Ken Ji's super-smooth 2:26.3 Onboard Lap Video at the 2010 Time To Attack Finale

[Laptimer]

Ask laptimer la.. he seems to know.. lol.. love to hear his technical explanation on it.. hahaha.

Ground station also don't have in malaysia, and suddenly can estimate
lateral acceleration at sepang track using geolocation data...

you so rude shiroetinshit!

hello is measure not estimate
dun anyhow say can
ask you your normal car how the speed is know?
is measure from wheel rpm after knowing circumference and derive
you wan to say your normal car speed is onli estimate ??
you knows how de accelerometer work? is by physical move and voltage or capacitance change
so the gforce is derive from de movement hahhahahahahhahahhahahahahhahahahah
so if you tink normal car speed is only estimate
den accelerometer is oso consider estimate
the true is accelerometer gps and normal speed is all measure one!!
ah seng not supid ok! dun anyhow say ting whack me cos my english not power
my understan is not bad ok
not say very good but enuff to see de rubbish ok!!
n i can see your rubbish!!!

gps is see the car position many time in one second
from change in position over time it calculate speed
you understan derivation or you need ah seng teach you??
go one more step and derivation the speed give you acceleration aka gforce
dis one is for gforce longitude

for gfroce lateral is same
with 3 point know de arc n de distance of arc n oso know de radius
with these calculate the gforce oredy by equation below
acceleration (gforce) = speed^2 / radius

don't say what ground station lah
dat one is for accurate compensate for de gps drift dis i oso know
but to calculate gforce while driving and every few 0.1 or 0.05 secon the gps drift is no factor

the pdf tok abt the gps error is actually wrong
you see gps n accelerometer data on same car
the gps usually filter and the lower the hz the more filtering naturally and always less than accelerometer number
oso de car use in the test can do 1.7 sustain lateral gforce on flat smooth skid pad
so on a circuit sure can spike jus under 2
also if the antena is put away from cg of car the number can spike higher oso
g-g trace include spike writer forget is not say sustain unless many point at there
can see there is not many point there most is concentration ard de 1.5

accelerometer oso need calibrate or got error oso
even temperature mus have de compensation table


you charles brudder is it? you all same no thinking style one!!
LS1 even more rude say the dirty word !! can he be ban for saying such work?

 

[shiroitenshi]

you so rude shiroetinshit!

hello is measure not estimate
dun anyhow say can
ask you your normal car how the speed is know?
is measure from wheel rpm after knowing circumference and derive
you wan to say your normal car speed is onli estimate ??
you knows how de accelerometer work? is by physical move and voltage or capacitance change
so the gforce is derive from de movement hahhahahahahhahahhahahahahhahahahah
so if you tink normal car speed is only estimate
den accelerometer is oso consider estimate
the true is accelerometer gps and normal speed is all measure one!!
ah seng not supid ok! dun anyhow say ting whack me cos my english not power
my understan is not bad ok
not say very good but enuff to see de rubbish ok!!
n i can see your rubbish!!!

gps is see the car position many time in one second
from change in position over time it calculate speed
you understan derivation or you need ah seng teach you??
go one more step and derivation the speed give you acceleration aka gforce
dis one is for gforce longitude

for gfroce lateral is same
with 3 point know de arc n de distance of arc n oso know de radius
with these calculate the gforce oredy by equation below
acceleration (gforce) = speed^2 / radius

don't say what ground station lah
dat one is for accurate compensate for de gps drift dis i oso know
but to calculate gforce while driving and every few 0.1 or 0.05 secon the gps drift is no factor

the pdf tok abt the gps error is actually wrong
you see gps n accelerometer data on same car
the gps usually filter and the lower the hz the more filtering naturally and always less than accelerometer number
oso de car use in the test can do 1.7 sustain lateral gforce on flat smooth skid pad
so on a circuit sure can spike jus under 2
also if the antena is put away from cg of car the number can spike higher oso
g-g trace include spike writer forget is not say sustain unless many point at there
can see there is not many point there most is concentration ard de 1.5

accelerometer oso need calibrate or got error oso
even temperature mus have de compensation table


you charles brudder is it? you all same no thinking style one!!
LS1 even more rude say the dirty word !! can he be ban for saying such work?

Whatever bro.. let you win lah.. your article also you say is mistaken.. "compensate for vehicle" roll clearly stated there... and "overestimated by GPS measurements" is quite clear. Your own source, now you twist to fit your needs.

Accelerometers are proven to provide better g-force measurements. They are not affected by satellite reception/minor errors in geolocation.

Even your link about VBOX also shows that there are errors, hence they have products like

VBOX 3i 100Hz
RLVB3i

VBOX 3i is the most powerful GPS data logging system built by Racelogic. Using a new GPS engine, VBOX 3i logs data 100 times a second, and features a 400MHz power PC processor. With IMU integration, USB and Bluetooth connectivity, compact flash card logging, and audio functionality for voice tagging, VBOX 3i represents a flexible solution to a range of testing requirements.

For accurate testing even in areas where view of the sky is obstructed, VBOX 3i has the ability to take the information from a Racelogic IMU (inertial measurement unit), pictured below, and combine this with the GPS data in real time to improve the quality of the measured parameters. The three accelerometers and three gyros inside the IMU are used to keep track of the attitude of the vehicle and will greatly increase the velocity and position accuracy during periods when satellite visibility is poor.

If you say measure also wrong, then everything measure also sure got some error, you also know what instrument error is. The idea is to set up the instrumentation for minimal error. That's why we always do zeroing/calibration, even on lab standard equipment. Suddenly you come in and say everything wrong, and only you is right. Better you become ruler/pembaris of the world.

Never mind, you win lah.. don't want to track this post already.

 

[Laptimer]

Whatever bro.. let you win lah.. your article also you say is mistaken.. "compensate for vehicle" roll clearly stated there... and "overestimated by GPS measurements" is quite clear. Your own source, now you twist to fit your needs.

sometime the doctor stuck in the lab too long study super high theory ting until he no and forget to test real world system in real world never see which always read lower n why

what he say abt gps is true in theory but you mus thinking n cannot anyhow accep whole thing
corner entry n exit where car roll or unroll the lateral acceleration phase and magnitude may not be completely accurate but for mos of de turn where roll is settling or settled already the sustained lateral will be accurate bcos de gps read only single point and that single point is steady alrdy!!

so gps kin of roll compensation is no same as accelerometer
accelerometer mid corner even steady state the roll will add to lateral usually
there are some situation where de roll will minus from lateral
you tinking can see how both can happen and when? :)

is not say i always right lah
the other thread i got say sorry and i am wrong how many time??? at least got 3 4 time leh!!
if you can show where laptimer wrong den laptimer sure say ok i learn and ok i sorry i wrong
dis is de interesting ways to living!!!

actually de racing need both theory and practical
mus balance but everyone will have different idea one
so we tok
then if cannot agree oso ok loh
you do your way i do my way
all is ok one
i never call you troll you dun call me troll loh!! fair right bro??

Accelerometers are proven to provide better g-force measurements. They are not affected by satellite reception/minor errors in geolocation.

true lah i oso use accelerometer but den you should not anyhow say gps NO WAY TO SEE LATERAL G
actually is more than accurate enofff for de normal driver
some normal driver oso install the accelerometer lagi worse and the number all wrong lah den oso signal got so much noise lah super vibration den wire never shelded anyhow run with other wire
for us do time attack gps is alrdy very good and no need compensate for sustain lateral one!!!
i been use the traqmate one is very good!!
http://store.traqmate.com/

of course use both is best lah can compare compare see

 

[shiroitenshi]

is not say i always right lah
the other thread i got say sorry and i am wrong how many time??? at least got 3 4 time leh!!
if you can show where laptimer wrong den laptimer sure say ok i learn and ok i sorry i wrong
dis is de interesting ways to living!!!

actually de racing need both theory and practical
mus balance but everyone will have different idea one
so we tok
then if cannot agree oso ok loh
you do your way i do my way
all is ok one
i never call you troll you dun call me troll loh!! fair right bro??

true lah i oso use accelerometer but den you should not anyhow say gps NO WAY TO SEE LATERAL G
actually is more than accurate enofff for de normal driver
some normal driver oso install the accelerometer lagi worse and the number all wrong lah den oso signal got so much noise lah super vibration den wire never shelded anyhow run with other wire
for us do time attack gps is alrdy very good and no need compensate for sustain lateral one!!!
i been use the traqmate one is very good!!
http://store.traqmate.com/

of course use both is best lah can compare compare see

Ac
[/quote]

If you talk like this, where people find you offensive? talk normally la. Even I also can accept if you discuss your ideas like this rather than simply say wrong, wrong, wrong. If you talk like this, I won't call you troll, fair or not?

Of course if cannot agree it's okay. I also got info from other people, like when I was doing ITB the first time... In the end, the way I did it was totally different from other people in the sense that I didn't use an idle valve. Are they wrong? NO, they did it earlier than me, and sucessfully too, but their way just different than mine. I wouldn't have found out if I never tried it myself. That's why say theory =/= real life or practical experience.

Like you also, you say can use GPS to calculate lateral G, but with accelerometer, it can measure it directly, but only with slight errors due to not compensating for vehicle roll. the 3 axis reduces the errors even further by actually factoring in vehicle roll. With two axis, can measure, but you lose out on the acceleration G.

One argument on gps accuracy is the GPS ground stations, in other countries, they have it to make GPS geolocation more accurate, while malaysia don't have, so our GPS accuracy not so good to make it a good source for lateral g calculations. errors of 3 metre or more is common, that why when you disable LOR on GPS, location sometimes off. What I meant by NO WAY to read G force is measuring it directly. If the data is wrong, then output will be wrong, GIGO (garbage in, garbage out).

But you provided a good alternative, I just think it's not accurate enough compared to using accelerometers.

Of course, using both is better, but not everyone has the dollar to buy high dollar datalogging systems and telemetry, so if have to pick one, better accelerometer.. most common datalogging and race ecu systems use accelerometers due to it's lower error factor.. is it 100% accurate? You also stated the errors common in measurements, so we try to minimize the errors by calibrating the best we can, if cannot reduce it completely.

 

[Laptimer]

as i say your point about measure gforce direct is not right cos accelerometer itself is derive it
can hang stick with heavy weight and use 2 video camera see stick angle as gforce sensor n you would say derive oso
gps derive it different way oni
all is derive you can say how accurate but all 3 actually accurate enough for us!!

i ask you how you know car speed? wheel speed derive? gps derive? radar derive? all is derive! all is accurate if set properly from start! All have GIGO

dun say 3m CEP all dis lah
oni 7 secon go through even the biggest turn
gps drift in 7 second is how many?
you tell me 1 hour 1 day i understan but you talking oni secons leh

i tell you i using both de accelorometer and de gps and both are more than enough for anyone reading dis!!! in fact gps in road car on track wun give so high reading make people read de spike think their car is f1 car oso de signal not so noisy installation not so tricky one

pple here is no need the 500 hz logger and high price very accurate accelerometer for chassis n shock research lah
we not proton lotus or toyota these kind got so much money

gps oso easy do laptime n de track map acceleometr track map always like sai have to ajus ajus to make only ok only
gps first time super liao
so if you acceleromatar onloy den you buy additional sensor for laptime? beacon? for what? use one thing do all loh!
den your real speed how? gps better than wheel speed tyre compress how? tyre grow how?
you go ask all thos pple include ken ji kamaza garager those touring car gt4 gt3 car team at sepang now go throw money buy xtra accelerometer put on the car maybe some will tell you say for what???? unless they do those very deep chassis or shock research n need it but they all never do cos the car n race seres type dun need one

is not lower error factor lah
is easier to use in place where got tall bilding tall tree
easier when look at forces n cmopensate for roll pitch yaw single gps cannot do this but actually multiple spot gps can do it but very accurate enough
but we all here is not doing dis one
oso last time gps tecnolgy no so good but last 10 year improving a lot
now got 10hz 20hz 100hz gps rtk all these ting
got more money oso can get us gov approve n use got some team oversea got approve before but ex

if you wan say ideal ideal den all car will have high qality 3 ax giro 3 ax accelometer n high accurate gps and many many other sensor all install properly all very ex dunno use for what we not f1 right???

tom dun ban me ok?? all these is traffic good for website
no law break no harm

 

[shiroitenshi]

Up to you. If you find gps more accurate in deriving your gforce, then it's your choice, if you think the data is valid, of course you will admit the output as valid. I already stated obvious about reducing errors.

In the end, it all depends on how it's used. If the data is relevant, it's useful, if it's not, it's not.

If you believe your interpretation of the data is correct, then it's time to put it to the test on a car. As a baseline, why not try it on a normal car. If it exceeds the norm of 0.8 constantly, isn't it time to revise your findings?

 

[Laptimer]

i alrdy try on car both same time on skid pad n on track n both are accurate
the norm of 0.8 is not for de modern sporty car
gps cos of low rate is always more realistic den de high rate high noise accelerometer
the reason to use accelerometer is not cos accuracy is cos is differen type of reseach
same as suspension research uses different sensor from engine research
is differen area oni

 

[shiroitenshi]

Ok bro. Whatever you say. :)

My report is finished! Time to sleep. If got time, please post videos. Hopefully zth forummers can benefit from exposure to the technical side of cars rather than just the girls and the sexier four wheel machines. Or is that the other way around?

Haha. Nite bro. Nice arguing with you. :)

You read too much product brochure. As if the marketing fellas will mention the error rate in their devices.

You want real info, you search for research papers. Feasibilty study for gps for the blind, chap 5. Gps vs alternatives, including accelerometers.
http://lapierre.jammys.net//masters/chapter5.html

Of course. Even with this, you are right, you are the greatest driver and smart that you are more knowledgeable than a masters level engineer.

Pandai la tu...

 

[Laptimer]

aiya i oso can anyhow link to many paper paper abt de accelerometer error if you wan
anyone can yahoo search oso mah
multipath error n atmophere all these is know alrdy and can be take care of if you careful
in the end you have to use your eye see what really is work for real world dat not too ex
touch your heart be honest ask yur self if you argue cos your pride or cos you realli correct
dun ask me for video if you dun pose your own video
i not interest in how many paper you can show link
not interest you master or phd or wadever
i oni interes in what you know weder reasonabal wat kind testing you do before what you fine out
dun say i oni read brochure ok
dun tink i dunno abt error
every electric will have error even f1
question yourself weder the error is too big FOR YOUR KIND OF DRIVING AND CAR
IF YOU NOT F1 DUN COME TOK ALL THESE F1 ERROR TOK LIKE IS IMPORTANT TO YOU
GO N WIN MSS FIRST B4 YOU WAN TO ACT ACT F1
how many lap you drive b4 compare gps and accelometer?
which 3 ax accelormetr you using? what car how fast how important to know the roll? what filter you use?
gps which one and how far from your acceleromter?
you got compare both on skid pad? how you know which is correc?

i oso can anyhow link accelemeter error chim chim http://www.ima.umn.edu/preprints/Sept96/1422d.pdf
n anyhow say ting out of contex wrong appli http://www.kompisar.net/fredrik/Exjobb_positionering.pdf
"Due to accelerometer inaccuracy the method mentioned above is not suitable
for navigation. For low speed movement however, the accuracy of such a system is poor when used
over a reasonable length of time. Small DC errors are accumulated and
gradually amount to large errors. The main source of error is the temperature coefficient, which is
approximately 2 mg/ºC. A small temperature deviation of only 0,5°C adds a
DC error of 1 mg, which is more than the desired signal itself."

OK BRO LOVE YOU

 

[arturo]

Laptimer...can pls control yrself? argue sporting a bit pls. 3rd party read oso kenot tahan with the way u put your opinion forward...i'm not saying what u say is wrong or right. i'm saying the WAY u push yr opinion is irritating.

hats off to shiro for being sporting n not causing this to escalate.

 

[shiroitenshi]

Actually i thought it would be a good way to make him post in a better manner, arturo. Now I'm just going to ignore already. No point if he won't take the effort to write english properly, yet take conscious effort to get only the terminology right. Don't you find it strange?

That's it. I'm stopping here.

 

[TitanRev]

Come on Laptimer bro...with only GPS you can't get GForce reading la....it can tell you position only. It needs to have a sensor inside the GPS unit to sense the Gforce..example accelerometer. Just like RSM...for the Gforce function to work you need to add the G sensor also mah....without any on board sensor on the car how will the gforce be measured.

Nice driving Kenji

 

[Laptimer]

for you brudder i surely try my best to haf best terminologology
i make sure i yahoo n googel very careful check with all de master all de phd confirm correct 1st den i pose to you
today ah seng learn the new word call DUE DILIGENCE oso mean same as what i jus mention

---------- Post added at 12:06 PM ---------- 6 hour anti-bump limit - Previous post was at 11:58 AM ----------

Come on Laptimer bro...with only GPS you can't get GForce reading la....it can tell you position only. It needs to have a sensor inside the GPS unit to sense the Gforce..example accelerometer. Just like RSM...for the Gforce function to work you need to add the G sensor also mah....without any on board sensor on the car how will the gforce be measured.

shirotenshi do you see what happen when you not careful n anyhow say ting?????
now even the moderator read what you anyhow say and now he beleving it!!!!
wat will happen to all pple here if all is like dis? a few month all pple belev wrong ting cos you anyhow say! TIAN AH!!!!!

 

[E3newbie]

I have to say that I didn't know lateral G force could be calculated with a fomula but I guess there is a calculation for everything these days.. That being said, the figures derived from such a calculation should be regarded as an estimate. One thing that I have to hand to Bro Ah Seng Laptimer is that keyboard warrior or not, he provides quite some information. As for his english, I belive he could well be Singaporean Or from Johore maybe. It's just for fun and laughter, like the radio advetisement of AH Seng Aquarium. I'm sure its quite obvious that Its all an act but hey, it adds a bit of color to the whole thread dose it not?

 

[Laptimer]

you can call these gps gforce estimation can!!
but das means your car the speed also call estimation!!
oso the acceleremter reading also call estimation!!!
if they all are estimation ok
if they all are measurment ok
only word different
as long as understan how it become and how can be use properly

i from macau lah now few year n other country in asia thailand china singapore malaysia
my english is try my best ok dun anyhow laff
if you all come de china forum down there i laff you say your chinese no good how you feel? no good right bro? as long de point can say can understan can already right?

anyone wan to ask ken ji his computer how can see the straight gforce and side gforce??? izzit by gps or accelrometer? got accelemetre inside meh? why he get that one if all the acceloration is all estimate one? you call him stupid is it? qstar digispice traqmate they all oso secretly put accelermeter in the gps so can work n den never tell customer? pls lah tink carefully read more

 

[E3newbie]

So what is it that you are trying so hard to tell us actually?

---------- Post added at 01:36 PM ---------- 6 hour anti-bump limit - Previous post was at 01:35 PM ----------

BTW, I didn't mean any of what I said as an insult, I just think you are cute.

 

[DanzEterna]

enuf wid that gps gforce edi...pening....

 

[E3newbie]

Hey Danz...
Too much G force could do that to you...

 

[arturo]

gps works by triangulation...i'm still wondering how it can measure g-forces unless it calculates sudden movements outside of the avg movement and then calculated again against a set of known values to how much movement/second = g-forces involved.

thats the only way i can see a gps unit can track g-forces. that said...any engineer would say KISS...and just install a accelerometer since it is cheap and data is raw and no need for a mega processor to calculate g-forces when it is already there in raw data.

i agree with E3newbie...if yr using a gps for g-forces calculation, it is taking 1 set of data - triangulation from 3 or more sats, then converting it to movement and then taking movement and then converting it to g-force which also needs to be compared to the avg movement vs sudden movement. it may signify hard data, but this data would be less accurate than taking an accelerometer and getting the raw data out of the sensor since it was built to provide that. dont compare with your car's speedometer sensor. not apple to apple comparison. that sensor was made to measure speed and speed alone. besides..even in iso TS standards, speedometer reading have allowances to +- variables. nothing is 100% precise.

 

[TitanRev]

Arturo, that's what I'm thinking...

I don't think GPS can read Lateral G without any sensor build into the unit. It can calculate your moving speed and time but not lateral G.

I think by just using a set of values and doing calculation will not be as accurate as a direct reading from a sensor inside the vehicle itself. Since a sensor will give you real time reading with all the physical elements taken into place.