Novatel DL-V3 Enabling L-BAND, REAL-TIME Kinematic RTK Positioning, External Oscillator

ENABLING L-BAND

L-band equipped receivers allow you to achieve sub-meter accuracy. To use this positioning mode, you must enable L-band tracking to the Canada-Wide Differential GPS (CDGPS) or OmniSTAR signal. A subscription to OmniSTAR is required to use the OmniSTAR VBS, XP or HP service (visit http:// www.omnistar.com with your receiver serial number ready). The CDGPS signal is free and available without subscription over North America (visit http://www.cdgps.com).

The ASSIGNLBAND command allows you to set OmniSTAR or CDGPS base station communication parameters. It should include a relevant frequency and data rate. The frequency assignment can be made in Hz or KHz. For example:

Hz: assignlband omnistar 1536782000 1200

KHz: assignlband omnistar 1536782 1200

A value entered in Hz is rounded to the nearest 500 Hz.

To confirm you are tracking an L-band signal, log the L-band status information by entering: log lbandstat. For example, if you are receiving CDGPS, the fifth field after the header should be 00c2:

lbandstata com1 0 43.5 finesteering 1295 149951.671 00000000 976f 34461;

1547546977 46.18 4541.0 0.00 00c2 00f0 ...

To specify the correction source, use the PSRDIFFSOURCE command as shown in the examples below:

PSRDIFFSOURCE OMNISSTAR or,

PSRDIFFSOURCE CDGPS

otherwise it is left at the default AUTOMATIC.

Refer to the OEMV Family Firmware Reference Manual for more on individual L-band, GLONASS or SBAS commands and logs.

REAL-TIME KINEMATIC (RTK) POSITIONING

Corrections can be transmitted from a base station to a rover station to improve position accuracy. The base station is the GNSS receiver which is acting as the stationary reference. It has a known position and transmits correction messages to the rover station. The rover station is the GNSS receiver which does not know its exact position and can receive correction messages from a base station to calculate differential GNSS positions.

In most cases, provide a data link between the base station and rover station (two NovAtel receivers) in order to receive corrections. SBAS and L-band corrections can be accomplished with one receiver and are exceptions to the base/rover concept. Generally a link capable of data throughput at a rate of 9600 bits per second, and less than 4.0 s latency, is recommended.

Once your base and rover are set up, you can configure them for RTCA, RTCM, RTCMV3, CMR+ or CMR corrections. Below is an RTCM example (replace the latitude, longitude and height coordinates shown with those of your base):

Base

interfacemode com2 none rtcm off

fix position 51.11358042 -114.04358013 1059.4105

log com2 rtcm3 ontime 10 log com2 rtcm22 ontime 10 1 log com2 rtcm1819 ontime 1 log com2 rtcm1 ontime 5

Rover

interfacemode com2 rtcm none off

RT-2 (OEMV-2 and OEMV-3) and RT-20 (OEMV-1, OEMV-1G, OEMV-2 and OEMV-3), all with AdVance RTK, are real-time kinematic software products developed by NovAtel. Optimal RTK performance is achieved when both the base and rovers are NovAtel products. However, AdVance RTK will operate with equipment from other manufacturers when using RTCM messaging.

RT-2 and RT-20 are supported by GPS-only and GPS+GLONASS OEMV-based models. Also, RT-20 with GPS+GLONASS provides faster convergence.

1. Refer to the GPGST log’s usage box in the OEMV Firmware Reference Manual for a definition of RMS and other statistics.

2.For more base/rover configurations, search the key words “rover base” on our Knowledge Database at: http://www.novatel.com/support/knowledgedb.htm

EXTERNAL OSCILLATOR

For certain applications requiring greater precision than what is possible using the on-board 20 MHz, voltage-controlled, temperature-compensated crystal oscillator (VCTCXO), you may wish to connect the DL-V3 to an external, high-stability oscillator. The external oscillator can be either 5 MHz or 10 MHz.

To install, connect a cable from the external oscillator to the DL- V3 port labelled EXT OSC. The receiver does not have to be powered down during this procedure.

Once the external oscillator has been installed, issue the EXTERNALCLOCK command to define the clock model (for

example, cesium, rubidium or ovenized crystal). If the input clock rate is 5 MHz, you must issue the EXTERNALCLOCK command to change the 10 MHz default rate.

POST PROCESSING

Post-mission data processing refers to when the GNSS data collected by the receiver is processed after the entire data- collection session is complete.

OEMV-based output is compatible with post-processing software from the Waypoint Products Group, NovAtel Inc. For details, visit our website at:

http://www.novatel.com/products/waypoint_pps.htm

MOUNTING BRACKET

A mounting kit is provided with the DL-V3 enclosure enabling you to mount the receiver to a surface. The mounting kit is not designed for use in high-dynamics/vibration environments. Refer also to its accompanying instruction sheet.

QUESTIONS OR COMMENTS

If you have any questions or comments regarding your DL-V3, please contact NovAtel using one of these methods:

Email: support@novatel.com

Web: www.novatel.com

Phone: 1-800-NOVATEL (U.S. & Canada)

+1-403-295-4900 (International)

Fax: +1-403-295-4901

Quick Start Guide: DL-V3:

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GM-14915065 Rev 4 2009/03/24