Hi! We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
But as we’re losing ad-revenue from this then why not make a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
There have been a few posts on this thread regarding the subject of road coverage maps and broadcast coverage and I wanted to provide you with an update. Apologies for the delayed response due to travel commitments.
We do indeed have very accurate data relating to coverage. However, often the difficulty is not just how make it available in away that can be visualised but also, and more importantly, in a way that is meaningful and does not mislead. The problem being that field strength, particularly at low elevations, can vary considerable over a very short distance (a few metres), and coupled with other effects such as multi-path (reflections), and phase inversions (signal cancellations) which also add to the problem at low antenna elevations, can make receiving and decoding RDS challenging to say the least.
We are working on some web based tools which we plan to make available and also some clearer signal coverage maps. On the topic of road coverage, we will also provide a map of this on the website.
Kentnicklloyd asked the question regarding sending the data out on other regions. We already do this which you correctly observed for bandwidth control reasons. The TMC Standard has limitations as to how many messages can be broadcast from any one transmitter so we regionalise the data, but for strategically important events on major roads these are also broadcast to adjacent transmitters, or sometimes nationally.
gps_fan and others have asked about the new radio networks. As we have already stated we are working on the new network and will make the information available as soon as we can. I hope you understand that there is a lot to do and we will endeavour to make these available during the course of the year.
One specific point, again made by gps_fan but also commented on other threads relates to the availability of the signal on Classic FM, including reference to the BBC. Classic FM network actually shares broadcast sites with all of the main BBC national transmitters; in fact it also shares common antennas and often broadcasts at high powers both from a main carrier and the RDS-sub-carrier perspective. The main aspect as I have posted before, relates to the fact that the antenna plays a key role in the successful reception of RDS.
Danny _________________ Danny Woolard
Technical Director - Wireless Technologies
ITIS Holdings plc
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
Posted: Thu Jun 28, 2007 3:02 pm Post subject:
Thanks for the response Danny, and I look forward to seeing the new information tools once they are available. _________________ Please don't be offended if I do not reply to a PM - please ask questions via the forums.
I begin to despair about TMC after my return journey (J4-J17) along the M4 yesterday evening!
There was a relatively minor accident shortly after J16 causing about 2 miles tailback - nothing too serious, only about a 5 - 10 min delay BUT
the TMC on my Mio correctly highlighted there was an accident at J16 and then showed it to be 8 miles further up the road at J17.
In other words, verbally it showed the correct incident at the correct junction although it suggested the junction was still 8 miles ahead of me rather than a mile behind me and then when I clicked on the incident to look at the map it showed me a view of J17!!!!!!!!!
So come on ITIS, if you are reading this, please try explaining that one away......................
Welcome back Danny and thanks for the explanation about signal strength and transmission of such.
I would still like to a response to the above please i.e. how is it that you can broadcast data that is just plain wrong? Is this human error with inputting the raw data into your systems or something else. How can you post an accident at the wrong junction?
I begin to despair about TMC after my return journey (J4-J17) along the M4 yesterday evening!
There was a relatively minor accident shortly after J16 causing about 2 miles tailback - nothing too serious, only about a 5 - 10 min delay BUT
the TMC on my Mio correctly highlighted there was an accident at J16 and then showed it to be 8 miles further up the road at J17.
In other words, verbally it showed the correct incident at the correct junction although it suggested the junction was still 8 miles ahead of me rather than a mile behind me and then when I clicked on the incident to look at the map it showed me a view of J17!!!!!!!!!
So come on ITIS, if you are reading this, please try explaining that one away......................
Welcome back Danny and thanks for the explanation about signal strength and transmission of such.
I would still like to a response to the above please i.e. how is it that you can broadcast data that is just plain wrong? Is this human error with inputting the raw data into your systems or something else. How can you post an accident at the wrong junction?
This incident was being correctly reported by ourselves on the M4 between J16 and J17. This was first reported to us at 17:24 and cancelled from the system at 17:57.
For an incident to be reported via TMC a primary location, secondary location (The Secondary is computed by an offset and direction) and event code is required. The secondary location is the location you would encounter first when heading towards the incident, in this case J16. The primary location in this case is J17.
This is why the text would have been “M4 Westbound between J16 and J17 accident”. When you go into your map this would then take you to J17 (the primary location for the incident) typically with a line of arrows or similar, back to J16, indicating the stretch of road affected by the accident.
This is why the text would have been “M4 Westbound between J16 and J17 accident”. When you go into your map this would then take you to J17 (the primary location for the incident) typically with a line of arrows or similar, back to J16, indicating the stretch of road affected by the accident.
Thanks for the prompt response but I have to respond further with this since your comments don't quite appear logical here. If however I am misunderstanding how such incidents are reported I am certainly interested to learn so that I can correctly interpret the information in future. I suspect I am not alone in this.
Your timings appear to be absolutely spot on, I was there about 1730.
The TMC incident message on the sat nav screen suggested the accident was at J16 approx 8.5 miles ahead of me i.e. it showed an accident icon accompanied by the words "M4 J16 8.5 miles" despite the fact that J16 was some 2.5 miles behind me.
When I clicked on the item it displayed a map of J17 showing an effected length (coloured road) of about 1 - 2 miles before J17. In fact the accident had occured some 8.5 miles earlier, and just 2.5 miles beyond J16 so I struggle to see how the 'primary' incident was in any way at J17? I don't remember the map showing any arrows or coloured roads back as far as J16 where the tailback commenced.
Surely the 'primary incident' was at J16 (or at least closer to) where one reached the tailback?
.......or are you suggesting that the system will only identify the whole stretch of road between 2 such junctions as congested i.e. it does not recognise that only 2.5 miles is blocked but instead suggests there is a problem over the whole 11 mile stretch?
If in common with others we are not interpreting such info correctly some guidance on how these are reported would be most useful.
This incident was being correctly reported by ourselves on the M4 between J16 and J17. This was first reported to us at 17:24 and cancelled from the system at 17:57.
For an incident to be reported via TMC a primary location, secondary location (The Secondary is computed by an offset and direction) and event code is required. The secondary location is the location you would encounter first when heading towards the incident, in this case J16. The primary location in this case is J17.
This is why the text would have been “M4 Westbound between J16 and J17 accident”. When you go into your map this would then take you to J17 (the primary location for the incident) typically with a line of arrows or similar, back to J16, indicating the stretch of road affected by the accident.
Danny, I know you are busy but any help you can provide with my question would be greatly appreciated.
I'm experiencing consistent and almost (if not completely) constant direction flow problems with TMC reports on a Mio C710. I've posted some pictures in an early post in this thread as an example.
Basically the direction flow in the first line of the report is usually correct but the second line almost always (if not always) reports an incorrect direction flow (the opposite of the direction flow to that reported in the headline). The problem is usually shown correctly on the map however.
Is the device or the ITIS data feed providing the direction flow data for the 2nd line of information?
My suspicion is that the device is the culprit because the system seems to work well in continental Europe where there is right side driving. The second line direction flow information would be correct if the UK used right hand side driving (i.e. the order of locations would agree with the place names in the headline information).
I noticed today however that the ITIS data feed displayed traffic congestion on the A322 from Guildford to Bracknell (at around 4:40PM) when in reality the jam was on the A322 from Bracknell to Guildford (direction wise). This is the first time in quite a while that I have seen what I think is a factual innacuracy in the main line direction. Oddly I noticed that the second line of the display on this occasion did tally with direction flow in the first line (Lightwater to Bagshot)!
I would like to investigate these further, as from the earlier posts there could well be a specific issue with the Mio device which I would like to raise with them and also do some testing internally. We have the ability to replay incidents so will check specifically in the devices in question.
Please allow us some time to undertake these investigations.
I would add that we monitor our services continuously and errors of this nature would have been specifically flagged up so I am confident that this is not a reporting error.
To answer the specific point about directionality and extent, the TMC message contains three basic elements that relate to location, these are:
Primary Location Code (each navigable node on the road network is assigned a numerical value), this is the point "ahead" of the incident.
Direction (+ or -) This indicates whether it is offset in a postive or negative direction in numerical coding terms. (roads are coded according to a Standards convention).
Extent (a value between 0 and 7) which is the number of locations offset according to direction, e.g. number of junctions. (0 = an AT location, e.g. At M1 Junction 14).
A distance can be contained within a TMC message (e.g. 3 Miles) however in terms of increasing or receding queue lengths these can be very dynamic, and due to the fact that the navigation function only works from node to node, i.e. TMC Location code to TMC Location code, plus they are not consistently implemented within a devices we do not use these types of messages
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Fri Jul 13, 2007 8:01 am Post subject:
dannyw wrote:
I would like to investigate these further, as from the earlier posts there could well be a specific issue with the Mio device which I would like to raise with them and also do some testing internally. We have the ability to replay incidents so will check specifically in the devices in question.
I have also raised this issue with Mio and it has been passed to their software developers for further investigation. _________________ Andy
PocketGPSWorld.com supports Help for Heroes - Read here
Things don't get any better and I am beginning to think this whole TMC thing is a complete waste of time. Coming Westbound down the M4 yesterday afternoon between 1430 and 1600 my Mio twice tried to reroute me off the motorway based upon ITIS derived traffic info suggesting there had been 2 accidents in the regions of J14 and J15. Since my T/master Freeway had remained totally silent I ignored the re-routing suggestion and just kept going.
Result - nothing, absolutely nothing even though the accident messages were showing on the screen. No evidence of accidents or anything, no cars on the hard shoulder ( - though there was a broken down car being rescued on the OTHER carriageway outside Membury services.)
I was amused (?) to see Auto Express extolling the virtues of TMC in Sat Navs this week. In theory this is great, in practice total rubbish and it's got to the 'boy crying wolf' situation now in so far as on the rare occasions the info is actually correct I will ignore it unless my Freeway says otherwise. About the only thing that it does get right are the locations of roadworks but then that' s hardly 'dynamic' information.
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Thu Jul 26, 2007 9:51 am Post subject:
Before I updated my Mio to a version of MioMap 3.2 using iTIS instead of TrafficMaster, my Mio would often warn me of problems ahead whilst my Freeway continued to tell me that the route was clear.
TMC is great when it works properly, but is a real pain in the **** when it doesn't.
A combination of TMC, TrafficMaster Freeway and radio traffic bulletins still isn't foolproof, but is better than TMC alone _________________ Andy
PocketGPSWorld.com supports Help for Heroes - Read here
Things don't get any better and I am beginning to think this whole TMC thing is a complete waste of time. Coming Westbound down the M4 yesterday afternoon between 1430 and 1600 my Mio twice tried to reroute me off the motorway based upon ITIS derived traffic info suggesting there had been 2 accidents in the regions of J14 and J15. Since my T/master Freeway had remained totally silent I ignored the re-routing suggestion and just kept going.
Result - nothing, absolutely nothing even though the accident messages were showing on the screen. No evidence of accidents or anything, no cars on the hard shoulder ( - though there was a broken down car being rescued on the OTHER carriageway outside Membury services.)
I was amused (?) to see Auto Express extolling the virtues of TMC in Sat Navs this week. In theory this is great, in practice total rubbish and it's got to the 'boy crying wolf' situation now in so far as on the rare occasions the info is actually correct I will ignore it unless my Freeway says otherwise. About the only thing that it does get right are the locations of roadworks but then that' s hardly 'dynamic' information.
I'm more and more convinced that there is a problem with the Mitac devices and the processing of iTis TMC. I've also noticed a large number of false alarms recently - and the occasional correct call. When there's a false alarm there's sometimes sign of traffic congestion on the opposite side of the road but not always.
I don't know what the answer is but bearing in mind the directional report problems there does seem to be a problem with Mio TMC processing on left hand drive roads.
With reception problems and the apparent reporting bugs I've more or less given up using TMC. It's a shame because it is in theory a good service but in practice I wouldn't trust the information too much - at least not as provided on the Mio.
I haven't had the opportunity to test a car equipped with OEM Satnav and TMC but I wonder if our issues when using portable equipment are simply poor antenna design?
The counter argument to that possibility is that the same hardware operates with very much better results on the continent.
The built-in satnav in our Nissan x-trail uses RDS-TMC & works perfectly, with updates landing within just a few minutes of starting the car!!
With all the floods & road closures in our area recently, we wanted the ability to have these updates no matter which vehicle we were driving so mistakenly purchased a 910 with the antenna - AARRGGHH!!!! Getting nowhere with TomTom support as yet...
Things don't get any better and I am beginning to think this whole TMC thing is a complete waste of time. Coming Westbound down the M4 yesterday afternoon between 1430 and 1600 my Mio twice tried to reroute me off the motorway based upon ITIS derived traffic info suggesting there had been 2 accidents in the regions of J14 and J15. Since my T/master Freeway had remained totally silent I ignored the re-routing suggestion and just kept going.
Result - nothing, absolutely nothing even though the accident messages were showing on the screen. No evidence of accidents or anything, no cars on the hard shoulder ( - though there was a broken down car being rescued on the OTHER carriageway outside Membury services.)
I was amused (?) to see Auto Express extolling the virtues of TMC in Sat Navs this week. In theory this is great, in practice total rubbish and it's got to the 'boy crying wolf' situation now in so far as on the rare occasions the info is actually correct I will ignore it unless my Freeway says otherwise. About the only thing that it does get right are the locations of roadworks but then that' s hardly 'dynamic' information.
On the 25th July between J14 and J15 Westbound and J15 and Membury Eastbound, we received reports of a fuel spillage. This was reporting to us between 15:05 and 16:00 for the westbound incident and between 14:56 and 15:56 for the eastbound incident.
I believe this would have been the incident which generated the icon you were referring to. Please can you tell me whether you looked at the list of incidents or purely at the icons on the map? Often Sat Nav terminals have a limted number fo Icons and may have interpreted this coded incident as an accident Icon.
Obviously we have to rely on our journalistic suppliers for the clarity of this information, these sources are checked against all available information provided by many different sources. In this case as you appear to have driven through what we were reporting to be an incident.
Can I also assure you we are continuing to investigate the remarks made earlier regarding your Mio system. _________________ Danny Woolard
Technical Director - Wireless Technologies
ITIS Holdings plc
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
Posted: Tue Aug 07, 2007 7:46 am Post subject:
Danny, is there any current testing being performed in the North West on frequency 100,4 - I am picking up signals from this frequency (WinterHill, Smooth FM) but never any data - if it is a test I am pleased to report it works well into the Fylde coast, as I am messing around with a modified receiver and external aerial it could be my set-up (only noticed the 100,4 transmissions over the past 4 or 5 days) - Mike
Joined: May 16, 2007 Posts: 14 Location: Thanet, Margate, Kent
Posted: Tue Aug 07, 2007 8:08 am Post subject:
mikealder wrote:
Danny, is there any current testing being performed in the North West on frequency 100,4 - I am picking up signals from this frequency (WinterHill, Smooth FM) but never any data - if it is a test I am pleased to report it works well into the Fylde coast, as I am messing around with a modified receiver and external aerial it could be my set-up (only noticed the 100,4 transmissions over the past 4 or 5 days) - Mike
Not yet had chance to test with ITIS (will do today) but I have two new transmitters in Cornwall (Atlantic and Pirate FM) showing up but no data under Traficmaster.
"Upgraded" to ITIS over the weekend and will be in their transmitter area today and will be testing, if ITIS are going to use "Spare" GWR transmitters this will be intersting.
O BTW I picked up TMC on a BBC Local station then other day (Under trafficmaster) nearly drove off the road with the shock!
Posted: Today Post subject: Pocket GPS Advertising
We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
Have you considered making a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
Hi! We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
But as we’re losing ad-revenue from this then why not make a donation towards website running costs?. Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!
Forum FAQ
Search
Usergroups
Profile
Log in for private messages
Log in
