of range folded data cd rmax legacy algorithm - strengths places v & sw at proper range extends beyond first trip (cd rmax) echoes overlaid and tover exceeded: one assigned v and sw other assigned rf mitigates “doppler dilemma” low prf for target range and intensity high prf for velocity and spectrum width legacy algorithm: limitations extensive echo coverage with echoes extended along radials (echo overlay maximized) v & sw unavailable for overlaid echoes if power ratio does not exceed tover sz-2 range unfolding algorithm run at rda signal processor only applies to split cut elevations on vcps 35, 212, & 215 legacy algorithm vs. sz-2 legacy range unfolding recovers velocity from one of the echoes sz-2 usually recovers velocity from both echoes legacy range unfolding sz-2 range unfolding sz-2 algorithm strengths sz-2 strengths significant increase in availability of velocity data best results with widespread returns sz-2 algorithm limitations all bins degrades sz-2 velocity procedures in place to address problem: cmd enabled: default clutter file used with sz-2 vcp cmd disabled: cmd enabled & default clutter file used with sz-2 vcp conclusion: range unfolding range unfolding necessary for cd data: velocity spectrum width two algorithms available (run at rda signal processor): legacy range unfolding algorithm sachidananda-zrnic (sz-2) range unfolding algorithm range unfolding algorithm usage depends on vcp employed: legacy: 12, 31, 32 sz-2: 35, 212, 215 sz-2 algorithm allows for recovery of more cd data, but all bins clutter suppression negatively impacts when in use incorrect incorrect: the tover setting cannot be edited at the radar product generator continue continue continue continue continue continue incorrect incorrect: the legacy range unfolding algorithm can only assign velocity and spectrum width for one of the overlaid echoes continue continue continue continue continue continue correct correct. continue continue continue continue continue continue incorrect incorrect: a low prf will not provide the best quality velocity data continue continue continue continue continue continue question #1 of 3 the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. the wsr-88d can use a low pulse repetition frequency (prf) for velocity data and a high prf for reflectivity data. one strength of the legacy range unfolding algorithm is that: velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width can often be displayed beyond the unambiguous range (cd rmax). velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. velocity and spectrum width are displayed for both overlaid echoes provided the power difference is > tover. tover can be edited at the radar product generator to meet varying meteorological conditions. tover can be edited at the radar product generator to meet varying meteorological conditions. tover can be edited at the radar product generator to meet varying meteorological conditions. tover can be edited at the radar product generator to meet varying meteorological conditions. tover can be edited at the radar product generator to meet varying meteorological conditions. tover can be edited at the radar product generator to meet varying meteorological conditions. incorrect correct. continue continue continue continue continue continue incorrect incorrect: sz-2 vcps are designed for widespread precipitation continue continue continue continue continue continue incorrect incorrect: doppler prfs are not editable since sz-2 requires a fixed number of pulses per radial continue continue continue continue continue continue incorrect incorrect: all bins applied to an sz-2 vcp can result in noisy velocity data continue continue continue continue continue continue question #2 of 3 the sachidananda-zrnic-2 (sz-2) volume control patterns (vcps): perform best with all bins clutter filtering applied. perform best with all bins clutter filtering applied. perform best with all bins clutter filtering applied. perform best with all bins clutter filtering applied. perform best with all bins clutter filtering applied. perform best with all bins clutter filtering applied. allow operators to edit the doppler prf. allow operators to edit the doppler prf. allow operators to edit the doppler prf. allow operators to edit the doppler prf. allow operators to edit the doppler prf. allow operators to edit the doppler prf. provide the best results with clear air. provide the best results with clear air. provide the best results with clear air. provide the best results with clear air. provide the best results with clear air. provide the best results with clear air. provide a significant increase in available velocity data. provide a significant increase in available velocity data. provide a significant increase in available velocity data. provide a significant increase in available velocity data. provide a significant increase in available velocity data. provide a significant increase in available velocity data. incorrect you did not select the correct response. continue continue continue continue continue continue correct that's right! you selected the correct response. continue continue continue continue continue continue false false false false false false true true true true true true question #3 of 3 for most overlaid echo cases, the legacy range unfolding algorithm can recover velocity for one of the overlaid echoes, while the sachdananda-zrnic-2 (sz-2) range unfolding algorithm can recover velocity for both overlaid echoes. roadmap <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Welcome to this lesson on the Principles of Meteorological Doppler Radar. This lesson will discuss range unfolding of precipitation echoes."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style /> <Span Text=" Here is a roadmap for the RAC Principles topic. This lesson, which is part of the Radar Fundamentals section, is highlighted. Once you have had a chance to look over the roadmap, advance to the next slide."> <Style FontFamily="+minor" FontSize="11" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" There is one objective for this lesson. Please read it over and advance to the next slide when you are ready. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Recall from our discussions of the Doppler dilemma that high PRFs are needed to allow for high Nyquist velocities, but also result in short maximum unambiguous ranges (or R"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> <Span Text="max"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Subscript" /> </Span> <Span Text="). When precipitation echoes are detected past the first “trip”, it is necessary to unfold the data to its appropriate range.&#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Through the next several slides, we will explain how the data are unfolded and the purple “RF” data areas are assigned on the Radial Velocity and Spectrum Width products. An important feature to notice in these products is the discontinuity in the velocity data at a fixed range as seen in the example shown here. You will often see this discontinuity in velocity and spectrum width data as long as there is sufficient areal coverage of echo over multiple trips. This discontinuity occurs at the range for R"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> <Span Text="max"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Subscript" /> </Span> <Span Text=" on the Contiguous Doppler (or high PRF) cut used for velocity data collection. The two important questions to ask are: “how did any velocity data end up being assigned beyond the first trip?” and “why does the radar assign some of those regions with valid velocity data and others with the RF ‘purple haze’?” "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Remember that the Continuous Surveillance scans (where reflectivity data are collected) use low PRFs that result in long maximum unambiguous ranges. So, these cuts produce reflectivity data with a R"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> <Span Text="max"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Subscript" /> </Span> <Span Text=" of ~250 nm and very little data that gets collected outside of the first trip. As a result, the color purple on Reflectivity products indicates very high dBZ values, not range folding."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" We will discuss two range unfolding techniques in this lesson, the first of which is the technique released initially with the WSR-88D. We will refer to this range unfolding algorithm as the Legacy Range Unfolding Algorithm.&#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The goal of the Legacy Range Unfolding Algorithm is to assign velocity and spectrum width data to its appropriate range. That range can be beyond the maximum unambiguous range for the Continuous Doppler scans. So, the precipitation echoes might be in the first trip, the second trip, or (in rare cases) even the third trip. This algorithm runs at the RDA signal processor, which is literally a black box, for VCPs 12, 31, and 32."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The next several slides will demonstrate two examples of how the Range Unfolding algorithm works: One with no echo overlay and one with overlay. We will walk through each example using numerous steps. For each of these slides, you will need to manually advance the slide to move to the next step."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 1: We look down a single radial in surveillance mode. That means we have a nice long unambiguous range. We have two targets along this radial. The first one is at 20 nm, and the second one is at 90 nm. Since both of these targets are within the first trip, we know their true range and we know their returned power. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 2. Prior to the switch to Doppler mode on the next rotation, the algorithm computes what the apparent ranges of these two targets will be. In this case, Our R"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> <Span Text="max"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Subscript" /> </Span> <Span Text=" of 60 nm in CD mode results in target A staying at 20 nm while target B will be folded into an apparent range of 30 nm. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 3: We know target B has an apparent range of 30 nm. At this step, the algorithm computes all the possible ranges for each target that shows up in the CD mode first trip, and these possible range go out into the second and third trips. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 4. With those calculations out of the way, the radar can collect data in Doppler mode. The energy from pulse 1 for target B (which was at 90 nm) propagates back to the RDA, but it does not arrive before the energy from pulse 2 is transmitted. That is how we get an apparent range for target B at 30 nm in CD mode."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" CustomTabStops="" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 5: Now that the RDA can begin the actual down radial comparison of the CS and CD data. The algorithm checks to see wherever there is a target in the CD data if there was something at that same range in CS data. So, when we get to target A, the algorithm checks if there was something at 20 nm in the CS data? And the answer is Yes, so we know the velocity for target A belongs at the range of 20 nm. "> <Style FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 6: When the algorithm gets to target B at an apparent range of 30 nm, it compares that location to the CS data. In this case, no there wasn’t a target at 30 nm in the CS data. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 7: Since no targets were detected at 30 nm in the CS data, the algorithm checks the next possible range which is 90 nm. And, yes, a target was detected in the Surveillance data at that range. That’s how we know that the velocity value that appears to be coming from 30 nm actually belongs at 90 nm. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Now let’s look at our second example where echoes are overlaid on top of each other.&#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 1: We start off with the same initial conditions. In Surveillance mode, the RDA detects targets at 20 and 90 nm. The maximum unambiguous range is 250 nm, so we know the returned power and range for each of these targets. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 2: This time, when the radar switches to Doppler mode, the maximum unambiguous range will be 70 nm. That means both of the targets will have an apparent range of 20 nm. It also means that pulses are returning back to the RDA at the same time, so this is an overlay situation. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 3: Just as before, the algorithm accounts for the apparent ranges of the targets across the first, second and third trips."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 4: Here's where the algorithm takes advantage of the fact that it knows the returned power for each of these two targets and their original range. The algorithm compares those returned powers to each other, and it computes a threshold (called TOVER) to determine whether the velocity and spectrum width data are assigned to one of these two targets. So, the higher powered target is compared to the lower power target, and if difference reaches this threshold, the algorithm can assign the velocity and spectrum width values to one of these overlaid targets."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 5: Now the actual Doppler data collection begins, and notice that information from pulses 1 and 2 come back to the radar at the same time. So the velocity and spectrum width values have an apparent range of 20 nm, that is composed of data from returned pulses for both targets A and B. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 6: Now the algorithm begins the comparison of the Doppler to the Surveillance data. The algorithm answers the question whether a target was at a specific range, and also determines if that target had the higher returned power. In this particular example, Target A had the lower power, so the answer is “No” at a range of 20 nm. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 7: Since the answer was no the first time, the algorithm looks at other possible ranges for this target. Was there something in the CS data at 90 nm? Yes. And was this the higher power target? Yes. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Step 8: Now that we know this velocity and spectrum width data at a range of 20 nm is more representative of the target that was at 90 nm. So, we assign the observed data to the bin at 90 nm, and range folding, or purple, to the echoes at 20 nm. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" This graphic represents the base data estimation process for a range bin when there is an echo overlay case such as in our previous example. Pulses from two different targets are received and processed at the same time, apparently from 20 nm. If the pulses from these two different targets could be analyzed separately, the result would be the black bell curves for targets A and B. However, the returned pulses can only be analyzed as a single target, which is represented by the blue bell curve. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Which one of the original targets does the blue curve better represent? Target B since it is returning significantly more power than target A. Recall that velocity estimates are power weighted, so this “hybrid” velocity estimate will more closely resemble the more “powerful” target B. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" Lastly, the algorithm needs to determine if the power returned by B is sufficiently greater than A for the “hybrid” velocity to be assigned to target B."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" The Range Unfolding Algorithm uses a parameter known as “threshold over”, or TOVER, to determine if the overlaid echoes have a sufficiently high difference in returned power to assign the hybrid velocity to one of them. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" The current setting for TOVER is 5 dB, and if the power ratio exceeds TOVER, the algorithm assigns velocity and spectrum width values to the echo which returned the higher power. The other echo is assigned RF. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" If the power ratio does not exceed TOVER, the algorithm assigns RF to both of the overlaid echoes."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Now for another look at the distribution of RF in Base Velocity, given the location of the echoes in Base Reflectivity. The strongest storms south of the radar are within the first trip, so there is no issue with the availability of the associated velocity data. There is an area of weaker echo to the south and southwest of the radar, some of which falls within both the first and second trip of the Contiguous Doppler scan data. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The yellow ovals highlight a group of gates in the same relative positions in the first and second trips, with purple assigned to both of the bins in most cases. In general, the overlaid echoes here did not return enough of a power difference to accurately assign velocity data to either one, so purple (RF) was assigned to both. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Now for a summation of Legacy Range Unfolding Algorithms strengths. In most instances, this algorithm achieves its objective of assigning velocity and spectrum width data to the appropriate range, including past the first trip, or R"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> <Span Text="max"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" Elevation="Subscript" /> </Span> <Span Text=", of the Contiguous Doppler (CD) scan. When echoes are overlaid, the Legacy Range Unfolding Algorithm can, at best, assign velocity and spectrum width to one of the overlaid echoes. The algorithm decides whether to assign the values based on the returned power of the separate echoes that contribute to the overlay. If TOVER is exceeded, then one of the echoes has returned sufficiently more power that the others and can be assigned the velocity and spectrum width values. The other echoes are assigned RF. &#xA;"> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The Legacy Range Unfolding Algorithm mitigates the Doppler Dilemma in this manner. For every radial, the low PRF, Contiguous Surveillance (CS) pulses provide returned power and target range. For that same radial, the high PRF, CD pulses provide more accurate velocity and spectrum width data. Comparing both data sources allows for “unfolding” the velocity and spectrum width to its appropriate range along the radial. "> <Style FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" Extensive echo coverage aligned along radials limits the Legacy Range Unfolding Algorithm ability to unambiguous unfold velocity CD data. These situations maximize echo overlay along a radial through the first, second, and third trips. The Legacy Range Unfolding algorithm can only assign overlaid data to one of the echoes, so the result of these situations is extensive range folded data. If the returned power from the overlaid echoes is too similar, than both echoes will be assigned RF values. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" This example shows a case where the TOVER requirement was met for most of the echoes in the first trip. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" Color="#000000" BulletFont="Arial" /> </Style> <Span Text=" The second range unfolding technique for the velocity and spectrum width data is known as SZ-2 Range Unfolding and was fielded in 2007. This technique is named for the two research scientists who developed it: Mangalore Sachidananda and Dusan Zrnic. This algorithm runs at the RDA signal processor, the literal black box, just like the Legacy Range Unfolding Algorithm. &#xA;"> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The SZ-2 algorithm is available only for the Split Cut elevations of VCPs: 35, 212, 215. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The SZ-2 Range Unfolding algorithm is particularly effective with widespread echo coverage. In this case, the Legacy Range Unfolding algorithm (VCP 12) is used for the data on the left, with SZ-2 (VCP 212) on the right. Use of VCP 212 dramatically improves the availability of velocity and spectrum width. Notice from the data that Continuous Doppler data are available from multiple trips over large areas, resulting in extensive echo overlay. Where there is echo overlay, the Legacy Range Unfolding Algorithm can recover, at best, one of the echoes. On the other hand, the SZ-2 technique usually recovers both overlaid echoes."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" The SZ-2 Range Unfolding Algorithm’s strength results from its increased availability of velocity data for multiple trips. The best results come with events with widespread echo coverage. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" With the Clutter Mitigation Detection algorithm active, the radar almost never needs All Bins clutter suppression. SZ-2 usage adds another reason to avoid All Bins suppression, as All Bins suppression can degrade the velocity data when SZ-2 is applied. In fact, the RPG software has built in procedures to avoid having All Bins and SZ-2 active at the same time. "> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" To wrap things up, the higher PRFs used during the Contiguous Doppler scan makes range unfolding of velocity and spectrum width data necessary because of the short maximum unambiguous ranges. The WSR-88D uses two different range unfolding algorithms at the signal processor to handle this process. The Legacy Range Unfolding Algorithm addresses the issue for VCPs 12, 31, and 32. The Sachidananda-Zrnic (or SZ-2) algorithm unfolds the CD scan data for VCPs 35, 212, and 215. The SZ-2 Algorithm generally outperforms the Legacy algorithm because it allows for the recovery of more CD velocity and spectrum width data during overlay situations. However, the downside to the SZ-2 Algorithm is All Bins clutter suppression negatively impacts data quality when SZ-2 is in use."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Content> <Block> <Style FlowDirection="LeftToRight" LeadingMargin="0" TrailingMargin="0" FirstLineMargin="0" Justification="Left" LineSpacingRule="Single" LineSpacing="20" SpacingBefore="0" SpacingAfter="0"> <ListStyle ListType="None" ListTypeFormat="Parentheses" BulletFont="Arial" /> </Style> <Span Text=" You have now completed this lesson on the range unfolding of velocity data. You are ready to proceed to the next lesson."> <Style FontFamily="+minor" FontSize="11" FontIsBold="False" FontIsItalic="False" FontIsUnderline="False" FontIsStrikeout="False" /> </Span> </Block> </Content> </Document>