A Satellite Navigation and Global Positioing Systems forum. Sat Nav Banter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » Sat Nav Banter forum » GPS and Sat Nav Newsgroups » sci.geo.satellite-nav (Global Satellite Navigation)
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

sci.geo.satellite-nav (Global Satellite Navigation) (sci.geo.satellite-nav) Discussion of global navigation satellite systems (GNSS). Topics include the technical aspects of GNSS operation, user experiences in the use of GNSS, information regarding GNSS products and discussion of GNSS policy (such as GPS selective availability).

INDOOR Positioning: New Solutions for Challenging Applications



 
 
Thread Tools Display Modes
  #11  
Old August 4th 04, 08:47 PM posted to sci.geo.satellite-nav
Carsten Kurz
external usenet poster
 
Posts: 1,498
Default INDOOR Positioning: New Solutions for Challenging Applications



Hans-Georg Michna schrieb:

The essence of what I'm saying is that existing data
transmissions can be used for positioning without modifying the
transmissions.


Of course they can. But where's the point if you have to set up a
separate transmission channel for the aiding data ...

Pure techtalk - how many TV transmitters would you expect to be oriented
around any given position? And how many GSM base stations are there,
with all the technology, precise position known, end user devices, etc.
already available?

We see technology demonstrations trying to 'compete' with GPS or GSM
cell-detection turning up here every four weeks. A technology
demonstration is not a product. In most cases they have a very simple
drawback if you think over it.


- Carsten

--
Audio Visual Systems fon: +49 (0)2234 601886
Carsten Kurz fax: +49 (0)2234 601887
Von-Werth-Straße 111 email:
50259 Pulheim / Germany WGS84:N50°57'50.2" E06°47'28.5"
  #12  
Old August 5th 04, 02:29 AM posted to sci.geo.satellite-nav
Dale DePriest
external usenet poster
 
Posts: 1,406
Default INDOOR Positioning: New Solutions for Challenging Applications



Hans-Georg Michna wrote:

On Wed, 04 Aug 2004 09:46:18 -0700, Dale DePriest
wrote:


Try
http://www.rosum.com/rosum_tv-gps_in...echnology.html

The basics are that a TV antenna is at a fixed location, The TV signal
contains a timestamp which can be used in the same way as a time stamp
in GPS. Thus 3 stations can results in a 2D fix in the same way that it
is done in a GPS system by getting pseudo ranges and then correcting.
You cannot get a 3D fix. Augmentation can be provided by another source
that provides clock correction data for the individual TV stations. It
doesn't work very well if all the stations in your area pick the same
hill for the transmitter towers.



Dale,

you didn't get the core of my idea. They need to modify the TV
transmitters to send predefined time signals. My invention
doesn't even touch the TV transmitters. It uses their unmodified
signals.

Hans-Georg


In the USA the signals are already time stamped so there is no
modification required. The paper is aimed at the new digital broadcasts
that put this data in every frame but even the old analog signals are
time stamped in the header fields these days.

Dale



--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs

  #13  
Old August 5th 04, 02:35 AM posted to sci.geo.satellite-nav
Dale DePriest
external usenet poster
 
Posts: 1,406
Default INDOOR Positioning: New Solutions for Challenging Applications



Carsten Kurz wrote:


Hans-Georg Michna schrieb:


The essence of what I'm saying is that existing data
transmissions can be used for positioning without modifying the
transmissions.



Of course they can. But where's the point if you have to set up a
separate transmission channel for the aiding data ...

Pure techtalk - how many TV transmitters would you expect to be oriented
around any given position? And how many GSM base stations are there,
with all the technology, precise position known, end user devices, etc.
already available?

We see technology demonstrations trying to 'compete' with GPS or GSM
cell-detection turning up here every four weeks. A technology
demonstration is not a product. In most cases they have a very simple
drawback if you think over it.


- Carsten


In the USA the TV coverage is better than the GSM coverage. I still
can't get any kind of decent cellphone coverage at my house. The new
digital transmitters that are required by the FCC have all the time code
data in them. Ephemeris doesn't change for a stationary location so it
only has to be collected once and can be stored in the unit. Increased
accuracy can be obtained with augmentation but the system works without it.

YOu are right in that it is only in the demonstration stages and may
never become a product but ...

Dale

--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs

  #14  
Old August 5th 04, 06:12 AM posted to sci.geo.satellite-nav
Hans-Georg Michna
external usenet poster
 
Posts: 764
Default INDOOR Positioning: New Solutions for Challenging Applications

On Wed, 04 Aug 2004 22:47:44 +0200, Carsten Kurz
wrote:

Hans-Georg Michna schrieb:


The essence of what I'm saying is that existing data
transmissions can be used for positioning without modifying the
transmissions.


Of course they can. But where's the point if you have to set up a
separate transmission channel for the aiding data ...

Pure techtalk - how many TV transmitters would you expect to be oriented
around any given position? And how many GSM base stations are there,
with all the technology, precise position known, end user devices, etc.
already available?

We see technology demonstrations trying to 'compete' with GPS or GSM
cell-detection turning up here every four weeks. A technology
demonstration is not a product. In most cases they have a very simple
drawback if you think over it.


Carsten,

I take it that you think Rosum is on the wrong track. Hmm, I see
your point.

However, current GSM positioning is only accurate to about
100 m. Do you think that could be improved?

Hans-Georg

--
No mail, please.
  #15  
Old August 5th 04, 06:12 AM posted to sci.geo.satellite-nav
Hans-Georg Michna
external usenet poster
 
Posts: 764
Default INDOOR Positioning: New Solutions for Challenging Applications

On Wed, 04 Aug 2004 19:29:22 -0700, Dale DePriest
wrote:

In the USA the signals are already time stamped so there is no
modification required. The paper is aimed at the new digital broadcasts
that put this data in every frame but even the old analog signals are
time stamped in the header fields these days.


Dale,

but are those time stamps accurate enough? For positioning you
need almost nanosecond accuracy.

Hans-Georg

--
No mail, please.
  #16  
Old August 5th 04, 10:03 AM posted to sci.geo.satellite-nav
Carsten Kurz
external usenet poster
 
Posts: 1,498
Default INDOOR Positioning: New Solutions for Challenging Applications



Hans-Georg Michna schrieb:

I take it that you think Rosum is on the wrong track. Hmm, I see
your point.


I don't think Rosum is on the wrong track. I just think it is no
product. Time will tell.

If you think of all the aspects of the GPS, you will see that they
really put a lot of thinking into it, like getting away without atomic
clock on the receiver side, in-band aiding data, etc.

One major aspect is global coverage. Those signals are useless if you
don't have the aiding data. Where do you get the aiding data? Is there a
decent coverage or station constellation? These conditions may change
every few hundred km. Yes, plain GSM cell detect will only work to
100-1000m using traditionel techniques (which can be improved or
enhanced by GPS). But what can be expected by a 'constellation' of three
TV stations?
Just recently we had an article where WLAN hotspots would be used for
positioning.
We had reports for proof of concepts where no signals are needed at all.
Usually the drawback is clearly visible.

- Carsten






--
Audio Visual Systems fon: +49 (0)2234 601886
Carsten Kurz fax: +49 (0)2234 601887
Von-Werth-Straße 111 email:
50259 Pulheim / Germany WGS84:N50°57'50.2" E06°47'28.5"
  #17  
Old August 5th 04, 01:42 PM posted to sci.geo.satellite-nav
Dale DePriest
external usenet poster
 
Posts: 1,406
Default INDOOR Positioning: New Solutions for Challenging Applications



Hans-Georg Michna wrote:

On Wed, 04 Aug 2004 19:29:22 -0700, Dale DePriest
wrote:


In the USA the signals are already time stamped so there is no
modification required. The paper is aimed at the new digital broadcasts
that put this data in every frame but even the old analog signals are
time stamped in the header fields these days.



Dale,

but are those time stamps accurate enough? For positioning you
need almost nanosecond accuracy.

Hans-Georg


Today, this depends on the station, but you can read the technical
articles on the site yourself. I suspect that TV station time is a item
that would be accurate since many folks set their clocks from TV
broadcasts. They are probably GPS based these days.

Dale


--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs

  #18  
Old August 8th 04, 03:52 PM posted to sci.geo.satellite-nav
Hans-Georg Michna
external usenet poster
 
Posts: 764
Default INDOOR Positioning: New Solutions for Challenging Applications

On Thu, 05 Aug 2004 12:03:59 +0200, Carsten Kurz
wrote:

Hans-Georg Michna schrieb:


I take it that you think Rosum is on the wrong track. Hmm, I see
your point.


I don't think Rosum is on the wrong track. I just think it is no
product. Time will tell.

If you think of all the aspects of the GPS, you will see that they
really put a lot of thinking into it, like getting away without atomic
clock on the receiver side, in-band aiding data, etc.

One major aspect is global coverage. Those signals are useless if you
don't have the aiding data. Where do you get the aiding data? Is there a
decent coverage or station constellation? These conditions may change
every few hundred km. Yes, plain GSM cell detect will only work to
100-1000m using traditionel techniques (which can be improved or
enhanced by GPS). But what can be expected by a 'constellation' of three
TV stations?
Just recently we had an article where WLAN hotspots would be used for
positioning.
We had reports for proof of concepts where no signals are needed at all.
Usually the drawback is clearly visible.


Carsten,

thanks for the good insights!

It seems that precise indoor positioning isn't easy and may not
come cheap.

Hans-Georg

--
No mail, please.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT. The time now is 04:20 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.SEO by vBSEO 2.4.0
Copyright ©2004-2018 Sat Nav Banter.
The comments are property of their posters.