Walk-by and drive-by data collection: what it is and how it works

What is walk-by and drive-by data collection and why is it used?

Walk-by and drive-by data collection is a system for acquiring meter readings based on wireless communication in 868MHz RadioFrequency technology. Field operators use receiving devices to collect data sent by the meters (usually consumption totalisers), simply by walking by them. The difference between the two depends on the signal reception capacity of the meters and the area in which they are located:

• walk-by: the operator walks to the vicinity of the gauges to take readings;
• drive-by: the operator collects data while remaining inside a vehicle, covering a larger area in less time.

Walk-by/drive-by collection has been used for a long time as the primary data transmission technology in the water sector (in so-called AMR systems), lately, with the advent of smart metering systems based on a fixed communication network capable of higher collection frequencies and wider distances (AMI systems), this technology is being used as a proximity back-up. In the remote data collection process that smart metering provides, in fact, there can be some hiccups that prevent the data from reaching the Meter Data Management directly. In some areas, in fact, the communication signal coverage of smart meters is not sufficient to guarantee the remote transmission of data and, for this reason, the distributor must send its operators into the field in order to retrieve the missing readings. In these cases, walk-by or drive-by collection allows operators to physically access the site to acquire the data without having to take manual readings individually, as was the case with traditional mechanical meters, thus saving a lot of time.

Compared to the traditional figure of the reader, who took a reading manually on each individual meter, walk-by and drive-by data collection offers several advantages:

• Operational efficiency: the operator acquires several readings in a single operation, without having to manually connect to each meter;
• Reduced time: collection takes place quickly, covering large areas in less time;
• Access to areas with poor coverage: even in areas where the signal for remote transmission is weak, data collection is guaranteed;
• Greater accuracy: the system filters the acquired data, reducing the risk of errors;
• Recovery of readings from inaccessible meters: the receiver is able to recover readings even from meters that are not physically accessible (such as building interiors or sewers).

Despite these benefits over manual readings, the limitation of this technology remains the fact that the number of readings collected is still linked to the number of physical passes made by an operator, although these are more efficient. 

Walk-by and drive-by data collection modes

At Terranova, we implement walk-by and drive-by collection both in stand-alone mode and through more structured reading campaigns.

In stand-alone mode, the field operator starts with a file containing the serial number and encryption key of the smart meter, which is loaded directly into the memory of the mobile device. The process is then structured as follows:

• The operator uploads the file to the mobile app;
• Starts the connection with a walk-by receiver;
• The receiver captures all available 868 MHz RadioFrequency plots and measurements;
• The Mobile app filters the captured data and selects only those related to the meters in the configuration file;
• The operator verifies the correctness of the data received.

In the case of more structured reading campaigns, however, the MDM (Meter Data Management) portal is used in addition to the mobile app. The process involves:

• The creation of a reading campaign on the MDM portal, where the users from which the data is to be collected are defined;
• The assignment of the activity to the field operators;
• The synchronisation of the activity between the portal and the TAMM Mobile app, with the list of reading runs to be performed;
• The collection and validation of readings in the field;
• The sending of the acquired data to the MDM portal for processing and invoicing.
  

It is therefore clear that walk-by and drive-by data collection represent a technological evolution in the field of meter reading, ensuring greater efficiency and reducing operating time, especially when used as a back-up technology to a fixed network-based smart metering system. Thanks to these methods, even in areas with poor signal coverage it is possible to acquire data accurately, ensuring correct metering of consumption. This saves time and effort, as well as increasing the quality of work and data available, for an all-round improvement of DSO activities.