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SPEEDBOXINSOption / DualAntennaINSInstallation

Dual Antenna INS Installation

The SPEEDBOX base unit should be mounted inside the vehicle. The base unit can be mounted in any orientation for the SPEEDBOX-INS, since the INS system takes all inertial measurements from the antenna assembly. The base unit should be isolated from excessive vibration, and the supplied power cable should be connected to a power supply between 9 and 30V. Power consumption is approximately 0.4A @ 12V for the INS system, but some additional capacity is required at start-up.

The antenna assembly should then be mounted on the roof of the vehicle in the correct orientation. Please follow the instructions for mounting the INS dual antenna assembly in this section.

Once the base unit and antenna assembly have been correctly fitted, they must be connected using the supplied cable. This cable contains both the data cable for the IMU and the GPS antenna cables. The routeing of the cable from the base unit to the antenna assembly should avoid as far as possible any sources of RF interference, in particular components of the vehicle ignition system, telemetry or radio systems, and in some cases video camera systems.

The data cable from the IMU to the SPEEDBOX base unit connects to the antenna assembly at one end, and to the “Expansion” port of the SPEEDBOX base unit at the other end. Whilst it is possible to connect to either the front or rear expansion port, it is likely that the rear port will be used in order to ensure that the GPS cables integrated into the main cable can reach the GPS connections. Note that the data cable must be connected prior to switching on the INS system in order for the antenna assembly to be correctly detected – if the power is supplied prior to plugging in the IMU cable then the SPEEDBOX will flash an error code to indicate that the IMU is not detected. In this case it is simply necessary to power-cycle the unit after plugging in the IMU cable.

The GPS antenna cables from the INS antenna assembly to the SPEEDBOX unit are colour coded using coloured heatshrink and washers. The red heatshrunk cable connects to GPS Antenna 1 “Base”, and the standard black cable connects to GPS Antenna 2 “Moving”. Antenna 1 “Base” connects to Rf 1 on the SPEEDBOX, and Antenna 2 “Moving” connects to Rf 2 on the SPEEDBOX. Please refer to Figure 3 below for clarification.

Figure 1