[LEAPSECS] Leap smear

[Keith Winstein]

On Fri, 30 Sep 2011, mike cook wrote:


> Le 30/09/2011 09:13, Keith Winstein a écrit :

>> 

>> DUT1 gets 31 bits, including the sign, and is in units of 2^(-24)

>> second. They also give a rate of change so it can be approximated to

>> first order by the receiver.

>

> Have you got a reference for this Keith? The only info I could find is from 

> Page 18 sub-frame 4 where the GPS-UTC delta is defined maybe the doc was 

> incomplete . And as a bonus, do you know of any receivers which report it?


Hi Mike,

The 31-bit DUT1 is actually part of the new GPS CNAV navigation message on 
L2. See IS-GPS-200E table 30-VIII. I'm not sure if they have actually 
started transmitting it yet.

The traditional GPS navigation message also sends ephemeris parameters to 
convert from ECI of the satellite ephemerides to ECEF, but I do not think 
DUT1 can necessarily be derived from these, since each ephemeris seems to 
be transmitted in a different ECI frame.

-Keith