June 24, 2009
Application Note Page 1 of 5
High Vibration (HV) Receivers
1 Introduction
In 2008, NovAtel released high-vibration versions of our OEMV receivers:
• The 1G now comes in two versions, the OEMV-1G, which is the standard version, and the
OEMV-1G-HV, which is the high-vibration version.
• The OEMV-3 still only comes in one version but the vibration performance has been
improved to the same level as the OEMV-1G-HV.
In this application note, we will refer to the OEMV-1G-HV and the improved version of the OEMV-3 as
the HV versions.
The HV versions use a high performance TCXO. Where the vibration specification for NovAtel’s standard
receivers is 7.7 GRMS random vibration, the HV version is rated at 19.4 GRMS.
For our vibration testing, we have followed the procedures outlined in MIL-STD-810G Department of
Defense Test Method Standard for Environmental Engineering Considerations and Laboratory Tests. We
have modified MIL-STD-810G method 514.6 category 24: All materiel – minimum integrity tests.
2 Test Method
We conducted the testing using our DS2200 vibration system, shown in Figures 1 and 2.
Figure 1 DS2200 Vibration System
Figure 2 DS2200 Control Panel
For each HV board variant, three boards were mounted in a test jig, which was installed on the DS2200
vibration system. This allowed simultaneous vibration testing of each board in the x, y and z axes, as
illustrated in Figure 3, Figure 4 and Figure 5.
NovAtel Inc.
1120 – 68th Avenue N.E. Calgary, AB, Canada T2E 8S5
Tel: (403) 295-4500
Fax: (403) 295-4501 Internet: http://www.novatel.com Email:
gps@novatel.com
NovAtel Application Note
Figure 3 OEMV-3 z-axis Mounting
Figure 4 OEMV-3 y-axis Mounting
Figure 5 OEMV-3 x-axis Mounting
APN-054 Rev 1 High Vibration (HV) Receivers page 2 of 5
NovAtel Application Note
The minimum integrity test profile, taken from MIL-STD-810G method 514.6 category 24, is shown in
Figure 6.
10
100 1000 10000
Frequency - Hz
Acceleration Spectral Density – g
2
/Hz
0.001
0.01
0.1
0.040
-6 dB/octave
200020
Figure 6 Minimum Integrity Test Profile
The acceleration spectral density for the minimum integrity test is 0.04 g
2
/Hz from 20 to 1000 Hz then it
drops off at 6 dB/octave from 1000 to 2000 Hz. The test duration is one hour per axis (x, y and z); rms =
7.7 G.
To test the HV versions, NovAtel modified this minimum integrity test profile, as shown in Figure 7.
10
100 1000 10000
Frequency - Hz
Acceleration Spectral Density – g
2
/Hz
-6 dB/octave
20 2000
0.01
0.1
1.0
Adjusted to set
profile to 19.4 GRMS
Figure 7 Modified Integrity Test Profile
The modified profile results in a random vibration level of 19.4 GRMS. This profile was applied to each
axis (x, y and z) for duration of 0.5 hour.
APN-054 Rev 1 High Vibration (HV) Receivers page 3 of 5
NovAtel Application Note
3 Test Results
As illustrated in Figure 8, the HV receivers locked on all available satellites and maintained this lock
through the duration of the 19.4 GRMS vibration test.
Figure 8 OEMV-3 Lock Time
The OEMV-1G-HV passed the same tests as the OEMV-3.
4 Recommendations
Proper mounting of HV receivers is necessary to meet the vibration specification. In particular, HV
modules need to be securely anchored along their longer dimension, on both sides. Recommended
mounting of the OEMV-3 is illustrated in Figure 9 and Figure 10:
APN-054 Rev 1 High Vibration (HV) Receivers page 4 of 5
NovAtel Application Note
Retaining Bars
Figure 9 Recommended Mounting – OEMV-3 – Plane View
OEMV-3
(Not to scale)
Figure 10 Recommended Mounting – OEMV-3 – Cross-sectional View
As shown, a retaining bar should be run along the full length of the long sides of the OEMV-3 and
screwed to the body of the enclosure or fixture to securely anchor the board. Holes in the board should not
be used for mounting HV modules to standoffs. Clearance should be provided above and below the board
for components and connector headers. As well, the retaining bar should be installed so that it does not
short out signal lines on the module; i.e., it should only come into contact with ground lines.
Both the RF connector (connected to J100) and the power/signal connector (connected to P1601) should
be secured by clamping them either from the top of the connectors or onto the body of the enclosure as
close to the connectors as possible. This will prevent the card from intermittently losing signals/power
during high vibration, especially in the z-axis.
Similar mounting is recommended for the OEMV-1G-HV.
5 Customer Service Contact Information
If you require any further information regarding the topics covered within this application, please contact:
NovAtel Customer Service
1120 – 68 Ave. N.E.
Calgary, Alberta, Canada, T2E 8S5
Phone: 1-800-NOVATEL (in Canada or the U.S.) or +1-403-295-4500
Fax: 403-295-4501
E-mail: support@novatel.ca
Website: www.novatel.com
APN-054 Rev 1 High Vibration (HV) Receivers page 5 of 5
