Introduction to Area Search Function
Area search function is mainly used to avoid communication issues between anchor during multistorey positioning. For example, we want to prevent a Tag at 1st floor to communicate with an anchor at 2nd floor. Area search function can also help avoid communication of Tags at different rooms.
Rationale of Area Search Function
A. First, start positioning function of Tag and set the floor and room number of Anchor. To avoid too many low signal anchors causing error with area selection, adjust the value of area search transmit power of Tag to a certain amount that would neglect those anchor with insufficient signal strength. The chapters later on will provide more details on how to set a reasonable threshold value using testing software
B. After the area search function of Tag is enabled, it will send an broadcasting signal to confirm the floor and room number to be positioned. The judgement criteria here is based on the signal strength of surrounding Anchors
For example there are two areas with its number:
Area A (Floor Num:1,Room Num:1) with Anchor #1, Anchor #2, Anchor #3
Area B (Floor Num:1,Room Num:2) with Anchor #4, Anchor #5, Anchor #6
After Tag sent a broadcasting packet and received a response packet from the surrounding anchors,
Anchors’ responding strength in area A: Anchor #1 (40), Anchor #2 (35), Anchor #3 (60)
Anchors’ responding strength in area B: Anchor #1 (30), Anchor #2 (31), Anchor #3 (35)
Tag will compare and determine the total area signal strength of those two areas:
Area A with total signal strength of 135, Area A with total signal strength of 96
As areas A has a stronger area signal strength, Tag will only position based on the anchors in Area A
C. Positioning based on anchors in area A means that when Tag reports positioning packet, there would be anchor information of area A for anchor of positioning packet
Positioning Packet
Parameter Types
Floor Number Setting
1. At the parameter setting interface of Anchor, find Extended function and under Floor Num set the number of the floor which the anchor is located
2. Anchor with the same Floor Num setting means they are located at the same floor, Tag can communicate with Anchor within the same floor, they will not perform positioning with Anchor from different floors. When Floor Num is set at 0, it means the anchor does not have a fixed floor number, it can respond to Tags from different floors within a certain communication range. Please refer to the two scenario diagram below.
(Under the premise which Room number is the same or set at 0, please refer to more details below)
A. Located at the same floor or Setting example below - Tag can perform positioning with all anchors within its communication range
*Note: This scenario also applies to room that cannot intercommunicate
B. In circumstances where there are multiple floors and anchor signal may allow communication with Tag, set floor number for anchors to avoid Tag from communicating with anchors located at another floor
As Floor Num is set, Tag at first floor will only position with Anchor at first floor, Tag at second floor will only position with Anchor at second floor and vice versa
Room Number Setting
1. With floor number setting, we make room number setting default at 0, which means that within the same floor and in a communication range, all anchor can commence positioning with anchor at the same time. This parameter could also be set so that anchor at different rooms can commence positioning with Tag at the same time. Please see details as below:
2. At the parameter setting interface of Anchor, find Extended function and Room Num to set the room number of which the anchor is located
3. Anchor with the same Room Num setting means they are located at the same room, Tag will communicate with Anchors in the same room, they will not perform positioning with Anchor from different floors. When Room Num is set at 0, it means the anchor does not have a fixed room number, it can respond to Tags from different rooms within a certain communication range. Please refer to the three scenario diagram below.
(Under the premise which Floor number is the same or set at 0, please refer to more details below)
A. There is only one floor or the tag in that floor cannot communicate with the anchors of other floors, and the anchors of other rooms will communicate with the tag.
Tag in room 1 can only use anchor in room 1 to perform position, Tag in room 2 can only use anchor in room 2 to perform position
B. Multiple floors with multiple rooms, and the anchor between floors and rooms may communication with Tag
In the picture above, Tag can only perform positioning with Anchor in the same room
C. In special conditions, please determine accordingly based on your need and environment
At the image above, anchor at the middle can provide measuring positioning two Tags at the neighboring rooms, but the anchors at the other room will not be involved in the positioning of this room, can try flexible overlapping positioning to reduce border jitter effect
Enable Tag Area Search Function
When attempting to use the area search function, not only should we set Floor Num or Room Num for anchor, we also have to enable the area search function of Tag. The function is disable for default, because the function will cause greater power consumption when enabled.
The image above is the two columns in the Extended Function of Tag’s parameter setting interface. Change Area Search En to Enable Tag area search function, then set the transmit power threshold, default threshold at 30, which is suitable for use in many situations. If modification is required, please refer to the method below:
Adjusting Transmit Power Threshold
Since the area search function is mainly used to solve problems caused by multiple floors, we will set the value of this parameter according to the signal strength of other floors. The parameter adjustment method of Area Search TxPower (transmission power used for area search) is as follows;
A. Connect UWB Dongle to usb port of computer, open Area Search.exe application
B. Select the corresponding serial port number, press Connect to connect UWB Dongle
C. Try search for the anchors at the floor beneath. The green little box represents UWB Dongle, blue triangle represents anchor, use Area Search.exe to search for Anchor by pressing Search. And try gradually lowering TxPower(0-67/67 maximum)until unable to find the anchor at the floor beneath, the TxPower value now is the Area Search TxPower value required to be set of Tag
* If the anchor at the floor beneath still cannot be found even when maximum value of 67 is set for TxPower, then there is no need to use area search function
Id:Anchor ID
Floor Num:Anchor floor number
Room Num:Anchor room number
Strenghth:Strength of the signal of the anchor, the larger value the stronger the signal
Precautions for Area Search Function
1、When using area search function for multistorey, user need to ensure the structure between the two floors has a shading effect, such as concrete. It is not suitable for hollow floor
2、In order for Tag to switch floors rapidly, it is recommended to place Tag at the entrance and exit of each floor
3、When using area search function to differentiate different rooms, as according to the first point, the stronger the covering effect to the signal between rooms, the better the effect
Demo video
https://drive.google.com/file/d/1siig9Qgw2kZYifnnrz6EldMb93C7TkcS/view?usp=sharing