chimps
Spatial-temporal dynamics processor for context-aware physical spaces and companion to barnacles.
chimps ingests a real-time stream of raddec objects and outputs spatem (SPAtial-TEMporal) objects based on positions calculated internally by positioning engines and/or externally by third-party systems.
chimps is a lightweight Node.js package that can run on resource-constrained edge devices as well as on powerful cloud servers and anything in between. It is typically connected with a barnowl and/or barnacles instance which sources real-time radio decodings from an underlying hardware layer. Together these packages are core components of reelyActive's Pareto Anywhere open source middleware.
Getting Started
Follow our step-by-step tutorials to get started with chimps bundled within Pareto Anywhere:
Learn "owl" about the spatem JSON data output:
Quick Start
Clone this repository, install package dependencies with npm install, and then from the root folder run at any time:
npm start
chimps will listen for raddec UDP packets on 0.0.0.0:50001 and print the spatial-temporal (spatem) data to the console.
spatem
The format of the spatem object, which is the sole output of chimps, is as follows:
{
deviceId: "bada55beac04",
deviceIdType: 2,
type: "location", // "position" or "location"
data: { /* FeatureCollection */ },
timestamp: 1645568542222
}
In the case where the position of the associated raddec cannot be matched with any Features in chimps' FeatureCollection, the spatem type will be a position and include a FeatureCollection of exactly one item, a "Point", as its data property. Else, the spatem type will be a location and include a FeatureCollection which adds all matched Features as its data property. Each type of spatem is described in full detail below.
position
A spatem of type position has the following format:
{
deviceId: "bada55beac04",
deviceIdType: 2,
type: "position",
data: {
type: "FeatureCollection",
features: [{
type: "Feature",
properties: { isDevicePosition: true, positioningEngine: "External" },
geometry: {
type: "Point",
coordinates: [ 0.0, 0.0, 0.0 ]
}
}]
},
timestamp: 1645568542222
}
chimps adds the property isDevicePosition to indicate that the "Point" represents the device position, as per the raddec.
location
A spatem of type location has the following format:
{
deviceId: "bada55beac04",
deviceIdType: 2,
type: "location",
data: {
type: "FeatureCollection",
features: [{
type: "Feature",
properties: { isDevicePosition: true,
positioningEngine: "AnchorAndPull" },
geometry: {
type: "Point",
coordinates: [ 0.0, 0.0, 0.0 ]
}
},{
type: "Feature",
id: "(from chickadee)",
properties: { name: "" },
geometry: {
type: "Polygon",
coordinates: [[[ 0, 1 ], [ 1, 0 ], [ 0, -1 ], [ -1, 0 ], [ 0, 1 ]]]
}
}
]},
timestamp: 1645568542222
}
Note that the first feature in the FeatureCollection will always be the "Point" representing the device position as per the raddec, with chimps adding the property isDevicePosition to differentiate from any other associated "Point" which may be present in the FeatureCollection.
Positioning Engines
chimps supports both internal and external positioning engines for estimating the real-time position of devices based on radio decodings and metadata. Positioning engines are configured through the positioningEngines option which has the following default setting:
[
{ inputFilterParameters: {}, engine: PositioningEngines.External },
{ inputFilterParameters: {
acceptedEvents: [ Raddec.events.APPEARANCE,
Raddec.events.DISPLACEMENT,
Raddec.events.KEEPALIVE ] },
engine: PositioningEngines.AnchorAndPull }
]
The first positioning engine in the array to meet the inputFilterParameters criteria and return a position will be observed. In other words, the positioning engines are priority-based and mutually exclusive.
The default setting prioritises external (third-party) positioning engines which add a position property to the raddec before it is ingested by chimps. If no position property is present, instead the anchor-and-pull engine will provide a position estimate, when possible, upon ingestion of a raddec from barnacles which corresponds with an appearance, displacement or keepalive event.
A user-defined positioning engine can be specified by providing as the engine property a Class which includes an estimatePosition function which takes as parameters a raddec and associations. For example:
engine:
class AlwaysAtParc {
constructor(options) {}
estimatePosition(raddec, associations) {
return [ -73.57123, 45.50883 ];
}
}Be advised that RSSI-based positioning in real-world conditions, especially with ambient devices and existing infrastructure, is inherently limited in accuracy. The anchor-and-pull method is provided as a low-overhead means to output "good enough" positions for applications which must consume data in the form of coordinates. If highly-accurate coordinate-based positioning is absolutely required, instead select the appropriate technologies and infrastructure that add a position property before it is ingested by chimps.
Options
chimps supports the following options:
| Property | Default | Description |
|---|---|---|
| inputFilterParameters | {} | Filter on inbound raddecs (see raddec-filter) |
| observedEvents | [ 'position', 'location' ] | List of event types that will produce a spatem output |
| maxStoredSpatems | 1 | The number of historic spatems to maintain in memory per device |
| historyMilliseconds | 5000 | How long to retain spatem data before it is flushed from memory |
| featureCollection | {} | Explicit FeatureCollection to use in the absence of a connected chickadee instance |
| associations | Map() | Explicit device associations to use in the absence of a connected chickadee instance |
| positioningEngines | (see above) | The positioning engines and parameters to use to estimate device positions |
| barnowl | null | barnowl instance providing source data |
| barnacles | null | barnacles instance providing source data |
What's in a name?
Chimpanzees (chimps) have outstanding spatial awareness. chimps is our first mascot-nameworthy module since perhaps 2015, and we intend to continue our tradition of mascot name storytelling, so check back soon!
Project History
chimps v1.0.0 was released in October 2022, developed to accommodate 2D and 3D real-time location data, initially from barnowl-rfcontrols.
Contributing
Discover how to contribute to this open source project which upholds a standard code of conduct.
Security
Consult our security policy for best practices using this open source software and to report vulnerabilities.
License
MIT License
Copyright (c) 2022-2023 reelyActive
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