Carbon Fibre blocks GPS Signals?

This an extract taken from an enquiry I received via the UK Telematics Online website and my subsequent response. 

Question: One other thing, which is slightly off track, is do you know anything about how carbon fibre affects GPS signals? I was having a discussion about this with a tutor from the school of art who insists carbon fibre would be detrimental to GPS effectiveness, however, I have doubts that a few mm or so would be significantly restrictive.

Answer:  In all honesty I was ignorant of the possibility that Carbon Fibre can block GPS signals.  Although, I’ve now just done a quick Google search and there were several items where people were discussing the issue, but in my brief search, I didn’t come across any empirical evidence.

However,  it is common practice in vehicle telematics, where a device could be installed deep inside the structure of a car or lorry and GPS reception could be degraded, to attach external antennas to the device.  This was accepted practice with most devices that use a SIRF II type GPS module and good practice. even today, where the latest devices will use a SIRF III type module.  The device could be installed in the bowels of the dashboard, but the antenna might, for example, be mounted behind the upholstery of the roof arm.  There is an article on GPS Passion which discuss the merits of various GPS receivers.

This link is to a Chinese manufacturer I came across while Googling, who happened to have an array of external GPS antennas.   This link discusses making your own external GPS antenna. 

If anyone has any comments or additional helpful information, please free to submit a post.

Regular topic and content updates are available here or shown now in full over at What are Vehicle Telematics and Vehicle Tracking? on the UK Telematics Online website.

Question on Accelerometers and GPS devices

This an extract taken from an enquiry I received via the UK Telematics Online website and my subsequent response. 

Question: Hi.  I was wondering if you could offer any advice regarding a project I am working on at University. I am aiming to be able to use an accelerometer or impact sensor to trigger a signal being sent to a website or phone. I got a lot of useful tips from your website, and was wondering if you could help further.  Could you tell me the most effective GPS for rural areas? Also, what hardware would be required to create a two way channel between a GPS device and a computer?
 

Answer: There are several commercially available GPS Telematics devices which, in addition to having a GPS/GPRS capability, also include an accelerometer.  Some of these devices contain an accelerometer which returns data for an x and y axis and others for an x, y and z axis.

Once such device is the Clear Box from Metasystems.  Another is the WT7000 made by WebTech Wireless. 

In reply to your question regarding GPS and rural areas, as I understand the matter, GPS is often not the key determining factor when measuring the effectiveness of a GPS Telematics Device.  Typically it is the ability of the device to communicate in areas of poor GSM/GPRS that is the key factor.  Although GPS effectiveness can be reduced when line of sight is restricted; this occurs in “Urban Canyons” as well as mountainous rural areas.  Advances in GPS technology have lead to GPS devices even being able to maintain a GPS signal while indoors, all be it at much reduced accuracy.
 

Many units are designed to store data packets in memory, if the device falls out of communications coverage. The device will then send these packets when the signal coverage returns.  In mission critical applications, where the need to maintain communications is paramount, Satellite Communications modules can be used instead of a GSM/GPRS module.

 
If anyone has any comments or additional helpful information, please free to submit a post.

Regular topic and content updates are available here or shown now in full over at What are Vehicle Telematics and Vehicle Tracking? on the UK Telematics Online website 

UK Vehicle Tracking industry in a state of flux

More than three years ago on my website UK Telematics Online, I warned potential buyers of Vehicle Tracking systems to be wary of buying vehicle tracking via fixed contract leasing agreements. I said at the time; " Be aware that the Telematics Service Provider is often only the supplier of the goods; the actual rental agreement is often done through a third party. If you have problems with the product or service, you will not get a sympathetic hearing from the finance company if you decide to stop payments."

For further advice on buying vehicle tracking systems, please visit the UK Telematics Online website  http://www.uktelematicsonline.co.uk/html/buying_tips__vehicle_tracking.html

Many of the major players in the UK Vehicle Tracking sector have found the going difficult over recent months. Issues of increased competition, the economic downturn, and the lack of available credit for both SME's and the vehicle tracking industry in general, has contributed to the financial difficulties of all but a few of the so called "leading" vehicle tracking suppliers.

Customers of a recent industry casualty, Globallive, were reportedly shocked to receive demands for an increase in payments from the new owners or risk having the service terminated, despite having originally signed what they thought were fixed period and fixed cost agreements. The new owners, Causeway, were likely caught between a rock and a hard place and felt they had little option but to increase the charges. Even so, these customers can hardly have been overjoyed at the new arrangement.

Innovations such as Pay As You Go while welcomed by many, have been derided by some suppliers, perhaps keen to bolster a sales model, which while vital to their cash flow model, provides little or no security to the customer should the provider cease being able to deliver the service agreed.

Once again, potential buyers of vehicle tracking need to pay special attention to the ability of the telematics service provider to continue delivering the vehicle tracking service throughout the term of any fixed period agreement.

Regular topic and content updates are available here or shown now in full over at What are Vehicle Telematics and Vehicle Tracking?. on the UK Telematics Online website