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Automotive FAQ

  • What is gx/ix?

    OxTS gx/ix technology is a powerful GNSS/inertial tight-coupling technology developed to take full advantage of OxTS’ extensive knowledge and experience in GNSS and inertial integration, Kalman filtering, and navigation processing. It is a combination of two independent technologies, gx and ix, which are each designed to improve performance in different scenarios. With gx/ix then, the system can intelligently switch between the different modes depending on the environment to ensure the best possible performance in any situation.


    GPS alone will not give you accurate slip angle as you cannot get the seperation required when using two antennas. The other significant problem with using GPS is that effectively you will measure the slip angle at the roof, not much use to chassis engineers ! The only way to really measure SLIP ANGLE correctly is to combine the GPS with an Inertial Navigation System, we have the answer. The RT range of systems will give you slip angles at all 4 wheels if you require it, in addition to the body slip angles. Give us a call and we will discuss your application with you.

  • Is there an easy way to produce a nice route map from data that I’ve collected using Microsat?

    The MicroSAT produces a data file (*.R1) which can be read in either MS History or the 2D ‘Race’ software. The MS History is a basic package allowing you to produce a latitude vs longtitude graph. The 2D ‘Race’ software for the microsat is a cut down version of the full racing analysis package, the software is free issue when you buy a microsat. The software will allow you to create track maps and analyse the GPS data that you logged.

  • Correvit Principle for OPTICAL Sensors

    CORREVIT Principle is the operating principle behind the optical sensors that we supply. The principle was initially devised by the Leica company in Germany over 20 years ago and has been the basis of the Correvit sensors ever since.

  • What is the vehicle co-ordinate system?

    The co-ordinate system for the test vehicle is defined in accordance with the DIN 70 000 standard. Each of the three co-ordinate axes (x, y and z) originate at the vehicle centre of gravity and coincide with the three main axes of inertia: The positive X-axis corresponds to the vehicle longitudinal axis, pointing forward. The positive Y-axis corresponds to the vehicle transversal axis, pointing left. The positive Z-axis corresponds to the vehicle vertical axis, pointing upward. Using your right hand,point your index finger forward (X-axis),your second finger at 90 degs (Y-axis) and your thumb up (Z-axis).

  • What is Pitch Angle?

    Pitch angle ‘b’ is the angle between the longitudinal axis (x-axis) of the vehicle and the projection of that axis to the road. ‘b’ is a positive value when the vehicle pitches forward, and a negative value when the vehicle pitches back.

  • What is Roll Angle?

    Roll angle ‘g’ is the angle between the transversal axis (y-axis) of the vehicle and the projection of that axis to the road. ‘g’ exhibits positive values when the vehicle rolls to the right, and exhibits negative values when the vehicle rolls to the left

  • Data logging? Are there different types?

    Data logging is purely the collection of data, although we see that there are two distinct areas: 1 – Time based data logging: this is normally used for long term data collection when vehicles are being monitored during extensive durability tests. The data can be gathered onboard and/or sent to a central base using GPRS connection. 2 – Specific data logging: this is where there is a defined start and stop condition to the test, brake and acceleration tests for example. The data logging is started on a pre-defined parameter such as speed or switch and is stopped on a different parameter e.g. brake tests from 100 kph to rest.

  • Data logging ?..What is it ?

    The process of data logging involves measuring data from various points around a vehicle and recording it against time/ distance. It can then be used to analyse engine parameters under certain conditions, driver/ rider inputs such as brake pressure, throttle and RPM, as well as suspension. Inertial Navigation equipment can be used to measure dynamics (lateral acceleration, pitch, roll, slip angle, as well as positional data.

  • MFDD….What is it ?

    MFDD – Mean Fully Developed Deceleration. There are a variety of ways to calculate deceleration using speed, distance and time formulae. The braking of a vehicle is greatly influenced by the initial braking system response to the pedal depression and the pitching of the vehicle,especially at low speed. The MFDD calculation starts at 80% of the start speed and stops at 10% of the start speed, this attempts to negate the effects mentioned above. Now some equations! The acceleration data may be calculated by different formula: 1/. a(v,t): (Ve – Va) / (Te – Ta): 2/. a(v,s):(Ve^2 – Va^2)/((Se – Sa) *2) 3/. a(s,t):2 * ((Se – Sa) / (Te – Ta)^2 – Va /(Te – Ta)) The MFDD (mean fully developed deceleration) is displayed only after deceleration tests. This value is calculated using the data between 80% and 10% of the start speed. You should enter the desired start and end speed (for example 100 and 0 km/h) in the test configuration. The test also works if it is started either by an external trigger or manually. The end speed should be set to 0. The formula of the MFDD-value is: a_mfdd: ABS (( v_01^2 – v_08^2 ) / (( s_01 – s_08 ) * )) with v_01 = 0.1 * (startSpeed-stopTrigger) if startSpeed > stopTrigger or 0.1 * (startSpeed) if stopTrigger > startSpeed v_08 = 0.8 * (startSpeed-stopTrigger) if startSpeed > stopTrigger or 0.8 * (startSpeed) if stopTrigger > startSpeed s_01 = distance in time of v_01 s_08 = distance in time of v_08 So now you know!

  • SLIP Angle?

    The common term of understeer / oversteer is really a measure of the SLIP ANGLE of a vehicle. Does the vehicle slip at the front or back or both? Have a look at the Slip Sensor in the product section.

  • CAN … What is it ?

    A message-based protocol developed originally for Automotive applications. The benefits include a high number of channels with minimal wiring. CAN-bus systems are now acknowledged as the automotive industry’s standard format used to transmit information around vehicles;interconnecting the ECU’s and Sensors which are vital to monitor and control all aspects of a modern vehicles systems. CAN is also used as the system-bus throughout our range of data acquisition units and sensors.Our data loggers also have the capability to link to the CAN-bus network on-board a vehicle to log and verify CAN-bus data “traffic”.

  • Vehicle Testing….What is it ?

    Vehicle testing can refer to diagnosing faults at your local garage to full blown development testing in Formula 1. Testing generally refers to the evaluation of prototype vehicles by manufacturers to determine functionality & performance.