[chrony-users] Not getting time from gpsd

Hello,

I'm having an issue with getting time from gpsd.

My setup is:

Raspberry Pi 3 running Jessie Lite

USB U-Blox gps

gpsd is receiving NMEA from the GPS, cgps also shows time and position properly.

My chrony.conf is:

server 0.us.pool.ntp.org
server 1.us.pool.ntp.org
server 2.us.pool.ntp.org
server 3.us.pool.ntp.org
driftfile /var/lib/chrony/drift
allow
refclock SHM 0 refid GPS precision 1e-1 offset 0.9999 delay 0.2
makestep 1 -1

Chronyc sources shows this:

$ chronyc sources
210 Number of sources = 5
MS Name/IP address Stratum Poll Reach LastRx Last sample
===============================================================================
#? GPS 0 4 0 10y +0ns[ +0ns] +/- 0ns
^+ time-c.nist.gov 1 9 375 110 -23ms[ -22ms] +/- 47ms
^* pool-96-248-122-64.cmdnnj 1 10 377 56 +9749us[ +11ms] +/- 18ms
^- 104.156.99.226 2 9 377 367 +15ms[ +17ms] +/- 107ms
^- 4.53.160.75

This system is going to be used on a boat and might not have internet. I can tell that both programs are accessing the shared memory using ipcs -m:

------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x4e545030 0 root 600 80 2
0x4e545031 32769 root 600 80 1

Any idea why chrony isn't getting time from the GPS?

Thanks