{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:I6S64QUQTTTX4IAR2BT4TKS324","short_pith_number":"pith:I6S64QUQ","canonical_record":{"source":{"id":"1805.10410","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2018-05-26T01:58:02Z","cross_cats_sorted":[],"title_canon_sha256":"ac25bf8f8d5844c74b2e731b451ff4bffb064977b61eb00f88eee69d33dafc82","abstract_canon_sha256":"b0734112b33fa2b08ec21e77f1678701b83c34890e5a6192e3792c0e18689ab3"},"schema_version":"1.0"},"canonical_sha256":"47a5ee42909ce77e2011d067c9aa5bd7398d6bf847efb9a32068c9f1d66456b3","source":{"kind":"arxiv","id":"1805.10410","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1805.10410","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"arxiv_version","alias_value":"1805.10410v1","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1805.10410","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"pith_short_12","alias_value":"I6S64QUQTTTX","created_at":"2026-05-18T12:32:28Z"},{"alias_kind":"pith_short_16","alias_value":"I6S64QUQTTTX4IAR","created_at":"2026-05-18T12:32:28Z"},{"alias_kind":"pith_short_8","alias_value":"I6S64QUQ","created_at":"2026-05-18T12:32:28Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:I6S64QUQTTTX4IAR2BT4TKS324","target":"record","payload":{"canonical_record":{"source":{"id":"1805.10410","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2018-05-26T01:58:02Z","cross_cats_sorted":[],"title_canon_sha256":"ac25bf8f8d5844c74b2e731b451ff4bffb064977b61eb00f88eee69d33dafc82","abstract_canon_sha256":"b0734112b33fa2b08ec21e77f1678701b83c34890e5a6192e3792c0e18689ab3"},"schema_version":"1.0"},"canonical_sha256":"47a5ee42909ce77e2011d067c9aa5bd7398d6bf847efb9a32068c9f1d66456b3","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:45:46.830512Z","signature_b64":"PHa54meQxDrm62fuuoRYw0StEJ/FwPUtKiVyCNx2MuQ7fveueleiZl4p/7ZEQPu+FjWO1TKiDT04zDq0doNjCg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"47a5ee42909ce77e2011d067c9aa5bd7398d6bf847efb9a32068c9f1d66456b3","last_reissued_at":"2026-05-17T23:45:46.829843Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:45:46.829843Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1805.10410","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:45:46Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"wUMxbtFZIdWnxwMv9gieZvpre9w2GRyv5X9UDG8xlhtvGsHJIc2dgMJFoqENdGAeXuZ10MC8k4Q6rH+R4czxDA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T08:40:46.046352Z"},"content_sha256":"0268038edf6c3e4d796724934c7dfed9769766ac6f308b533c12753a9d5d066d","schema_version":"1.0","event_id":"sha256:0268038edf6c3e4d796724934c7dfed9769766ac6f308b533c12753a9d5d066d"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:I6S64QUQTTTX4IAR2BT4TKS324","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Contact-Aided Invariant Extended Kalman Filtering for Legged Robot State Estimation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cs.RO","authors_text":"Jessy W. Grizzle, Maani Ghaffari Jadidi, Ross Hartley, Ryan M. Eustice","submitted_at":"2018-05-26T01:58:02Z","abstract_excerpt":"This paper derives a contact-aided inertial navigation observer for a 3D bipedal robot using the theory of invariant observer design. Aided inertial navigation is fundamentally a nonlinear observer design problem; thus, current solutions are based on approximations of the system dynamics, such as an Extended Kalman Filter (EKF), which uses a system's Jacobian linearization along the current best estimate of its trajectory. On the basis of the theory of invariant observer design by Barrau and Bonnabel, and in particular, the Invariant EKF (InEKF), we show that the error dynamics of the point co"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1805.10410","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:45:46Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"878hnfp3Ll/DymtI9lvI943L7dse/lZvSYsRobnK9mQ3X+eXc3IYN7SJnNLpee8VCldjgJVqGkokLkBDNHwlDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T08:40:46.046991Z"},"content_sha256":"15e26ccef3397e19e0f70fe2c6782d7631d1ad99e9462dd90e667b5e78e05b9b","schema_version":"1.0","event_id":"sha256:15e26ccef3397e19e0f70fe2c6782d7631d1ad99e9462dd90e667b5e78e05b9b"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/I6S64QUQTTTX4IAR2BT4TKS324/bundle.json","state_url":"https://pith.science/pith/I6S64QUQTTTX4IAR2BT4TKS324/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/I6S64QUQTTTX4IAR2BT4TKS324/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-05-27T08:40:46Z","links":{"resolver":"https://pith.science/pith/I6S64QUQTTTX4IAR2BT4TKS324","bundle":"https://pith.science/pith/I6S64QUQTTTX4IAR2BT4TKS324/bundle.json","state":"https://pith.science/pith/I6S64QUQTTTX4IAR2BT4TKS324/state.json","well_known_bundle":"https://pith.science/.well-known/pith/I6S64QUQTTTX4IAR2BT4TKS324/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:I6S64QUQTTTX4IAR2BT4TKS324","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"b0734112b33fa2b08ec21e77f1678701b83c34890e5a6192e3792c0e18689ab3","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2018-05-26T01:58:02Z","title_canon_sha256":"ac25bf8f8d5844c74b2e731b451ff4bffb064977b61eb00f88eee69d33dafc82"},"schema_version":"1.0","source":{"id":"1805.10410","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1805.10410","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"arxiv_version","alias_value":"1805.10410v1","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1805.10410","created_at":"2026-05-17T23:45:46Z"},{"alias_kind":"pith_short_12","alias_value":"I6S64QUQTTTX","created_at":"2026-05-18T12:32:28Z"},{"alias_kind":"pith_short_16","alias_value":"I6S64QUQTTTX4IAR","created_at":"2026-05-18T12:32:28Z"},{"alias_kind":"pith_short_8","alias_value":"I6S64QUQ","created_at":"2026-05-18T12:32:28Z"}],"graph_snapshots":[{"event_id":"sha256:15e26ccef3397e19e0f70fe2c6782d7631d1ad99e9462dd90e667b5e78e05b9b","target":"graph","created_at":"2026-05-17T23:45:46Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"This paper derives a contact-aided inertial navigation observer for a 3D bipedal robot using the theory of invariant observer design. Aided inertial navigation is fundamentally a nonlinear observer design problem; thus, current solutions are based on approximations of the system dynamics, such as an Extended Kalman Filter (EKF), which uses a system's Jacobian linearization along the current best estimate of its trajectory. On the basis of the theory of invariant observer design by Barrau and Bonnabel, and in particular, the Invariant EKF (InEKF), we show that the error dynamics of the point co","authors_text":"Jessy W. Grizzle, Maani Ghaffari Jadidi, Ross Hartley, Ryan M. Eustice","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2018-05-26T01:58:02Z","title":"Contact-Aided Invariant Extended Kalman Filtering for Legged Robot State Estimation"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1805.10410","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:0268038edf6c3e4d796724934c7dfed9769766ac6f308b533c12753a9d5d066d","target":"record","created_at":"2026-05-17T23:45:46Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"b0734112b33fa2b08ec21e77f1678701b83c34890e5a6192e3792c0e18689ab3","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cs.RO","submitted_at":"2018-05-26T01:58:02Z","title_canon_sha256":"ac25bf8f8d5844c74b2e731b451ff4bffb064977b61eb00f88eee69d33dafc82"},"schema_version":"1.0","source":{"id":"1805.10410","kind":"arxiv","version":1}},"canonical_sha256":"47a5ee42909ce77e2011d067c9aa5bd7398d6bf847efb9a32068c9f1d66456b3","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"47a5ee42909ce77e2011d067c9aa5bd7398d6bf847efb9a32068c9f1d66456b3","first_computed_at":"2026-05-17T23:45:46.829843Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:45:46.829843Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"PHa54meQxDrm62fuuoRYw0StEJ/FwPUtKiVyCNx2MuQ7fveueleiZl4p/7ZEQPu+FjWO1TKiDT04zDq0doNjCg==","signature_status":"signed_v1","signed_at":"2026-05-17T23:45:46.830512Z","signed_message":"canonical_sha256_bytes"},"source_id":"1805.10410","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:0268038edf6c3e4d796724934c7dfed9769766ac6f308b533c12753a9d5d066d","sha256:15e26ccef3397e19e0f70fe2c6782d7631d1ad99e9462dd90e667b5e78e05b9b"],"state_sha256":"894d700410d1359f16885e02179cad5957a3675b7cef84eb22a03c73acbba0b2"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"mFXknuClO9cb8rpAtiWzghjVxNAmhDJBOYrS2S3Apeem+r8rzGkXvAByeyMSUuM3UjnyW2KhQHTWd9GtF4LdDw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-27T08:40:46.050589Z","bundle_sha256":"f2e72b5dff3839484a6feef081891119f0b58b2c1d0fee75597a835e6fbbb711"}}