Beidou Launch Completes Regional Nav System

Beidou Launch Completes *Regional* Nav System

http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regional-nav-system-12375

December 6, 2011

"The Beidou-2/Compass IGSO-5 (fifth inclined geosynchonous orbit)
satellite was launched on December 1 from Xichang, China. Exact launch
time was 21:07:04.189 UTC. The third stage of the CZ-3A rocket with the
satellite attached achieved a geosynchronous transfer orbit and the
satellite subsequently separated according to NORAD/JSpOC. As of
December 7, the satellite is still in geosynchronous transfer orbit
(GTO), orbiting the Earth about twice a day with a highly eliptic orbit.
To get to geosynchronous orbit, the satellite's apogee kick motor will
have to be fired. The satellite is not drifting to its intended orbit,
for example, like a GLONASS satellite might".

See:
http://www.gpsworld.com/gnss-system/news/beidou-launch-completes-regional-nav-system-12375

...

Thanks Sam,

The persistent question is where is the ICD !!!
Per the usual China stonewalls the open market every time it's to
their advantage.
Boycott Compass. Boycott China (to the largest extent possible).
We must make them hurts somehow, so they understand the only
acceptable behavior is to be open, democratic, and fair trading
practices.

Marcelo Pacheco

On 2011-12-08 15:48 , macpacheco wrote:

http://www.insidegnss.com/node/1712


The Chinese will never espouse fair trade, it is a one-way blanket pull.
In the meantime avoid buying from them (you can't boycott 100% - they
are into everything at the lowest cost and buyers around the world
gravitate to low prices).

For satellite positioning the best thing is to wait until someone like
Garmin makes a receiver with GPS+GLONASS+Galileo+Beidou-2.

Garmin for example (at least to present) make their receivers in Taiwan.

--
"I see!" said the blind man as he picked up his hammer and saw.

On 12/8/2011 1:14 PM, Alan Browne wrote:

I assume current generation of GPSs are heavily DSP if not SDR, but
often the more things you make a device do, the less it does well.
Smartphones are the perfect example. Jack of all trades, master of none.
Well a few brands have decent voice quality, so maybe master of one thing.

On 2011-12-10 01:15 , miso wrote:

GPS's use dedicated hardware correlator channels driven by software to
detect and track the signal. It is relatively cheap and easy to add
channels although those for GPS are different than those for GLONASS and
will also be different for Galileo and Compass. Some GPS receivers that
cost a few dollars (in bulk) have about 60 channels. When future civil
channels are added they will require more hardware channels as well.

They are cheap and are not usually DSP|SDR (it's just not the cheapest
way to go, esp. for low power consumption devices).

So, you can indeed have "more" and not lose anything at all. The
question then becomes optimizing the algorithms to truly get the best
information for position determination.

In GPS it's called "over determination". But unless craftily
implemented, using all sources for a position fix could lead to a
greater error when the worst satellite PR's are used with the best. An
example is mixing GPS with GLONASS (the later being a little less
accurate than GPS at present).

Smartphones that I know of use very low power GPS devices and are also
driven "lazily" to conserve power. That aside, the performance of my
iPhone 4 as a GPS is more than adequate for what it was designed to do
(get me to the restaurant). In comparing with dedicated GPS', it has an
error range of about 5-20 metres where the dedicated GPS is 3-5 metres
in the same conditions. The newer iPhone 4S also has GLONASS so
presumably acquires quicker, but if driven lazily, is probably not more
accurate than the iPhone 4.

--
"I see!" said the blind man as he picked up his hammer and saw.