Knowing which zone something is in is not the same as knowing where it is. Faststream builds Bluetooth Angle-of-Arrival real-time location systems — array-antenna anchors and a fusion engine that place a person, an asset or a vehicle to sub-metre accuracy indoors, continuously, where GPS never reaches.
RSSI guesses distance from how loud a signal is — and a washroom wall, a metal rack or a passing forklift changes loudness without moving anything. Angle of Arrival measures the physical direction the signal comes from instead, which the environment cannot fake.
Each anchor carries an antenna array. As a Bluetooth 5.1 tag transmits, the anchor reads the phase difference across its antennas and recovers the pitch and heading angle of the incoming signal. From a single anchor and the known mounting height, that resolves to a 2D position on the floor; where two or more anchors see the same tag, the intersection of their angles gives a full 3D coordinate.
A fusion engine sits above the anchors. It cross-validates angles from every anchor that can see a tag, filters the reflections and BLE signal-bleed that defeat simpler systems, and outputs one stable position rather than a cloud of competing estimates. Adding anchors extends coverage across corridors, rooms and yards without changing the method — the same maths, more eyes.
Angle-of-arrival gives a bearing to a tag — the direction it lies in from an anchor — and triangulating bearings from several anchors fixes its position. Bluetooth Channel Sounding, introduced in Core 6.0, supplies the other half: a true, secure measure of distance, to centimetre scale, read from the phase of the radio and the round-trip time rather than guessed from signal strength.
The two are complementary. Distance from Channel Sounding tightens a fix, can cut the number of anchors a bearing-only deployment needs, and adds secure proximity — distance bounding that resists the relay attacks signal-strength proximity is prey to. Where an application has to know not only where a tag is but that a device is genuinely close — a key, a phone, a credential — range and angle together answer it.
On the ranging method itself: Bluetooth Channel Sounding — measuring distance, not guessing it.
Angle of Arrival is a Bluetooth 5.1 direction-finding method. An anchor with an antenna array measures the phase difference of an incoming signal to recover the angle it arrived from; combining angles from several anchors gives a position. It is a positioning method, where RSSI is a strength estimate pressed into service as one.
Typically 0.3 to 0.5 m in a well-surveyed deployment — against 5 to 10 m for RSSI and zone-level for RFID. Accuracy depends on anchor density, mounting and the environment, which is why coverage is designed rather than assumed.
Both are sub-metre. UWB is marginally tighter and dearer per tag; Bluetooth AoA rides the standard Bluetooth ecosystem, so phones and ordinary BLE wearables can be located without a special tag, and tag cost and power stay low. The right answer depends on tag volume and how tight the accuracy has to be.
Low on both. The tag only transmits; the anchor does the measuring. A duty-cycled tag runs for years on a coin cell, and the tag is the cheap end of the system — the intelligence is in the anchor and the engine.
Tell us the space, the accuracy and the tag count. We will size the anchors and the engine to the site, not to a brochure.