[w_scott]

I've been using google maps for a long time on my Q10. It's working fine, but eats a lot of battery. Yesterday, I had a long trip and no plug, so I decided to try again BlackBerry Maps. I thought a native app would be more efficient and save battery. I rediscovered it, and was impressed : it has now a better cartography, gets traffic information, directions are clear. It took us to destination as efficiently as the two other cars taking different routes, using different apps.

Maybe I can soon uninstall google maps...

One think I was wondering : why doesn't it use the embedded sensors to keep working under tunnels. Not precise enough ?

Q10SQN100-3/10.3.1.1154

Posted via CB10

[balenax]

The GPS receiver needs to communicate with the GPS satellites and the tunnels are completely blocking this. It also happens indoors and in most places where you don't really see the sky.

Sent via my square wonder thingie

[w_scott]

Aware of that. But our phones also embed gyrometers and accelerometers, that could be used when GPS signal is lost...

Posted via CB10

[allbetsareoff29]

There aren't any sensors that measure speed on any phone (not just blackberry).
Phones can only measure acceleration. And when you are using cruise control driving 65 on a highway, your phone only sees the acceleration down, towards the middle of earth - gravity. As far as acceleration forward/backwards or left/right - there is 0 acceleration in those directions because relative to your car seat/pocket/cup holder, your phone is stationary.

So as far as what your phone thinks: it thinks it's in one place, not moving.

Now you could say: why not just take last known speed of GPS and as long as the forward/backward acceleration is equal zero, the speed will be the same?

The problem with that theory is that there are too many "estimation" hops.
First, to find out what your speed is, you need to calculate distance over time. Your phone has no concept of distance. It only knows series of lat:long coordinates at precise time point.
What's worse, your phone "doesn't actually know " the lat:long coordinates. It only measures the time it takes to ping each of many GPS satellites. Based on the time it took to ping first satellite, combined with how long it took to ping second satelite... there is a big formula that is based on known constants that calculates your lat:long coordinates.
So getting back to calculating speed, you have your lat:long coordinates at time X and your lat:long coordinates at time Y. You can't get the speed just from those - you have to first calculate what is the distance between those two lat:long coordinates. And there is another formula here.
OK so now that we have distance, we divide it by the difference in time (Y - X).
Cool so we got our speed. Now what?
Now you have to keep repeating that few times per second.
Lastly, you have to translate K amount of acceleration over L amount of time into M change in velocity... that yet another lovely formula

So basically, each time ANY measurement is taken by your device, there must be some rounding. If you payed attention, you noticed that your phone can really only measure 2 things: time, and acceleration (yes, I am ignoring compass as it does not pertain to the point I'm making)

Time it took to ping 1st satellite at time X : rounding
Time it took to ping 2nd satellite at time X : rounding
Time it took to ping 3rd satellite at time X : rounding
Time it took to ping each additional satellite at time X : rounding
Calculate latitude at time X: rounding
Calculate longitude at time X: rounding

Time it took to ping 1st satellite at time Y : rounding
Time it took to ping 2nd satellite at time Y : rounding
Time it took to ping 3rd satellite at time Y : rounding
Time it took to ping each additional satellite at time Y : rounding
Calculate latitude at time Y: rounding
Calculate longitude at time Y: rounding

Calculate distance between two lat:long coordinates: likely rounding

Calculate difference between time Y and time X: possible rounding

Measure acceleration at time X: one rounding per axis of acceleration

Measure acceleration at time Y: one rounding per axis of acceleration
Calculate change in velocity : rounding

Calculate new theoretical speed at time Y: rounding

Repeat at least couple of times per second to have any decent chance of even being in a ballpark =)


TLDR:
Phone doesn't have a way of measuring speed. It can only calculate it from other (many) input variables. These calculations aren't precise and need to be rounded. The sensors measuring the input variables for calculations aren't 100% accurate either and also might be rounding.

Too many rounded variables from inaccurate sensors are used in complex, time sensitive calculations which themselves are rounded...aka... can't deduce the speed of vehicle with any reasonable or reliable accuracy

Posted via CB10

[cbvinh]

Aware of that. But our phones also embed gyrometers and accelerometers, that could be used when GPS signal is lost...

The gyroscope only measures the orientation of the phone, face up/down, rotated left/right, etc. The accelerometer measures the change in speed of the phone, relative to its previous position, not how fast it's moving in a car. The phone is stationary in the car.

What you're hoping for is Assisted GPS to kick in and use cell towers to help locate the car when the GPS satellite signal is weak. That's supposed to work, but probably not over long periods of travel where the GPS signal has been weak or missing for quite a while.

I've been using BlackBerry Maps recently too, mostly in Los Angeles, where I've been traveling. I was impressed that the routing took into account traffic and verbally warned me of upcoming traffic and reported accidents. Further, 30 min. - 1 hr. trips only consumed about 30-50 MB of data when using the navigation. That's not too bad.

[BigBadWulf]

It's also pretty safe to assume, you didn't make a wrong turn in the tunnel.

[tushargkwd]

I'm liking BlackBerry Maps too... but it has lower tags on the maps for popular places like Google maps has...
Maybe adding a coordinate feature to search a location can help...
That said.. the routing and the directions are super clear and its a joy to use!

Posted via CB10 and my awesome Z30STA100-2/10.2.1.3442

[Gearheadaddy]

There aren't any sensors that measure speed on any phone (not just blackberry).
Phones can only measure acceleration. And when you are using cruise control driving 65 on a highway, your phone only sees the acceleration down, towards the middle of earth - gravity. As far as acceleration forward/backwards or left/right - there is 0 acceleration in those directions because relative to your car seat/pocket/cup holder, your phone is stationary.

So as far as what your phone thinks: it thinks it's in one place, not moving.

Now you could say: why not just take last known speed of GPS and as long as the forward/backward acceleration is equal zero, the speed will be the same?

The problem with that theory is that there are too many "estimation" hops.
First, to find out what your speed is, you need to calculate distance over time. Your phone has no concept of distance. It only knows series of lat:long coordinates at precise time point.
What's worse, your phone "doesn't actually know " the lat:long coordinates. It only measures the time it takes to ping each of many GPS satellites. Based on the time it took to ping first satellite, combined with how long it took to ping second satelite... there is a big formula that is based on known constants that calculates your lat:long coordinates.
So getting back to calculating speed, you have your lat:long coordinates at time X and your lat:long coordinates at time Y. You can't get the speed just from those - you have to first calculate what is the distance between those two lat:long coordinates. And there is another formula here.
OK so now that we have distance, we divide it by the difference in time (Y - X).
Cool so we got our speed. Now what?
Now you have to keep repeating that few times per second.
Lastly, you have to translate K amount of acceleration over L amount of time into M change in velocity... that yet another lovely formula

So basically, each time ANY measurement is taken by your device, there must be some rounding. If you payed attention, you noticed that your phone can really only measure 2 things: time, and acceleration (yes, I am ignoring compass as it does not pertain to the point I'm making)

Time it took to ping 1st satellite at time X : rounding
Time it took to ping 2nd satellite at time X : rounding
Time it took to ping 3rd satellite at time X : rounding
Time it took to ping each additional satellite at time X : rounding
Calculate latitude at time X: rounding
Calculate longitude at time X: rounding

Time it took to ping 1st satellite at time Y : rounding
Time it took to ping 2nd satellite at time Y : rounding
Time it took to ping 3rd satellite at time Y : rounding
Time it took to ping each additional satellite at time Y : rounding
Calculate latitude at time Y: rounding
Calculate longitude at time Y: rounding

Calculate distance between two lat:long coordinates: likely rounding

Calculate difference between time Y and time X: possible rounding

Measure acceleration at time X: one rounding per axis of acceleration

Measure acceleration at time Y: one rounding per axis of acceleration
Calculate change in velocity : rounding

Calculate new theoretical speed at time Y: rounding

Repeat at least couple of times per second to have any decent chance of even being in a ballpark =)


TLDR:
Phone doesn't have a way of measuring speed. It can only calculate it from other (many) input variables. These calculations aren't precise and need to be rounded. The sensors measuring the input variables for calculations aren't 100% accurate either and also might be rounding.

Too many rounded variables from inaccurate sensors are used in complex, time sensitive calculations which themselves are rounded...aka... can't deduce the speed of vehicle with any reasonable or reliable accuracy

Posted via CB10

Great post! Excellent explanation on how GPS works.
Actually there is an app that measures speed that uses the obd2 port and a Bluetooth OBD2 adapter...it is "Torque Pro". I have both the app and adapter and use it with an old android phone. The app does way more than that...it measures speed and ecu functions in real time and shows such on-screen simultaneously and records also so you can view all of that at a later date at home sitting in a chair. Kind of off topic there with my speech on that app but you are right about the GPS signal getting blocked

Crackberry Genius on Verizon Z10 on10.3.1.1154

[Gearheadaddy]

Oh...and I like BlackBerry Maps better now also...

Crackberry Genius on Verizon Z10 on10.3.1.1154

[BigBadWulf]

Only pet peeve I have with BlackBerry Maps, is it always says my destination is straight ahead. Would be wonderful to know right or left, as straight ahead is rarely the correct answer.

I do still have trouble finding a place once in a while, but foursquare is a fantastic supplement, that launches maps from within.

[potatoguy]

I used to think it was great, never had the problems most reported , but then last summer while taking my son to UNB, it took me to places way out of the way. I would think That a University would be well marked in a mapping system. Took me twice to some side street on the other side of Fredericton. No where's near the campus.
Haven't used it since.

[HotFix]

My one wish list item for BlackBerry Maps is walking directions. I use it a lot in DC to find places when I am walking, like restaurants, and driving directions don't help much.

I do agree the app is better and more reliable than it was a year ago. Back then it would infamously tell me to take a turn as I was driving through an intersection. Let's just say the app and I were not on good speaking terms for quite a while. :-)

Posted via CB10 on my Z30STA100-5/10.3.1.1154

[BigBadWulf]

I used to think it was great, never had the problems most reported , but then last summer while taking my son to UNB, it took me to places way out of the way. I would think That a University would be well marked in a mapping system. Took me twice to some side street on the other side of Fredericton. No where's near the campus.
Haven't used it since.

Weird! There are a lot of buildings on campus:



But except for the first one, they all appear correct:



At least when compared to the UNB site. Maybe you should have started in Chicago.

[BigBadWulf]

My one wish list item for BlackBerry Maps is walking directions. I use it a lot in DC to find places when I am walking, like restaurants, and driving directions don't help much.

I do agree the app is better and more reliable than it was a year ago. Back then it would infamously tell me to take a turn as I was driving through an intersection. Let's just say the app and I were not on good speaking terms for quite a while. :-)

Posted via CB10 on my Z30STA100-5/10.3.1.1154

Walking directions would be awesome!

It still routes me onto an exit, then back onto the highway in one spot. It's an unusual piece of highway, and I really need to remember to report it. Also still doesn't tell me to turn as soon as I'd like from time to time. Typically when it's a turn right after a turn.

My biggest problem though is my navigator. When she is in control of the app, it's always on the list view, so I'll try and grab a quick glance to see WTF, and that's when the fighting starts.

[backfire101]

Navigon uses your speed en compass before it will loose GPS signal. It estimates were you will be based on the speed and compass. That way when you exit a tunnel it wil have a good indication where you are and can give you directions much quicker. I don't know how BB Maps is doing that, but i guess TomTom is working like Navigon. Better to have an apprixmate location then no location at all.

[HotFix]

Walking directions would be awesome!

It still routes me onto an exit, then back onto the highway in one spot. It's an unusual piece of highway, and I really need to remember to report it. Also still doesn't tell me to turn as soon as I'd like from time to time. Typically when it's a turn right after a turn.

My biggest problem though is my navigator. When she is in control of the app, it's always on the list view, so I'll try and grab a quick glance to see WTF, and that's when the fighting starts.

How do you report bad directions? Is there an official process?

Posted via CB10 on my Z30STA100-5/10.3.1.1154

[BigBadWulf]

How do you report bad directions? Is there an official process?

Posted via CB10 on my Z30STA100-5/10.3.1.1154

LoL, I hadn't looked for that in so long, I must be thinking of the beta. There's nowhere in the app to do it, so I guess we need to add that to the list of desires. Meantime, I'll do some digging and report if I find a channel for grievances beyond twit.

Edit - A little birdie told me to use [email protected]

[gregorylkelly]

Navigon uses your speed en compass before it will loose GPS signal. It estimates were you will be based on the speed and compass. That way when you exit a tunnel it wil have a good indication where you are and can give you directions much quicker. I don't know how BB Maps is doing that, but i guess TomTom is working like Navigon. Better to have an apprixmate location then no location at all.

That is unless the estimate is completely wrong and presented to you as if it is correct. Then it is better to have no location than an incorrect estimate.

Posted via my BlackBerry Z30

[backfire101]

That is unless the estimate is completely wrong and presented to you as if it is correct. Then it is better to have no location than an incorrect estimate.

Posted via my BlackBerry Z30

In a car going 100kph? You must have a strange gps tool

[tickerguy]

The only issue I've had with Maps recently is that in extremely heavy traffic it will sometimes try to route you around it by taking you off an exit ramp and right back on the same freeway. This is in fact faster, probably, but only because the traffic on the freeway is basically stopped while that on the ramp is moving!

Nonetheless while it's "technically" correct there needs to be some sort of sanity filter on the routing algorithm -- if that can be reasonably accomplished.

The dynamic routing around traffic is in fact very, very good now and handily beats "no traffic knowledge" no-data-required GPS apps (such as Mireo's Don't Panic.) I'd like a bicycle and pedestrian mode but for vehicle use Maps works great.

[I will be back]

The gyroscope only measures the orientation of the phone, face up/down, rotated left/right, etc. The accelerometer measures the change in speed of the phone, relative to its previous position, not how fast it's moving in a car. The phone is stationary in the car.

So, when BB Maps see that car is moving with 40km/h, doesn't change direction and doesn't change speed, it can calculate your position without GPS.
With some error level it could calculate you position using gyroscope and accelerometer and simple assumption that you are not driving on a sidewalk.
Necessary calibrations could be done when GPS signal is available.

[Powdah]

Would like to see it have an off line mode. Could work line Here Mapping. Speaking of which, it would be better if BB would just use Here Mapping.

[LuvULongTime]

Glad to hear they have traffic embedded now. As another poster mentioned, walking directions would be nice as would transit. Does this version have points of interest?

[allbetsareoff29]

So, when BB Maps see that car is moving with 40km/h, doesn't change direction and doesn't change speed, it can calculate your position without GPS.
With some error level it could calculate you position using gyroscope and accelerometer and simple assumption that you are not driving on a sidewalk.
Necessary calibrations could be done when GPS signal is available.

That's the way i'd approach it too. But the challenge is that the gyroscope doesn't work well in small enclosed places (such a tunnel) and when surrounded by big metal cars and trucks, gyro goes nuts.

So assuming the tunnel scenario, the way i'd do it would be cross reference acceleration input with GPS data before you enter tunnel (this would be continuous function, running all the time of course). Let's say last 5 inputs before GPS lost signal were 65mph, 65mph 66mph, 40mph, 11mph, lost signal. If I cross reference the time stamps that these 5 GPS signals were taken at with accelerometer data at same time stamps, it will be "safe to assume " the speed remained 65. Then, we couuld use time elapsed since GPS data loss with the last known speed to predict the position of car in tunnel.
Since we can rough-guestimate the distance traveled since the GPS signal loss, we'd relay the info to mapping app and we'd trust that the mapping algorithm would be smart enough to figure out that the car didn't just travel in straight line but actually followed the curves of the tunnel.

This will only work with straight line tunnels though. We can "assume" you followed the highlighted route and there is nowhere to exit

Posted via CB10

[Jimberry Storm]

That tunnel thing got me a couple of times in Boston, lost about an hour and a half.

Posted via CB10