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Accruate GPS Fuel Monitoring Solution

GPS Tracker, Fuel Sensor and GPS51

Accuracy of GPS Fuel Monitoring

By In Blog On January 10, 2024

When talk about fuel monitoring, what we care most is the accuracy. The more accurate the fuel monitoring solution, the more we can learn how the fuel of the vehicle is used or abused.

GPS fuel monitoring is composed of 3 parts: Fuel sensor, GPS Tracker and Fuel monitoring software. The accuracy of each part will finally decide the accuracy of a complete fuel monitoring system.

Fuel Level sensor

In types: Rod sensor (mainly capacitive sensor) and ultrasonic types. No matter which type of fuel sensor, they measure the fuel level height inside tank. The height accuracy is from 0.1mm to 1mm.

In signal out: Analog voltage and digital output (RS232 or RS485) mainly in market Voltage output value is 0 to 5V. Digital output value is 0 to 65535.

Signal out value is the first factor that will decide the accuracy of a complete fuel monitoring system. Digital output is much better than analog output, as it is much larger.

Analog voltage output sensor

The sensor measures fuel level height and gives voltage output per change of fuel level height. If the tank is full, the max output value is 5V. If the tank is empty, the minimum output value is 0V. The output voltage at most keeps two decimal points. From 0.00V to 5.00V, we can have 500 values in total. It means the tank height is divided into 500 parts.

Digital output sensor

The sensor also measures fuel level height and gives digital value per change of fuel level height. If the tank is full, the max output value is 65535. If the tank is empty, the minimum output value is 0. From 0 to 65535, we have 65535 values in total. It means the tank height is divided into 65535 parts.

Clearly, 65535 parts is more precise than 500 parts. Not to mention analog voltage sensor only keeps 1 decimal point. In this case, digital output sensor wins.

GPS Tracker

GPS tracker is a connection between fuel level sensor and GPS tracking software. Its stability and collection of data is important for accurate fuel monitoring.


GPS tracker in market are either built upon MCU or chip. GPS tracker with MCU is more stable and robust. However, GPS tracker built upon chip is cheaper. As for fuel monitoring GPS tracker, we advise GPS tracker with MCU, so is our UM777 4G GPS Tracker. What’s more, GPS tracker with MCU can do more algorithm to analyze the fuel data validity to remove effect of harsh braking or harsh accelerations.

Collection of data

For voltage output value, GPS tracker normally will multiply 10 send it to fuel monitoring software. For examples, if the output voltage vale is 2.01, GPS tracking software shall receive 20.1. However, 20.1 is normally rounded to 20 and 20 is the value sent to fuel monitoring software.

For digital output value, GPS tracker sends what it receives exactly to fuel monitoring software.

Clearly, GPS tracker with digital fuel sensor wins.

Fuel monitoring software

Fuel monitoring software receives the data sent by GPS tracker. With proper algorithm, it gives fuel monitoring display, reports, and alarms in litter.

Normal GPS Tracking Software

Normal GPS tracking software does not have detailed fuel monitoring reports, and they just display the value sent by GPS tracker. Once the tank specification is filled, it is fixed. There is no correction area to make the fuel monitoring more accurate. This is why we do not advise GPSPOS for fuel monitoring.

GPS51 Fuel monitoring software

GPS51 is specially designed for accurate fuel consumption monitoring to avoid abuse of fuel. It has in total 12 fuel monitoring reports, mainly including Fuel consumption report per day/week/month, Refuel report, Leak report, Fuel consumption per 100KM, Fuel consumption Trend, etc.

In terms of calibration, it comes with a detailed calibration Excel. After filling of tank specification, it shall automatically generate a series of data which is to be uploaded to GPS51.

In terms of correction, it has a correction area to make adjustments of calibration per real fuel amount. After installation of GPS fuel monitoring system, when the tank is refueled, compare the actual refueled amount with software displayed amount. If it is not same, we can do a second calibration on tracking software, so as to make it more accurate.

To conclude, the accuracy of a GPS fuel monitoring system is composed of Digital output fuel sensor, UM777 GPS Tracker with MCU and GPS51 fuel monitoring software.

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